Measurement Properties of the Activities-Specific Balance Confidence Scale in Adults From the General Population With Concussion: A Report From the Toronto Concussion Study.

OBJECTIVE: The aim of this study was to establish the internal consistency and construct validity of the Activities-specific Balance Confidence (ABC) Scale and ABC-6 in adults from the general population with concussion. DESIGN: Prospective analysis. SETTING: Outpatient concussion care clinic. PARTICIPANTS: Adults from the general population with concussion referred to a concussion care clinic within 7 days of injury (N=511). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Balance confidence was assessed with the Activities-specific Balance Confidence (ABC) Scale and the ABC-6. Concussion symptoms were characterized using the Sport Concussion Assessment Tool version 5 (SCAT5) symptom checklist. Instrumented measures of balance and gait included center of pressure velocity and double support time, respectively. Balance was also assessed using the mBESS. RESULTS: The ABC and ABC-6 were strongly correlated (ρ=0.980, P<.001). Cronbach α for ABC and ABC-6 was 0.966 and 0.940, respectively. Factor analysis verified the existence of 2 components of the ABC, 1 including all items of the ABC-6 as well as 3 additional items. ABC and ABC-6 were moderately significantly correlated with SCAT5 symptom number, severity, and symptom domain (ρ=-0.350 to -0.604). However, correlations between ABC and ABC-6 with instrumented measures of balance and gait were not statistically significant, except for double support time during dual-task gait with ABC-6 (ρ=-0.218). CONCLUSIONS: In community-dwelling adults with concussion, the ABC and ABC-6 have good internal consistency. Convergent validity is stronger for symptom endorsement measures within SCAT5 domains, which has a similar construct (subjectivity) to balance confidence. Both the ABC and ABC-6 are valid measures of balance self-efficacy in adults from the general population with concussion. The ABC-6 may be a useful tool for characterizing the effect of concussion on perceptions of the ability to perform functional tasks that challenge balance and mobility.

Reliability of force plate-based measures of standing balance in the sub-acute stage of post-stroke recovery.

Background: Difficulty controlling balance is one of the major contributors to the increased risk of falls among individuals with stroke. It is important to use reliable and objective measures to improve examination of balance impairments post-stroke, and to in turn inform clinical decision-making. The main objective of this study was to examine the relative and absolute reliabilities of force plate-based balance measures in quiet standing, in the sub-acute stage of stroke recovery. Methods: Twenty-four people with sub-acute stroke (mean age = 61 years) performed two trials of quiet standing, each 30 s long. Sixteen force plate-based balance measures in the time, frequency, or nonlinear domains were calculated. Within-session test-retest reliabilities were investigated using intraclass correlation coefficient (ICC), standard error of measurement, and minimal detectable change. Results: Mean speed of displacements of the centre of pressure along the anterior-posterior axis (ICC = 0.91; CI95 % = [0.83, 0.95]), and directional weight-bearing asymmetry (ICC = 0.91; CI95 % = [0.82, 0.95]) demonstrated high relative reliabilities, followed by the speed-based symmetry index and absolute weight-bearing asymmetry (both ICCs = 0.86; CI95 % = [0.74, 0.93]). Conclusions: Mean speeds of centre of pressure, directional weight-bearing asymmetry, and speed-based symmetry index are the most reliable force plate-based measures that were evaluated in our study, and can be included in the balance assessments of individuals within the sub-acute stage of post-stroke recovery. These findings can better inform clinicians about the specific balance problems experienced by people in this population.

The Toronto Concussion Study: a prospective investigation of characteristics in a cohort of adults from the general population seeking care following acute concussion, 2016-2020.

