Cerebellar Dysfunction in Multiple Sclerosis: Considerations for Research and Rehabilitation Therapy

Introduction. Cerebellar pathology is common among persons with multiple sclerosis (PwMS). The cerebellum is well recognized for its role in motor control and motor learning and cerebellar pathology in multiple sclerosis is associated with enhanced motor impairment and disability progression. The Problem. To mitigate motor disability progression, PwMS are commonly prescribed exercise and task-specific rehabilitation training. Yet, whether cerebellar dysfunction differentially affects rehabilitation outcomes in this population remains unknown. Furthermore, we lack rehabilitation interventions targeting cerebellar dysfunction. The Solution. Here, we summarize the current understanding of the impact of cerebellar dysfunction on motor control, motor training, and rehabilitation in persons with multiple sclerosis. Recommendations. Additionally, we highlight critical knowledge gaps and propose that these guide future research studying cerebellar dysfunction in persons with multiple sclerosis.

Quantification of Daily-Living Gait Quantity and Quality Using a Wrist-Worn Accelerometer in Huntington's Disease

Background: Huntington's disease (HD) leads to altered gait patterns and reduced daily-living physical activity. Accurate measurement of daily-living walking that takes into account involuntary movements (e.g. chorea) is needed. Objective: To evaluate daily-living gait quantity and quality in HD, taking into account irregular movements. Methods: Forty-two individuals with HD and fourteen age-matched non-HD peers completed clinic-based assessments and a standardized laboratory-based circuit of functional activities, wearing inertial measurement units on the wrists, legs, and trunk. These activities were used to train and test an algorithm for the automated detection of walking. Subsequently, 29 HD participants and 22 age-matched non-HD peers wore a tri-axial accelerometer on their non-dominant wrist for 7 days. Measures included gait quantity (e.g., steps per day), gait quality (e.g., regularity) metrics, and percentage of walking bouts with irregular movements. Results: Measures of daily-living gait quantity including step counts, walking time and bouts per day were similar in HD participants and non-HD peers (p > 0.05). HD participants with higher clinician-rated upper body chorea had a greater percentage of walking bouts with irregular movements compared to those with lower chorea (p = 0.060) and non-HD peers (p < 0.001). Even after accounting for irregular movements, within-bout walking consistency was lower in HD participants compared to non-HD peers (p < 0.001), while across-bout variability of these measures was higher (p < 0.001). Many of the daily-living measures were associated with disease-specific measures of motor function. Conclusions: Results suggest that a wrist-worn accelerometer can be used to evaluate the quantity and quality of daily-living gait in people with HD, while accounting for the influence of irregular (choreic-like) movements, and that gait features related to within- and across-bout consistency markedly differ in individuals with HD and non-HD peers.

Measures of postural control and mobility during dual-tasking as candidate markers of instability in Huntington's disease

BACKGROUND

Individuals with Huntington's disease (HD) have impairments in performing dual-tasks, however, there is limited information about the effects of changing postural and cognitive demands as well as which measures are best suited as markers of underlying motor-cognitive interference.

METHODS

Forty-three individuals with HD and 15 healthy controls (HC) completed single tasks of walking (Timed Up & Go (TUG), 7 m walk), standing (feet together, feet apart and foam surface) and seated cognitive performance (Stroop, Symbol Digit Modalities Test (SDMT), Delis-Kaplan Executive Function System (DKEFS) Sorting test) and dual cognitive-motor tasks while standing (+ Stroop) and walking (+ DKEFS, TUG cognitive). APDM Opal sensors recorded measures of postural sway and time to complete motor tasks.

RESULTS

Individuals with HD had a greater increase in standing postural sway compared to HC from single to dual-tasks and with changes to support surface. Both groups demonstrated a decrease in gait performance during the TUG cognitive, however, this difference was greater in people with HD compared to HC. While those with HD showed a greater dual-task motor cost compared to HC, both groups behaved similarly as condition complexity increased.

CONCLUSIONS

Standing postural sway is a more sensitive marker of instability than change in standard gait speed, particularly under dual-task conditions. The more complex TUG cognitive is a sensitive measure of walking dual-task performance. The results of this study provide insights about the nature of motor-cognitive impairments in HD and provide support for a distinction between static and dynamic postural control mechanisms during performance of dual-tasks.

Validating the walking while talking test to measure motor, cognitive, and dual-task performance in ambulatory individuals with multiple sclerosis

INTRODUCTION

Multiple Sclerosis (MS) is associated with demyelination of the central nervous system that negatively impacts both motor and cognitive function, resulting in difficulty performing simultaneous motor and cognitive tasks, or dual-tasks. Declines in dual-tasking have been linked with falls in MS; thus, dual-task assessment with the Walking While Talking Test (WWTT) is commonly utilized in the clinical setting. However, the validity and minimal detectable change (MDC) of the WWTT has not been established for persons with MS. The primary objective of the study was to establish the WWTT as a valid measure of dual-task function by examining concurrent validity with other motor, cognitive and dual-task measures, and to establish the MDC for both the simple and complex conditions of the WWTT.

