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1,153 results on '"Graff‐Guerrero, Ariel"'

251. F6. Is it Possible to Elicit Progressive Functioning Decline Without Having Beta-Amyloid Pathology? Clinical Trajectories of Mild Cognitive Impairment With Suspected Non-Alzheimer's Pathology

Author

Chung, Jun Ku, primary, Plitman, Eric, additional, Nakajima, Shinichiro, additional, Caravaggio, Fernando, additional, Shinagawa, Shunichiro, additional, Iwata, Yusuke, additional, Gerretsen, Philip, additional, Kim, Julia, additional, Takeuchi, Hiroyoshi, additional, Patel, Raihaan, additional, Chakravarty, Mallar, additional, Strafella, Antonio, additional, and Graff-Guerrero, Ariel, additional

Published
2018
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252. S175. AMOTIVATION IS ASSOCIATED WITH SMALLER VENTRAL STRIATUM VOLUMES IN OLDER PATIENTS WITH SCHIZOPHRENIA

Author

Caravaggio, Fernando, primary, Fervaha, Gagan, additional, Iwata, Yusuke, additional, Plitman, Eric, additional, Chung, Jun Ku, additional, Nakajima, Shinichiro, additional, Mar, Wanna, additional, Gerretsen, Philip, additional, Kim, Julia, additional, Chakravarty, Mallar, additional, Mulsant, Benoit, additional, Pollock, Bruce, additional, Mamo, David, additional, Remington, Gary, additional, and Graff-Guerrero, Ariel, additional

Published
2018
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253. F178. NEUROANATOMICAL PROFILES OF TREATMENT-RESISTANCE IN PATIENTS WITH SCHIZOPHRENIA

Author

Plitman, Eric, primary, Iwata, Yusuke, additional, Nakajima, Shinichiro, additional, Chung, Jun Ku, additional, Patel, Raihaan, additional, Caravaggio, Fernando, additional, Kim, Julia, additional, De Luca, Vincenzo, additional, Chavez, Sofia, additional, Remington, Gary, additional, Mallar Chakravarty, M, additional, Gerretsen, Philip, additional, and Graff-Guerrero, Ariel, additional

Published
2018
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255. S16. GLUTAMATERGIC NEUROMETABOLITE LEVELS IN PATIENTS WITH TREATMENT-RESISTANT SCHIZOPHRENIA: A CROSS-SECTIONAL 3T PROTON MRS STUDY

Author

Iwata, Yusuke, primary, Nakajima, Shinichiro, additional, Plitman, Eric, additional, Chung, Jun Ku, additional, Caravaggio, Fernando, additional, Kim, Julia, additional, Brown, Eric, additional, Chan, Nathan, additional, Shah, Parita, additional, Chavez, Sofia, additional, Gerretsen, Philip, additional, Mimura, Masaru, additional, Remington, Gary, additional, and Graff-Guerrero, Ariel, additional

Published
2018
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256. BASIS: The blood pressure awareness and insight scale

Author

Gerretsen, Philip, primary, Kim, Julia, additional, Shah, Parita, additional, Quilty, Lena, additional, Balakumar, Thushanthi, additional, Caravaggio, Fernando, additional, Plitman, Eric, additional, Chung, Jun Ku, additional, Iwata, Yusuke, additional, Pollock, Bruce G., additional, Dash, Satya, additional, Sockalingam, Sanjeev, additional, and Graff-Guerrero, Ariel, additional

Published
2018
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257. Prefrontal and Striatal Gamma-Aminobutyric Acid Levels and the Effect of Antipsychotic Treatment in First-Episode Psychosis Patients

Author

de la Fuente-Sandoval, Camilo, primary, Reyes-Madrigal, Francisco, additional, Mao, Xiangling, additional, León-Ortiz, Pablo, additional, Rodríguez-Mayoral, Oscar, additional, Jung-Cook, Helgi, additional, Solís-Vivanco, Rodolfo, additional, Graff-Guerrero, Ariel, additional, and Shungu, Dikoma C., additional

Published
2018
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259. Amotivation is associated with smaller ventral striatum volumes in older patients with schizophrenia.

