The effect of rehabilitation interventions on freezing of gait in people with Parkinson's disease is unclear: a systematic review and meta-analyses.

PURPOSE: To summarize the effects of rehabilitation interventions to reduce freezing of gait (FOG) in people with Parkinson's disease. METHODS: A systematic review with meta-analyses of randomized trials of rehabilitation interventions that reported a FOG outcome was conducted. Quality of included studies and certainty of FOG outcome were assessed using the PEDro scale and GRADE framework. RESULTS: Sixty-five studies were eligible, with 62 trialing physical therapy/exercise, and five trialing cognitive and/or behavioral therapies. All meta-analyses produced very low-certainty evidence. Physical therapy/exercise had a small effect on reducing FOG post-intervention compared to control (Hedges' g= -0.26, 95% CI= -0.38 to -0.14, 95% prediction interval (PI)= -0.38 to -0.14). We are uncertain of the effects on FOG post-intervention when comparing: exercise with cueing to without cueing (Hedges' g= -0.58, 95% CI= -0.86 to -0.29, 95% PI= -1.23 to 0.08); action observation training plus movement strategy practice to practice alone (Hedges' g= -0.56, 95% CI= -1.16 to 0.05); and dance to multimodal exercises (Hedges' g= -0.64, 95% CI= -1.53 to 0.25). CONCLUSIONS: We are uncertain if physical therapy/exercise, cognitive or behavioral therapies, are effective at reducing FOG.Implications for rehabilitationFOG leads to impaired mobility and falls, but the effect of rehabilitation interventions (including physical therapy/exercise and cognitive/behavioral therapies) on FOG is small and uncertain.Until more robust evidence is generated, clinicians should assess FOG using both self-report and physical measures, as well as other related impairments such as cognition, anxiety, and fear of falling.Interventions for FOG should be personalized based on the individual's triggers and form part of a broader exercise program addressing gait, balance, and falls prevention.Interventions should continue over the long term and be closely monitored and adjusted as individual circumstances change.

The Ziegler Test Is Reliable and Valid for Measuring Freezing of Gait in People With Parkinson Disease.

OBJECTIVE: The purpose of this study was to determine interrater and test-retest reliability of the Ziegler test to measure freezing of gait (FOG) severity in people with Parkinson disease. Secondary aims were to evaluate test validity and explore Ziegler test duration as a proxy FOG severity measure. METHODS: Physical therapists watched 36 videos of people with Parkinson disease and FOG perform the Ziegler test and rated FOG severity using the rating scale in real time. Two researchers rated 12 additional videos and repeated the ratings at least 1 week later. Interrater and test-retest reliability were calculated using intraclass correlation coefficients (ICCs). Bland-Altman plots were used to visualize agreement between the researchers for test-retest reliability. Correlations between the Ziegler scores, Ziegler test duration, and percentage of time frozen (based on video annotations) were determined using Pearson r. RESULTS: Twenty-four physical therapists participated. Overall, the Ziegler test showed good interrater (ICC2,1 = 0.80; 95% CI = 0.65-0.92) and excellent test-retest (ICC3,1 = 0.91; 95% CI = 0.82-0.96) reliability when used to measure FOG. It was also a valid measure, with a high correlation (r = 0.72) between the scores and percentage of time frozen. Ziegler test duration was moderately correlated (r = 0.67) with percentage of time frozen and may be considered a proxy FOG severity measure. CONCLUSION: The Ziegler test is a reliable and valid tool to measure FOG when used by physical therapists in real time. Ziegler test duration may be used as a proxy for measuring FOG severity. IMPACT: Despite FOG being a significant contributor to falls and poor mobility in people with Parkinson disease, current tools to assess FOG are either not suitably responsive or too resource intensive for use in clinical settings. The Ziegler test is a reliable and valid measure of FOG, suitable for clinical use, and may be used by physical therapists regardless of their level of clinical experience.

The accuracy of self-report logbooks of adherence to prescribed home-based exercise in Parkinson's disease.

