588 results on '"Frewen, P."'
Search Results
2. Use of a decision support tool and quick start onboarding tool in individuals with type 1 diabetes using advanced automated insulin delivery: a single-arm multi-phase intervention study
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Shekhar Sehgal, Martin De Bock, Benyamin Grosman, Jonathan Williman, Natalie Kurtz, Vanessa Guzman, Andrea Benedetti, Anirban Roy, Kamuran Turksoy, Magaly Juarez, Shirley Jones, Carla Frewen, Antony Watson, Barry Taylor, and Benjamin J. Wheeler
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Closed loop devices ,Decision support tools ,Glycemia ,Type 1 diabetes ,Continuous glucose monitoring ,Diseases of the endocrine glands. Clinical endocrinology ,RC648-665 - Abstract
Abstract Background Multiple clinician adjustable parameters impact upon glycemia in people with type 1 diabetes (T1D) using Medtronic Mini Med 780G (MM780G) AHCL. These include glucose targets, carbohydrate ratios (CR), and active insulin time (AIT). Algorithm-based decision support advising upon potential settings adjustments may enhance clinical decision-making. Methods Single-arm, two-phase exploratory study developing decision support to commence and sustain AHCL. Participants commenced investigational MM780G, then 8 weeks Phase 1-initial optimization tool evaluation, involving algorithm-based decision support with weekly AIT and CR recommendations. Clinicians approved or rejected CR and AIT recommendations based on perceived safety per protocol. Co-design resulted in a refined algorithm evaluated in a further identically configured Phase 2. Phase 2 participants also transitioned to commercial MM780G following “Quick Start” (algorithm-derived tool determining initial AHCL settings using daily insulin dose and weight). We assessed efficacy, safety, and acceptability of decision support using glycemic metrics, and the proportion of accepted CR and AIT settings per phase. Results Fifty three participants commenced Phase 1 (mean age 24.4; Hba1c 61.5mmol/7.7%). The proportion of CR and AIT accepted by clinicians increased between Phases 1 and 2 respectively: CR 89.2% vs. 98.6%, p
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- 2024
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3. Large-scale functional hyperconnectivity patterns in trauma-related dissociation: an rs-fMRI study of PTSD and its dissociative subtype
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Shaw, Saurabh B., Terpou, Braeden A., Densmore, Maria, Théberge, Jean, Frewen, Paul, McKinnon, Margaret C., and Lanius, Ruth A.
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- 2023
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4. Interviews with Indigenous Māori with type 1 diabetes using open-source automated insulin delivery in the CREATE randomised trial
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Burnside, Mercedes, Haitana, Tracy, Crocket, Hamish, Lewis, Dana, Meier, Renee, Sanders, Olivia, Jefferies, Craig, Faherty, Ann, Paul, Ryan, Lever, Claire, Price, Sarah, Frewen, Carla, Jones, Shirley, Gunn, Tim, Wheeler, Benjamin J., Pitama, Suzanne, de Bock, Martin, and Lacey, Cameron
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- 2023
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5. Cold Plasma Deposition of Tobramycin as an Approach to Localized Antibiotic Delivery to Combat Biofilm Formation
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Beatrice Olayiwola, Fiona O’Neill, Chloe Frewen, Darren F. Kavanagh, Rosemary O’Hara, and Liam O’Neill
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cold atmospheric plasma ,tobramycin ,coating ,antibiotic efficacy ,biofilm formation ,titanium ,Medicine - Abstract
Hospital-acquired infections (HAIs) remain a significant factor in hospitals, with implant surfaces often becoming contaminated by highly resistant strains of bacteria. Recent studies have shown that electrical plasma discharges can reduce bacterial load on surfaces, and this approach may help augment traditional antibiotic treatments. To investigate this, a cold atmospheric plasma was used to deposit tobramycin sulphate onto various surfaces, and the bacterial growth rate of K. pneumoniae in its planktonic and biofilm form was observed to probe the interactions between the plasma discharge and the antibiotic and to determine if there were any synergistic effects on the growth rate. The plasma-deposited tobramycin was still active after passing through the plasma field and being deposited onto titanium or polystyrene. This led to the significant inhibition of K. pneumoniae, with predictable antibiotic dose dependence. Separate studies have shown that the plasma treatment of the biofilm had a weak antimicrobial effect and reduced the amount of biofilm by around 50%. Combining a plasma pre-treatment on exposed biofilm followed by deposited tobramycin application proved to be somewhat effective in further reducing biofilm growth. The plasma discharge pre-treatment produced a further reduction in the biofilm load beyond that expected from just the antibiotic alone. However, the effect was not additive, and the results suggest that a complex interaction between plasma and antibiotic may be at play, with increasing plasma power producing a non-linear effect. This study may contribute to the treatment of infected surgical sites, with the coating of biomaterial surfaces with antibiotics reducing overall antibiotic use through the targeted delivery of therapeutics.
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- 2024
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6. A tale of two targets: examining the differential effects of posterior cingulate cortex- and amygdala-targeted fMRI-neurofeedback in a PTSD pilot study
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Jonathan M. Lieberman, Daniela Rabellino, Maria Densmore, Paul A. Frewen, David Steyrl, Frank Scharnowski, Jean Théberge, Niki Hosseini-Kamkar, Richard W. J. Neufeld, Rakesh Jetly, Benicio N. Frey, Tomas Ros, Ruth A. Lanius, and Andrew A. Nicholson
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post-traumatic stress disorder ,fMRI neurofeedback ,posterior cingulate cortex ,amygdala ,default mode network ,Neurosciences. Biological psychiatry. Neuropsychiatry ,RC321-571 - Abstract
IntroductionReal-time fMRI-based neurofeedback (rt-fMRI-NFB) is a non-invasive technology that enables individuals to self-regulate brain activity linked to neuropsychiatric symptoms, including those associated with post-traumatic stress disorder (PTSD). Selecting the target brain region for neurofeedback-mediated regulation is primarily informed by the neurobiological characteristics of the participant population. There is a strong link between PTSD symptoms and multiple functional disruptions in the brain, including hyperactivity within both the amygdala and posterior cingulate cortex (PCC) during trauma-related processing. As such, previous rt-fMRI-NFB studies have focused on these two target regions when training individuals with PTSD to regulate neural activity. However, the differential effects of neurofeedback target selection on PTSD-related neural activity and clinical outcomes have not previously been investigated.MethodsHere, we compared whole-brain activation and changes in PTSD symptoms between PTSD participants (n = 28) that trained to downregulate activity within either the amygdala (n = 14) or the PCC (n = 14) while viewing personalized trauma words.ResultsFor the PCC as compared to the amygdala group, we observed decreased neural activity in several regions implicated in PTSD psychopathology – namely, the bilateral cuneus/precuneus/primary visual cortex, the left superior parietal lobule, the left occipital pole, and the right superior temporal gyrus/temporoparietal junction (TPJ) – during target region downregulation using rt-fMRI-NFB. Conversely, for the amygdala as compared to the PCC group, there were no unique (i.e., over and above that of the PCC group) decreases in neural activity. Importantly, amygdala downregulation was not associated with significantly improved PTSD symptoms, whereas PCC downregulation was associated with reduced reliving and distress symptoms over the course of this single training session. In this pilot analysis, we did not detect significant between-group differences in state PTSD symptoms during neurofeedback. As a critical control, the PCC and amygdala groups did not differ in their ability to downregulate activity within their respective target brain regions. This indicates that subsequent whole-brain neural activation results can be attributed to the effects of the neurofeedback target region selection in terms of neurophysiological function, rather than as a result of group differences in regulatory success.ConclusionIn this study, neurofeedback-mediated downregulation of the PCC was differentially associated with reduced state PTSD symptoms and simultaneous decreases in PTSD-associated brain activity during a single training session. This novel analysis may guide researchers in choosing a neurofeedback target region in future rt-fMRI-NFB studies and help to establish the clinical efficacy of specific neurofeedback targets for PTSD. A future multi-session clinical trial of rt-fMRI-NFB that directly compares between PCC and amygdala target regions is warranted.
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- 2023
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7. A randomized controlled trial of Deep Brain Reorienting: a neuroscientifically guided treatment for post-traumatic stress disorder
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Breanne E. Kearney, Frank M. Corrigan, Paul A. Frewen, Stephanie Nevill, Sherain Harricharan, Krysta Andrews, Rakesh Jetly, Margaret C. McKinnon, and Ruth A. Lanius
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psychotherapy ,ptsd ,posttraumatic stress ,trauma ,deep brain reorienting ,rct ,Psychiatry ,RC435-571 - Abstract
Background: Advanced neuroscientific insights surrounding post-traumatic stress disorder (PTSD) and its associated symptomatology should beget psychotherapeutic treatments that integrate these insights into practice. Deep Brain Reorienting (DBR) is a neuroscientifically-guided psychotherapeutic intervention that targets the brainstem-level neurophysiological sequence that transpired during a traumatic event. Given that contemporary treatments have non-response rates of up to 50% and high drop-out rates of >18%, DBR is investigated as a putative candidate for effective treatment of some individuals with PTSD. Objective: To conduct an interim evaluation of the effectiveness of an eight-session clinical trial of videoconference-based DBR versus waitlist (WL) control for individuals with PTSD. Method: Fifty-four individuals with PTSD were randomly assigned to DBR (N = 29) or WL (N = 25). At baseline, post-treatment, and three-month follow-up, participants’ PTSD symptom severity was assessed using the Clinician Administered PTSD Scale (CAPS-5). This is an interim analysis of a clinical trial registered with the U. S. National Institute of Health (NCT04317820). Results: Significant between-group differences in CAPS-total and all subscale scores (re-experiencing, avoidance, negative alterations in cognitions/mood, alterations in arousal/reactivity) were found at post-treatment (CAPS-total: Cohen’s d = 1.17) and 3-month-follow-up (3MFU) (CAPS-total: Cohen’s d = 1.18). Significant decreases in CAPS-total and all subscale scores were observed within the DBR group pre – to post-treatment (36.6% CAPS-total reduction) and pre-treatment to 3MFU (48.6% CAPS-total reduction), whereas no significant decreases occurred in the WL group. After DBR, 48.3% at post-treatment and 52.0% at 3MFU no longer met PTSD criteria. Attrition was minimal with one participant not completing treatment; eight participants were lost to 3MFU. Conclusions: These findings provide emerging evidence for the effectiveness of DBR as a well-tolerated treatment that is based on theoretical advances highlighting alterations to subcortical mechanisms in PTSD and associated symptomatology. Additional research utilizing larger sample sizes, neuroimaging data, and comparisons or adjacencies with other psychotherapeutic approaches is warranted. Trial registration: ClinicalTrials.gov identifier: NCT04317820..