Author

Caravaggio, Fernando, Fervaha, Gagan, Iwata, Yusuke, Plitman, Eric, Chung, Jun Ku, Nakajima, Shinichiro, Mar, Wanna, Gerretsen, Philip, Kim, Julia, Chakravarty, M. Mallar, Mulsant, Benoit, Pollock, Bruce, Mamo, David, Remington, Gary, Graff‐Guerrero, Ariel, and Graff-Guerrero, Ariel

Subjects
SCHIZOPHRENIA treatment, PEOPLE with schizophrenia, OLDER patients, ANTIPSYCHOTIC agents, POSITRON emission tomography
Abstract

Objective: Motivational deficits are prevalent in patients with schizophrenia, persist despite antipsychotic treatment, and predict long-term outcomes. Evidence suggests that patients with greater amotivation have smaller ventral striatum (VS) volumes. We wished to replicate this finding in a sample of older, chronically medicated patients with schizophrenia. Using structural imaging and positron emission tomography, we examined whether amotivation uniquely predicted VS volumes beyond the effects of striatal dopamine D2/3 receptor (D2/3 R) blockade by antipsychotics.Methods: Data from 41 older schizophrenia patients (mean age: 60.2 ± 6.7; 11 female) were reanalysed from previously published imaging data. We constructed multivariate linear stepwise regression models with VS volumes as the dependent variable and various sociodemographic and clinical variables as the initial predictors: age, gender, total brain volume, and antipsychotic striatal D2/3 R occupancy. Amotivation was included as a subsequent step to determine any unique relationships with VS volumes beyond the contribution of the covariates. In a reduced sample (n = 36), general cognition was also included as a covariate.Results: Amotivation uniquely explained 8% and 6% of the variance in right and left VS volumes, respectively (right: β = -.38, t = -2.48, P = .01; left: β = -.31, t = -2.17, P = .03). Considering cognition, amotivation levels uniquely explained 9% of the variance in right VS volumes (β = -.43, t = -0.26, P = .03).Conclusion: We replicate and extend the finding of reduced VS volumes with greater amotivation. We demonstrate this relationship uniquely beyond the potential contributions of striatal D2/3 R blockade by antipsychotics. Elucidating the structural correlates of amotivation in schizophrenia may help develop treatments for this presently irremediable deficit. [ABSTRACT FROM AUTHOR]

Published
2018
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264. Effect of agitation and aggression on quality of life in patients with dementia.

Author

Choudhury, Samira, Leventhal, Natalie, Soffer, Matan, Zarei, Shadi, Burhan, Amer M., Colman, Sarah, Chu, Li, Davies, Simon, Derkach, Peter, Elmi, Sarah, Gerretsen, Philip, Graff‐Guerrero, Ariel, Hussain, Maria, Ismail, Zahinoor, Kim, Donna, Krisman, Linda, Moghabghab, Rola, Mulsant, Benoit H., Nair, Vasavan, and Pollock, Bruce G.

Abstract

Background: Behavioral and psychological symptoms of dementia (BPSD) are highly prevalent in patients with dementia during the course of the disease. Among BPSD symptoms, agitation and aggression are a source of distress for both the patients and their caregivers. In this study, we investigated the impact of agitation and aggression on Quality of Life (QoL) of patients with dementia living in long‐term care homes or admitted to psychiatric inpatient units. Method: Data were obtained from the Standardizing Care for Neuropsychiatric Symptoms and Quality of Life in Dementia (StaN) study, a multisite trial conducted in Canada. Agitation and aggression were assessed with the Cohen‐Mansfield Agitation Inventory (CMAI) and the Neuropsychiatric Inventory Clinician rating scale (NPI‐C); QoL with the informant‐rated Alzheimer's Disease Related Quality of Life (ADRQL) tool; stage of dementia with the Functional Assessment Staging Tool (FAST); and burden of physical illness with the Cumulative Illness Rating Scale‐Geriatric (CIRS‐G). Regressions were performed to investigate the associations between agitation or aggression and QoL controlling for demographic factors, FAST score, and CIRS‐G score. Result: 179 participants were included (52.5% female; mean (SD) age = 80.79 (9.45) years. The ADRQL score was correlated with: (1) CMAI total frequency score (Pearson's r = ‐.333, p<.001); (2) NPI‐C agitation score (Pearson's r = ‐.209, p =.005); and (3) NPI‐C aggression score (Pearson's r = ‐.300, p<.001). The associations remained significant for the CMAI total frequency score (β = ‐.235, SE B = 0.054, p<.001), and NPI‐C agitation and aggression composite score (β = ‐.288, SE B = 1.254, p<.001) after controlling for age, sex, current residence, FAST score and CIRS‐G score. Conclusion: QoL is related to agitation and aggression in patients with dementia. The relationship is independent of demographic factors, stage of dementia, and burden of comorbid physical illness. This suggests that better management of agitation and aggression may be an important factor in improving QoL in patients with dementia. [ABSTRACT FROM AUTHOR]