PURPOSE: This study compared self-report logbooks of exercise performance to objective measures of performance to determine the accuracy of and patterns of misreporting in self-report logbooks in people with Parkinson's disease. MATERIALS AND METHODS: Fifteen participants from the intervention arm of a randomized control trial were prescribed a minimally supervised, 12-week, home-based upper limb exergame program (ACTRN 12614001048673). The exergame system provided an objective electronic measure of adherence for comparison with self-report logbooks. RESULTS: Logbooks showed excellent to good accuracy of overall reported adherence to prescribed sessions (Intraclass correlation (ICC) = 0.83) and games (ICC 0.71). Logbooks were also a good to fair representation of weekly adherence across participants for both sessions (ICC 0.66) and games (ICC 0.56). Individual participant ICCs ranged from minimal to perfect agreement between logbooks and electronic records (ICC sessions range: -0.02 to 1; games range: -0.24 to 0.99). The pattern of logbook reporting suggested some participants were biasing entries to match prescribed exercise. CONCLUSIONS: Self-report logbooks may provide an accurate measure of overall adherence. However, the accuracy of individual logbooks was highly variable indicating caution is needed in using self-report measures to assess individual adherence in intervention studies and for clinical decision making. Clinical Trial Registration: Registered in Australia and New Zealand Clinical Trials Registry (https://www.anzctr.org.au/): Registration number: ACTRN12614001048673.Implications for rehabilitationAdherence to prescribed unsupervised exercise is usually self-reported.Self-reported logbooks gave a good to excellent indication of exercise adherence overall when compared to electronically captured records for a group of participants with mild to moderate Parkinson's disease.There were high levels of variability in the accuracy of individual logbooks with a tendency to record prescribed rather than actual exercise.Logbooks may be accurate to monitor group adherence, but caution is required when using them to assess an individual's adherence to an exercise prescription.

How does perceived fall risk influence decisions about whether to undertake activities in people with Parkinson's disease and their care partners? A qualitative study.

PURPOSE: To explore how perceptions of fall risk influence decisions to undertake activities in people with Parkinson's disease who have fallen, along with their care-partners. MATERIALS AND METHODS: This qualitative study used semi-structured interviews to collect data from eight people with moderate to severe Parkinson's Disease and freezing of gait (including those with cognitive impairments) and their care-partners. An inductive approach to thematic analysis was used to analyse the data. RESULTS: Four main, interconnected themes emerged, and a framework was developed to illustrate these connections. Weighing up the risks and benefits reflected the constant tension between assessing the likelihood of falling and potential benefit of any activity; Being fearful heightened the perceived risk resulting in a tendency to avoid or modify activities; Desire to lead a normal life heightened the perceived benefit of any activity, leading towards risk taking behaviour; It's a part of Parkinson's provided the context in which the decision-making process took place, with the reality of a progressive disorder influencing choices and contributing to a belief that falls were inevitable. CONCLUSIONS: There is a complex interaction between perceptions of fall risk and behaviour. An understanding of these interactions will assist therapists to tailor individualised fall prevention interventions.IMPLICATIONS FOR REHABILITATIONPeople are constantly weighing up the risks and benefits of activities while balancing fear of falling and a desire to lead a normal life in the context of Parkinson's disease.The resulting activity choices vary along a continuum from avoiding activities to taking risks, with a common approach to minimise the risk and then embrace the activity.Therapists can help people with Parkinson's and their care-partners to determine what level of risk is acceptable for them when balancing risk with quality of life.Understanding how people decide if they will undertake an activity that poses a risk of falling will allow therapists and patients to co-design fall prevention and management interventions based on the patient's values and priorities.

A Video Self-Modeling Intervention Using Virtual Reality Plus Physical Practice for Freezing of Gait in Parkinson Disease: Feasibility and Acceptability Study.

