Lori Quinn

Coordination of Prehensile Forces during Precision Grip in Huntington's Disease

The present study examined the coordination of prehensile forces during precision grip in subjects with Huntingtons disease (HD). Fingertip forces were measured in 12 subjects with HD and 12 age-matched controls during the lifting of an instrumented object whose weight and surface texture were varied. The results indicate that subjects with HD have impaired initiation and delayed transitions between movement sequences and produce excessive and variable forces. However, subjects with HD demonstrated anticipatory scaling of force development based on the objects expected physical properties (planning) and adjustment of the force to the objects actual physical properties (sensorimotor integration). The observed findings generally were unrelated to the overall disease severity. However, the variability in forces was correlated with functional capacity and motor performance suggesting that variability is a key feature of the motor deficit. These results provide insights into the impaired hand function observed in individuals with HD.

Reliability of spatiotemporal gait outcome measures in Huntington's disease

Gait impairments are very important in Huntingtons disease (HD), because loss of independence in gait is an important predictor of nursing home placement. Given this importance, it is imperative to test reliable and sensitive outcome measures that can be tested easily in various clinical environments. Here, we examined the test–retest reliability of gait outcome measures using the GAITRite instrumented carpet. We tested 12 subjects with HD and 12 age‐matched controls in two separate sessions. At each session, subjects walked across the GAITRite carpet at a comfortable speed. We used the intraclass correlation coefficient (ICC) and coefficient of variation (CoV) to measure test–retest reliability. Reliability was very high for all outcome measures (velocity, cycle time, stride length, cadence, and base of support), as seen by high ICC scores (0.86 to 0.95) and low CoV scores (0.042–0.102). In addition, the performance across the two subject groups was very different, indicating that the GAITRite is sensitive enough to distinguish between populations. Given that the GAITRite is a relatively inexpensive and portable piece of equipment, it can be used in a wide variety of clinical settings and clinical trials. Our data on high test–retest reliability and sensitivity extends the utility of the GAITRite to the HD population.

Dystonia in Huntington's disease: Prevalence and clinical characteristics

The prevalence and clinical characteristics of dystonia in Huntingtons disease (HD) have not been formally assessed.

Applying principles of motor learning and control to upper extremity rehabilitation

The purpose of this article is to provide a brief review of the principles of motor control and learning. Different models of motor control from historical to contemporary are presented with emphasis on the Systems model. Concepts of motor learning including skill acquisition, measurement of learning, and methods to promote skill acquisition by examining the many facets of practice scheduling and use of feedback are provided. A fictional client case is introduced and threaded throughout the article to facilitate understanding of these concepts and how they can be applied to clinical practice.

What effect does a structured home-based exercise programme have on people with Huntington’s disease? A randomized, controlled pilot study

Objective: The aim of this study was to explore feasibility, safety and outcome of an exercise intervention in people with Huntington’s disease. Design: A randomized controlled pilot trial. Setting: A home-based exercise programme. Subjects: A total of 25 subjects with early to mid-stage Huntington’s disease. Intervention: Subjects were randomly allocated to either an exercise intervention (n = 13) or a control group (n = 12). Subjects in the exercise intervention group were asked to perform exercises at home three times a week for eight weeks using an exercise DVD, specifically developed for this purpose. The control group received their usual care. Measures: Adherence in the intervention group was calculated from exercise diaries. Measures of gait, balance, function, level of physical activity and quality of life were evaluated. Analysis of covariance was used to compare follow-up scores across groups after adjustment for chance baseline differences. Effect sizes were calculated. Results: Eleven participants from the intervention and ten from the control group completed the study. Mean adherence was 29.4 SD 1.8 for the 32 prescribed sessions. There were no related adverse events. Differences between groups were observed in gait speed, balance, function and level of physical activity, but not quality of life as measured by the SF36. Effect sizes were large (>0.8) for the majority of the outcomes. Conclusions: Short-term structured home exercise programmes are feasible, beneficial and safe for people with early to mid-stage of Huntington’s disease. Our findings support the implementation of a larger trial of longer-term home exercise.

Objective assessment of progression in Huntington’s disease: A 3-year follow-up study

Objective measures to assess progression of Huntington’s disease (HD) are desirable. The authors have previously found that patients with HD with higher Unified Huntington’s Disease Rating Scale (UHDRS) motor scores exhibited higher variability of isometric grip forces while grasping an object. Therefore, the authors assessed grip force variability during this task in 10 HD patients with a 3-year follow-up. Grip force variability increased in all patients at the follow-up. Thus, grip force variability during grasping might be an objective and quantitative measure to assess motor deficits associated with the progression of HD.