Purpose: There is limited research regarding the characteristics of those from the general population who seek care following acute concussion. Methods: To address this gap, a large cohort of 473 adults diagnosed with an acute concussion (female participants = 287; male participants = 186) was followed using objective measures prospectively over 16 weeks beginning at a mean of 5.1 days post-injury. Results: Falls were the most common mechanism of injury (MOI) (n = 137, 29.0%), followed by sports-related recreation (n = 119, 25.2%). Male participants were more likely to be injured playing recreational sports or in a violence-related incident; female participants were more likely to be injured by falling. Post-traumatic amnesia (PTA) was reported by 80 participants (16.9 %), and loss of consciousness (LOC) was reported by 110 (23.3%). In total, 54 participants (11.4%) reported both PTA and LOC. Male participants had significantly higher rates of PTA and LOC after their injury compared to their female counterparts. Higher initial symptom burden was associated with a longer duration of recovery for both male and female participants. Female participants had more symptoms and higher severity of symptoms at presentation compared to male participants. Female participants were identified to have a longer recovery duration, with a mean survival time of 6.50 weeks compared to 5.45 weeks in male participants (p < 0.0001). A relatively high proportion of female and male participants in this study reported premorbid diagnoses of depression and anxiety compared to general population characteristics. Conclusion: Although premorbid diagnoses of depression and/or anxiety were associated with higher symptom burden at the initial visit, the duration of symptoms was not directly associated with a pre-injury history of psychological/psychiatric disturbance. This cohort of adults, from the general population, seeking care for their acute concussion attained clinical and functional recovery over a period of 4-12 weeks.

Transcranial direct current stimulation leads to faster acquisition of motor skills, but effects are not maintained at retention.

Practice is required to improve one's shooting technique in basketball or to play a musical instrument well. Learning these motor skills may be further enhanced by transcranial direct current stimulation (tDCS). We aimed to investigate whether tDCS leads to faster attainment of a motor skill, and to confirm prior work showing it improves skill acquisition and retention performance. Fifty-two participants were tested; half received tDCS with the anode on primary motor cortex and cathode on the contralateral forehead while concurrently practicing a sequential visuomotor isometric pinch force task on Day 1, while the other half received sham tDCS during practice. On Day 2, retention of the skill was tested. Results from a Kaplan-Meier survival analysis showed that participants in the anodal group attained a pre-defined target level of skill faster than participants in the sham group (χ2 = 9.117, p = 0.003). Results from a nonparametric rank-based regression analysis showed that the rate of improvement was greater in the anodal versus sham group during skill acquisition (F(1,249) = 5.90, p = 0.016), but there was no main effect of group or time. There was no main effect of group or time, or group by time interaction when comparing performance at the end of acquisition to retention. These findings suggest anodal tDCS improves performance more quickly during skill acquisition but does not have additional benefits on motor learning after a period of rest.

The Toronto Concussion Study: Reference Data for Balance and Gait Measures in Community-Dwelling Adults With Concussion.

OBJECTIVE: Concussion can cause deficits in balance and gait. Much of what is known about how concussion affects balance and gait has been derived from studies involving youth, high school, and university athletes. However, investigation into the effects of concussion on balance and gait in community-dwelling young, middle-age, and older aged adults is limited. This study aimed to present descriptive reference values for common balance and gait measures in community-dwelling adults between the ages of 20 and 69 years with concussion. METHODS: In this observational study, 318 participants were enrolled from a concussion care clinic at a rehabilitation hospital in an urban center and were assessed within 7 days of injury. Balance measures included the Balance Error Scoring System (BESS), modified BESS, and center-of-pressure root mean square during quiet standing. Gait measures included velocity (absolute and height adjusted), cadence, and step length during self-paced gait. Data were binned by decade-long age range. RESULTS: Mean (SD) per-decade scores for the BESS ranged from 14.8 (5.1) to 21.8 (5.6) errors and 4.0 (3.0) to 9.4 (4.6) errors for the modified BESS. Mean values for center-of-pressure root mean square in the anteroposterior direction ranged from 0.42 (0.18) to 0.52 (0.26) with the eyes open, and from 0.49 (0.19) to 0.62 (0.39) with eyes closed. Mean absolute gait velocity ranged from 98.5 (9.1) to 119.3 (21.3) cm/s. The range of step length values was 58.2 (6.8) to 66.3 (7.3) cm and cadence ranged from 102.1 (9.8) to 108.6 (10.8) steps/min across age groups. CONCLUSION: These data provide insight into the impact of concussion on balance and mobility in community-dwelling adults across the lifespan. IMPACT: Community-dwelling adults can experience concussion across the lifespan. Availability of reference values for commonly used balance and gait measures can help to inform clinical strategies and progression of recovery of balance and mobility after injury.

Associations Between Lower Limb Isometric Torque, Isokinetic Torque, and Explosive Force With Phases of Reactive Stepping in Young, Healthy Adults.