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- 2023
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8. Consensus on the reporting and experimental design of clinical and cognitive-behavioural neurofeedback studies (CRED-nf checklist).
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Paret, Christian, Ossadtchi, Alexei, Nicholson, Andrew, Nan, Wenya, Minguez, Javier, Micoulaud-Franchi, Jean-Arthur, Mehler, David, Lührs, Michael, Lubar, Joel, Lotte, Fabien, Linden, David, Lewis-Peacock, Jarrod, Lebedev, Mikhail, Lanius, Ruth, Kübler, Andrea, Kranczioch, Cornelia, Koush, Yury, Konicar, Lilian, Kohl, Simon, Kober, Silivia, Klados, Manousos, Jeunet, Camille, Janssen, T, Huster, Rene, Hoedlmoser, Kerstin, Hirshberg, Laurence, Heunis, Stephan, Hendler, Talma, Hampson, Michelle, Guggisberg, Adrian, Guggenberger, Robert, Gruzelier, John, Göbel, Rainer, Gninenko, Nicolas, Gharabaghi, Alireza, Frewen, Paul, Fovet, Thomas, Fernández, Thalía, Escolano, Carlos, Ehlis, Ann-Christine, Drechsler, Renate, Christopher deCharms, R, Debener, Stefan, De Ridder, Dirk, Davelaar, Eddy, Congedo, Marco, Cavazza, Marc, Breteler, Marinus, Brandeis, Daniel, Bodurka, Jerzy, Birbaumer, Niels, Bazanova, Olga, Barth, Beatrix, Bamidis, Panagiotis, Auer, Tibor, Arns, Martijn, Thibault, Robert, Ros, Tomas, Enriquez-Geppert, Stefanie, Zotev, Vadim, Young, Kymberly, Wood, Guilherme, Whitfield-Gabrieli, Susan, Wan, Feng, Vuilleumier, Patrik, Vialatte, François, Van De Ville, Dimitri, Todder, Doron, Surmeli, Tanju, Sulzer, James, Strehl, Ute, Sterman, Maurice, Steiner, Naomi, Sorger, Bettina, Soekadar, Surjo, Sitaram, Ranganatha, Sherlin, Leslie, Schönenberg, Michael, Scharnowski, Frank, Schabus, Manuel, Rubia, Katya, Rosa, Agostinho, Reiner, Miriam, and Pineda, Jaime
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checklist ,consensus ,guidelines ,neurofeedback ,regulation ,Adult ,Checklist ,Consensus ,Female ,Humans ,Male ,Middle Aged ,Neurofeedback ,Peer Review ,Research ,Research Design ,Stakeholder Participation - Abstract
Neurofeedback has begun to attract the attention and scrutiny of the scientific and medical mainstream. Here, neurofeedback researchers present a consensus-derived checklist that aims to improve the reporting and experimental design standards in the field.
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- 2020
9. Consensus on the reporting and experimental design of clinical and cognitive-behavioural neurofeedback studies (CRED-nf checklist)
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Ros, Tomas, Enriquez-Geppert, Stefanie, Zotev, Vadim, Young, Kymberly D, Wood, Guilherme, Whitfield-Gabrieli, Susan, Wan, Feng, Vuilleumier, Patrik, Vialatte, François, Van De Ville, Dimitri, Todder, Doron, Surmeli, Tanju, Sulzer, James S, Strehl, Ute, Sterman, Maurice Barry, Steiner, Naomi J, Sorger, Bettina, Soekadar, Surjo R, Sitaram, Ranganatha, Sherlin, Leslie H, Schönenberg, Michael, Scharnowski, Frank, Schabus, Manuel, Rubia, Katya, Rosa, Agostinho, Reiner, Miriam, Pineda, Jaime A, Paret, Christian, Ossadtchi, Alexei, Nicholson, Andrew A, Nan, Wenya, Minguez, Javier, Micoulaud-Franchi, Jean-Arthur, Mehler, David MA, Lührs, Michael, Lubar, Joel, Lotte, Fabien, Linden, David EJ, Lewis-Peacock, Jarrod A, Lebedev, Mikhail A, Lanius, Ruth A, Kübler, Andrea, Kranczioch, Cornelia, Koush, Yury, Konicar, Lilian, Kohl, Simon H, Kober, Silivia E, Klados, Manousos A, Jeunet, Camille, Janssen, TWP, Huster, Rene J, Hoedlmoser, Kerstin, Hirshberg, Laurence M, Heunis, Stephan, Hendler, Talma, Hampson, Michelle, Guggisberg, Adrian G, Guggenberger, Robert, Gruzelier, John H, Göbel, Rainer W, Gninenko, Nicolas, Gharabaghi, Alireza, Frewen, Paul, Fovet, Thomas, Fernández, Thalía, Escolano, Carlos, Ehlis, Ann-Christine, Drechsler, Renate, deCharms, R Christopher, Debener, Stefan, De Ridder, Dirk, Davelaar, Eddy J, Congedo, Marco, Cavazza, Marc, Breteler, Marinus HM, Brandeis, Daniel, Bodurka, Jerzy, Birbaumer, Niels, Bazanova, Olga M, Barth, Beatrix, Bamidis, Panagiotis D, Auer, Tibor, Arns, Martijn, and Thibault, Robert T
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Mind and Body ,Adult ,Checklist ,Consensus ,Female ,Humans ,Male ,Middle Aged ,Neurofeedback ,Peer Review ,Research ,Research Design ,Stakeholder Participation ,neurofeedback ,regulation ,consensus ,checklist ,guidelines ,Medical and Health Sciences ,Psychology and Cognitive Sciences ,Neurology & Neurosurgery - Abstract
Neurofeedback has begun to attract the attention and scrutiny of the scientific and medical mainstream. Here, neurofeedback researchers present a consensus-derived checklist that aims to improve the reporting and experimental design standards in the field.
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- 2020
10. User experiences during the transition to calibration-free sensors with remote monitoring while using automated insulin delivery - a qualitative study
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Shekhar Sehgal, Martin De Bock, Shirley Jones, Carla Frewen, and Benjamin J. Wheeler
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type 1 diabetes mellitus ,continuous glucose monitoring ,interview ,patient satisfaction ,remote monitoring ,Diseases of the endocrine glands. Clinical endocrinology ,RC648-665 - Abstract
IntroductionTo evaluate the experiences of patients with type 1 diabetes following transition from a calibration-requiring to a calibration-free sensor and remote monitoring in the context of using automated insulin delivery (AID).Research design and methodsFifteen participants aged 7–65 years with type 1 diabetes participating in a longitudinal study used a Medtronic® advanced hybrid closed loop (AHCL) device with initially calibration-requiring then calibration-free sensors. Qualitative interviews were conducted ≥20 weeks following use of the calibration-requiring and ≥4 weeks after use of the calibration-free sensors/remote monitoring. Thematic analysis was used to identify key themes and subthemes.ResultsAt baseline, mean diabetes duration was 14.5 years ( ± 10.9), mean Hba1c 54.8 mmol/mol ( ± 10.2) (7.2 ± 0.9%) and Time in range 75.4% ( ± 11.6). Participants reported a progressive improvement in digital and lifestyle integration, and device trust following transition to calibration-free sensors with remote monitoring potential. They also reported a reduced need for capillary glucose, increased device satisfaction and trust, and reduced burden of diabetes care. Negative aspects reported included periodic early sensor loss, and for some, impaired integration with mobile devices.ConclusionTransitioning to calibration-free sensors with remote monitoring while using AHCL was associated with better user experience, including perceptions of improved quality of life and a reduced burden of diabetes care. Appropriate expectation setting, training, and ongoing support allow for the optimal user experience while using AHCL.Clinical trial registrationhttps://www.anzctr.org.au, identifier ACTRN12621000360819
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- 2023
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11. Being where, with whom, and when it happens: spatial, interpersonal, and temporal presence while viewing live streaming of collegiate sports in virtual reality
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Andrew Vincent and Paul Frewen
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virtual reality ,sports ,presence ,spatial presence ,temporal presence ,social presence ,Electronic computers. Computer science ,QA75.5-76.95 - Abstract
Introduction: Although virtual reality (VR) is most popularly known for its applications to gaming, other entertainment applications are increasingly being explored including in the sports media industry, but little research has so far examined the experiences induced by VR viewing of a live sporting event.Materials and methods: Participants (n = 93) were university students who were approached in the context of a field study from a nearby community eatery area on the university campus to watch brief segments of a 360° live stream of the home games of their university volleyball and basketball teams both while wearing and not wearing an inexpensive smart-phone based head-mounted display (HMD). Immediately afterward, participants then reported on their relative experience of spatial, interpersonal, and temporal presence, as well as their satisfaction-preference with each of the two viewing modalities, in response to brief face-valid screening questions.Results: The majority of participants experienced greater presence while wearing the VR headset, and approximately one in every two reported preferring to watch the games in VR. Participants’ experience of spatial presence independently correlated with preferring to watch the games in VR.Discussion: Media vendors should offer VR viewing of sports including via inexpensive, smart-phone mediated VR as an additional, cost-effective alternative means of heightening fans’ experience of virtual presence at the games when fans are unable to go to the games in person.