Published
2023
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265. Treatment-Resistant Schizophrenia:Treatment Response and Resistance in Psychosis (TRRIP) Working Group Consensus Guidelines on Diagnosis and Terminology

Author

Howes, Oliver D, McCutcheon, Rob, Agid, Ofer, de Bartolomeis, Andrea, van Beveren, Nico J M, Birnbaum, Michael L, Bloomfield, Michael A P, Bressan, Rodrigo A, Buchanan, Robert W, Carpenter, William T, Castle, David J, Citrome, Leslie, Daskalakis, Zafiris J, Davidson, Michael, Drake, Richard J, Dursun, Serdar, Ebdrup, Bjørn H, Elkis, Helio, Falkai, Peter, Fleischacker, W Wolfgang, Gadelha, Ary, Gaughran, Fiona, Glenthøj, Birte Y, Graff-Guerrero, Ariel, Hallak, Jaime E C, Honer, William G, Kennedy, James, Kinon, Bruce J, Lawrie, Stephen M, Lee, Jimmy, Leweke, F Markus, MacCabe, James H, McNabb, Carolyn B, Meltzer, Herbert, Möller, Hans-Jürgen, Nakajima, Shinchiro, Pantelis, Christos, Reis Marques, Tiago, Remington, Gary, Rossell, Susan L, Russell, Bruce R, Siu, Cynthia O, Suzuki, Takefumi, Sommer, Iris E, Taylor, David, Thomas, Neil, Üçok, Alp, Umbricht, Daniel, Walters, James T R, Kane, John, Howes, Oliver D, McCutcheon, Rob, Agid, Ofer, de Bartolomeis, Andrea, van Beveren, Nico J M, Birnbaum, Michael L, Bloomfield, Michael A P, Bressan, Rodrigo A, Buchanan, Robert W, Carpenter, William T, Castle, David J, Citrome, Leslie, Daskalakis, Zafiris J, Davidson, Michael, Drake, Richard J, Dursun, Serdar, Ebdrup, Bjørn H, Elkis, Helio, Falkai, Peter, Fleischacker, W Wolfgang, Gadelha, Ary, Gaughran, Fiona, Glenthøj, Birte Y, Graff-Guerrero, Ariel, Hallak, Jaime E C, Honer, William G, Kennedy, James, Kinon, Bruce J, Lawrie, Stephen M, Lee, Jimmy, Leweke, F Markus, MacCabe, James H, McNabb, Carolyn B, Meltzer, Herbert, Möller, Hans-Jürgen, Nakajima, Shinchiro, Pantelis, Christos, Reis Marques, Tiago, Remington, Gary, Rossell, Susan L, Russell, Bruce R, Siu, Cynthia O, Suzuki, Takefumi, Sommer, Iris E, Taylor, David, Thomas, Neil, Üçok, Alp, Umbricht, Daniel, Walters, James T R, and Kane, John

Abstract

OBJECTIVE: Research and clinical translation in schizophrenia is limited by inconsistent definitions of treatment resistance and response. To address this issue, the authors evaluated current approaches and then developed consensus criteria and guidelines.METHOD: A systematic review of randomized antipsychotic clinical trials in treatment-resistant schizophrenia was performed, and definitions of treatment resistance were extracted. Subsequently, consensus operationalized criteria were developed through 1) a multiphase, mixed methods approach, 2) identification of key criteria via an online survey, and 3) meetings to achieve consensus.RESULTS: Of 2,808 studies identified, 42 met inclusion criteria. Of these, 21 studies (50%) did not provide operationalized criteria. In the remaining studies, criteria varied considerably, particularly regarding symptom severity, prior treatment duration, and antipsychotic dosage thresholds; only two studies (5%) utilized the same criteria. The consensus group identified minimum and optimal criteria, employing the following principles: 1) current symptoms of a minimum duration and severity determined by a standardized rating scale; 2) moderate or worse functional impairment; 3) prior treatment consisting of at least two different antipsychotic trials, each for a minimum duration and dosage; 4) systematic monitoring of adherence and meeting of minimum adherence criteria; 5) ideally at least one prospective treatment trial; and 6) criteria that clearly separate responsive from treatment-resistant patients.CONCLUSIONS: There is considerable variation in current approaches to defining treatment resistance in schizophrenia. The authors present consensus guidelines that operationalize criteria for determining and reporting treatment resistance, adequate treatment, and treatment response, providing a benchmark for research and clinical translation.