This study aimed to determine the relationship between lower limb muscle strength and explosive force with force plate-derived timing measures of reactive stepping. Nineteen young, healthy adults responded to 6 perturbations using an anterior lean-and-release system. Foot-off, swing, and restabilization times were estimated from force plates. Peak isokinetic torque, isometric torque, and explosive force of the knee extensors/flexors and plantar/dorsiflexors were measured using isokinetic dynamometry. Correlations were run based on a priori hypotheses and corrected for the number of comparisons (Bonferroni) for each variable. Knee extensor explosive force was negatively correlated with swing time (r = -.582, P = .009). Knee flexor peak isometric torque also showed a negative association with restabilization time (r = -.459, P = .048); however, this was not statistically significant after correcting for multiple comparisons. There was no significant relationship between foot-off time and knee or plantar flexor explosive force (P > .025). These findings suggest that there may be utility to identifying specific aspects of reactive step timing when studying the relationship between muscle strength and reactive balance control. Exercise training aimed at improving falls risk should consider targeting specific aspects of muscle strength depending on specific deficits in reactive stepping.

Differential Effects of Speech and Language Therapy and rTMS in Chronic Versus Subacute Post-stroke Aphasia: Results of the NORTHSTAR-CA Trial.

BACKGROUND & OBJECTIVE: Contralesional 1-Hz repetitive transcranial magnetic stimulation (rTMS) over the right pars triangularis combined with speech-language therapy (SLT) has shown positive results on the recovery of naming in subacute (5-45 days) post-stroke aphasia. NORTHSTAR-CA is an extension of the previously reported NORTHSTAR trial to chronic aphasia (>6 months post-stroke) designed to compare the effectiveness of the same rTMS protocol in both phases. METHODS: Sixty-seven patients with left middle cerebral artery infarcts (28 chronic, 39 subacute) were recruited (01-2014 to 07-2019) and randomized to receive rTMS (N = 34) or sham stimulation (N = 33) with SLT for 10 days. Primary outcome variables were Z-score changes in naming, semantic fluency and comprehension tests and adverse event frequency. Intention-to-treat analyses tested between-group effects at days 1 and 30 post-treatment. Chronic and subacute results were compared. RESULTS: Adverse events were rare, mild, and did not differ between groups. Language outcomes improved significantly in all groups irrespective of treatment and recovery phase. At 30-day follow-up, there was a significant interaction of stimulation and recovery phase on naming recovery (P <.001). Naming recovery with rTMS was larger in subacute (Mdn = 1.91/IQR = .77) than chronic patients (Mdn = .15/IQR = 1.68/P = .015). There was no significant rTMS effect in the chronic aphasia group. CONCLUSIONS: The addition of rTMS to SLT led to significant supplemental gains in naming recovery in the subacute phase only. While this needs confirmation in larger studies, our results clarify neuromodulatory vs training-induced effects and indicate a possible window of opportunity for contralesional inhibitory stimulation interventions in post-stroke aphasia. NORTHSTAR TRIAL REGISTRATION: https://clinicaltrials.gov/ct2/show/NCT02020421.

Investigation of the Kinematic Upper-Limb Movement Assessment (KUMA): A Pilot Study.

Purpose: Upper limb movement disorders are common after stroke and can severely impact activities of daily living. Available clinical measures of these disorders are subjective and may lack the sensitivity needed to track a patient's progress and to compare different therapies. Kinematic analyses can provide clinicians with more objective measures for evaluating the effects of rehabilitation. We present a novel method to assess the quality of upper limb movement: the Kinematic Upper-limb Movement Assessment (KUMA). This assessment uses motion capture to provide three kinematic measures of upper limb movement: active range of motion, speed, and compensatory trunk movement. The researchers sought to evaluate the ability of the KUMA to distinguish motion in the affected versus unaffected limb. Method: We used the KUMA with three participants with stroke to assess three single-joint movements in: wrist flexion and extension, elbow flexion and extension, and shoulder flexion/extension and abduction/adduction. Participants also completed the Modified Ashworth Scale and the Chedoke-McMaster Stroke Assessment, two clinical measures of functional ability. Results: The KUMA distinguished between affected and unaffected upper limb motion. Conclusions: The KUMA provides clinicians with supplementary objective information for motion characterization that is not available through clinical measures alone. The KUMA can complement existing clinical measures such as the MAS and CMSA and can be helpful for monitoring patient progress.

