Search

Parkinson's disease (PD) has been associated with greater total power in canonical frequency bands (i.e., alpha, beta) of the resting electroencephalogram (EEG). However, PD has also been associated with a reduction in the proportion of total power across all frequency bands. This discrepancy may be explained by aperiodic activity (exponent and offset) present across all frequency bands. Here, we examined differences in the eyes-open (EO) and eyes-closed (EC) resting EEG of PD participants (N = 26) on and off medication, and age-matched healthy controls (CTL; N = 26). We extracted power from canonical frequency bands using traditional methods (total alpha and beta power) and extracted separate parameters for periodic (parameterized alpha and beta power) and aperiodic activity (exponent and offset). Cluster-based permutation tests over spatial and frequency dimensions indicated that total alpha and beta power, and aperiodic exponent and offset were greater in PD participants, independent of medication status. After removing the exponent and offset, greater alpha power in PD (vs. CTL) was only present in EO recordings and no reliable differences in beta power were observed. Differences between PD and CTL in the resting EEG are likely driven by aperiodic activity, suggestive of greater relative inhibitory neural activity and greater neuronal spiking. Our findings suggest that resting EEG activity in PD is characterized by medication-invariant differences in aperiodic activity which is independent of the increase in alpha power with EO. This highlights the importance of considering aperiodic activity contributions to the neural correlates of brain disorders., (© 2023 The Authors. Psychophysiology published by Wiley Periodicals LLC on behalf of Society for Psychophysiological Research.)

SpecParam (formally known as FOOOF) allows for the refined measurements of electroencephalography periodic and aperiodic activity, and potentially provides a non-invasive measurement of excitation: inhibition balance. However, little is known about the psychometric properties of this technique. This is integral for understanding the usefulness of SpecParam as a tool to determine differences in measurements of cognitive function, and electroencephalography activity. We used intraclass correlation coefficients to examine the test-retest reliability of parameterized activity across three sessions (90 minutes apart and 30 days later) in 49 healthy young adults at rest with eyes open, eyes closed, and during three eyes closed cognitive tasks including subtraction (Math), music recall (Music), and episodic memory (Memory). Intraclass correlation coefficients were good for the aperiodic exponent and offset (intraclass correlation coefficients > 0.70) and parameterized periodic activity (intraclass correlation coefficients > 0.66 for alpha and beta power, central frequency, and bandwidth) across conditions. Across all three sessions, SpecParam performed poorly in eyes open (40% of participants had poor fits over non-central sites) and had poor test-retest reliability for parameterized periodic activity. SpecParam mostly provides reliable metrics of individual differences in parameterized neural activity. More work is needed to understand the suitability of eyes open resting data for parameterization using SpecParam., (© The Author(s) 2023. Published by Oxford University Press.)

New Findings: What is the central question of this study? What is the predictive relationship between self-reported scales to quantify perceptions of fatigue during exercise and gold standard measures used to quantify the development of neuromuscular fatigue? What is the main finding and its importance? No scale was determined to be substantively more effective than another. However, the number of ongoing contractions performed was shown to be a better predictor of fatigue in the motor system than any of the subjective scales., Abstract: The purpose of this study was to determine the relationship between transcranial magnetic stimulation (TMS) measures of performance fatigability and commonly used scales that quantify perceptions of fatigue during exercise. Twenty healthy participants (age 23 ± 3 years, 10 female) performed 10 submaximal isometric elbow flexions at 20% maximal voluntary contraction (MVC) for 2 min, separated by 45 s of rest. Biceps brachii muscle electromyography and elbow flexion torque responses to single-pulse TMS were obtained at the end of each contraction to assess central factors of performance fatigability. A rating of perceived exertion (RPE) scale, Omnibus Resistance scale, Likert scale, Rating of Fatigue scale and a visual analogue scale (VAS) were used to assess perceptions of fatigue at the end of each contraction. The RPE (root mean square error (RMSE) = 0.144) and Rating of Fatigue (RMSE = 0.145) scales were the best predictors of decline in MVC torque, whereas the Likert (RMSE= 0.266) and RPE (RMSE= 0.268) scales were the best predictors of electromyographic amplitude. Although the Likert (RMSE = 7.6) and Rating of Fatigue (RMSE = 7.6) scales were the best predictors of voluntary muscle activation of any scale, the number of contractions performed during the protocol was a better predictor (RMSE = 7.3). The ability of the scales to predict TMS measures of performance fatigability were in general similar. Interestingly, the number of contractions performed was a better predictor of TMS measures than the scales themselves., (© 2023 The Authors. Experimental Physiology published by John Wiley & Sons Ltd on behalf of The Physiological Society.)