Published
2017

269. Amotivation is associated with smaller ventral striatum volumes in older patients with schizophrenia

Author

Caravaggio, Fernando, primary, Fervaha, Gagan, additional, Iwata, Yusuke, additional, Plitman, Eric, additional, Chung, Jun Ku, additional, Nakajima, Shinichiro, additional, Mar, Wanna, additional, Gerretsen, Philip, additional, Kim, Julia, additional, Chakravarty, M. Mallar, additional, Mulsant, Benoit, additional, Pollock, Bruce, additional, Mamo, David, additional, Remington, Gary, additional, and Graff-Guerrero, Ariel, additional

Published
2017
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272. The relationship between subcortical brain volume and striatal dopamine D2/3receptor availability in healthy humans assessed with [11C]-raclopride and [11C]-(+)-PHNO PET

Author

Caravaggio, Fernando, primary, Ku Chung, Jun, additional, Plitman, Eric, additional, Boileau, Isabelle, additional, Gerretsen, Philip, additional, Kim, Julia, additional, Iwata, Yusuke, additional, Patel, Raihaan, additional, Chakravarty, M. Mallar, additional, Remington, Gary, additional, and Graff-Guerrero, Ariel, additional

Published
2017
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273. Intranasal oxytocin does not modulate jumping to conclusions in schizophrenia: Potential interactions with caudate volume and baseline social functioning

Author

Caravaggio, Fernando, primary, Gerretsen, Philip, additional, Mar, Wanna, additional, Chung, Jun Ku, additional, Plitman, Eric, additional, Nakajima, Shinichiro, additional, Kim, Julia, additional, Iwata, Yusuke, additional, Patel, Raihaan, additional, Chakravarty, M. Mallar, additional, Remington, Gary, additional, Graff-Guerrero, Ariel, additional, and Menon, Mahesh, additional

Published
2017
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279. Investigating the effects of norepinephrine α1 receptor blockade on dopamine levels: A pilot PET study with [11C]-(+)-PHNO in controls

Author

Le Foll, Bernard, primary, Thiruchselvam, Thulasi, additional, Lu, Shawna Xiaoyun, additional, Mohammed, Shakira, additional, Mansouri, Esmaeil, additional, Lagzdins, Dina, additional, Nakajima, Shinichiro, additional, Wilson, Alan A., additional, Graff-Guerrero, Ariel, additional, Di Ciano, Patricia, additional, and Boileau, Isabelle, additional

Published
2017
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280. Structural and Clinical Trajectories of Mild Cognitive Impairment with Suspected Non-Amyloid Pathology: A 2-Year Longitudinal Study

Author

Chung, Jun Ku, primary, Plitman, Eric, additional, Nakajima, Shinichiro, additional, Shinagawa, Shunichiro, additional, Iwata, Yusuke, additional, Gerretsen, Philip, additional, Caravaggio, Fernando, additional, Kim, Julia, additional, Patel, Raihaan, additional, Chakravarty, Mallar M., additional, and Graff-Guerrero, Ariel, additional

Published
2017
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282. Impaired illness awareness and leftward visuospatial inattention in schizophrenia are attributable to a common neural deficit – Posterior parietal hemispheric imbalance

Author

Kim, Julia, primary, Plitman, Eric, additional, Nakajima, Shinichiro, additional, Chung, Jun Ku, additional, Alshehri, Youssef, additional, Iwata, Yusuke, additional, Caravaggio, Fernando, additional, Pollock, Bruce G., additional, Pothier, Dave, additional, Graff-Guerrero, Ariel, additional, and Gerretsen, Philip, additional

Published
2017
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283. SU56. Impaired Illness Awareness and Leftward Visuospatial Inattention in Schizophrenia Are Attributable to a Common Neural Deficit—Posterior Parietal Hemispheric Imbalance