BACKGROUND: Despite optimal medical and surgical intervention, freezing of gait commonly occurs in people with Parkinson disease. Action observation via video self-modeling, combined with physical practice, has potential as a noninvasive intervention to reduce freezing of gait. OBJECTIVE: The aim of this study is to determine the feasibility and acceptability of a home-based, personalized video self-modeling intervention delivered via a virtual reality head-mounted display (HMD) to reduce freezing of gait in people with Parkinson disease. The secondary aim is to investigate the potential effect of this intervention on freezing of gait, mobility, and anxiety. METHODS: The study was a single-group pre-post mixed methods pilot trial for which 10 participants with Parkinson disease and freezing of gait were recruited. A physiotherapist assessed the participants in their homes to identify person-specific triggers of freezing and developed individualized movement strategies to overcome freezing of gait. 180° videos of the participants successfully performing their movement strategies were created. Participants watched their videos using a virtual reality HMD, followed by physical practice of their strategies in their own homes over a 6-week intervention period. The primary outcome measures included the feasibility and acceptability of the intervention. Secondary outcome measures included freezing of gait physical tests and questionnaires, including the Timed Up and Go Test, 10-meter walk test, Goal Attainment Scale, and Parkinson Anxiety Scale. RESULTS: The recruitment rate was 24% (10/42), and the retention rate was 90% (9/10). Adherence to the intervention was high, with participants completing a mean of 84% (SD 49%) for the prescribed video viewing and a mean of 100% (SD 56%) for the prescribed physical practice. One participant used the virtual reality HMD for 1 week and completed the rest of the intervention using a flat-screen device because of a gradual worsening of his motion sickness. No other adverse events occurred during the intervention or assessment. Most of the participants found using the HMD to view their videos interesting and enjoyable and would choose to use this intervention to manage their freezing of gait in the future. Five themes were constructed from the interview data: reflections when seeing myself, my experience of using the virtual reality system, the role of the virtual reality system in supporting my learning, developing a deeper understanding of how to manage my freezing of gait, and the impact of the intervention on my daily activities. Overall, there were minimal changes to the freezing of gait, mobility, or anxiety measures from baseline to postintervention, although there was substantial variability between participants. The intervention showed potential in reducing anxiety in participants with high levels of anxiety. CONCLUSIONS: Video self-modeling using an immersive virtual reality HMD plus physical practice of personalized movement strategies is a feasible and acceptable method of addressing freezing of gait in people with Parkinson disease.

Executive Functioning, Muscle Power and Reactive Balance Are Major Contributors to Gait Adaptability in People With Parkinson's Disease.

Background and Aim: The ability to adapt gait when negotiating unexpected hazards is crucial to maintain stability and avoid falling. This study investigated cognitive, physical and psychological factors associated with gait adaptability required for obstacle and stepping target negotiation in people with Parkinson's disease (PD). Methods: Fifty-four people with PD were instructed to either: (a) avoid an obstacle at usual step distance; or (b) step onto a target at either a short or long step distance projected on a walkway two heel strikes ahead and then continue walking. Participants also completed clinical [Hoehn & Yahr rating scale; Movement Disorders Society version of the Unified Parkinson's Disease Rating Scale motor section (MDS-UPDRS-III)], cognitive [simple reaction time, Trail Making and Stroop stepping (difference between incongruent and standard Choice Stepping Reaction Time, CSRT) tests], physical [hip abductor muscle power and reactive balance (pull test from the MDS-UPDRS-III)] and psychological (Fall Efficacy Scale-International) assessments. Results: Discriminant function analysis revealed Stroop stepping test (inhibitory control) performance was the best predictor of stepping errors across the Gait Adaptability Test (GAT) conditions. Poorer executive function [Trail Making Test (TMT)] and reactive balance predicted poorer stepping accuracy in the short target condition; poorer reactive balance predicted increased number of steps taken to approach the obstacle and the long target; and poorer executive function predicted obstacle avoidance. Weaker hip abductor muscle power, poorer reactive balance, slower reaction time, poorer executive function and higher concern about falling were significant predictors of shorter step length while negotiating the obstacle/targets. Conclusion: Superior executive function, effective reactive balance and good muscle power were associated with successful gait adaptability. Executive function and reactive balance appear particularly important for precise foot placements; and cognitive capacity for step length adjustments for avoiding obstacles. These findings suggest that impaired inhibitory control contributes to stepping errors and may increase fall risk in people with PD. These findings help elucidate mechanisms for why people with PD fall and may facilitate fall risk assessments and fall prevention strategies for this group.