The purpose of this study was to assess how severe acute hypoxia alters the neural mechanisms of muscle activation across a wide range of torque output in a fatigued muscle. Torque and electromyography responses to transcranial and motor nerve stimulation were collected from 10 participants (27 years ± 5 years, 1 female) following repeated performance of a sustained maximal voluntary contraction that reduced torque to 60% of the pre-fatigue peak torque. Contractions were performed after 2 h of hypoxic exposure and during a sham intervention. For hypoxia, peripheral blood oxygen saturation was titrated to 80% over a 15-min period and remained at 80% for 2 h. Maximal voluntary torque, electromyography root mean square, voluntary activation and corticospinal excitability (motor evoked potential area) and inhibition (silent period duration) were then assessed at 100%, 90%, 80%, 70%, 50% and 25% of the target force corresponding to the fatigued maximal voluntary contraction. No hypoxia-related effects were identified for voluntary activation elicited during motor nerve stimulation. However, during measurements elicited at the level of the motor cortex, voluntary activation was reduced at each torque output considered (P = .002, η p 2  = .829). Hypoxia did not impact the correlative linear relationship between cortical voluntary activation and contraction intensity or the correlative curvilinear relationship between motor nerve voluntary activation and contraction intensity. No other hypoxia-related effects were identified for other neuromuscular variables. Acute severe hypoxia significantly impairs the ability of the motor cortex to voluntarily activate fatigued muscle across a wide range of torque output., (© 2022 The Authors. European Journal of Neuroscience published by Federation of European Neuroscience Societies and John Wiley & Sons Ltd.)

People with multiple sclerosis (PwMS) typically experience greater levels of exercise-induced fatigue compared with healthy individuals. Therefore, this study examined performance fatigability in PwMS when executing a prolonged submaximal contraction. Nine PwMS (38 ± 7 yr, 6 females) and nine healthy controls (35 ± 6 yr, 4 females) performed an elbow flexion at 15% maximal voluntary contraction (MVC) for 26 min. MVCs were performed every 2 min during, and following, the contraction to determine if maximal force was impaired by the low-intensity contraction. Single-pulse transcranial magnetic stimulation (TMS) was delivered to the primary motor cortex with a circular coil during each MVC and during the submaximal contraction. Superimposed and resting twitches were calculated from elbow flexion torque, whereas motor-evoked potentials were calculated from biceps brachii electromyography. Ratings of perceived exertion (RPE) were obtained before each MVC. During the fatiguing contraction protocol, the MS group exhibited a reduced MVC torque compared with the healthy control group ( P = 0.044), which aligned with group differences in biceps brachii EMG activity ( P = 0.022) and superimposed twitch amplitude ( P = 0.016). Fatigue-related decrements in MVC torque ( P = 0.044) and biceps brachii EMG activity ( P = 0.043) demonstrated in the MS group persisted throughout recovery. However, MS did not affect the RPE during the fatigue task. These findings suggest that PwMS may have greater levels of performance fatigability due to decreased voluntary drive from the motor cortex, which is not associated with greater ratings of perceived exertion. NEW & NOTEWORTHY By combining TMS and motor nerve stimulation during a low-intensity exercise task, we were able to uncover the contribution that different levels of the CNS have during fatiguing exercise in PwMS. Our findings are novel and revealed that PwMS experienced decreased voluntary drive from the motor cortex during a low-intensity sustained fatiguing task that was associated with heightened levels of performance fatigability.