Objectif : les troubles des mouvements de membres supérieurs sont courants après un accident vasculaire cérébral et peuvent nuire fortement aux activités de la vie quotidienne. Les mesures cliniques disponibles pour ces troubles sont subjectives et ne possèdent peut-être pas la sensibilité nécessaire pour suivre le progrès d'un patient et comparer les diverses thérapies. Les analyses de cinématique peuvent fournir aux cliniciens des mesures plus objectives pour évaluer les effets de la réadaptation. Les auteurs présentent une nouvelle méthode pour évaluer la qualité des mouvements des membres supérieurs : l'évaluation cinématique des mouvements des membres supérieurs (KUMA, pour Kinematic Upper-limb Movement Assessment ). Cette évaluation fait appel à la capture des mouvements pour fournir trois mesures cinématiques des mouvements des membres supérieurs : l'amplitude de mouvements actifs, la vitesse et le mouvement compensatoire du tronc. Les chercheurs ont cherché à évaluer la capacité de la KUMA à distinguer le mouvement du membre touché par rapport au membre non touché. Méthodologie : les chercheurs ont utilisé la KUMA auprès de trois participants ayant subi un accident vasculaire cérébral pour évaluer trois mouvements monoarticulaires : flexion et extension du poignet, flexion et extension du coude, et flexion et extension, abduction et adduction de l'épaule. Les participants ont également utilisé l'échelle modifiée d'Ashworth (MAS) et l'évaluation Chedoke-McMaster de l'accident vasculaire cérébral (AVC), deux mesures cliniques de la capacité fonctionnelle. Résultats : la KUMA distinguait le mouvement du membre supérieur atteint de celui qui ne l'était pas. Conclusions : La KUMA fournit aux cliniciens de l'information objective supplémentaires pour caractériser les mouvements d'une manière qui n'est pas disponible par les seules mesures cliniques. La KUMA peut compléter les mesures cliniques en place comme l'échelle modifiée d'Ashworth et l'évaluation Chedoke-McMaster de l'AVC et peut être utile pour surveiller le progrès des patients.

The effect of frequency of feedback on overground temporal gait asymmetry post stroke.

BACKGROUND AND OBJECTIVES: Temporal gait asymmetry (TGA) affects 55% of people with stroke. This study investigated the effects of augmented feedback during overground gait training, on TGA. METHODS: Eighteen people with chronic stroke were randomized to receive one of two feedback displays (A or B) and one of three feedback frequencies; no feedback (0%), after alternate walking trials (50%) or after every trial (100%). Display A depicted the TGA ratio as a vertical line along a horizontal axis with perfect symmetry in the middle. Display B depicted single limb stance duration of each leg as a bar graph. Participants completed 25 repetitions of 30 second trials with their assigned feedback (acquisition). Participants completed 10 repetitions of 30 second trials without feedback 24 hours later (retention). A pressure sensitive mat recorded TGA and speed. Changes in TGA and speed were investigated by plotting individual motor learning curves and fitting a curve with locally estimated scatterplot smoothing (LOESS) for each feedback group. An effect of feedback was defined a priori as a LOESS fitted curve with a decreasing slope from acquisition to retention. RESULTS: LOESS curve exhibited a decreasing slope for TGA in the 100B group only and for speed in the 50A and 0FB groups. DISCUSSION: This study provides preliminary evidence that visual feedback delivered at a high frequency during a single session of overground walking can change TGA post-stroke without reducing gait speed. An overground gait intervention with high frequency visual feedback to improve TGA post-stroke is worthwhile to investigate.

The Toronto concussion study: a cross-sectional analysis of balance deficits following acute concussion in community-dwelling adults.