METHODS

In a single visit, 38 adults (34 female, mean (SD) age 49.8(±9.1), Patient Determined Disease Steps (PDDS) mean 3, range 1-6) completed the WWTT simple (walk while reciting the alphabet) and complex (walk while reciting every other letter of the alphabet) conditions as well as a battery of cognitive and motor tests. Spearman correlations were used to examine concurrent validity. The sample was divided into low and high disability groups to determine the impact of disability severity on relationships among WWTT and cognitive and motor function.

RESULTS

Excellent concurrent validity (r ≥ 0.79; p < 0.001) was observed for the WWTT simple and complex with both motor (Timed Up-and-Go, Timed 25-Foot Walk, forward and backward walking velocity, Six-Spot Step Test) and dual-task measures (Timed Up-and-Go Cognitive). The WWTT-simple demonstrated moderate concurrent validity with measures of processing speed (Symbol Digit Modalities Test, p = 0.041) and was related to all motor and dual-task measures across disability levels. The WWTT complex was only related to complex motor tasks in the low disability group. Within the low disability group, WWTT was associated with processing speed (p = 0.045) and working memory (California Verbal Learning Test, p = 0.012). The MDC values were established for WWTT simple (6.9 s) and complex (8 s) conditions.

DISCUSSION

The WWTT is a quick, easy-to-administer clinical measure that captures both motor and cognitive aspects of performance for persons with MS. Clinicians should consider adding the WWTT to the evaluation of persons with MS to examine dual-task performance.

Evaluation of gait initiation using inertial sensors in Huntington's Disease: insights into anticipatory postural adjustments and cognitive interference

BACKGROUND

Understanding the contribution of anticipatory postural adjustments (APA) to walking ability in individuals with Huntington's disease (HD) may provide insight into motor planning and the functional consequences of HD-specific cortical-basal ganglia pathway dysfunctions.

RESEARCH QUESTION

How do inertial measurement unit (IMU)-derived APAs and first step parameters differ between individuals with HD and non-HD peers under no load and cognitive load conditions, and what is their relationship to gait speed and clinical measures?

METHODS

33 individuals with manifest HD and 15 non-HD peers wore three Opal APDM IMUs during a 14-meter walk under no load and cognitive load conditions. APA acceleration amplitudes, APA durations, first step range of motion (ROM), and first step durations were compared, along with their relationship to gait speed.

RESULTS

Individuals with HD had greater APA acceleration amplitudes, smaller first step ROM and longer first step durations compared to non-HD peers. No differences in APA durations were present between groups in both conditions. Cognitive loading influenced first step ROM but not other APA parameters. Mediolateral APA acceleration amplitudes were a significant predictor of gait speed and were related to disease-specific measures.

SIGNIFICANCE

Larger acceleration amplitudes and smaller first step ROMs of greater duration, accompanied by the preservation of APA durations, reveal a discrepancy in movement scaling in HD. Additionally, the mediolateral component of the APA is likely a rate-limiting factor that drives a compensatory response in gait initiation. Further research is needed to explore the neural correlates of HD-related movement scaling.

Immediate effects of treadmill walking in individuals with Lewy body dementia and Huntington's disease

BACKGROUND

Treadmill training may improve gait disorders associated with neurodegenerative diseases. In Parkinson's disease (PD), treadmill training alters gait patterns after one session, and long-term training improves gait parameters, fall risk, and quality of life.

RESEARCH QUESTION

What is the feasibility and safety of using this intervention for people with Lewy body dementia (LBD) or Huntington's disease (HD)?

METHODS

In this observational study, 10 individuals with HD, 8 individuals with LBD, and 10 control individuals walked for 20 min on a treadmill using a speed dependent protocol starting at a slow comfortable speed and increasing incrementally toward their normal overground speed. Feasibility was determined by compliance to protocol and safety by no incidents of abnormal vital signs or expressions of distress. Changes in gait measures, Timed Up and Go (TUG) scores and quantitative motor function measures (Q-Motor; precision grasp force variability, finger and foot tapping frequency) before and after treadmill walking were analyzed using linear models.

RESULTS

Treadmill training is feasible and safe in LBD and HD; although, participants could not initiate treadmill walking at their comfortable overground speeds, and only 3 participants with HD were able to achieve their overground walking speed within the 20-minute session. No changes in gait measures, TUG times, and Q-Motor measures were found among LBD and HD participants after treadmill walking, although control participants demonstrated significant increases in several gait measures, and foot tap frequency (estimated difference = 0.290; p = 0.026).