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- 2023
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12. Posterior cingulate cortex targeted real‐time fMRI neurofeedback recalibrates functional connectivity with the amygdala, posterior insula, and default‐mode network in PTSD
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Jonathan M. Lieberman, Daniela Rabellino, Maria Densmore, Paul A. Frewen, David Steyrl, Frank Scharnowski, Jean Théberge, Richard W. J. Neufeld, Christian Schmahl, Rakesh Jetly, Sandhya Narikuzhy, Ruth A. Lanius, and Andrew A. Nicholson
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default mode network ,fMRI neurofeedback ,posterior cingulate cortex ,posttraumatic stress disorder ,Neurosciences. Biological psychiatry. Neuropsychiatry ,RC321-571 - Abstract
Abstract Background Alterations within large‐scale brain networks—namely, the default mode (DMN) and salience networks (SN)—are present among individuals with posttraumatic stress disorder (PTSD). Previous real‐time functional magnetic resonance imaging (fMRI) and electroencephalography neurofeedback studies suggest that regulating posterior cingulate cortex (PCC; the primary hub of the posterior DMN) activity may reduce PTSD symptoms and recalibrate altered network dynamics. However, PCC connectivity to the DMN and SN during PCC‐targeted fMRI neurofeedback remains unexamined and may help to elucidate neurophysiological mechanisms through which these symptom improvements may occur. Methods Using a trauma/emotion provocation paradigm, we investigated psychophysiological interactions over a single session of neurofeedback among PTSD (n = 14) and healthy control (n = 15) participants. We compared PCC functional connectivity between regulate (in which participants downregulated PCC activity) and view (in which participants did not exert regulatory control) conditions across the whole‐brain as well as in a priori specified regions‐of‐interest. Results During regulate as compared to view conditions, only the PTSD group showed significant PCC connectivity with anterior DMN (dmPFC, vmPFC) and SN (posterior insula) regions, whereas both groups displayed PCC connectivity with other posterior DMN areas (precuneus/cuneus). Additionally, as compared with controls, the PTSD group showed significantly greater PCC connectivity with the SN (amygdala) during regulate as compared to view conditions. Moreover, linear regression analyses revealed that during regulate as compared to view conditions, PCC connectivity to DMN and SN regions was positively correlated to psychiatric symptoms across all participants. Conclusion In summary, observations of PCC connectivity to the DMN and SN provide emerging evidence of neural mechanisms underlying PCC‐targeted fMRI neurofeedback among individuals with PTSD. This supports the use of PCC‐targeted neurofeedback as a means by which to recalibrate PTSD‐associated alterations in neural connectivity within the DMN and SN, which together, may help to facilitate improved emotion regulation abilities in PTSD.
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- 2023
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13. Improved technology satisfaction and sleep quality with Medtronic MiniMed® Advanced Hybrid Closed-Loop delivery compared to predictive low glucose suspend in people with Type 1 Diabetes in a randomized crossover trial
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Wheeler, Benjamin J., Collyns, Olivia J., Meier, Renee A., Betts, Zara L., Frampton, Chris, Frewen, Carla M., Galland, Barbara, Hewapathirana, Niranjala M., Jones, Shirley D., Chan, Denis S. H., Roy, Anirban, Grosman, Benyamin, Kurtz, Natalie, Shin, John, Vigersky, Robert A., and de Bock, Martin I.
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- 2022
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14. Increased top-down control of emotions during symptom provocation working memory tasks following a RCT of alpha-down neurofeedback in PTSD
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Saurabh Bhaskar Shaw, Andrew A. Nicholson, Tomas Ros, Sherain Harricharan, Braeden Terpou, Maria Densmore, Jean Theberge, Paul Frewen, and Ruth A. Lanius
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Post-traumatic stress disorder (PTSD) ,Neurofeedback (NFB) ,Functional magnetic resonance imaging (fMRI) ,DLPFC ,Top-down control ,Cognition ,Computer applications to medicine. Medical informatics ,R858-859.7 ,Neurology. Diseases of the nervous system ,RC346-429 - Abstract
Background: Posttraumatic stress disorder (PTSD) has been found to be associated with emotion under-modulation from the prefrontal cortex and a breakdown of the top-down control of cognition and emotion. Novel adjunct therapies such as neurofeedback (NFB) have been shown to normalize aberrant neural circuits that underlie PTSD psychopathology at rest. However, little evidence exists for NFB-linked neural improvements under emotionally relevant cognitive load. The current study sought to address this gap by examining the effects of alpha-down NFB in the context of an emotional n-back task. Methods: We conducted a 20-week double-blind randomized, sham-controlled trial of alpha-down NFB and collected neuroimaging data before and after the NFB protocol. Participants performed an emotional 1-back and 2-back working memory task, with interleaved trauma-neutral and trauma-relevant cues in the fMRI scanner. Data from 35 participants with a primary diagnosis of PTSD were analyzed in this study (n = 18 in the experimental group undergoing alpha-down NFB, n = 17 in the sham-control group). Results: Firstly, within-group analyses showed clinically significant reductions in PTSD symptom severity scores at the post-intervention timepoint and 3-month follow-up for the experimental group, and not for the sham-control group. The neuroimaging analyses revealed that alpha-down NFB enhanced engagement of top-down cognitive and emotional control centers, such as the dorsolateral prefrontal cortex (dlPFC), and improved integration of the anterior and posterior parts of the default mode network (DMN). Finally, our results also indicate that increased alpha-down NFB performance correlated with increased activity in brain regions involved in top-down control and bodily consciousness/embodied processing of self (TPJ and posterior insula). Conclusion: This is the first study to provide mechanistic insights into how NFB may normalize dysfunctional brain activity and connectivity in PTSD under cognitive load with simultaneous symptom provocation, adding to a growing body of evidence supporting the therapeutic neuromodulatory effects of NFB. This preliminary study highlights the benefits of alpha-down NFB training as an adjunctive therapy for PTSD and warrants further investigation into its therapeutic effects on cognitive and emotion control in those with PTSD.
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- 2023
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15. Study protocol: Safety and efficacy of smart watch integrated do-it-yourself continuous glucose monitoring in adults with Type 1 diabetes, a randomised controlled trial
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Sehgal, Shekhar, De Bock, Martin, Williman, Jonathan, Taylor, Barry, Elbalshy, Mona, Galland, Barbara, Hall, Rosemary, Paul, Ryan, Boucsein, Alisa, Jones, Shirley, Frewen, Carla, and Wheeler, Benjamin J.
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- 2021
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16. Delusional infestation in healthcare professionals: Outcomes from a multi‐centre case series
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John Frewen, Peter Lepping, Jonathan M. R. Goulding, Stephen Walker, and Anthony Bewley
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Dermatology ,RL1-803 - Abstract
Abstract Delusional infestation (DI) describes an unwavering fixed belief of infestation with pathogens, despite a lack of medical evidence supporting this. Effective management of DI with antipsychotics is made challenging by the fixed belief that the condition is an infestation or infection rather than a mental illness. A case series of individuals diagnosed with DI included 11% who were healthcare professionals (HCPs). We sought to characterise a cohort of HCPs who presented with DI in the UK. The case notes of HCPs diagnosed with DI at specialist clinics between 2015 and 2019 were reviewed. Demographic and clinical data were obtained. Twelve HCPs were identified out of a total of 381 individuals diagnosed with DI. Median age was 52.5 (IQR = 14.5) years. 75% (n = 9) were women. Ten individuals had primary DI, whilst two had secondary DI (one to recreational drug use, one to depression). Four individuals (33%) engaged with antipsychotic treatment. Two responded well, both had secondary DI. Of the two individuals with primary DI who engaged, one did not respond to antipsychotic medication and the other was unable to tolerate two antipsychotic drugs. In Primary DI (n = 10), the rate of adherence was lower at 20% (n = 2). In DI, high engagement and adherence rates to treatment have been reported in specialist centres. Improvement has been reported as high as 70%–75%. This indicates that a large proportion of individuals who adhere to treatment appear to derive benefit. In this series, engagement with treatment by HCPs with primary DI was low at 20%, and improvement was only achieved in individuals with secondary DI. Mental illness‐related stigma, feelings of distress and difficulty forming therapeutic relationships with a professional peer are significant challenges. Developing rapport is key to treatment success in DI. In HCPs this may be suboptimal due to these negative feelings, resulting in lower engagement. A diagnosis of DI in a HCP may raise concerns regarding fitness to practise. An assessment of the impact of DI and the potential to interfere with professional duties warrants consideration. We highlight the occurrence of DI in HCPs, and the apparent lower engagement with treatment in this cohort.
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- 2022
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17. Neurofeedback Tunes Scale-Free Dynamics in Spontaneous Brain Activity
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Ros, Tomas, Frewen, Paul, Theberge, Jean, Kluetsch, Rosemarie, Mueller, Andreas, Candrian, Gian, Jetly, Rakesh, Vuilleumier, Patrik, and Lanius, Ruth
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Quantitative Biology - Neurons and Cognition - Abstract
Brain oscillations exhibit long-range temporal correlations (LRTCs), which reflect the regularity of their fluctuations: low values representing more random (decorrelated) while high values more persistent (correlated) dynamics. LRTCs constitute supporting evidence that the brain operates near criticality, a state where neuronal activities are balanced between order and randomness. Here, healthy adults used closed-loop brain training (neurofeedback, NFB) to reduce the amplitude of alpha oscillations, producing a significant increase in spontaneous LRTCs post-training. This effect was reproduced in patients with post-traumatic stress disorder, where abnormally random dynamics were reversed by NFB, correlating with significant improvements in hyperarousal. Notably, regions manifesting abnormally low LRTCs (i.e., excessive randomness) normalized toward healthy population levels, consistent with theoretical predictions about self-organized criticality. Hence, when exposed to appropriate training, spontaneous cortical activity reveals a residual capacity for "self-tuning" its own temporal complexity, despite manifesting the abnormal dynamics seen in individuals with psychiatric disorder. Lastly, we observed an inverse-U relationship between strength of LRTC and oscillation amplitude, suggesting a breakdown of long-range dependence at high/low synchronization extremes, in line with recent computational models. Together, our findings offer a broader mechanistic framework for motivating research and clinical applications of NFB, encompassing disorders with perturbed LRTCs.