Objective: To characterize balance deficits in community-dwelling adults following acute concussion.Design: Cross-sectional observational study.Methods: Individuals with acute concussion (n=100) and healthy controls (n=20) completed the BESS (Balance Error Scoring System) and quiet standing trials on forceplates with the eyes open, closed, or during a cognitive dual task. BESS score and centre-of-pressure root mean square and high-frequency power (0.4-3Hz) were used to characterize group differences. In a secondary analysis, participants were subdivided based on self-reported symptoms of balance problems and dizziness using the SCAT-3 (Sport Concussion Assessment Tool - Third Edition) Symptom Checklist.Results: In comparing individuals with concussion and controls, BESS score (16.0 ± 6.0 vs 12.6 ± 3.8; F(1,116) = 5.814, p = .017) and anteroposterior [F(1.78, 204.2) = 11.93, p < .001] and mediolateral [F(1, 114) = 10.05, p = .002] high-frequency power revealed significant group differences. Dividing individuals based on self-reported symptoms revealed significant differences in mediolateral high frequency power, such that participants reporting balance and dizziness problems as well as those participants not reporting balance or dizziness symptoms following concussion were less stable than controls.Conclusions: Deficits in clinical and posturographic measures of balance occur in community-dwelling adults with concussion. These measures do not align with self-reported balance symptoms. Future research and clinical practice aimed at careful selection of optimized balance assessment is recommended.

Test-retest reliability of force plate-derived measures of reactive stepping.

Characterizing reactive stepping is important to describe the response's effectiveness. Timing of reactive step initiation, execution, and termination have been frequently reported to characterize reactive balance control. However, the test-retest reliabilities of these measures are unknown. Accordingly, the purpose of this study was to determine the between- and within-session test-retest reliabilities of various force plate-derived measures of reactive stepping. Nineteen young, healthy adults responded to 6 small (~8-10% of body weight) and 6 large perturbations (~13-15% of body weight) using an anterior lean-and-release system. Tests were conducted during two visits separated by at least two days. Participants were instructed to recover balance in as few steps as possible. Step onset, foot-off, swing, and restabilization times were extracted from force plates. Relative test-retest reliability was determined through intraclass correlation coefficients (ICCs) and 95% confidence intervals (CIs). Absolute test-retest reliability was assessed using the standard error of the measurement (SEM). Foot-off and swing times had the highest between- and within-session test-retest reliabilities regardless of perturbation size (between-session ICC = 0.898-0.942; within-session ICC = 0.455-0.753). Conversely, step onset and restabilization times had lower ICCs and wider CIs (between-session ICC = 0.495-0.825; within-session ICC = -0.040-0.174). Between-session test-retest reliability was higher (ICC = 0.495-0.942) for all measures than within-session test-retest reliability (ICC = -0.040-0.753). Time to restabilization had the highest SEM, indicating the worst absolute reliability of the measures. These findings suggest multiple baseline sessions are needed for measuring restabilization and step onset times. The minimal detectable changes reported provide an index for measuring meaningful change due to an intervention.

The Toronto Concussion Study: a longitudinal analysis of balance deficits following concussion in community-dwelling adults.

OBJECTIVE: To characterize recovery of balance deficits in community-dwelling adults with concussion. HYPOTHESIS: Balance measures will improve 2 weeks after injury and persist over 12 weeks. DESIGN: Prospective longitudinal observational study. METHODS: Assessments included the Balance Error Scoring System (BESS) and quiet standing during eyes open, eyes closed, and a cognitive dual task. Recovery was determined using a Hierarchical Growth Curve Model (HGCM) at Week1 (n = 61), Week2 (n = 58), Week4 (n = 53), Week8 (n = 51), and Week12 (n = 39) post-injury. Within-individual follow-up analysis was conducted using the coefficient of variation (quiet standing measures) and a reliable change index (BESS) on 28 individuals with concussion assessed at all 5 time points. RESULTS: Self-reported symptom score recovered between Week 4-8. Anteroposterior COP velocity (eyes closed) was the only variable to show statistically significant (p < .05) recovery in the HGCM. The within-individual analysis identified fewer than 43% (12/28) of participants recovered by Week 12, relative to their own Week 1 assessment. CONCLUSIONS: While recovery of balance deficits was observed in 1 variable over 12 weeks, less than half of the participants included in all assessments demonstrated improvement in balance outcomes. Future research and clinical practice should focus on the unique characteristics of community-dwelling adults with concussion to optimize recovery in this cohort.

Effect of reactive balance training on physical fitness poststroke: study protocol for a randomised non-inferiority trial.