The purpose of this study was to determine how severe acute hypoxia alters neural mechanisms during, and following, a sustained fatiguing contraction. Fifteen participants (25 ± 3.2 years, six female) were exposed to a sham condition and a hypoxia condition where they performed a 10 min elbow flexor contraction at 20% of maximal torque. For hypoxia, peripheral blood oxygen saturation ( S p O 2 ) was titrated to 80% over a 15 min period and maintained for 2 h. Maximal voluntary contraction torque, EMG root mean square, voluntary activation, rating of perceived muscle fatigue, and corticospinal excitability (motor-evoked potential) and inhibition (silent period duration) were then assessed before, during and for 6 min after the fatiguing contraction. No hypoxia-related effects were identified for neuromuscular variables during the fatigue task. However, for recovery, voluntary activation assessed by motor point stimulation of biceps brachii was lower for hypoxia than sham at 4 min (sham: 89% ± 7%; hypoxia: 80% ± 12%; P = 0.023) and 6 min (sham: 90% ± 7%; hypoxia: 78% ± 11%; P = 0.040). Similarly, voluntary activation (P = 0.01) and motor-evoked potential area (P = 0.002) in response to transcranial magnetic stimulation of the motor cortex were 10% and 11% lower during recovery for hypoxia compared to sham, respectively. Although an S p O 2 of 80% did not affect neural activity during the fatiguing task, motor cortical output and corticospinal excitability were reduced during recovery in the hypoxic environment. This was probably due to hypoxia-related mechanisms involving supraspinal motor circuits. KEY POINTS: Acute hypoxia has been shown to impair voluntary activation of muscle and alter the excitability of the corticospinal motor pathway during exercise. However, little is known about how hypoxia alters the recovery of the motor system after performing fatiguing exercise. Here we assessed hypoxia-related responses of motor pathways both during active contractions and during recovery from active contractions, with transcranial magnetic stimulation and motor point stimulation of the biceps brachii. Fatiguing exercise caused reductions in voluntary activation, which was exacerbated during recovery from a 10 min sustained elbow flexion in a hypoxic environment. These results suggest that reductions in blood oxygen concentration impair the ability of motor pathways in the CNS to recover from fatiguing exercise, which is probably due to hypoxia-induced mechanisms that reduce output from the motor cortex., (© 2021 The Authors. The Journal of Physiology © 2021 The Physiological Society.)

Background: The impact on psychosocial health of injectable facial treatments such as hyaluronic acid fillers and botulinum toxin type A remains poorly defined. The aim of this study was to measure changes in psychosocial health following aesthetic intervention with injectables in routine clinical practice using the validated FACE-Q patient-reported outcome measure., Methods: This was a prospective assessment of patients presenting at a single center for the first time for aesthetic treatment of the face with injectables in February 2020. Participants completed 3 FACE-Q scales at the baseline and again 2 weeks posttreatment: Psychological Function; Social Function; and Appearance-related Psychosocial Distress., Results: Complete data were available for 35 individuals (n = 32 women [91%]; mean age: 45.9 ± 13.8 years). Twenty-nine (83%) were treated with hyaluronic acid filler (mean: 2.3 ± 1.3 syringes), and 12 (34%) received onabotulinumtoxinA (mean: 2.0 ± 0.7 areas of the upper face). There were significant improvements on each FACE-Q scale posttreatment: mean change in Psychological Function score was +12.4 [95% CI: 7.9, 16.9; P < 0.001; standardized effect size by Cohen's d : 0.93]; mean change in Social Function score was +7.9 (95% CI: 3.3, 12.5; P = 0.001; effect size: 0.50); and mean change in Appearance-related Psychosocial Distress score was -20.9 (95% CI: -27.4, -14.3; P < 0.001; effect size: 1.27)., Conclusions: Aesthetic treatment with injectables was associated with significant improvements in patient-reported psychological and social functioning and reductions in appearance-related distress. This change underlines the value of these therapies for improving psychosocial health in well-selected patients., Competing Interests: Disclosure: DJM has been a consultant for Allergan., (Copyright © 2021 The Author. Published by Wolters Kluwer Health, Inc. on behalf of The American Society of Plastic Surgeons.)