Author

Kim, Julia, primary, Plitman, Eric, additional, Nakajima, Shinichiro, additional, Ku Chung, Jun, additional, Alshehri, Youssef, additional, Iwata, Yusuke, additional, Caravaggio, Fernando, additional, Pollock, Bruce, additional, Pothier, Dave, additional, Graff-Guerrero, Ariel, additional, and Gerretsen, Philip, additional

Published
2017
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285. Treatment-Resistant Schizophrenia: Treatment Response and Resistance in Psychosis (TRRIP) Working Group Consensus Guidelines on Diagnosis and Terminology

Author

Howes, Oliver D., primary, McCutcheon, Rob, additional, Agid, Ofer, additional, de Bartolomeis, Andrea, additional, van Beveren, Nico J.M., additional, Birnbaum, Michael L., additional, Bloomfield, Michael A.P., additional, Bressan, Rodrigo A., additional, Buchanan, Robert W., additional, Carpenter, William T., additional, Castle, David J., additional, Citrome, Leslie, additional, Daskalakis, Zafiris J., additional, Davidson, Michael, additional, Drake, Richard J., additional, Dursun, Serdar, additional, Ebdrup, Bjørn H., additional, Elkis, Helio, additional, Falkai, Peter, additional, Fleischacker, W. Wolfgang, additional, Gadelha, Ary, additional, Gaughran, Fiona, additional, Glenthøj, Birte Y., additional, Graff-Guerrero, Ariel, additional, Hallak, Jaime E.C., additional, Honer, William G., additional, Kennedy, James, additional, Kinon, Bruce J., additional, Lawrie, Stephen M., additional, Lee, Jimmy, additional, Leweke, F. Markus, additional, MacCabe, James H., additional, McNabb, Carolyn B., additional, Meltzer, Herbert, additional, Möller, Hans-Jürgen, additional, Nakajima, Shinchiro, additional, Pantelis, Christos, additional, Reis Marques, Tiago, additional, Remington, Gary, additional, Rossell, Susan L., additional, Russell, Bruce R., additional, Siu, Cynthia O., additional, Suzuki, Takefumi, additional, Sommer, Iris E., additional, Taylor, David, additional, Thomas, Neil, additional, Üçok, Alp, additional, Umbricht, Daniel, additional, Walters, James T.R., additional, Kane, John, additional, and Correll, Christoph U., additional

Published
2017
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286. M5. Beta Amyloid Level is not Elevated in Elderly Patients With Schizophrenia: Are There Potential Neuroprotective Effects of Antipsychotics on Beta-Amyloid Pathology?

Author

Chung, Jun Ku, primary, Nakajima, Shinichiro, additional, Plitman, Eric, additional, Caravaggio, Fernando, additional, Gerretsen, Philip, additional, Iwata, Yusuke, additional, Uy, Danielle, additional, Chakravarty, M. Mallar, additional, and Graff-Guerrero, Ariel, additional

Published
2017
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289. M2. Kynurenic Acid in Schizophrenia: A Systematic Review and Meta-analysis

Author

Plitman, Eric, primary, Caravaggio, Fernando, additional, Iwata, Yusuke, additional, Nakajima, Shinichiro, additional, Chung, Jun Ku, additional, Gerretsen, Philip, additional, Kim, Julia, additional, Takeuchi, Hiroyoshi, additional, Chakravarty, M. Mallar, additional, Remington, Gary, additional, and Graff-Guerrero, Ariel, additional

Published
2017
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290. SU84. Neurometabolite Levels in Antipsychotic Naive/Free Patients With Schizophrenia: A Meta-Analysis of 1H-MRS Studies

Author

Iwata, Yusuke, primary, Nakajima, Shinichiro, additional, Plitman, Eric, additional, Mihashi, Yukiko, additional, Caravaggio, Fernando, additional, Chung, Jun Ku, additional, Kim, Julia, additional, Gerretsen, Philip, additional, Mimura, Masaru, additional, Remington, Gary, additional, and Graff-Guerrero, Ariel, additional

Published
2017
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291. Kynurenic Acid in Schizophrenia: A Systematic Review and Meta-analysis

Author

Plitman, Eric, primary, Iwata, Yusuke, additional, Caravaggio, Fernando, additional, Nakajima, Shinichiro, additional, Chung, Jun Ku, additional, Gerretsen, Philip, additional, Kim, Julia, additional, Takeuchi, Hiroyoshi, additional, Chakravarty, M Mallar, additional, Remington, Gary, additional, and Graff-Guerrero, Ariel, additional