Stepping reaction time and gait adaptability are significantly impaired in people with Parkinson's disease: Implications for fall risk.

BACKGROUND: Decline in the ability to take effective steps and to adapt gait, particularly under challenging conditions, may be important reasons why people with Parkinson's disease (PD) have an increased risk of falling. This study aimed to determine the extent of stepping and gait adaptability impairments in PD individuals as well as their associations with PD symptoms, cognitive function and previous falls. METHODS: Thirty-three older people with PD and 33 controls were assessed in choice stepping reaction time, Stroop stepping and gait adaptability tests; measurements identified as fall risk factors in older adults. RESULTS: People with PD had similar mean choice stepping reaction times to healthy controls, but had significantly greater intra-individual variability. In the Stroop stepping test, the PD participants were more likely to make an error (48 vs 18%), took 715 ms longer to react (2312 vs 1517 ms) and had significantly greater response variability (536 vs 329 ms) than the healthy controls. People with PD also had more difficulties adapting their gait in response to targets (poorer stepping accuracy) and obstacles (increased number of steps) appearing at short notice on a walkway. Within the PD group, higher disease severity, reduced cognition and previous falls were associated with poorer stepping and gait adaptability performances. CONCLUSIONS: People with PD have reduced ability to adapt gait to unexpected targets and obstacles and exhibit poorer stepping responses, particularly in a test condition involving conflict resolution. Such impaired stepping responses in Parkinson's disease are associated with disease severity, cognitive impairment and falls.

Home-based step training using videogame technology in people with Parkinson's disease: a single-blinded randomised controlled trial.

OBJECTIVES: To determine whether 12-week home-based exergame step training can improve stepping performance, gait and complementary physical and neuropsychological measures associated with falls in Parkinson's disease. DESIGN: A single-blinded randomised controlled trial. SETTING: Community (experimental intervention), university laboratory (outcome measures). SUBJECTS: Sixty community-dwelling people with Parkinson's disease. INTERVENTIONS: Home-based step training using videogame technology. MAIN MEASURES: The primary outcomes were the choice stepping reaction time test and Functional Gait Assessment. Secondary outcomes included physical and neuropsychological measures associated with falls in Parkinson's disease, number of falls over six months and self-reported mobility and balance. RESULTS: Post intervention, there were no differences between the intervention ( n = 28) and control ( n = 25) groups in the primary or secondary outcomes except for the Timed Up and Go test, where there was a significant difference in favour of the control group ( P = 0.02). Intervention participants reported mobility improvement, whereas control participants reported mobility deterioration-between-group difference on an 11-point scale = 0.9 (95% confidence interval: -1.8 to -0.1, P = 0.03). Interaction effects between intervention and disease severity on physical function measures were observed ( P = 0.01 to P = 0.08) with seemingly positive effects for the low-severity group and potentially negative effects for the high-severity group. CONCLUSION: Overall, home-based exergame step training was not effective in improving the outcomes assessed. However, the improved physical function in the lower disease severity intervention participants as well as the self-reported improved mobility in the intervention group suggest home-based exergame step training may have benefits for some people with Parkinson's disease.

An interactive videogame for arm and hand exercise in people with Parkinson's disease: A randomized controlled trial.