INTRODUCTION: Regular exercise is essential in the chronic phase of stroke recovery for improving or maintaining function, and reducing the risk of a second stroke. To achieve these goals, multiple components of fitness should be targeted with poststroke exercise, including aerobic capacity, strength and balance. However, following the recommended frequency and duration of each component separately can take a long time and lead to fatigue in people with stroke. Therefore, finding types of exercise that target multiple components of fitness all together is valuable.Reactive balance training (RBT) is a novel type of exercise where individuals repeatedly lose their balance in order to practise balance reactions. When people do RBT, they increase their heart rate and exert forces with their leg muscles which could improve aerobic fitness and muscle strength, respectively. This means that RBT could have the potential to improve multiple components of fitness, simultaneously. METHODS AND ANALYSIS: This is a randomised controlled non-inferiority trial with internal pilot study. Participants with chronic stroke will be randomly assigned to one of two groups: (1) RBT or (2) aerobic and strength training (AST). Participants in both groups will complete 1 hour of exercise, three times/week for 12 weeks. The primary objective is to determine the effect of RBT on aerobic capacity and knee muscles' strength. The secondary objective is to determine the effects of RBT and AST on balance control and balance confidence. We expect to find that RBT is superior to AST in terms of improving balance control and balance confidence, yet not inferior to AST in terms of its effects on aerobic capacity and strength. ETHICS AND DISSEMINATION: Research ethics approval has been received. Results will be disseminated directly to study participants at the end of the trial, and to other stakeholders via publication in a peer-reviewed journal. TRIAL REGISTRATION NUMBER: NCT04042961.

Determining Corticospinal Tract Injury from Stroke Using Computed Tomography.

INTRODUCTION: Damage to the corticospinal tract (CST) from stroke leads to motor deficits. The damage can be quantified as the amount of overlap between the stroke lesion and CST (CST Injury). Previous literature has shown that the degree of motor deficits post-stroke is related to the amount of CST Injury. These studies delineate the stroke lesion from structural T1-weighted magnetic resonance imaging (MRI) scans, often acquired for research. In Canada, computed tomography (CT) is the most common imaging modality used in routine acute stroke care. In this proof-of-principle study, we determine whether CST Injury, using lesions delineated from CT scans, significantly explains the variability in motor impairment in individuals with stroke. METHODS: Thirty-seven participants with stroke were included in this study. These individuals had a CT scan within the acute stage (7 days) of their stroke and underwent motor assessments. Brain images from CT scans were registered to MRI space. We performed a stepwise regression analysis to determine the contribution of CST injury and demographic variables in explaining motor impairment variability. RESULTS: Using clinically available CT scans, we found modest evidence that CST Injury explains variability in motor impairment (R2adj = 0.12, p = 0.02). None of the participant demographic variables entered the model. CONCLUSION: We show for the first time a relationship between CST Injury and motor impairment using CT scans. Further work is required to evaluate the utility of data derived from clinical CT scans as a biomarker of stroke motor recovery.

The effect of bed rest on balance control in healthy adults: A systematic scoping review.

The objective of this study was to determine the effect of bed rest on balance control and the mechanisms responsible for these changes. Searches were conducted in six databases. Studies had to be conducted on healthy adults who were subjected to bed rest (≥5 days), with balance control measures obtained before and after bed rest in order to be included. Risk of bias was assessed using the NIH Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies. After screening 9,785 articles, 18 were included for qualitative synthesis. Fifteen studies found decrements in at least one balance control measure following bed rest, either compared to baseline or controls, with eight studies observing impairments in >50% of their balance control measures. Of the 14 studies that included an intervention, four (mechanical stimuli, lower-body negative pressure, and training targeting strength, balance and/or aerobic capacity) successfully offset the majority of balance control deficits and targeted the musculoskeletal and cardiovascular systems. The findings of this review support bed rest negatively affecting balance control in healthy individuals. In clinical populations, these deficits may be further accentuated due to various comorbidities that impact balance control systems. PROSPERO Registration: CRD42018098887.

Non-invasive brain stimulation as add-on therapy for subacute post-stroke aphasia: a randomized trial (NORTHSTAR).