Published
2017
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293. Threshold of Dopamine D2/3 Receptor Occupancy for Hyperprolactinemia in Older Patients With Schizophrenia

Author

Iwata, Yusuke, primary, Nakajima, Shinichiro, additional, Caravaggio, Fernando, additional, Suzuki, Takefumi, additional, Uchida, Hiroyuki, additional, Plitman, Eric, additional, Chung, Jun Ku, additional, Mar, Wanna, additional, Gerretsen, Philip, additional, Pollock, Bruce G., additional, Mulsant, Benoit H., additional, Rajji, Tarek K., additional, Mamo, David C., additional, and Graff-Guerrero, Ariel, additional

Published
2016
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294. Neuroimaging findings in treatment-resistant schizophrenia: a systematic review: Lack of neuroimaging correlates of treatment-resistant schizophrenia

Author

Nakajima, Shinichiro, Takeuchi, Hiroyoshi, Plitman, Eric, Fervaha, Gagan, Gerretsen, Philip, Caravaggio, Fernando, Chung, Jun Ku, Iwata, Yusuke, Remington, Gary, and Graff-Guerrero, Ariel

Subjects
Drug Resistance, Schizophrenia, Humans, Neuroimaging, Article, Antipsychotic Agents
Abstract

Recent developments in neuroimaging have advanced the understanding of biological mechanisms underlying schizophrenia. However, neuroimaging correlates of treatment-resistant schizophrenia (TRS) and superior effects of clozapine on TRS remain unclear.Systematic search was performed to identify neuroimaging characteristics unique to TRS and ultra-resistant schizophrenia (i.e. clozapine-resistant [URS]), and clozapine's efficacy in TRS using Embase, Medline, and PsychInfo. Search terms included (schizophreni*) and (resistan* OR refractory OR clozapine) and (ASL OR CT OR DTI OR FMRI OR MRI OR MRS OR NIRS OR PET OR SPECT).25 neuroimaging studies have investigated TRS and effects of clozapine. Only 5 studies have compared TRS and non-TRS, collectively providing no replicated neuroimaging finding specific to TRS. Studies comparing TRS and healthy controls suggest that hypometabolism in the prefrontal cortex, hypermetabolism in the basal ganglia, and structural anomalies in the corpus callosum contribute to TRS. Clozapine may increase prefrontal hypoactivation in TRS although this was not related to clinical improvement; in contrast, evidence has suggested a link between clozapine efficacy and decreased metabolism in the basal ganglia and thalamus.Existing literature does not elucidate neuroimaging correlates specific to TRS or URS, which, if present, might also shed light on clozapine's efficacy in TRS. This said, leads from other lines of investigation, including the glutamatergic system can prove useful in guiding future neuroimaging studies focused on, in particular, the frontocortical-basal ganglia-thalamic circuits. Critical to the success of this work will be precise subtyping of study subjects based on treatment response/nonresponse and the use of multimodal neuroimaging.

Published
2015

295. Levels of glutamatergic neurometabolites in patients with severe treatment-resistant schizophrenia: a proton magnetic resonance spectroscopy study

Author

Tarumi, Ryosuke, Tsugawa, Sakiko, Noda, Yoshihiro, Plitman, Eric, Honda, Shiori, Matsushita, Karin, Chavez, Sofia, Sawada, Kyosuke, Wada, Masataka, Matsui, Mie, Fujii, Shinya, Miyazaki, Takahiro, Chakravarty, M. Mallar, Uchida, Hiroyuki, Remington, Gary, Graff-Guerrero, Ariel, Mimura, Masaru, and Nakajima, Shinichiro