A randomized feasibility study of a 12-week community-based exercise program for people with Huntington's Disease

Background and Purpose: The beneficial role of exercise as a treatment approach in Huntingtons disease (HD) has support from both preclinical work and small-scale studies; however, there have been no controlled studies of gym-based exercise in people with HD. This phase 2 randomized trial (ISRCTN 59910670) assessed feasibility, safety, acceptability, and benefit of a structured exercise program. Methods: Thirty-one participants (16 men; mean [SD] age = 50.4 [11.4] years) were randomly allocated to intervention (n = 16) or control group (usual care; n = 15). The intervention entailed a weekly supervised gym session of stationary cycling and resistance exercises, and a twice weekly independent home-based walking program. Retention and adherence rates and adverse events were recorded. Acceptability was determined from subjective reports of tolerability and physiological measures recorded during the gym sessions. Assessment of benefit included measures of physical abilities, disease severity, and quality of life (36-Item Short Form Health Survey). Analysis of covariance was used to test outcomes of interest. Results: The retention rate was 81% (9 of the 11 individuals who started the intervention completed it) and of the 9 who completed the program, 7 attended more than 75% (9/12) of the gym sessions. There were no related adverse events and the intervention was well tolerated by most participants. The between-group effect estimate for the Mental Component Summary score of the 36-Item Short Form Health Survey (n = 9; intervention, n = 13; control) was 7 (95% CI: 0.4–13.7) Moderate effect sizes for cognitive outcomes and measures of walking were also observed. Discussion and Conclusions: Observed effect sizes for clinical outcomes suggest the structured exercise program has benefit for persons with HD; larger scale trials are warranted. Video Abstract available (see Video, Supplemental Digital Content 1, http://links.lww.com/JNPT/A60) for more insights from the authors.

Physical Therapy Intervention for People With Huntington Disease

Background and Purpose: The clinical symptoms of Huntington disease (HD) include progressive movement disorders, cognitive deficits, and behavioral changes, all of which affect an individuals ability to participate in activities of daily living. To date, very few quantitative or qualitative studies have been conducted to guide physical therapists working with people with HD. The objective of this study was to characterize current physical therapist practice for people with HD, thus informing the development of standardized clinical care and future research studies. Subjects and Methods: Consultation with physical therapists working with people with HD was undertaken in the form of mailed questionnaires (n=49) and semistructured interviews (n=8). The development of the interview schedule was aided by consideration of the data obtained from the questionnaires. Themes identified from the interviews were considered in light of published literature and questionnaire responses. Results: The main issues that emerged from the interviews were classified into 3 subthemes: (1) there is insufficient use of routine physical therapy–related outcome measures at different stages of HD, (2) there is underutilization of physical therapy services in managing HD (particularly in the early stages), and (3) the management of falls and mobility deficit progression is a key treatment aim for people with HD. Discussion and Conclusion: A conceptual framework for physical therapy intervention in HD was developed on the basis of the themes that emerged from the data in this study. Such a framework has utility for complex, progressive conditions such as HD and may facilitate clinical decision making and standardization of practice and affect the development of future physical therapy trials.

Altered movement trajectories and force control during object transport in Huntington's disease.

Individuals with Huntingtons Disease (HD) have difficulty grasping and transporting objects, however, the extent to which specific impairments affect their performance is unknown. The present study examined the kinematics and force coordination during transport of an object in 12 subjects with HD and 12 age‐matched controls. Subjects grasped an object between their thumb and index finger, transported it 25 cm forward, replaced and released it while their fingertip forces and the objects position were recorded. Five trials were performed with each of three weights (200 g, 400 g, and 800 g). While bradykinesia was evident in subjects with HD, this slowness was not consistently observed in all phases of the movement. The slowness of movement seen during the task appears to be due to impairments in sequencing and the movement strategies selected by the subjects. Compared to control subjects, subjects with HD produced highly curvilinear hand paths and more variable grip forces that were dependent on the weight of the object. Isometric force development and movement speed during transport were unaffected by the disease. The results suggest that prolonged task durations in subjects with HD are not necessarily due to slowness of movement, per se. These findings have clinical implications for understanding the task‐specific nature of movement impairments in HD and developing effective intervention strategies.

Adherence to Use of a Home-Based Exercise DVD in People With Huntington Disease: Participants' Perspectives

Background Individualized exercise instruction on a regular basis may be desirable for people with Huntington disease (HD). Sustained interventions, however, may not be the most feasible for lifelong disease management. It is critical, therefore, for physical therapists to find ways to facilitate engagement in independent exercise programs. The capabilities of DVD technology can make the DVD a useful format to facilitate engagement for people with HD who have motivational and cognitive problems. Objective The purpose of this study was to explore how people with HD used a home-based exercise DVD and how it was perceived by the participants and their caregivers. Design An exploratory, mixed-method design was used in this study. Methods Fifteen participants with HD were provided with an exercise DVD, developed by the authors, to support their engagement in a home-based exercise program. Exercise diaries were used to record adherence rates. Semistructured interviews were conducted to explore what factors affected the usability of the DVD. Conversations were audio recorded and fully transcribed. Content analysis approach was used to analyze the interviews. Results Most of the participants (11/15, 73.3%) adhered well to the use of the DVD. Participants felt that the exercises were suitable. Commitment of the caregiver as a key to the success of the program was the main theme that emerged from the data. Participants identified barriers and facilitators that affected adherence to using the exercise DVD and described management strategies that helped promote adherence to the exercise program. Conclusions The DVD was perceived to be suitable and supportive. The DVD could be appropriate for use in supporting people with HD to engage in exercise at home, either outside of therapy sessions or upon completion of a therapy program.