Cryolipolysis is a nonsurgical body sculpting technique that uses controlled cooling for localized fat reduction. The aim of the present study was to assess whether an intensive regimen of CoolSculpting based on multiple cycles/sessions on the same body area(s) could yield greater (more clinically significant) improvements in body contour. This was a prospective analysis of consecutive, healthy, adult patients undergoing CoolSculpting in routine practice across a variety of treatment areas. Patients underwent ≤4 cycles of CoolSculpting per body area during an initial treatment session, and ≤4 further cycles 4 weeks later (if required). They were followed up for ≥12 weeks. Twenty-eight patients were enrolled (n = 26 female; mean age: 51.6 ± 9.0 years; mean body weight: 69.4 ± 13.7 kg). They were treated across 58 body areas: 48 in a single session; 10 across two sessions. The mean number of cycles per area was 2.8 ± 1.5. Twenty-seven patients (54 body areas) were considered as treatment "responders." In these individuals, mean skinfold thickness decreased from 35.4 ± 9.9 mm pretreatment to 22.2 ± 7.6 mm at 12 weeks (mean change: -40%; P < .001). Mean change in skinfold thickness was greater with ≥3 vs 1 to 2 cycles of CoolSculpting (P = .01). Patient satisfaction was high (n = 51/58; 88%). No adverse events were recorded. The study shows that multiple cycles/sessions of CoolSculpting can safely improve overall treatment benefit in body contouring, with greater decreases in skinfold thickness than have typically been previously observed., (© 2021 The Authors. Dermatologic Therapy published by Wiley Periodicals LLC.)

New Findings: What is the central question of this study? How does acute hypoxia alter central and peripheral fatigue during brief and sustained maximal voluntary muscle contractions? What is the main finding and its importance? Perception of fatigue during muscle contractions was increased progressively for 2 h after hypoxic exposure. However, an increase in motor cortex excitability and a decrease in voluntary activation of skeletal muscle were observed across the entire protocol when performing brief (3 s) maximal contractions. These adaptations were abolished if the brief contraction was held for a duration of 20 s, which was presumably attributable to a successful redistribution of blood to overcome the reduced oxygen content., Abstract: Few studies have examined the time course of changes in the motor system after acute exposure to hypoxia. Thus, the purpose of this study was to examine how acute hypoxia affects corticospinal excitability, voluntary activation (VA) and the perception of fatigue during brief (3 s) and sustained (20 s) maximal voluntary contractions (MVCs). Fourteen healthy individuals (23 ± 2.2 years of age; four female) were exposed to hypoxia and sham conditions. During hypoxia, peripheral blood oxygen saturation was titrated over a 15 min period and remained at 80% during testing. Corticospinal excitability and VA were assessed before titration (Pre), 0, 1 and 2 h after. At each time point, the brief and sustained elbow flexion MVCs were performed. Motor evoked potentials (MEPs) were obtained using transcranial magnetic stimulation. Superimposed and resting twitches were obtained from motor point stimulation of biceps brachii to calculate the level of VA, and ratings of perceived fatigue were obtained with a modified CR-10 Borg scale. A condition-by-time interaction was detected for the CR-10 Borg scale, whereby perception of fatigue increased progressively throughout the hypoxia protocol. However, main effects of MEP area and VA indicated that corticospinal excitability increased, and VA of the biceps brachii decreased, throughout the hypoxia protocol. Given that these changes in MEP area and VA were seen only when performing the brief MVCs (and not during the sustained MVCs), performing longer contractions might overcome reduced oxygen content by redirecting blood flow to active areas of the motor system., (© 2020 The Authors. Experimental Physiology © 2020 The Physiological Society.)