Abstract

Approximately 30% of patients with schizophrenia do not respond to antipsychotics and are thus considered to have treatment-resistant schizophrenia (TRS). To date, only four studies have examined glutamatergic neurometabolite levels using proton magnetic resonance spectroscopy (1H-MRS) in patients with TRS, collectively suggesting that glutamatergic dysfunction may be implicated in the pathophysiology of TRS. Notably, the TRS patient population in these studies had mild-to-moderate illness severity, which is not entirely reflective of what is observed in clinical practice. In this present work, we compared glutamate + glutamine (Glx) levels in the dorsal anterior cingulate cortex (dACC) and caudate among patients with TRS, patients with non-TRS, and healthy controls (HCs), using 3T 1H-MRS (PRESS, TE = 35 ms). TRS criteria were defined by severe positive symptoms (i.e., ≥5 on 2 Positive and Negative Syndrome Scale (PANSS)-positive symptom items or ≥4 on 3 PANSS-positive symptom items), despite standard antipsychotic treatment. A total of 95 participants were included (29 TRS patients [PANSS = 111.2 ± 20.4], 33 non-TRS patients [PANSS = 49.8 ± 13.7], and 33 HCs). dACC Glx levels were higher in the TRS group vs. HCs (group effect: F[2,75] = 4.74, p= 0.011; TRS vs. HCs: p= 0.012). No group differences were identified in the caudate. There were no associations between Glx levels and clinical severity in either patient group. Our results are suggestive of greater heterogeneity in TRS relative to non-TRS with respect to dACC Glx levels, necessitating further research to determine biological subtypes of TRS.

Published
2020
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296. Brain degeneration in Parkinson's disease patients with cognitive decline: a coordinate-based meta-analysis.

Author

Mihaescu, Alexander S., Masellis, Mario, Graff-Guerrero, Ariel, Kim, Jinhee, Criaud, Marion, Cho, Sang Soo, Ghadery, Christine, Valli, Mikaeel, and Strafella, Antonio P.

Subjects
BRAIN, FRONTAL lobe, DISEASE progression, RESEARCH, LIMBIC system, TEMPORAL lobe, META-analysis, RESEARCH methodology, MAGNETIC resonance imaging, COGNITION, EVALUATION research, MEDICAL cooperation, NEUROPSYCHOLOGICAL tests, ATROPHY, COMPARATIVE studies, PARKINSON'S disease, DEMENTIA, RESEARCH funding, CEREBRAL cortex, NEURODEGENERATION, NEURORADIOLOGY
Abstract

Cognitive decline in Parkinson's disease (PD) is a common sequela of the disease, with its severity increasing as the neurodegenerative process advances. The present meta-analysis used anisotropic effect size seed-based d mapping software to perform analyses using both functional and structural brain imaging data. The analyses were between PD patients with mild cognitive impairment (PD-MCI) and PD patients with dementia (PDD) compared to PD cognitively unimpaired patients (PD-CU) and PD patients without dementia (PD-ND) respectively. Thirty-four studies were found and split into three analyses: 405 PD-MCI patients compared to 559 PD-CU patients from 1) 15 studies with structural imaging modalities and 2) eight studies with functional imaging modalities, as well as 178 PDD patients compared to 278 PD-ND patients (which includes both PD-CU and PD-MCI) in 3) 11 studies with structural imaging modalities. Statistical threshold was set to uncorrected p < 0.001. We found several brain regions that differed between PD-MCI and PD-CU patients: the left insula, bilateral dorsolateral prefrontal cortex, left angular gyrus, midcingulate cortex, and right supramarginal gyrus. The brain regions identified in the PD-MCI analyses are associated with the somatosensory network and executive processing. In PDD patients, the bilateral insula and right hippocampus were found as regions of structural atrophy. The insula was found in both structural analyses of PD-MCI and PDD, with unilateral insula involvement in PD-MCI extending to bilateral insula involvement in PDD. The results found both a spectrum of increasing brain atrophy in PD cognitive impairment and supports the existence of sub-typing in PD-MCI. [ABSTRACT FROM AUTHOR]

Published
2019
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297. The Dysregulation of the Glymphatic System in Patients with Psychosis Spectrum Disorders Minimally Exposed to Antipsychotics: La dérégulation du système glymphatique en présence de troubles psychotiques chez des patients peu exposés à des antipsychotiques

Author

Korann, Vittal, Panganiban, Kristoffer J., Stogios, Nicolette, Remington, Gary, Graff-Guerrero, Ariel, Chintoh, Araba, Hahn, Margaret K., and Agarwal, Sri Mahavir