SIGNIFICANCE

Longer and more frequent treadmill sessions may be needed to see gait and motor function effects in LBD and HD. Motor and cognitive impairments associated with these diseases may make them less amenable to the effects of treadmill training.

Standardizing Outcome Assessment in Parkinson Disease: A Knowledge Translation Project

BACKGROUND AND PURPOSE

Rehabilitation therapists do not consistently utilize standardized outcome measures. The purpose of this study was to develop and implement a tailored knowledge translation (KT) intervention to facilitate application of standardized outcome measures used in patients with Parkinson disease (PD) receiving outpatient rehabilitation.

METHODS

Four clinics within a hospital-based outpatient system including physical therapists (n = 7) and occupational therapists (n = 2) collaborated with researcher clinicians. A mixed-methods study, using the knowledge to action (KTA) framework, was executed to standardize the assessment battery completed on patients with PD. The project was titled iKNOW-PD (integrating KNOWledge translation for Parkinson Disease).

RESULTS

Four measures were selected for iKNOW-PD (9-Hole Peg Test, miniBESTest, 10-m walk test, and 5 times sit-to-stand). A multimodal intervention that overcame specific identified barriers (equipment, time) was implemented to ensure successful uptake. Consistency of utilizing iKNOW-PD measures on initial evaluation and discharge, across therapists and clinics, was evaluated. Therapists significantly increased the use of iKNOW-PD measures from 1.9 to 3.1 on initial evaluation (P < 0.001). The 10-meter walk test demonstrated the greatest uptake (>50%) from pre-iKNOW-PD to post-iKNOW-PD.

DISCUSSION AND CONCLUSIONS

Standardizing outcome assessment for persons with PD in an outpatient setting can be successfully implemented. Overcoming identified barriers and capitalizing on facilitators promoted the uptake of standardized outcomes. Following the 6-month intervention period, therapists endorsed an improvement in their application of standardized measures and labeled iKNOW-PD as a positive experience that allowed them to minimize variability in practice.Video Abstract available for more insights from the authors (see the Video, Supplemental Content 1, available at: http://links.lww.com/JNPT/A329).

Combining Magnetization Transfer Ratio MRI and Quantitative Measures of Walking Improves the Identification of Fallers in MS

Multiple sclerosis (MS) impacts balance and walking function, resulting in accidental falls. History of falls and clinical assessment are commonly used for fall prediction, yet these measures have limited predictive validity. Falls are multifactorial; consideration of disease-specific pathology may be critical for improving fall prediction in MS. The objective of this study was to examine the predictive value of clinical measures (i.e., walking, strength, sensation) and corticospinal tract (CST) MRI measures, both discretely and combined, to fall status in MS. Twenty-nine individuals with relapsing-remitting MS (mean ± SD age: 48.7 ± 11.5 years; 17 females; Expanded Disability Status Scale (EDSS): 4.0 (range 1-6.5); symptom duration: 11.9 ± 8.7 years; 14 fallers) participated in a 3T brain MRI including diffusion tensor imaging and magnetization transfer ratio (MTR) and clinical tests of walking, strength, sensation and falls history. Clinical measures of walking were significantly associated with CST fractional anisotropy and MTR. A model including CST MTR, walk velocity and vibration sensation explained >31% of the variance in fall status (R2 = 0.3181) and accurately distinguished 73.8% fallers, which was superior to stand-alone models that included only MRI or clinical measures. This study advances the field by combining clinical and MRI measures to improve fall prediction accuracy in MS.

Fatigue in patients with hereditary neuropathy with liability to pressure palsies

OBJECTIVE

Hereditary Neuropathy with Liability to Pressure Palsies (HNPP) is caused by a heterozygous deletion of peripheral myelin protein-22 (PMP22) gene resulting in focal sensorimotor deficits. Our lab has identified a disruption of myelin junctions in excessively permeable myelin that impairs action potential propagation. This mechanism is expected to cause fatigue in patients with HNPP. Therefore, the objective was to characterize fatigue in patients with HNPP and determine the relationship of fatigue to nerve pathology, disability, and quality of life.

METHODS

Nine females with HNPP participated in a single visit that included genotyping, nerve conduction studies, neurological exam, quantitative magnetic resonance imaging, and a physical therapy exam incorporating upper and lower extremity function and survey measures of fatigue. This visit was followed by 2 weeks of ecological momentary assessment (wrist-worn device) that captured fatigue ratings five times per day.

RESULTS

Participants demonstrated mild neurological impairment (CMTNS: 5.7 ± 2.8), yet reported high fatigue levels (average fatigue intensity over 2 weeks: 5.9 out of 10). Higher fatigue levels were associated with poorer quality of life and more pain. Higher fatigue was associated with significantly greater distal nerve proton density changes on peripheral nerve MRI, which is in line with hyper-permeable myelin in HNPP.