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- 2015
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18. Desynchronization of autonomic response and central autonomic network connectivity in posttraumatic stress disorder.
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Thome, Janine, Densmore, Maria, Frewen, Paul, McKinnon, Margaret, Théberge, Jean, Nicholson, Andrew, Koenig, Julian, Thayer, Julian, and Lanius, Ruth
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central autonomic network ,fMRI ,heart rate variability ,periaqueductal gray ,posttraumatic stress disorder ,top-down modulation ,Adult ,Autonomic Nervous System ,Autonomic Nervous System Diseases ,Brain ,Female ,Heart Rate ,Humans ,Image Processing ,Computer-Assisted ,Magnetic Resonance Imaging ,Male ,Middle Aged ,Neural Pathways ,Rest ,Retrospective Studies ,Stress Disorders ,Post-Traumatic ,Young Adult - Abstract
OBJECTIVES: Although dysfunctional emotion regulatory capacities are increasingly recognized as contributing to posttraumatic stress disorder (PTSD), little work has sought to identify biological markers of this vulnerability. Heart rate variability (HRV) is a promising biomarker that, together with neuroimaging, may assist in gaining a deeper understanding of emotion dysregulation in PTSD. The objective of the present study was, therefore, to characterize autonomic response patterns, and their related neuronal patterns in individuals with PTSD at rest. METHODS: PTSD patients (N = 57) and healthy controls (N = 41) underwent resting-state fMRI. Connectivity patterns of key regions within the central autonomic network (CAN)-including the ventromedial prefrontal cortex (vmPFC), amygdala, and periaqueductal gray (PAG)-were examined using a seed-based approach. Observed connectivity patterns were then correlated to resting HRV. RESULTS: In contrast to controls, individuals with PTSD exhibited lower HRV. In addition, whereas controls engaged a localized connectivity pattern of CAN-related brain regions, in PTSD, key CAN regions were associated with widespread connectivity patterns in regions related to emotional reactivity (vmPFC and amygdala to insular cortex and lentiform nucleus; PAG to insula) and motor readiness (vmPFC and amygdala to precentral gyrus; PAG to precentral gyrus and cerebellum). Critically, whereas CAN connectivity in controls was strongly related to higher HRV (insula, mPFC, superior frontal cortex, thalamus), HRV covariation was absent in PTSD subjects. CONCLUSIONS: This study provides the first evidence for a specific psychophysiological-neuronal profile in PTSD individuals characterized by lower resting HRV and a lack of HRV covariation with CAN-related brain connectivity. Hum Brain Mapp 38:27-40, 2017. © 2016 Wiley Periodicals, Inc.
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- 2017
19. Meditating in Virtual Reality 3: 360° Video of Perceptual Presence of Instructor
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Waller, Madison, Mistry, Divya, Jetly, Rakesh, and Frewen, Paul
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- 2021
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20. A bi-criteria path planning algorithm for robotics applications
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Clawson, Zachary, Ding, Xuchu, Englot, Brendan, Frewen, Thomas A., Sisson, William M., and Vladimirsky, Alexander
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Computer Science - Robotics ,Computer Science - Systems and Control ,68T40, 93C85, 68W25, 90C29, 90C39, 05C38, 05C85 ,I.2.8 ,I.2.9 ,G.2.2 - Abstract
Realistic path planning applications often require optimizing with respect to several criteria simultaneously. Here we introduce an efficient algorithm for bi-criteria path planning on graphs. Our approach is based on augmenting the state space to keep track of the "budget" remaining to satisfy the constraints on secondary cost. The resulting augmented graph is acyclic and the primary cost can be then minimized by a simple upward sweep through budget levels. The efficiency and accuracy of our algorithm is tested on Probabilistic Roadmap graphs to minimize the distance of travel subject to a constraint on the overall threat exposure of the robot. We also present the results from field experiments illustrating the use of this approach on realistic robotic systems., Comment: 19 pages, 12 figures; submitted for publication to IEEE Transactions on Automation Science and Engineering
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- 2015
21. The Effect of Stellar Evolution on Migrating Warm Jupiters
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Frewen, Shane and Hansen, Brad
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Astrophysics - Solar and Stellar Astrophysics - Abstract
Warm jupiters are an unexpected population of extrasolar planets that are too near to their host to have formed in situ, but distant enough to retain a significant eccentricity in the face of tidal damping. These planets are curiously absent around stars larger than two solar radii. We hypothesize that the warm jupiters are migrating due to Kozai-Lidov oscillations, which leads to transient episodes of high eccentricity and a consequent tidal decay. As their host evolves, such planets would be rapidly dragged in or engulfed at minimum periapse, leading to a rapid depletion of the population with increasing stellar radius, as is observed. Using numerical simulations, we determine the relationship between periapse distance and orbital migration rate for planets 0.1 to 10 Jupiter masses and with orbital periods between 10 and 100 days. We find that Kozai-Lidov oscillations effectively result in planetary removal early in the evolution of the host star, possibly accounting for the observed deficit. While the observed eccentricity distribution is inconsistent with the simulated distribution for an oscillating and migrating warm jupiter population, observational biases may explain the discrepancy., Comment: 16 pages, 18 figures; to appear in Monthly Notices of the Royal Astronomical Society
- Published
- 2015
22. Constraining Neutrino Cooling using the Hot White Dwarf Luminosity Function in the Globular Cluster 47 Tucanae
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Hansen, Bradley, Richer, Harvey, Kalirai, Jason, Goldsbury, Ryan, Frewen, Shane, and Heyl, Jeremy
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Astrophysics - Solar and Stellar Astrophysics - Abstract
We present Hubble Space Telescope observations of the upper part (T_eff> 10 000 K) of the white dwarf cooling sequence in the globular cluster 47 Tucanae and measure a luminosity function of hot white dwarfs. Comparison with previous determinations from large scale field surveys indicates that the previously determined plateau at high effective temperatures is likely a selection effect, as no such feature is seen in this sample. Comparison with theoretical models suggests that the current estimates of white dwarf neutrino emission (primarily by the plasmon channel) are accurate, and variations are restricted to no more than a factor of two globally, at 95% confidence. We use these constraints to place limits on various proposed exotic emission mechanisms, including a non-zero neutrino magnetic moment, formation of axions, and emission of Kaluza-Klein modes into extra dimensions., Comment: 13 pages, 12 figures, to appear in the Astrophysical Journal
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- 2015
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23. Meditating in Virtual Reality 2: Phenomenology of Vividness, Egocentricity and Absorption-Immersion
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Miller, Melissa, Mistry, Divya, Jetly, Rakesh, and Frewen, Paul
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- 2021
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24. Eccentric Planets and Stellar Evolution as a Cause of Polluted White Dwarfs
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Frewen, Shane F. N. and Hansen, Brad M. S.
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Astrophysics - Earth and Planetary Astrophysics - Abstract
A significant fraction of white dwarfs (WDs) are observed to be polluted with metals despite high surface gravities and short settling times. The current theoretical model for this pollution is accretion of rocky bodies delivered to the WD through perturbations by orbiting planets. Using N-body simulations, we examine the possibility of a single planet as the source of pollution. We determine the stability of test particles on circular orbits in systems with a single planet located at 4 au for a range of masses and eccentricities, comparing the fractions that are ejected and accreted. In particular, we compare the instabilities that develop before and after the star loses mass to form a WD, a process which causes orbiting bodies to migrate outward. We determine that a planet must be eccentric (e > 0.02) to deliver significant (> 0.5 per cent) amounts of material to the host and that the amount increases with the planetary eccentricity. This result is robust with respect to the initial eccentricities of the particles for planetary eccentricity above ~0.4 and for randomly-distributed particle long. of pericentre. We also find that the efficiency of pollution is enhanced as planetary mass is reduced. We demonstrate that a 0.03 M_Jup planet with substantial eccentricity (e > 0.4) can account for the observed levels of pollution for initial disc masses of order 1 M_Earth. Such discs are within the range estimated for initial planetesimals discs and below that estimated for the solar system. However, their survival to the WD stage is uncertain as estimates for the collisional evolution of planetesimal discs suggest they should be ground down below the required levels on Gyr timescales. Thus, planetary scattering by eccentric, sub-Jovian planets can explain the observed levels of WD pollution, but only if current estimates of the collisional erosion of planetesimal discs are in error., Comment: 18 pages, 19 figures, accepted to MNRAS
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- 2014
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25. Differential mechanisms of posterior cingulate cortex downregulation and symptom decreases in posttraumatic stress disorder and healthy individuals using real‐time fMRI neurofeedback
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Andrew A. Nicholson, Daniela Rabellino, Maria Densmore, Paul A. Frewen, David Steyrl, Frank Scharnowski, Jean Théberge, Richard W.J. Neufeld, Christian Schmahl, Rakesh Jetly, and Ruth A. Lanius
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machine learning ,neurofeedback ,post‐traumatic stress disorder ,real‐time fMRI ,Neurosciences. Biological psychiatry. Neuropsychiatry ,RC321-571 - Abstract
Abstract Background Intrinsic connectivity networks, including the default mode network (DMN), are frequently disrupted in individuals with posttraumatic stress disorder (PTSD). The posterior cingulate cortex (PCC) is the main hub of the posterior DMN, where the therapeutic regulation of this region with real‐time fMRI neurofeedback (NFB) has yet to be explored. Methods We investigated PCC downregulation while processing trauma/stressful words over 3 NFB training runs and a transfer run without NFB (total n = 29, PTSD n = 14, healthy controls n = 15). We also examined the predictive accuracy of machine learning models in classifying PTSD versus healthy controls during NFB training. Results Both the PTSD and healthy control groups demonstrated reduced reliving symptoms in response to trauma/stressful stimuli, where the PTSD group additionally showed reduced symptoms of distress. We found that both groups were able to downregulate the PCC with similar success over NFB training and in the transfer run, although downregulation was associated with unique within‐group decreases in activation within the bilateral dmPFC, bilateral postcentral gyrus, right amygdala/hippocampus, cingulate cortex, and bilateral temporal pole/gyri. By contrast, downregulation was associated with increased activation in the right dlPFC among healthy controls as compared to PTSD. During PCC downregulation, right dlPFC activation was negatively correlated to PTSD symptom severity scores and difficulties in emotion regulation. Finally, machine learning algorithms were able to classify PTSD versus healthy participants based on brain activation during NFB training with 80% accuracy. Conclusions This is the first study to investigate PCC downregulation with real‐time fMRI NFB in both PTSD and healthy controls. Our results reveal acute decreases in symptoms over training and provide converging evidence for EEG‐NFB targeting brain networks linked to the PCC.