This study aimed to quantify how acute hypoxia impacts firing characteristics of biceps brachii motor units (MUs) during sustained isometric elbow flexions. MU data were extracted from surface electromyography (EMG) during 25% maximal voluntary contractions (MVC) in 10 healthy subjects (age 22 ± 1 yr). Blood oxygen saturation (SpO 2 ) was then stabilized at 80% by reducing 1% of the fraction of inspired oxygen every 3 min for 35 min. MU data were once again collected 1 h and 2 h following the 35-min desaturation phase. Although MVC remained unaffected during 2 h of 80% SpO 2 , subject-specific changes in MU firing rate were observed. Four of 10 subjects exhibited a decrease in firing rate 1 h postdesaturation (12 ± 11%) and 2 h postdesaturation (16 ± 12%), whereas 6 of 10 subjects exhibited an increase in firing rate 1 h (9 ± 6%) and 2 h (9 ± 4%) postdesaturation. These bidirectional changes in firing rate were strongly correlated to the desaturation phase and the subjects' SpO 2 sensitivity to oxygen availability, where subjects who had decreased firing rates reached the target SpO 2 20 min into the desaturation phase ( R 2 = 0.90-0.98) and those who had increased firing rates reached the target SpO 2 35 min into the desaturation phase ( R 2 = 0.87-0.98). It is unlikely that a single mechanism accounted for these subject-specific changes in firing rate. Instead, differences in intrinsic properties of the neurons, afferent input to the motoneurons, neuromodulators, and sympathetic nerve activity may exist between groups. NEW & NOTEWORTHY The mechanisms of compromised motor control when exposed to hypoxia are largely unknown. The current study examined how severe acute hypoxia affects motor unit firing rate during sustained isometric contractions of the bicep brachii. The response to hypoxia was different across subjects, where motor unit firing rate increased for some individuals and decreased for others. This bidirectional change in firing rate was associated with how fast subjects desaturated during hypoxic exposure.

Recent advances in body-worn sensor technology have increased the scope for harnessing quantitative information from the timed-up-and-go test (TUG), well beyond simply the time taken to perform the test. Previous research has shown that the quantitative TUG method can differentiate fallers from non-fallers with greater success than the manually timed TUG or the Berg Balance Test. In order to advance this paradigm of falls risk estimation it is necessary to investigate the robustness of the quantitative TUG variables. This study investigated the inter-session and intra-session reliability of 44 quantitative TUG variables measured from the shanks and lower back of 33 study participants aged between 55-65 yrs. For intra-session reliability, 25 variables demonstrated excellent reliability (ICC>0.75), and 12 demonstrated "fair to good reliability" with ICCs between 0.4 and 0.75. Analysis of test-retest reliability resulted in ICC > 0.75 for 18 out of 44 variables, with 20 variables showing fair to good reliability. Turn time parameters demonstrated poor reliability. We conclude that this is a reliable instrument that may be used as part of a long-term falls risk assessment, with further work required to improve certain turn parameters.

Introduction: The optimal timing of breast reconstruction is controversial. Immediate breast reconstruction (IBR) has been gaining in popularity due to the aesthetic and psychological benefits, although its role is less certain when postoperative radiotherapy may be required. There is some evidence that long term cosmetic outcome of IBR using the autologous latissimus dorsi (ALD) flap may be impaired if the reconstruction is subjected to postoperative radiotherapy. We compared the long term cosmetic outcome and patient satisfaction between a group of patients who underwent IBR with postoperative radiotherapy and a group who underwent delayed ALD reconstruction., Methods: Patients who underwent ALD breast reconstruction between 1997 and 2000 were invited to attend a research clinic. At the clinic up-to-date photographs were obtained and a quality of life questionnaire was completed. Cosmetic outcome was assessed by a panel of judges including surgeons, nurses and lay people., Results: Thirteen patients who had IBR and postoperative radiotherapy and 11 patients who had delayed reconstruction attended for follow up. In the long term both groups fell within an acceptable cosmetic outcome range. However, there was a trend towards a better outcome in patients undergoing delayed reconstruction, with the volume and contour of the upper pole being most affected in the irradiated reconstructions. Patient satisfaction was similar between the two groups, however most patients in retrospect would have preferred an immediate reconstruction., Conclusions: Immediate ALD breast reconstruction, even in the setting of postoperative radiotherapy, yields satisfactory results. We continue to offer it to patients undergoing mastectomy operations, even when postoperative radiotherapy is likely to be required.