INTERPRETATION

Fatigue is common and severe among patients with HNPP whose disabilities are minimal by conventional outcome measures. Therapeutic interventions targeting fatigue have the potential to improve quality of life and may serve as a robust outcome measure to show longitudinal changes for patients with HNPP.

Declines in grip strength may indicate early changes in cognition in healthy middle-aged adults

Declining grip strength is an indicator of cognitive loss in older individuals but it has not been explored people younger than 65 years old. The purpose of this study was to investigate the relationship between grip strength and specific cognitive tests known to decline with mild cognitive impairment in young and middle-aged adults. Declines in cognitive performance in middle-aged adults may provide evidence that these changes occur earlier than previously reported. A cross sectional design was used to compare differences between young and middle-aged healthy adults and to investigate associations between cognitive and grip strength measures within groups. Healthy young (20–30 years old) and middle-aged (45–65 years old) adults completed five cognitive tests including the Stroop, California Verbal Learning Test, Symbol Digit Modalities Test, Trail Making Tests and the Controlled Oral Word Association Test. All participants completed right and left maximum grip strength measures. Middle-aged adults performed significantly worse on right and left grip strength and the Stroop test (p<0.05) when compared to the younger group. There were no significant relationships among grip strength and cognitive performance at the whole-group level or within the younger-age group; however, weaker grip strength was significantly associated with poorer Controlled Oral Word Association Test total cluster (r = 0.458; p < .05) and Stroop interference (r = 0.471; p < .05) scores in the middle-aged group. Findings from this study suggest that cognitive changes may occur earlier than previously thought (prior to age 65). Weaker grip strength was significantly associated with poorer function in two of the cognitive measures in the middle-age group, suggesting that some domains of cognition, specifically semantic categorization and executive function, may be particularly sensitive to age-related changes.

Positive Affect and Well-Being in Huntington's Disease Moderates the Association Between Functional Impairment and HRQOL Outcomes

BACKGROUND

Positive affect is associated with resiliency and beneficial health outcomes, but little is known about associations between positive affect and health-related quality of life (HRQOL) in Huntington's disease (HD).

OBJECTIVE

This longitudinal study determined the association between positive affect and several HRQOL outcomes in persons with HD. Functional status was examined as a moderator of the association between positive affect and HRQOL.

METHODS

Participants, with premanifest (i.e., genetically at risk but no clinical diagnosis, n = 50) and manifest HD (early-stage n = 171; late-stage n = 101), completed a measure of positive affect and well-being and several HRQOL measures at baseline, 12-, and 24-month follow-ups. UHDRS Functional Assessment scale indicated functional status.

RESULTS

Positive affect was associated with better HRQOL for persons with premanifest and manifest HD over the 24-month time frame. These associations were moderated by functional status. For persons with higher functional status, positive affect was associated with better HRQOL, including less depression, lower anxiety, less anger, better social role satisfaction, better executive functions, greater upper extremity function, less dyscontrol, and less concern with death and dying. For persons with lower functional status, positive affect was not associated with HRQOL.

CONCLUSIONS

Positive affect predicted better self-reported HRQOL over a 24-month period in persons with premanifest and manifest HD, particularly when participnats had better functional status. Interventions to enhance positive affect in HD may have beneficial effects on HRQOL.

Daily Temporal Associations Between Physical Activity and Symptoms in Multiple Sclerosis

Background

Symptom severity is negatively associated with physical activity in multiple sclerosis (MS). However, it is unclear how physical activity and symptoms correlate on a day-to-day basis in persons with MS.

Purpose

To determine the temporal within-person associations of pain, fatigue, depressed mood, and perceived cognitive function with physical activity in MS.

Methods

Ambulatory adults with MS (N = 107) completed 7 days of home monitoring. Continuous physical activity data (assessed via wrist-worn accelerometer) and concurrent ecological momentary assessment (5X/day) of pain, fatigue, depressed mood, and perceived cognitive function were collected. Data were analyzed using multilevel mixed modeling.

Results

Fatigue and depressed mood demonstrated bidirectional associations with physical activity, whereas pain and cognitive function did not. Higher than usual fatigue (B = -5.83, p = .001) and depressed mood (B = -4.12, p = .03) were followed by decreased physical activity. In contrast, higher than usual physical activity was associated with subsequent decline in fatigue (B = -0.001, p = .02) and depressed mood (B = -0.0007, p = .02); however, the association between physical activity and fatigue varied across the day.

Conclusions

Physical activity is dynamically related to fatigue and mood on a moment-to-moment basis in MS. Efforts to increase physical activity in MS must incorporate a focus on how symptoms affect and are affected by activity.

Clinical recommendations to guide physical therapy practice for Huntington disease

OBJECTIVE

In the past decade, an increasing number of studies have examined the efficacy of physical therapy interventions in people with Huntington disease (HD).