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- 2022
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26. Inviting Scientific Discourse on Traumatic Dissociation: Progress Made and Obstacles to Further Resolution
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Dalenberg, Constance J., Brand, Bethany L., Loewenstein, Richard J., Frewen, Paul A., and Spiegel, David
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- 2020
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27. Scalable Approach to Uncertainty Quantification and Robust Design of Interconnected Dynamical Systems
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Banaszuk, Andrzej, Fonoberov, Vladimir A., Frewen, Thomas A., Kobilarov, Marin, Mathew, George, Mezic, Igor, Pinto, Alessandro, Sahai, Tuhin, Sane, Harshad, Speranzon, Alberto, and Surana, Amit
- Subjects
Computer Science - Systems and Control - Abstract
Development of robust dynamical systems and networks such as autonomous aircraft systems capable of accomplishing complex missions faces challenges due to the dynamically evolving uncertainties coming from model uncertainties, necessity to operate in a hostile cluttered urban environment, and the distributed and dynamic nature of the communication and computation resources. Model-based robust design is difficult because of the complexity of the hybrid dynamic models including continuous vehicle dynamics, the discrete models of computations and communications, and the size of the problem. We will overview recent advances in methodology and tools to model, analyze, and design robust autonomous aerospace systems operating in uncertain environment, with stress on efficient uncertainty quantification and robust design using the case studies of the mission including model-based target tracking and search, and trajectory planning in uncertain urban environment. To show that the methodology is generally applicable to uncertain dynamical systems, we will also show examples of application of the new methods to efficient uncertainty quantification of energy usage in buildings, and stability assessment of interconnected power networks.
- Published
- 2011
28. Self-Referential Processing Effects of Non-invasive Brain Stimulation: A Systematic Review
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Zhongjie Bao, Belal Howidi, Amer M. Burhan, and Paul Frewen
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self-referential processing ,neuromodulation ,non-invasive brain stimulation (NIBS) ,systematic review ,bodily self-consciousness ,Neurosciences. Biological psychiatry. Neuropsychiatry ,RC321-571 - Abstract
Systematic reviews of neuroimaging studies confirm stimulus-induced activity in response to verbal and non-verbal self-referential processing (SRP) in cortical midline structures, temporoparietal cortex and insula. Whether SRP can be causally modulated by way of non-invasive brain stimulation (NIBS) has also been investigated in several studies. Here we summarize the NIBS literature including 27 studies of task-based SRP comparing response between verbal and non-verbal SRP tasks. The studies differed in design, experimental tasks and stimulation parameters. Results support the role of left inferior parietal lobule (left IPL) in verbal SRP and for the medial prefrontal cortex when valenced stimuli were used. Further, results support roles for the bilateral parietal lobe (IPL, posterior cingulate cortex), the sensorimotor areas (the primary sensory and motor cortex, the premotor cortex, and the extrastriate body area) and the insula in non-verbal SRP (bodily self-consciousness). We conclude that NIBS may differentially modulate verbal and non-verbal SRP by targeting the corresponding brain areas.
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- 2021
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29. Coronal radiation belts
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Hudson, H. S., MacKinnon, A. L., Frewen, S. F. N., and DeRosa, M. L.
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Astrophysics - Solar and Stellar Astrophysics ,Astrophysics - High Energy Astrophysical Phenomena - Abstract
The magnetic field of the solar corona has a large-scale dipole character, which maps into the bipolar field in the solar wind. Using standard representations of the coronal field, we show that high-energy ions can be trapped stably in these large-scale closed fields. The drift shells that describe the conservation of the third adiabatic invariant may have complicated geometries. Particles trapped in these zones would resemble the Van Allen Belts and could have detectable consequences. We discuss potential sources of trapped particles.
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- 2009
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30. Exploration of Effective Potential Landscapes using Coarse Reverse Integration
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Frewen, Thomas A., Hummer, Gerhard, and Kevrekidis, Ioannis G.
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Physics - Chemical Physics - Abstract
We describe a reverse integration approach for the exploration of low-dimensional effective potential landscapes. Coarse reverse integration initialized on a ring of coarse states enables efficient "navigation" on the landscape terrain: escape from local effective potential wells, detection of saddle points, and identification of significant transition paths between wells. We consider several distinct ring evolution modes: backward stepping in time, solution arc--length, and effective potential. The performance of these approaches is illustrated for a deterministic problem where the energy landscape is known explicitly. Reverse ring integration is then applied to "noisy" problems where the ring integration routine serves as an outer "wrapper" around a forward-in-time inner simulator. Three versions of such inner simulators are considered: a system of stochastic differential equations, a Gillespie--type stochastic simulator, and a molecular dynamics simulator. In these "equation-free" computational illustrations, estimation techniques are applied to the results of short bursts of "inner" simulation to obtain the unavailable (in closed form) quantities (local drift and diffusion coefficient estimates) required for reverse ring integration; this naturally leads to approximations of the effective landscape., Comment: article submitted to J Chem Phys
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- 2008
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31. Coarse-grained dynamics of an activity bump in a neural field model
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Laing, C. R., Frewen, T. A., and Kevrekidis, I. G.
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Mathematics - Dynamical Systems - Abstract
We study a stochastic nonlocal PDE, arising in the context of modelling spatially distributed neural activity, which is capable of sustaining stationary and moving spatially-localized ``activity bumps''. This system is known to undergo a pitchfork bifurcation in bump speed as a parameter (the strength of adaptation) is changed; yet increasing the noise intensity effectively slowed the motion of the bump. Here we revisit the system from the point of view of describing the high-dimensional stochastic dynamics in terms of the effective dynamics of a single scalar "coarse" variable. We show that such a reduced description in the form of an effective Langevin equation characterized by a double-well potential is quantitatively successful. The effective potential can be extracted using short, appropriately-initialized bursts of direct simulation. We demonstrate this approach in terms of (a) an experience-based "intelligent" choice of the coarse observable and (b) an observable obtained through data-mining direct simulation results, using a diffusion map approach., Comment: Corrected aknowledgements
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- 2006
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32. Variable-free exploration of stochastic models: a gene regulatory network example
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Erban, Radek, Frewen, Thomas A., Wang, Xiao, Elston, Timothy C., Coifman, Ronald, Nadler, Boaz, and Kevrekidis, Ioannis G.
- Subjects
Quantitative Biology - Quantitative Methods ,Physics - Computational Physics ,Quantitative Biology - Molecular Networks - Abstract
Finding coarse-grained, low-dimensional descriptions is an important task in the analysis of complex, stochastic models of gene regulatory networks. This task involves (a) identifying observables that best describe the state of these complex systems and (b) characterizing the dynamics of the observables. In a previous paper [13], we assumed that good observables were known a priori, and presented an equation-free approach to approximate coarse-grained quantities (i.e, effective drift and diffusion coefficients) that characterize the long-time behavior of the observables. Here we use diffusion maps [9] to extract appropriate observables ("reduction coordinates") in an automated fashion; these involve the leading eigenvectors of a weighted Laplacian on a graph constructed from network simulation data. We present lifting and restriction procedures for translating between physical variables and these data-based observables. These procedures allow us to perform equation-free coarse-grained, computations characterizing the long-term dynamics through the design and processing of short bursts of stochastic simulation initialized at appropriate values of the data-based observables., Comment: 26 pages, 9 figures
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- 2006
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33. INBOX.
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Oboler, Steven, Johnson, Robert, GEORGE, STEPHEN C., and Frewen, Flo
- Abstract
This article from Discover magazine includes three letters from readers responding to previous articles. The first letter requests an image of a moon rock mentioned in an article about NASA-collected moon rocks. The editors respond by providing an image and additional information about the rock. The second letter points out the omission of information about Neanderthal DNA in a cover story about Neanderthals. The editor acknowledges the oversight and promises to cover the topic in a future issue. The third letter questions why the name of the director of curatorial affairs at the First Americans Museum was not capitalized in an article about museums. The editors explain that it was not a typo, but rather the director's preference to have her name written in lowercase as a form of objection to colonialist language hierarchy. [Extracted from the article]
- Published
- 2024
34. Restoring large scale brain networks in the aftermath of trauma: implications for neuroscientifically-informed treatments
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R. A. Lanius, P. A. Frewen, A. N. Nicholson, and M. C. McKinnon
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Psychiatry ,RC435-571 - Abstract
Background: Several intrinsic networks in the brain, including the default mode network, the salience network, and the central executive network, have shown to be critical to higher cognitive functioning. Importantly, these networks have been demonstrated to be compromised in psychopathology, including posttraumatic stress disorder (PTSD) (Akiki, Averill, & Abdallah, ; Lanius, Frewen, Tursich, Jetly, & McKinnon, ; Lanius, Terpou, & McKinnon, ; Szeszko & Yehuda, ). Objective: 1) To outline the major large-scale networks of the human brain and their impaired functioning in PTSD; 2) to describe neuroscientifically-informed interventions targeting directly the abnormalities observed in these brain networks in PTSD. Methods: Literature relevant to this topic will be reviewed. Results: Increasing evidence for impaired functioning of the default mode network, the salience network, the central executive network, and the dorsal/ventral attention networks in PTSD has been described. Each network has been proposed to be associated with specific clinical symptoms observed in PTSD, including an altered sense of self (default mode network), increased or decreased or arousal/interoception (salience network), cognitive dysfunction (central executive network; attentional networks). Specific neuroscientifically-informed treatments designed to restore each of these brain networks and the related clinical symptomatology will be discussed. Conclusions: Neuroscientifically-informed treatments will be critical to future research and personalized medicine agendas aimed at targeting specific PTSD symptomatology and restoring functioning in the aftermath of this often devastating disorder.