INTRODUCTION: Non-invasive brain stimulation (NIBS) with speech therapy might improve recovery from post-stroke aphasia. This three-armed sham-controlled blinded prospective proof-of-concept study tested 1 Hz subthreshold repetitive transcranial magnetic stimulation (rTMS) and 2-mA cathodal transcranial direct current stimulation (ctDCS) on the right pars triangularis in subacute post-stroke aphasia. PATIENTS AND METHODS: Sixty-three patients with left middle cerebral artery infarcts were recruited in five hospitals (Canada/United States/Germany, 01-2014/03-2018) and randomized to receive rTMS (N = 20), ctDCS (N = 24) or sham stimulation (N = 19) with ST for 10 days. Primary outcome variables were Z-score changes in naming, semantic fluency and comprehension tests and adverse event frequency. Secondary outcome variable was the percent change in the Unified Aphasia Score. Intention-to-treat analyses tested between-group effects at days 1 and 30 post-treatment with a pre-planned subgroup analysis for lesion location (affecting Broca's area or not). RESULTS: Naming was significantly improved by rTMS (median = 1.91/interquartile range = 0.77/p = .01) at 30 days versus ctDCS (median = 1.11/interquartile range = 1.51) and sham stimulation (median = 1.02/interquartile range = 1.71). All other primary results were non-significant. The rTMS effect was driven by the patient subgroup with intact Broca's area where NIBS tended to improve UnAS (median = 33.2%/interquartile range = 46.7%/p = .062) versus sham stimulation (median = 12.5%/interquartile range = 7.9%) at day 30. Conversely, in patients with infarcted Broca's area, UnAS tended to improve more with sham stimulation (median = 75.0%/interquartile range = 86.9%/p = .053) versus NIBS (median = 12.7%/interquartile range = 31.7).Conclusion: We found a delayed positive effect of low-frequency rTMS targeting the right pars triangularis on the recovery of naming performance in subacute post-stroke aphasia. This intervention may be beneficial only in patients with morphologically intact Broca's area.

Spectral analysis of centre of pressure identifies altered balance control in individuals with moderate-severe traumatic brain injury.

Purpose: To identify impairments and recovery of balance control after moderate-severe traumatic brain injury (TBI) through spectral analyses of static balance tasks and to characterise the contributions of each limb to balance control.Methods: A retrospective analysis of longitudinal balance data from force platforms at 2, 5, and 12 months post-injury in 31 individuals with moderate to severe TBI was performed. Single-visit data from age-matched controls (n = 22) were collected for descriptive comparison. Net and individual limb centre of pressure measures and inter-limb centre of pressure coherence were calculated in low (≤0.4 Hz) and high (≥0.4 Hz) frequencies in the anteroposterior and mediolateral directions during standing with the eyes open and closed.Results: Standing with the eyes closed increased net centre of pressure spectral power in low and high frequencies. Individuals with TBI demonstrated recovery in high frequencies in net centre of pressure in the mediolateral direction. Inter-limb coherence in the anteroposterior and mediolateral directions increased (recovered) over time in high frequencies. Weight-bearing asymmetry was visible in high frequencies in the anteroposterior and mediolateral directions.Conclusions: Increased amplitude of low and high-frequency power suggests that individuals with TBI included in this study have impaired anticipatory and reactive balance mechanisms, which may be driven by weight-bearing asymmetries and which recover over time.Implications for rehabilitationAnticipatory and reactive balance impairments after traumatic brain injury may place individuals at increased risk for falls.Analyses from postural sway in static balance tasks infer changes in anticipatory or reactive balance control after traumatic brain injury.Addressing weight-bearing asymmetries in rehabilitation interventions post-traumatic brain injury may improve between-limb coordination for anticipatory and reactive balance control.

Movement kinematics and proprioception in post-stroke spasticity: assessment using the Kinarm robotic exoskeleton.

BACKGROUND: Motor impairment after stroke interferes with performance of everyday activities. Upper limb spasticity may further disrupt the movement patterns that enable optimal function; however, the specific features of these altered movement patterns, which differentiate individuals with and without spasticity, have not been fully identified. This study aimed to characterize the kinematic and proprioceptive deficits of individuals with upper limb spasticity after stroke using the Kinarm robotic exoskeleton. METHODS: Upper limb function was characterized using two tasks: Visually Guided Reaching, in which participants moved the limb from a central target to 1 of 4 or 1 of 8 outer targets when cued (measuring reaching function) and Arm Position Matching, in which participants moved the less-affected arm to mirror match the position of the affected arm (measuring proprioception), which was passively moved to 1 of 4 or 1 of 9 different positions. Comparisons were made between individuals with (n = 35) and without (n = 35) upper limb post-stroke spasticity. RESULTS: Statistically significant differences in affected limb performance between groups were observed in reaching-specific measures characterizing movement time and movement speed, as well as an overall metric for the Visually Guided Reaching task. While both groups demonstrated deficits in proprioception compared to normative values, no differences were observed between groups. Modified Ashworth Scale score was significantly correlated with these same measures. CONCLUSIONS: The findings indicate that individuals with spasticity experience greater deficits in temporal features of movement while reaching, but not in proprioception in comparison to individuals with post-stroke motor impairment without spasticity. Temporal features of movement can be potential targets for rehabilitation in individuals with upper limb spasticity after stroke.