METHODS

We performed a mixed-methods systematic review using Joanna Briggs Institute (JBI) methodology and included experimental and observational study designs. The search resulted in 23 quantitative studies and 3 qualitative studies from which we extracted data using JBI standardized extraction tools. Results of this review suggested that physical therapy interventions may improve motor impairments and activity limitations in people with HD. Here, we expand on the review findings to provide specific recommendations to guide clinical practice.

RESULTS

We recommend the following specific physical therapy interventions for people with HD: aerobic exercise (grade A evidence), alone or in combination with resistance training to improve fitness and motor function, and supervised gait training (grade A evidence) to improve spatiotemporal features of gait. In addition, there is weak (grade B) evidence that exercise training improves balance but does not show a reduction in the frequency of falls; inspiratory and expiratory training improves breathing function and capacity; and training of transfers, getting up from the floor, and providing strategies to caregivers for involvement in physical activity in the midstages of HD may improve performance. There is expert consensus for the use of positioning devices, seating adaptations, and caregiver training in late stages of HD.

CONCLUSIONS

There is strong evidence to support physical therapy interventions to improve fitness, motor function, and gait in persons with HD.

Quantitative vibratory sensation measurement is related to sensory cortical thickness in MS

Objective

Vibratory sensation is a quantifiable measure of physical dysfunction and is often related to spinal cord pathology; however, its association with relevant brain areas has not been fully explored. Our objective was to establish a cortical structural substrate for vibration sensation.

Methods

Eighty‐four individuals with multiple sclerosis (MS) (n = 54 relapsing, n = 30 progressive) and 28 controls participated in vibratory sensation threshold quantification at the great toe and a 3T MRI evaluating volume of the thalamus and cortical thickness primary and secondary sensory cortices.

Results

After controlling for age, sex, and disability level, vibratory sensation thresholds were significantly related to cortical thickness of the anterior cingulate (P = 0.041), parietal operculum (P = 0.022), and inferior frontal gyrus pars operculum (P = 0.044), pars orbitalis (P = 0.007), and pars triangularis (P = 0.029). Within the progressive disease subtype, there were significant relationships between vibratory sensation and thalamic volume (P = 0.039) as well as reduced inferior frontal gyrus pars operculum (P = 0.014) and pars orbitalis (P = 0.005) cortical thickness.

Conclusions

The data show significant independent relationships between quantitative vibratory sensation and measures of primary and secondary sensory cortices. Quantitative clinical measurement of vibratory sensation reflects pathological changes in spatially distinct brain areas and may supplement information captured by brain atrophy measures. Without overt relapses, monitoring decline in progressive forms of MS has proved challenging; quantitative clinical assessment may provide a tool to examine pathological decline in this cohort. These data suggest that quantitative clinical assessment may be a reliable way to examine pathological decline and have broader relevance to progressive forms of MS.

Supplementary motor area connectivity and dual-task walking variability in multiple sclerosis

BACKGROUND

Despite the prevalence of dual-task (e.g., walking while talking) deficits in people with multiple sclerosis (MS), no neuroimaging studies to date have examined neuronal networks used for dual-task processing or specific brain areas related to dual-task performance in this population. A better understanding of the relationship among underlying brain areas and dual-task performance may improve targeted rehabilitation programs. The objective of this study was to examine relationships between neuroimaging measures and clinical measures of dual-task performance, and reported falls in persons with MS.

MATERIALS AND METHODS

All participants completed measures of dual-task performance, a fall history, and neuroimaging on a 3 T MRI scanner. Spearman correlations were used to examine relationships among dual-task performance, falls and neuroimaging measures.

RESULTS

Eighteen females with relapsing-remitting MS [mean age = 45.5 ± 8.2 SD; mean symptom duration = 12.3 ± 6.7 years; Expanded Disability Status Scale median 2.25 (range 1.5-4)] participated in this study. Structural imaging measures of supplementary motor area (SMA) interhemispheric connectivity were significantly related to dual-task walking variability.

CONCLUSIONS

The SMA interhemispheric tract may play a role in dual-task performance. Structural neuroimaging may be a useful adjunct to clinical measures to predict performance and provide information about recovery patterns in MS. Functional recovery can be challenging to objectively report in MS; diffusion tensor imaging could show microstructural improvements and suggest improved connectivity.