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- 2021
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35. Global Psychotrauma Screen (GPS): psychometric properties in two Internet-based studies
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Paul Frewen, Ian McPhail, Ulrich Schnyder, Misari Oe, and Miranda Olff
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trauma ,ptsd ,depression ,anxiety ,dissociation ,substance use ,child maltreatment ,global ,international ,assessment ,screening instrument ,Psychiatry ,RC435-571 - Abstract
Background: Potentially traumatic stressors can lead to various transdiagnostic outcomes beyond PTSD alone but no brief screening tools exist for measuring posttraumatic responses in a transdiagnostic manner. Objective: Assess the psychometric characteristics of a new 22-item transdiagnostic screening measure, the Global Psychotrauma Screen (GPS). Method: An internet survey was administered with English speaking participants recruited passively via the website of the Global Collaboration on Traumatic Stress (GC-TS) (nGC-TS = 1,268) and actively via Amazon’s MTurk (nMTurk = 1,378). Exploratory factor analysis, correlational analysis, sensitivity and specificity analysis, and comparisons in response between the two samples and between male and female respondents were conducted. Results: Exploratory factor analysis revealed a single factor underlying symptom endorsements in both samples, suggesting that such problems may form a unitary transdiagnostic, posttraumatic outcome. Convergent validity of the GPS symptom and risk factors was established with measures of PTSD and dissociative symptoms in the MTurk sample. Gender differences were seen primarily at the item level with women more often endorsing several symptoms and specific risk factors in the MTurk sample, and the GC-TS recruited sample endorsed more symptoms and risk factors than the MTurk sample, suggesting that the GPS may be sensitive to group differences. A GPS symptom cut-off score of 8 identified optimized sensitivity and specificity relative to probable PTSD based on PCL-5 scores. Conclusions: The current results provide preliminary support for the validity of the GPS as a screener for the concurrent measurement of several transdiagnostic outcomes of potentially traumatic stressors and the apparent unifactorial structure of such symptoms is suggestive of a single or unitary posttraumatic outcome. Future research is needed to evaluate whether similarly strong psychometric properties can be yielded in response to completion of the GPS in other languages.
- Published
- 2021
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36. Validation and cross-cultural comparisons of the German Childhood Attachment and Relational Trauma Screen (CARTS)
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Louisa Leuchter, Paul Frewen, and Brigitte Lueger-Schuster
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child maltreatment ,attachment ,carts ,microsystem ,childhood trauma ,validation ,Psychiatry ,RC435-571 - Abstract
Background: Child maltreatment is embedded in a complex system of familial, societal and cultural influences. However, the microsystemic framework in which child maltreatment occurs has not been sufficiently accounted for in previous measures of trauma history. In order to include this relational context, a novel survey method, the Childhood Attachment and Relational Trauma Screen (CARTS), was developed, focusing specifically on the familial environment and childhood attachment relationships. Prior validation studies of the English and Italian versions of the CARTS have tended to support its use. Objective: The current study aims at evaluating the psychometric properties of the German version of the CARTS as well as conducting cross-cultural comparison analyses. It is part of an international research project of the Global Collaboration on Traumatic Stress which was initiated by the International Society for Traumatic Stress Studies (ISTSS). Method: The sample consisted of n = 140 participants from the German general population aged 18 or older. Further trauma specific measures (GPS, BSI-18, CTQ-SF, ECR-R, PBI) were included for validation. Cross-cultural comparisons were conducted with a German subsample of students in reference to Italian- and English-speaking student samples. Results: Most CARTS subscales showed acceptable internal consistency. Statistically significant relationships were observed with other measures of childhood trauma exposure and parental bonding, as well as PTSD- and other distress-related outcomes. Comparing the German-speaking sample with Italian- and English-speaking samples indicated significant differences with regard to childhood attachment and child maltreatment. Conclusion: The present findings are consistent with previous results concerning the CARTS and advance the validation of this novel survey method within German-speaking samples. Further, the CARTS appears to be sensitive to cross-sample differences in childhood attachment and child maltreatment. Further psychometric evaluations of the CARTS in other languages and within further German-speaking samples are needed.
- Published
- 2021
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37. Peripersonal Space and Bodily Self-Consciousness: Implications for Psychological Trauma-Related Disorders
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Daniela Rabellino, Paul A. Frewen, Margaret C. McKinnon, and Ruth A. Lanius
- Subjects
peripersonal space ,bodily self-consciousness ,trauma-related disorders ,neurobiology ,defense response ,multisensory processing ,Neurosciences. Biological psychiatry. Neuropsychiatry ,RC321-571 - Abstract
Peripersonal space (PPS) is defined as the space surrounding the body where we can reach or be reached by external entities, including objects or other individuals. PPS is an essential component of bodily self-consciousness that allows us to perform actions in the world (e.g., grasping and manipulating objects) and protect our body while interacting with the surrounding environment. Multisensory processing plays a critical role in PPS representation, facilitating not only to situate ourselves in space but also assisting in the localization of external entities at a close distance from our bodies. Such abilities appear especially crucial when an external entity (a sound, an object, or a person) is approaching us, thereby allowing the assessment of the salience of a potential incoming threat. Accordingly, PPS represents a key aspect of social cognitive processes operational when we interact with other people (for example, in a dynamic dyad). The underpinnings of PPS have been investigated largely in human models and in animals and include the operation of dedicated multimodal neurons (neurons that respond specifically to co-occurring stimuli from different perceptive modalities, e.g., auditory and tactile stimuli) within brain regions involved in sensorimotor processing (ventral intraparietal sulcus, ventral premotor cortex), interoception (insula), and visual recognition (lateral occipital cortex). Although the defensive role of the PPS has been observed in psychopathology (e.g., in phobias) the relation between PPS and altered states of bodily consciousness remains largely unexplored. Specifically, PPS representation in trauma-related disorders, where altered states of consciousness can involve dissociation from the body and its surroundings, have not been investigated. Accordingly, we review here: (1) the behavioral and neurobiological literature surrounding trauma-related disorders and its relevance to PPS; and (2) outline future research directions aimed at examining altered states of bodily self-consciousness in trauma related-disorders.
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- 2020
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38. Screening for consequences of trauma – an update on the global collaboration on traumatic stress
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Miranda Olff, Anne Bakker, Paul Frewen, Helene Aakvaag, Dean Ajdukovic, Douglas Brewer, Diane L. Elmore Borbon, Marylène Cloitre, Philip Hyland, Nancy Kassam-Adams, Matthias Knefel, Juliana A. Lanza, Brigitte Lueger-Schuster, Angela Nickerson, Misari Oe, Monique C. Pfaltz, Carolina Salgado, Soraya Seedat, Anne Wagner, Ulrich Schnyder, and Global Collaboration on Traumatic Stress (GC-TS)
- Subjects
psychotrauma ,screening ,childhood abuse ,global mental health ,questionnaire ,Psychiatry ,RC435-571 - Abstract
This letter provides an update on the activities of “The Global Collaboration on Traumatic Stress” (GC-TS) as first described by Schnyder et al. in 2017. It presents in further detail the projects of the first theme, in particular the development of and initial data on the Global Psychotrauma Screen (GPS), a brief instrument designed to screen for the wide range of potential outcomes of trauma. English language data and ongoing studies in several languages provide a first indication that the GPS is a feasible, reliable and valid tool, a tool that may be very useful in the current pandemic of the coronavirus disease 2019 (COVID-19). Further multi-language and cross-cultural validation is needed. Since the start of the GC-TS, new themes have been introduced to focus on in the coming years: a) Forcibly displaced persons, b) Global prevalence of stress and trauma related disorders, c) Socio-emotional development across cultures, and d) Collaborating to make traumatic stress research data “FAIR”. The most recent theme added is that of Global crises, currently focusing on COVID-19-related projects.
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- 2020
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39. Screening for psychotrauma related symptoms: Japanese translation and pilot testing of the Global Psychotrauma Screen
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Misari Oe, Yudai Kobayashi, Tetsuya Ishida, Hiromi Chiba, Michiko Matsuoka, Tatsuyuki Kakuma, Paul Frewen, and Miranda Olff
- Subjects
screening ,domestic violence ,anxiety ,depression ,dissociation ,problem drinking ,complex ptsd ,ptsd ,global psychotrauma screen ,Psychiatry ,RC435-571 - Abstract
Background: The impact of traumatic experiences or adverse life experiences has been shown to potentially affect a wide range of mental health outcomes. However, there was no brief instrument to screen for a range of psychological problems in different domains after a potentially traumatic event, and for risk factors and protective factors. Objective: The aim of this study is to examine the internal consistency and concurrent validity of the Japanese version of the Global Psychotrauma Screen (GPS) in a traumatized sample in Japan. Method: A total sample (n = 58) with varying levels of potential posttrauma symptoms due to domestic violence or other events were recruited into this study. Self-rating measures of posttraumatic stress disorder (PTSD), depression, anxiety, and alcohol problems were conducted to investigate the concurrent validity. Results: The results show that a range of posttrauma symptoms assessed by the GPS were highly endorsed by this traumatized sample in all domains except for self-harm, derealization, and depersonalization. The GPS sum score was highly correlated (r > 0.79) with other measures of PTSD, depression, and anxiety symptoms. Also, the subdomain scores showed acceptable correlations with corresponding domain measures. Participants who had been sexually assaulted or had unwanted sexual experiences, and participants who had been physically assaulted during childhood, had higher scores on the total GPS and on subdomains of PTSD, as well as symptoms associated with Complex PTSD. Conclusions: This study provides an initial indication that the GPS may be a useful screening tool for trauma survivors and elucidates that the consequences of trauma are not limited to PTSD.