Background: The purpose of this study was to assess the effectiveness of the buccal myomucosal flap in secondary repairs of cleft palate., Methods: Twenty-two patients who underwent secondary palatoplasty between 1989 and 2004 in which a buccal myomucosal flap was used were reviewed retrospectively. All patients had undergone at least one previous attempted repair at other institutions. Indications for the secondary repair included velopharyngeal incompetence and/or oronasal fistula. Patients were evaluated preoperatively for oronasal fistula status, velopharyngeal competence, nasal resonance, speech quality, and nasal escape., Results: The buccal myomucosal flap was used in all patients. The patients' mean age was 8.5 years (range, 1 to 23 years). Correction was indicated in seven patients with velopharyngeal incompetence (32 percent), five patients with oronasal fistulas (23 percent), and 10 patients with both conditions (45 percent). Preoperative assessment revealed four patients (18 percent) with an associated syndrome, 17 of 20 patients with hyperresonance (85 percent), 16 of 20 patients with nasal escape (80 percent), and 12 of 20 patients with poor speech (60 percent). The buccal myomucosal flap technique was used alone in 50 percent of patients, six patients had a staged correction (27 percent) and five patients required multiple procedures (23 percent). All fistulas remained closed. Two patients showed mild velopharyngeal incompetence (p = 0.001) and two patients continued to display hyperresonance (p < 0.001). Speech quality improved to a good level in 17 patients (77 percent) (p < 0.001)., Conclusion: Palate re-repair combined with a buccal myomucosal flap, occasionally in conjunction with other techniques, is an effective method for correcting failed cleft palate repairs.

The relationship between circulating C-reactive protein concentrations and potential cytokine and receptor mediators (interleukin-6, leukaemia inhibitory factor (LIF), ciliary neurotrophic factor (CNTF), soluble IL-6 receptor, soluble gp130, soluble TNF receptor, interleukin-1 receptor antagonist and interleukin-8 (IL-8)) of this acute phase protein were examined in healthy subjects (n=11) and patients with non-small-cell lung cancer (n=50). Leukaemia inhibitory factor and CNTF were below detection limits in all controls and patients. C-reactive protein, interleukin-6, soluble gp130, soluble TNF receptor, interleukin-1 receptor antagonist and IL-8 concentrations were significantly elevated in cancer patients (P< or =0.001). Cancer patients with elevated C-reactive protein concentrations had greater concentrations of interleukin-6 (P<0.01) and interleukin-1 receptor antagonist (P<0.05). On regression analysis only interleukin-6 was independently associated with C-reactive protein (r=0.616, P<0.001). Interleukin-6 is an important independent mediator of elevated C-reactive protein concentrations in patients with non-small-cell lung cancer.

A seroepidemiologic hepatitis B survey of students and staff at schools for the mentally retarded in the City of Toronto found 2.5% of students to be carriers, 5% to be immune without being immunized, 11.3% to have immunization underway or complete, and 81.2% to be susceptible. The first two groups were older and more likely to have been born in countries with intermediate or high hepatitis B marker prevalence. Among staff tested, 4.1% were immune without immunization while all others were susceptible. Because hepatitis B control recommendations could not be made on the basis of these results alone, local Medical Officers of Health also considered other studies and practical experience to recommend the following: (1) Use Ontario Ministry of Health Guidelines for mentally retarded hepatitis B carriers in regular schools; (2) Offer hepatitis B vaccine to all susceptible students and staff in schools specifically for the mentally retarded.