Cognitive-Motor Interference in Neurodegenerative Disease: A Narrative Review and Implications for Clinical Management

This paper provides a narrative review of cognitive motor interference in neurodegeneration, including brain imaging findings specific to interference effects in neurodegenerative disease, and dual task assessment and intervention in Parkinson’s disease (PD), multiple sclerosis (MS), and Huntington’s disease (HD). In a healthy central nervous system the ability to process information is limited. Limitations in capacity to select and attend to inputs influence the ability to prepare and perform multiple tasks. As a result, the system balances demands, switching attention to the most task-relevant information as it becomes available. Limitations may become more apparent in persons with neurodegenerative diseases (ND) with system-specific impairments in PD, MS, and HD. These ND affect both cognitive and motor function and are thus particularly susceptible to dual task interference. Issues related to performer and task characteristics and implications of these findings for both the standard assessment of dual task abilities as well as development and evaluation of interventions aimed at improving dual task ability are discussed. In addition, we address the need for optimizing individualized assessment, intervention and evaluation of dual task function by choosing cognitive and motor tasks and measures that are sensitive to and appropriate for the individual’s level of function. Finally, we use current evidence to outline a 5-step process of clinical decision making that uses the dual task taxonomy as a framework for assessment and intervention.

Cognitive Dysfunction Contributes to Mobility Impairments in Huntington's Disease

Background:

Huntington’s disease (HD) is a progressive neurodegenerative disorder that results in a gradual decline in mobility and balance. Increasing evidence has documented an important role of executive function in the safe ambulation of the elderly and people with a variety of neurological disorders. Little is known about the contribution of cognitive deficits to decline in mobility over time in HD.

Objective:

This study examined the relationships of mobility, motor and cognitive function measures at baseline, and of mobility and cognitive measures over four years.

Methods:

A retrospective chart review was performed on 70 patients with genetically confirmed HD (age 20–75 years old) across 121 HD clinic visits. Correlations between Unified Huntington’s Disease Rating Scale – Total Motor, Tinetti Mobility Test (TMT), and cognitive measures (Letter Verbal Fluency, Symbol Digit Modalities Test (SDMT), and Stroop Test) were analyzed. Longitudinal relationships between TMT and cognitive measures were examined using mixed effect regression models.

Results:

Gait and balance measures representing domains of mobility (TMT scores) were significantly correlated with each of the cognitive measures with the exception of the Verbal Fluency score. Mixed effects regression modeling showed that the Stroop Interference sub-test and SDMT were significant predictors (p-values <0.01) of TMT total scores.

Conclusions:

Impairments in executive function measures correlate highly with measures of gait, balance and mobility in individuals with HD. Interventions designed to improve mobility and decrease fall risk should also address issues of cognitive impairments with particular consideration given to interventions that may focus on motor-cognitive dual task training.

Physical Therapy and Exercise Interventions in Huntington's Disease: A Mixed Methods Systematic Review

Background:

A number of studies evaluating physical therapy and exercise interventions in Huntington’s disease have been conducted over the past 15 years. However, an assessment of the quality and strength of the evidence in support of these interventions is lacking.

Objective:

The purpose of this systematic review was to investigate the effectiveness of physical therapy and exercise interventions in people with Huntington’s disease, and to examine the perceptions of patients, families and caregivers of these interventions.

Methods:

This mixed-methods systematic review utilized the Joanna Briggs Institute (JBI) approach and extraction tools to evaluate the literature from January 2003 until May 2016. The review considered interventions that included exercise and physical therapy interventions, and included both quantitative and qualitative outcome measures.

Results:

Twenty (20) studies met the inclusion criteria, including eighteen (18) that had quantitative outcome measures and two (2) that utilized qualitative methods. JBI Levels of evidence for the 18 quantitative studies were as follows: Eight studies were at evidence Level 1, seven were at Level 2, two were at Level 3, and one was at Level 4.

Conclusions:

Our review suggests that there is preliminary support for the benefits of exercise and physical activity in Huntington’s disease in terms of motor function, gait speed, and balance, as well as a range of physical and social benefits identified through patient-reported outcomes. Variability in mode of intervention as well as outcome measures limits the interpretability of these studies, and high-quality studies that incorporate adaptive trial designs for this rare disease are needed.

Relationships Among Apathy, Health-Related Quality of Life, and Function in Huntington's Disease

Up to 90% of individuals with Huntington's disease (HD)-a progressive, inherited neurodegenerative disorder-experience apathy. Apathy is particularly debilitating because it is marked by a reduction in goal-directed behaviors, including self-care, social interactions, and mobility. The objective of this study was to examine relationships between variables of apathy, functional status, physical function, cognitive function, behavioral status/emotional function, and health-related quality of life. Clinician-rated measures of physical, cognitive, and behavioral function, including one clinician-rated item on apathy, and self-reported measures of physical function, health-related quality of life, and emotional, cognitive, and social function were collected in a single session from 487 persons with the HD mutation (prodromal, N=193; early-stage manifest, N=186; late-stage manifest, N=108). Multiple linear regression models were used to examine which outcomes best predicted clinician-rated apathy after controlling for disease stage. Greater apathy related to less independence, increased motor impairment, and more clinician-rated behavioral problems (i.e., anger, irritability, depression). Similarly, poorer self-reported health-related quality of life; greater chorea; greater upper- and lower-extremity dysfunction; greater speech and swallowing dysfunction; worse anxiety, depression, and behavioral dyscontrol; worse cognitive function; and less satisfaction with social roles related to greater apathy. In conclusion, apathy related to physical, cognitive, and behavioral dysfunction across disease stages. Future work should explore whether clinical interventions targeting different functional domains may have the potential to reduce apathy in this patient population.