Self-reported Balance Disturbance and Performance-Based Balance Impairment After Concussion in the General Population.

OBJECTIVE: To characterize the prevalence of, and relationship between, self-reported balance disturbance and performance-based balance impairment in the general population with concussion. SETTING: Rehabilitation hospital outpatient concussion clinic. PARTICIPANTS: One hundred six individuals with concussion (49 males, mean age = 32.4; SD = 11.5 years), mean (SD) = 5 (1.8) days postinjury. DESIGN: Cross-sectional observational study. MAIN MEASURES: SCAT3 Symptoms Subscale, Balance Error Scoring System, modified Balance Error Scoring System, and center-of-pressure root-mean-square amplitude and velocity in eyes open and closed conditions. RESULTS: The majority of participants reported balance or dizziness symptoms (54% and 63%, respectively) and demonstrated balance impairment on the Balance Error Scoring System and modified Balance Error Scoring System (66% and 58%, respectively). The prevalence of balance impairment across center-of-pressure measures varied from 32% to 48%. There was no effect of balance or dizziness symptom severity on any of the balance measures (F2,103 = 1.02; P = .44) and (F2,103 = 1.45; P = .10), respectively. There was poor agreement between self-report of balance/dizziness symptoms and identified balance impairment across all balance measures (all κ ≤ 0.26 and κ ≤ 0.20, respectively). CONCLUSIONS: There was no clear relationship between the subjective experience of balance disturbance and objective measures of balance impairment in the general population. These results have implications for clinical evaluation of postconcussive deficits and determination of recovery.

Does perturbation-based balance training prevent falls among individuals with chronic stroke? A randomised controlled trial.

OBJECTIVES: No intervention has been shown to prevent falls poststroke. We aimed to determine if perturbation-based balance training (PBT) can reduce falls in daily life among individuals with chronic stroke. DESIGN: Assessor-blinded randomised controlled trial. SETTING: Two academic hospitals in an urban area. INTERVENTIONS: Participants were allocated using stratified blocked randomisation to either 'traditional' balance training (control) or PBT. PBT focused on improving responses to instability, whereas traditional balance training focused on maintaining stability during functional tasks. Training sessions were 1 hour twice/week for 6 weeks. Participants were also invited to complete 2 'booster' training sessions during the follow-up. PARTICIPANTS: Eighty-eight participants with chronic stroke (>6 months poststroke) were recruited and randomly allocated one of the two interventions. Five participants withdrew; 42 (control) and 41 (PBT group) were included in the analysis. PRIMARY AND SECONDARY OUTCOME MEASURES: The primary outcome was rate of falls in the 12 months post-training. Negative binomial regression was used to compare fall rates between groups. Secondary outcomes were measures of balance, mobility, balance confidence, physical activity and social integration. RESULTS: PBT participants reported 53 falls (1.45 falls/person-year) and control participants reported 64 falls (1.72 falls/person-year; rate ratio: 0.85(0.42 to 1.69); p=0.63). Per-protocol analysis included 32 PBT and 34 control participants who completed at least 10/12 initial training sessions and 1 booster session. Within this subset, PBT participants reported 32 falls (1.07 falls/person-year) and control participants reported 57 falls (1.75 falls/person-year; rate ratio: 0.62(0.29 to 1.30); p=0.20). PBT participants had greater improvement in reactive balance control than the control group, and these improvements were sustained 12 months post-training. There were no intervention-related serious adverse effects. CONCLUSIONS: The results are inconclusive. PBT may help to prevent falls in daily life poststroke, but ongoing training may be required to maintain the benefits. TRIAL REGISTRATION NUMBER: ISRCTN05434601; Results.