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- 2020
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40. Trauma- and Stressor-Related History and Symptoms Predict Distress Experienced during a Brief Mindfulness Meditation Sitting: Moving toward Trauma-Informed Care in Mindfulness-Based Therapy
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Zhu, Jenney, Wekerle, Christine, Lanius, Ruth, and Frewen, Paul
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- 2019
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41. Trauma-Related Dissociation Is No Fantasy: Addressing the Errors of Omission and Commission in Merckelbach and Patihis (2018)
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Brand, Bethany L., Dalenberg, Constance J., Frewen, Paul A., Loewenstein, Richard J., Schielke, Hugo J., Brams, Jolie S., and Spiegel, David
- Published
- 2018
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42. Proof of Concept of an Eclectic, Integrative Therapeutic Approach to Mental Health and Well-Being Through Virtual Reality Technology
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Paul Frewen, Divya Mistry, Jenney Zhu, Talia Kielt, Christine Wekerle, Ruth A. Lanius, and Rakesh Jetly
- Subjects
virtual reality ,integrative psychotherapy ,posttraumatic stress disorder (PTSD) ,dissociative experiences ,wellbeing ,positive affect (PA) ,Psychology ,BF1-990 - Abstract
Across three studies, we provide a proof-of-concept evaluation of an integrative psychotherapeutic application of virtual reality (VR) technology. Study 1 (n = 36) evaluated an unguided “safe-place” imagery task, where participants were instructed “to create a safe space… [such as] a scene, item, design, or any visual representation that makes you feel safe” using either the Google Tilt Brush application (VR condition), the standard Microsoft Paint application (2-D condition), or via eyes-closed mental imagery alone (IMG condition). Study 2 (n = 48) evaluated a narrative episodic recall task, where participants viewed their childhood and adult homes and places of schooling either using either the Google Earth VR application (VR condition) or the standard Google Earth application (2-D condition) or recalled these places with their eyes closed via mental imagery alone (IMG condition). Finally, Study 3 (n = 48) evaluated a guided wilderness imagery task, during which different scripts were narrated, specifically, a trail walk in autumn, a spring meadow, and a hillside walk in snowy winter, while either these same scenes were visually presented using the Nature Treks VR application (VR condition), the scenes were presented using the same software but shown on standard computer monitor (2-D condition), or participants’ eyes were closed (IMG condition). Order of intervention format was randomized across participants. Across all three studies, quantitative survey ratings showed that the VR format of intervention delivery produced greater positive affect and satisfaction and perceived credibility ratings as an intervention for trauma- and stressor-related disorders and psychological well-being as rated by university students who varied in traumatic and stressful life event history and symptoms of posttraumatic stress disorder, whereas qualitative findings revealed additional themes of experiential response including increased experience of presence and vividness in the VR condition. Future research directions and clinical applications are discussed.
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- 2020
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43. Processing of Positive Visual Stimuli Before and After Symptoms Provocation in Posttraumatic Stress Disorder – A Functional Magnetic Resonance Imaging Study of Trauma-Affected Male Refugees
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Sigurd W. Uldall, Kristoffer H. Madsen, Hartwig R. Siebner, Ruth Lanius, Paul Frewen, Elvira Fischer, Camilla G. Madsen, Anne-Mette Leffers, Egill Rostrup, Jessica L. Carlsson, and Ayna B. Nejad
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Psychiatry ,RC435-571 - Abstract
Background Symptoms of anhedonia are often central to posttraumatic stress disorder (PTSD), but it is unclear how anhedonia is affected by processes induced by reliving past traumatic memories. Methods Sixty-nine male refugees (PTSD = 38) were interviewed and scanned with functional magnetic resonance imaging while viewing positive, neutral and Scrambled Pictures after being read personalized scripts evoking an emotionally neutral memory and a traumatic memory. We further measured postprovocation state symptoms, physiological measures and PTSD symptoms. We tested whether neural activity associated with positive picture viewing in participants with PTSD was differentially affected by symptom provocation compared to controls. Results For the pictures > scrambled contrast (Positive contrast), PTSD participants had significantly less activity than controls in fusiform gyrus, right inferior temporal gyrus and left middle occipital gyrus. The Positive contrast activity in fusiform gyrus scaled negatively with anhedonia symptoms in PTSD participants after controlling for total PTSD severity. Relative to the emotionally Neutral Script, the Trauma Script decreased positive picture viewing activity in posterior cingulate cortex, precuneus and left calcarine gyrus, but there was no difference between PTSD participants and controls. Conclusions We found reduced responsiveness of higher visual processing of emotionally positive pictures in PTSD. The significant correlation found between positive picture viewing activity and anhedonia suggests the reduced responsiveness to be due to the severity of anhedonia.
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- 2020
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44. A randomized, controlled trial of alpha-rhythm EEG neurofeedback in posttraumatic stress disorder: A preliminary investigation showing evidence of decreased PTSD symptoms and restored default mode and salience network connectivity using fMRI
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Andrew A. Nicholson, Tomas Ros, Maria Densmore, Paul A. Frewen, Richard W.J. Neufeld, Jean Théberge, Rakesh Jetly, and Ruth A. Lanius
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PTSD ,Neurofeedback ,fMRI ,Connectivity ,Default mode network ,Salience network ,Computer applications to medicine. Medical informatics ,R858-859.7 ,Neurology. Diseases of the nervous system ,RC346-429 - Abstract
Objective: The default-mode network (DMN) and salience network (SN) have been shown to display altered connectivity in posttraumatic stress disorder (PTSD). Restoring aberrant connectivity within these networks with electroencephalogram neurofeedback (EEG-NFB) has been shown previously to be associated with acute decreases in symptoms. Here, we conducted a double-blind, sham-controlled randomized trial of alpha-rhythm EEG-NFB in participants with PTSD (n = 36) over 20-weeks. Our aim was to provide mechanistic evidence underlying clinical improvements by examining changes in network connectivity via fMRI. Methods: We randomly assigned participants with a primary diagnosis of PTSD to either the experimental group (n = 18) or sham-control group (n = 18). We collected resting-state fMRI scans pre- and post-NFB intervention, for both the experimental and sham-control PTSD groups. We further compared baseline brain connectivity measures pre-NFB to age-matched healthy controls (n = 36). Results: With regard to the primary outcome measure of PTSD severity, we found a significant main effect of time in the absence of a group × time interaction. Nevertheless, we found significantly decreased PTSD severity scores in the experimental NFB group only, when comparing post-NFB (dz = 0.71) and 3-month follow-up scores (dz = 0.77) to baseline measures. Interestingly, we found evidence to suggest a shift towards normalization of DMN and SN connectivity post-NFB in the experimental group only. Both decreases in PTSD severity and NFB performance were correlated to DMN and SN connectivity post-NFB in the experimental group. Critically, remission rates of PTSD were significant higher in the experimental group (61.1%) as compared to the sham-control group (33.3%). Conclusion: The current study shows mechanistic evidence for therapeutic changes in DMN and SN connectivity that are known to be associated with PTSD psychopathology with no patient dropouts. This preliminary investigation merits further research to demonstrate fully the clinical efficacy of EEG-NFB as an adjunctive therapy for PTSD.
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- 2020
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45. The hijacked self: Disrupted functional connectivity between the periaqueductal gray and the default mode network in posttraumatic stress disorder using dynamic causal modeling
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Braeden A. Terpou, Maria Densmore, Jean Théberge, Paul Frewen, Margaret C. McKinnon, Andrew A. Nicholson, and Ruth A. Lanius
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Posttraumatic stress disorder ,Dynamic causal modeling ,Periaqueductal gray ,Default mode network ,Trauma ,Computer applications to medicine. Medical informatics ,R858-859.7 ,Neurology. Diseases of the nervous system ,RC346-429 - Abstract
Self-related processes define assorted self-relevant or social-cognitive functions that allow us to gather insight and to draw inferences related to our own mental conditions. Self-related processes are mediated by the default mode network (DMN), which, critically, shows altered functionality in individuals with posttraumatic stress disorder (PTSD). In PTSD, the midbrain periaqueductal gray (PAG) demonstrates stronger functional connectivity with the DMN [i.e., precuneus (PCN), medial prefrontal cortex (mPFC)] as compared to healthy individuals during subliminal, trauma-related stimulus processing. Here, we analyzed the directed functional connectivity between the PAG and the PCN, as well as between the PAG and the mPFC to more explicitly characterize the functional connectivity we have observed previously on the corresponding sample and paradigm. We evaluated three models varying with regard to context-dependent modulatory directions (i.e., bi-directional, bottom-up, top-down) among individuals with PTSD (n = 26) and healthy participants (n = 20), where Bayesian model selection was used to identify the most optimal model for each group. We then compared the effective connectivity strength for each parameter across the models and between our groups using Bayesian model averaging. Bi-directional models were found to be favoured across both groups. In PTSD, we revealed the PAG to show stronger excitatory effective connectivity to the PCN, as well as to the mPFC as compared to controls. In PTSD, we further demonstrated that PAG-mediated effective connectivity to the PCN, as well as to the mPFC were modulated more strongly during subliminal, trauma-related stimulus conditions as compared to controls. Clinical disturbances towards self-related processes are reported widely by participants with PTSD during trauma-related stimulus processing, where altered functional connectivity directed by the PAG to the DMN may elucidate experiential links between self- and trauma-related processing in traumatized individuals.