Distinguishing among multiple sclerosis fallers, near-fallers and non-fallers

BACKGROUND

Fall rates among adults with multiple sclerosis are consistently greater than 50%, but near-falls (i.e. a trip or stumble) are often undocumented. Furthermore, little is known about the circumstances surrounding fall and near-fall events. The purpose of this study was to examine the similarities and differences among non-fallers, near-fallers and fallers with multiple sclerosis, including the circumstances that surround falls and near-falls.

METHODS

In a single visit, 135 multiple sclerosis participants completed the Hopkins Falls Grading Scale, a custom questionnaire investigating circumstances surrounding falls and near-falls, and performed the Timed Up and Go and Timed 25-Foot Walk tests. Mann-Whitney tests were used to examine differences between fallers, near-fallers and non-fallers. Multiple logistic regression with AIC criterion was used to examine associations of circumstances with the odds of falling vs. near-falling. Cumulative odds ordinal logistic regression was used to analyze the association between each of the walking tests and the susceptibility of the individual for falls or near-falls.

RESULTS

30% of individuals reported falls, while 44% reported near-falls over a 1-year period. Non-fallers completed the walking tests more quickly than near-fallers (p < 0.0045), and fallers (p < 0.0001); near-fallers and fallers demonstrated similar motor profiles. Individuals were more likely to sustain a fall rather than a near-fall under the following circumstances: transferring outside the home (p = 0.015) and tripping over an obstacle (p = 0.025). Performing 1-second slower on the walking tests increased the odds of a history of a fall by 6-20%.

CONCLUSION

Near-falls occur commonly in individuals with MS; near-fallers and fallers reported similar circumstances surrounding fall events and demonstrated similar performance on standard timed walking tests. Clinicians monitoring individuals with MS should consider evaluation of the circumstances surrounding falls in combination with quantitative walking measures to improve determination of fall risk and appropriate rehabilitation interventions.

Handgrip strength as a means of monitoring progression of cognitive decline - A scoping review

Cognitive decline in older adults contributes to reduced ability to perform daily tasks and continued disuse leads to muscle weakness and potentiates functional loss. Despite explicit links between the motor and cognitive systems, few health care providers assess motor function when addressing the needs of individuals with cognitive loss. Early and easy measurable biomarkers of cognitive decline have the potential to improve care for individuals with dementia and mild cognitive impairment. The aim of this study was to conduct a systematic search to determine the relationship among handgrip strength, as a measure of global muscle strength, and cognitive decline over time. Fifteen prospective, cohort, longitudinal studies of adults >60years old who were healthy or at risk of cognitive decline at study onset were included in the review. Studies that investigated changes in cognition relative to baseline grip strength and, those that investigated changes in grip strength relative to cognitive function were revealed. Findings here support the use of handgrip strength as a way to monitor cognitive changes and show that reduced handgrip strength over time may serve as a predictor of cognitive loss with advancing age.

Pain, cognition and quality of life associate with structural measures of brain volume loss in multiple sclerosis

BACKGROUND

Multiple sclerosis (MS) is characterized by physical and mental impairments that often result in pain and reduced quality of life.

OBJECTIVE

To understand the relationship of pain, quality of life, and cognition to structural measures of brain volume.

METHODS

Behavioral measures were assessed in a single session using standardized questionnaires and rating scales. Brain volume measures were assessed with structural magnetic resonance imaging (MRI).

RESULTS

Twenty-nine individuals with relapsing-remitting MS and 29 age-matched controls participated in this study. Pain, quality of life, and cognition were significantly interrelated. Higher fluid attenuation inversion recovery weighted lesion volume was significantly associated with increased reports of pain (p = 0.01), lower physical quality of life (p < 0.0001), and lower cognitive performance (p = 0.001) in our cohort.

CONCLUSIONS

Assessment of pain and quality of life along with structural MRI highlights the importance of understanding structure-function relationships in MS and suggests that therapists should not only evaluate individuals for cognition and quality of life, but should consider rehabilitation goals that target these areas.