Abstract

Objective The pathophysiological mechanisms influencing psychosis spectrum disorders are largely unknown. The glymphatic system, which is a brain waste clearance pathway, has recently been implicated in its pathophysiology and has also been shown to be disrupted in various neurodegenerative and vascular diseases. Initial studies examining the glymphatic system in psychosis spectrum disorders have reported disruptions, but the findings have been confounded by medication effects as they included antipsychotic-treated patients. In this study, we used diffusion tensor imaging analysis along the perivascular space (DTI-ALPS) as a technique to measure the functionality of the glymphatic system in a sample of antipsychotic-minimally exposed patients with psychosis spectrum disorders and healthy controls.Methods The study included 13 antipsychotic-minimally exposed (2 weeks antipsychotic exposure in the past 3 months/lifetime) patients with psychosis spectrum disorders and 114 healthy controls. We quantified water diffusion metrics along the x-, y-, and z-axes in both projection and association fibres to derive the DTI-ALPS index, a proxy for glymphatic activity. Between-group differences were analyzed using two-way ANCOVA controlling for age and sex. Partial correlations were used to assess the association between the ALPS index and clinical variables.Results Analyses revealed that antipsychotic-minimally exposed psychosis spectrum disorder patients had a lower DTI-ALPS index value than healthy controls in both hemispheres and the whole brain (all P< 0.005). Significant differences were also observed between the xand yprojections/associations between patients and healthy controls (P< 0.001). Furthermore, we did not find any significant correlations (all P> 0.05) between the DTI-ALPS index with age, body mass index, symptomatology, and metabolic parameters.Conclusion This study shows that the glymphatic system is dysregulated in antipsychotic-minimally exposed patients with psychosis spectrum disorders. Understanding the mechanisms that influence the glymphatic system may help to understand the pathophysiology of psychosis spectrum disorders as proper waste clearance is needed for normal brain functioning.

Published
2024
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299. Amyloid deposition in semantic dementia: a positron emission tomography study.

Author

Brown, Eric E., Graff‐Guerrero, Ariel, Houle, Sylvain, Mizrahi, Romina, Wilson, Alan A., Pollock, Bruce G., Mulsant, Benoit H., Felsky, Daniel, Voineskos, Aristotle N., Tang‐Wai, David F., Verhoeff, Nicolaas P. L. G., Freedman, Morris, Ismail, Zahinoor, Chow, Tiffany W., Graff-Guerrero, Ariel, and Tang-Wai, David F

Subjects
*AMYLOID beta-protein, *DEMENTIA, *ALZHEIMER'S disease, *NEURODEGENERATION, *FRONTOTEMPORAL dementia, *AMINES, *CEREBRAL cortex, *PEPTIDES, *THIAZOLES, *POSITRON emission tomography, *CASE-control method
Abstract

Background: Pittsburgh compound B ([11C]-PIB) identifies amyloid-β (Aβ) deposition in vivo. Asymptomatic Aβ deposition has been reported consistently in some healthy older subjects. Of patients with frontotemporal dementia, those who have later onset have a higher potential for Aβ deposition.Objective: Comparison of Aβ deposition in Alzheimer's disease (AD), healthy older controls, and patients with early- and late-onset semantic dementia (SD), a subtype of frontotemporal dementia.Methods: Subjects were recruited from tertiary academic care centers specializing in assessment and management of patients with neurodegenerative disease. We used the radiotracer [11C]-PIB in a high-resolution positron emission tomography scanner to evaluate 11 participants with SD (six with onset before age 65 and five with later onset), 9 with probable AD, and 10 controls over age 60. The main outcome measures were frontal, temporal, parietal, and total [11C]-PIB standardized uptake value ratios to establish PIB-positive (PIB+) cutoff.Results: The five patients with late-onset SD were PIB-negative. Two of six with early-onset SD, seven of nine with AD, and 1 of 10 controls were PIB+. The SD participants who were PIB+ did not have memory or visuospatial deficits that are typical in AD.Conclusions: Aβ deposition does not seem to be associated with late-onset SD. Future larger studies might confirm whether a significant minority of early-onset SD patients exhibit Aβ deposition. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Published
2016
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300. Benzodiazepine Use Attenuates Cortical β-Amyloid and is Not Associated with Progressive Cognitive Decline in Nondemented Elderly Adults: A Pilot Study Using F18-Florbetapir Positron Emission Tomography

Author

Chung, Jun Ku, primary, Nakajima, Shinichiro, additional, Shinagawa, Shunichiro, additional, Plitman, Eric, additional, Chakravarty, M. Mallar, additional, Iwata, Yusuke, additional, Caravaggio, Fernando, additional, Pollock, Bruce G., additional, Gerretsen, Philip, additional, and Graff-Guerrero, Ariel, additional

Published
2016
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