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- 2020
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46. Classifying heterogeneous presentations of PTSD via the default mode, central executive, and salience networks with machine learning
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Andrew A. Nicholson, Sherain Harricharan, Maria Densmore, Richard W.J. Neufeld, Tomas Ros, Margaret C. McKinnon, Paul A. Frewen, Jean Théberge, Rakesh Jetly, David Pedlar, and Ruth A. Lanius
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Computer applications to medicine. Medical informatics ,R858-859.7 ,Neurology. Diseases of the nervous system ,RC346-429 - Abstract
Intrinsic connectivity networks (ICNs), including the default mode network (DMN), the central executive network (CEN), and the salience network (SN) have been shown to be aberrant in patients with posttraumatic stress disorder (PTSD). The purpose of the current study was to a) compare ICN functional connectivity between PTSD, dissociative subtype PTSD (PTSD+DS) and healthy individuals; and b) to examine the use of multivariate machine learning algorithms in classifying PTSD, PTSD+DS, and healthy individuals based on ICN functional activation. Our neuroimaging dataset consisted of resting-state fMRI scans from 186 participants [PTSD (n = 81); PTSD + DS (n = 49); and healthy controls (n = 56)]. We performed group-level independent component analyses to evaluate functional connectivity differences within each ICN. Multiclass Gaussian Process Classification algorithms within PRoNTo software were then used to predict the diagnosis of PTSD, PTSD+DS, and healthy individuals based on ICN functional activation. When comparing the functional connectivity of ICNs between PTSD, PTSD+DS and healthy controls, we found differential patterns of connectivity to brain regions involved in emotion regulation, in addition to limbic structures and areas involved in self-referential processing, interoception, bodily self-consciousness, and depersonalization/derealization. Machine learning algorithms were able to predict with high accuracy the classification of PTSD, PTSD+DS, and healthy individuals based on ICN functional activation. Our results suggest that alterations within intrinsic connectivity networks may underlie unique psychopathology and symptom presentation among PTSD subtypes. Furthermore, the current findings substantiate the use of machine learning algorithms for classifying subtypes of PTSD illness based on ICNs.
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- 2020
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47. Overlapping frontoparietal networks in response to oculomotion and traumatic autobiographical memory retrieval: implications for eye movement desensitization and reprocessing
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Sherain Harricharan, Margaret C. McKinnon, Mischa Tursich, Maria Densmore, Paul Frewen, Jean Théberge, Bessel van der Kolk, and Ruth A. Lanius
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post-traumatic stress disorder ,eye movement desensitization and reprocessing ,emotion regulation ,oculomotion ,autobiographical memory ,Psychiatry ,RC435-571 - Abstract
Background: Oculomotor movements have been shown to aid in the retrieval of episodic memories, serving as sensory cues that engage frontoparietal brain regions to reconstruct visuospatial details of a memory. Frontoparietal brain regions not only are involved in oculomotion, but also mediate, in part, the retrieval of autobiographical episodic memories and assist in emotion regulation. Objective: We sought to investigate how oculomotion influences retrieval of traumatic memories by examining patterns of frontoparietal brain activation during autobiographical memory retrieval in post-traumatic stress disorder (PTSD) and in healthy controls. Method: Thirty-nine participants (controls, n = 19; PTSD, n = 20) recollected both neutral and traumatic/stressful autobiographical memories while cued simultaneously by horizontal and vertical oculomotor stimuli. The frontal (FEF) and supplementary (SEF) eye fields were used as seed regions for psychophysiological interaction analyses in SPM12. Results: As compared to controls, upon retrieval of a traumatic/stressful memory while also performing simultaneous horizontal eye movements, PTSD showed: i) increased SEF and FEF connectivity with the right dorsolateral prefrontal cortex, ii) increased SEF connectivity with the right dorsomedial prefrontal cortex, and iii) increased SEF connectivity with the right anterior insula. By contrast, as compared to PTSD, upon retrieval of a traumatic/stressful memory while also performing simultaneous horizontal eye movements, controls showed: i) increased FEF connectivity with the right posterior insula and ii) increased SEF connectivity with the precuneus. Conclusions: These findings provide a neurobiological account for how oculomotion may influence the frontoparietal cortical representation of traumatic memories. Implications for eye movement desensitization and reprocessing are discussed.
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- 2019
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48. Lifetime traumatic stressors and adverse childhood experiences uniquely predict concurrent PTSD, complex PTSD, and dissociative subtype of PTSD symptoms whereas recent adult non-traumatic stressors do not: results from an online survey study
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Paul Frewen, Jenney Zhu, and Ruth Lanius
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ptsd ,dissociation ,trauma ,stress ,adverse childhood experiences (ace) ,Psychiatry ,RC435-571 - Abstract
This retrospective survey study compared the differential risk of lifetime traumatic stressors, so-called “non-traumatic stressors” experienced over the past year, referring to life events that do not meet the criteria for A1 traumatic events, and adverse childhood experiences (ACE) on severity of DSM-5 versus ICD-11 PTSD, Complex PTSD (CPTSD), and dissociative subtype of PTSD (D-PTSD) symptoms among 418 participants recruited online. In pairwise analyses, all stress types were associated with all outcomes. However, multiple regression and factor analyses indicated that whereas the number of different lifetime traumatic events participants reported experiencing, together with the number of ACE participants experienced, uniquely predicted DSM-5 PTSD, D-PTSD and ICD-11 PTSD and CPTSD symptoms, the number of non-traumatic stressors they experienced during the last year did not. Moreover, ACE uniquely predicted all outcomes even after accounting for lifetime traumatic stress. These results provide further support for the particularly high risk of lifetime traumatic stressors and ACE in predicting trauma and stressor-related symptoms. Future research directions are discussed.
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- 2019
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49. The Threatful Self: Midbrain Functional Connectivity to Cortical Midline and Parietal Regions During Subliminal Trauma-Related Processing in PTSD
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Braeden A. Terpou, Maria Densmore, Jean Théberge, Janine Thome, Paul Frewen, Margaret C. McKinnon, and Ruth A. Lanius
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Psychiatry ,RC435-571 - Abstract
Background The innate alarm system consists of a subcortical network of interconnected midbrain, lower brainstem, and thalamic nuclei, which together mediate the detection of evolutionarily-relevant stimuli. The periaqueductal gray is a midbrain structure innervated by the innate alarm system that coordinates the expression of defensive states following threat detection. In participants with post-traumatic stress disorder, the periaqueductal gray displays overactivation during the subliminal presentation of trauma-related stimuli as well as altered resting-state functional connectivity. Aberrant functional connectivity is also reported in post-traumatic stress disorder for the default-mode network, a large-scale brain network recruited during self-referential processing and autobiographical memory. Here, research lacks investigation on the extent to which functional interactions are displayed between the midbrain and the large-scale cortical networks in post-traumatic stress disorder. Methods Using a subliminal threat presentation paradigm, we investigated psycho-physiological interactions during functional neuroimaging in participants with post-traumatic stress disorder (n = 26) and healthy control subjects (n = 20). Functional connectivity of the periaqueductal gray was investigated across the whole-brain of each participant during subliminal exposure to trauma-related and neutral word stimuli. Results As compared to controls during subliminal threat presentation, the post-traumatic stress disorder group showed significantly greater periaqueductal gray functional connectivity with regions of the default-mode network (i.e., angular gyrus, precuneus, superior frontal gyrus). Moreover, multiple regression analyses revealed that the functional connectivity between the periaqueductal gray and the regions of the default-mode network correlated positively to symptoms of avoidance and state dissociation in post-traumatic stress disorder. Conclusion Given that the periaqueductal gray engages the expression of defensive states, stronger midbrain functional coupling with the default-mode network may have clinical implications to self-referential and trauma-related processing in participants with post-traumatic stress disorder.
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- 2019
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50. Assessing Post-Traumatic Tonic Immobility Responses: The Scale for Tonic Immobility Occurring Post-Trauma
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Chantelle S. Lloyd, Ruth A. Lanius, Matthew F. Brown, Richard J. Neufeld, Paul A. Frewen, and Margaret C. McKinnon
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Psychiatry ,RC435-571 - Abstract
Background Peri-traumatic tonic immobility has been associated with the development and course of post-traumatic stress disorder. Despite serving as an adaptive late-stage defense response, tonic immobility that continues in response to post-traumatic reminders may lead to reduced functioning and a diminished sense of well-being. At present, no validated self-report measures assess post-traumatic tonic immobility responses specifically. Methods The primary objective of the present study was to evaluate the Scale for Tonic immobility Occurring Post-trauma (STOP), the first self-report measure developed to assess for the presence and severity of tonic immobility responses that persist following trauma exposure as part of post-traumatic symptomatology. Trauma-exposed clinical and non-clinical participants ( N = 462) with a history of tonic immobility completed a demographic questionnaire, the STOP, and measures of post-traumatic symptoms, dissociation, anxiety, and depression. Results STOP assessed four latent constructs, which were interpreted following the human defense cascade model. Together, these factors capture the sensorimotor and perceptual alterations , and dissociative experiences, associated with post-traumatic tonic immobility as a trauma-related altered state. Residual symptoms and the experience of negative affect following this response (including guilt and shame) are also represented. STOP scores demonstrated excellent reliability, as well as good construct and convergent validity, with other measures of dissociation and post-traumatic stress disorder. Results from the present study suggest tonic immobility is most consistent with other dissociative post-traumatic symptomatology. Conclusions STOP demonstrates excellent preliminary psychometric properties and may be useful for researchers and clinicians wishing to assess chronic forms of tonic immobility across trauma-exposed, clinical and community samples.
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- 2019
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