Quantitative biomechanical assessment of trunk control in Huntington's disease reveals more impairment in static than dynamic tasks

Postural instability is common in individuals with Huntington's disease (HD), yet little is known about control of the trunk during static and dynamic activities. We compared the trunk motion of 41 individuals with HD and 36 controls at thoracic and pelvic levels during sitting, standing, and walking using wearable iPod sensors. We also examined the ability of individuals with HD to respond to an auditory cue to modify trunk position when the pelvis moved >8° in sagittal or frontal planes during sitting using custom software. We found that amplitude of thoracic and pelvic trunk movements was significantly greater in participants with HD, and differences were more pronounced during static (i.e. sitting, standing) than dynamic (i.e. walking) tasks. In contrast to the slow, smooth sinusoidal trunk movements of controls, individuals with HD demonstrated rapid movements with varying amplitudes that continuously increased without stabilizing. Ninety-seven percent of participants with HD were able to modify their trunk position in response to auditory cues. Our results demonstrate that wearable iPod sensors are clinically useful for rehabilitation professionals to measure and monitor trunk stability in persons with HD. Additionally, auditory cueing holds potential as a useful training tool to improve trunk stability in HD.

Quantitative measures of walking and strength provide insight into brain corticospinal tract pathology in multiple sclerosis

At least 85% of individuals with multiple sclerosis report walking dysfunction as their primary complaint. Walking and strength measures are common clinical measures to mark increasing disability or improvement with rehabilitation. Previous studies have shown an association between strength or walking ability and spinal cord MRI measures, and strength measures with brainstem corticospinal tract magnetization transfer ratio. However, the relationship between walking performance and brain corticospinal tract magnetization transfer imaging measures and the contribution of clinical measurements of walking and strength to the underlying integrity of the corticospinal tract has not been explored in multiple sclerosis. The objectives of this study were explore the relationship of quantitative measures of walking and strength to whole-brain corticospinal tract-specific MRI measures and to determine the contribution of quantitative measures of function in addition to basic clinical measures (age, gender, symptom duration and Expanded Disability Status Scale) to structural imaging measures of the corticospinal tract. We hypothesized that quantitative walking and strength measures would be related to brain corticospinal tract-specific measures, and would provide insight into the heterogeneity of brain pathology. Twenty-nine individuals with relapsing-remitting multiple sclerosis (mean(SD) age 48.7 (11.5) years; symptom duration 11.9(8.7); 17 females; median[range] Expanded Disability Status Scale 4.0 [1.0-6.5]) and 29 age and gender-matched healthy controls (age 50.8(11.6) years; 20 females) participated in clinical tests of strength and walking (Timed Up and Go, Timed 25 Foot Walk, Two Minute Walk Test ) as well as 3 T imaging including diffusion tensor imaging and magnetization transfer imaging. Individuals with multiple sclerosis were weaker (p = 0.0024) and walked slower (p = 0.0013) compared to controls. Quantitative measures of walking and strength were significantly related to corticospinal tract fractional anisotropy (r > 0.26; p < 0.04) and magnetization transfer ratio (r > 0.29; p < 0.03) measures. Although the Expanded Disability Status Scale was highly correlated with walking measures, it was not significantly related to either corticospinal tract fractional anisotropy or magnetization transfer ratio (p > 0.05). Walk velocity was a significant contributor to magnetization transfer ratio (p = 0.006) and fractional anisotropy (p = 0.011) in regression modeling that included both quantitative measures of function and basic clinical information. Quantitative measures of strength and walking are associated with brain corticospinal tract pathology. The addition of these quantitative measures to basic clinical information explains more of the variance in corticospinal tract fractional anisotropy and magnetization transfer ratio than the basic clinical information alone. Outcome measurement for multiple sclerosis clinical trials has been notoriously challenging; the use of quantitative measures of strength and walking along with tract-specific imaging methods may improve our ability to monitor disease change over time, with intervention, and provide needed guidelines for developing more effective targeted rehabilitation strategies.

Motor-cognitive dual-task deficits in individuals with early-mid stage Huntington disease

BACKGROUND

Huntington disease (HD) results in a range of cognitive and motor impairments that progress throughout the disease stages; however, little research has evaluated specific dual-task abilities in this population, and the degree to which they may be related to functional ability.

OBJECTIVES

The purpose of this study was to a) examine simple and complex motor-cognitive dual-task performance in individuals with HD, b) determine relationships between dual-task walking ability and disease-specific measures of motor, cognitive and functional ability, and c) examine the relationship of dual-task measures to falls in individuals with HD.

METHODS

Thirty-two individuals with HD were evaluated for simple and complex dual-task ability using the Walking While Talking Test. Demographics and disease-specific measures of motor, cognitive and functional ability were also obtained.

RESULTS

Individuals with HD had impairments in simple and complex dual-task ability. Simple dual-task walking was correlated to disease-specific motor scores as well as cognitive performance, but complex dual-task walking was correlated with total functional capacity, as well as a range of cognitive measures. Number of prospective falls was moderately-strongly correlated to dual-task measures.

CONCLUSIONS

Our results suggest that individuals with HD have impairments in cognitive-motor dual-task ability that are related to disease progression and specifically functional ability. Dual-task measures appear to evaluate a unique construct in individuals with early to mid-stage HD, and may have value in improving the prediction of falls risk in this population.