INTRODUCTION: People with Parkinson's disease (PD) have difficulty performing upper extremity (UE) activities. The aim of this study was to investigate if exergames targeting the UE improve arm and hand activities and impairments and to establish the acceptability and feasibility of these games in people with PD. METHODS: Two tablet-based exergames were developed which were controlled with finger movements or unimanual whole arm movements. Participants with PD were randomized to an exergame (n = 19) or control (n = 19) group. The exergame group performed UE exergames at home, 3 times per week for 12 weeks. The primary outcome measure was the nine hole peg test. Secondary outcomes included measures of UE activities and impairments, including the tapping test [speed (taps/60s), and error (weighted error score/speed)]. RESULTS: There were no between group differences in the nine hole peg test, or in any secondary outcome measures except for the tapping test. Horizontal tapping test results showed that exergame participants improved their speed (mean difference = 10.9 taps/60s, p < 0.001) but increased error (mean difference = 0.03, p = 0.03) compared to the control group. Participants enjoyed the games and improved in their ability to play the games. There were no adverse events. CONCLUSION: The UE exergames were acceptable and safe, but did not translate to improvement in functional activities. It is likely that the requirement of the games resulted in increased movement speed at the detriment of accuracy. The design of exergames should consider task specificity.

Exercise for falls prevention in Parkinson disease: a randomized controlled trial.

OBJECTIVE: To determine whether falls can be prevented with minimally supervised exercise targeting potentially remediable fall risk factors, i.e., poor balance, reduced leg muscle strength, and freezing of gait, in people with Parkinson disease. METHODS: Two hundred thirty-one people with Parkinson disease were randomized into exercise or usual-care control groups. Exercises were practiced for 40 to 60 minutes, 3 times weekly for 6 months. Primary outcomes were fall rates and proportion of fallers during the intervention period. Secondary outcomes were physical (balance, mobility, freezing of gait, habitual physical activity), psychological (fear of falling, affect), and quality-of-life measures. RESULTS: There was no significant difference between groups in the rate of falls (incidence rate ratio [IRR] = 0.73, 95% confidence interval [CI] 0.45-1.17, p = 0.18) or proportion of fallers (p = 0.45). Preplanned subgroup analysis revealed a significant interaction for disease severity (p < 0.001). In the lower disease severity subgroup, there were fewer falls in the exercise group compared with controls (IRR = 0.31, 95% CI 0.15-0.62, p < 0.001), while in the higher disease severity subgroup, there was a trend toward more falls in the exercise group (IRR = 1.61, 95% CI 0.86-3.03, p = 0.13). Postintervention, the exercise group scored significantly (p < 0.05) better than controls on the Short Physical Performance Battery, sit-to-stand, fear of falling, affect, and quality of life, after adjusting for baseline performance. CONCLUSIONS: An exercise program targeting balance, leg strength, and freezing of gait did not reduce falls but improved physical and psychological health. Falls were reduced in people with milder disease but not in those with more severe Parkinson disease. CLASSIFICATION OF EVIDENCE: This study provides Class III evidence that for patients with Parkinson disease, a minimally supervised exercise program does not reduce fall risk. This study lacked the precision to exclude a moderate reduction or modest increase in fall risk from exercise. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry (ACTRN12608000303347).

Predictors of Adherence to a Falls Prevention Exercise Program for People with Parkinson's Disease.

BACKGROUND: Long-term benefits of exercise for people with Parkinson's disease (PD) require regular and sustained participation. This study aimed to investigate predictors of adherence to a minimally supervised exercise program designed to reduce falls in people with PD. METHOD: People with idiopathic PD who participated in the exercise arm of a randomized, controlled trial were included. Exercises were prescribed three times per week for 6 months. Adherence was defined as the percentage of prescribed sessions participants reported as having undertaken. Potential predictors of adherence included baseline measures of demographic variables, disease severity and duration, falls and fear of falling, pain, self-reported health and quality of life, cognition, physical activity levels, freezing of gait, functional mobility and balance, and knee extensor strength. RESULTS: The 108 participants included undertook a mean of 72% (standard deviation: 38%) of prescribed sessions. Participants had higher levels of adherence if they had shorter disease duration, less bodily pain, and better self-reported health and quality of life. A multivariate model (including disease duration, severity of bodily pain, self-reported physical well-being, the Frontal Assessment Battery, the Short Physical Performance Battery, and maximum walking time) explained 9% of the variance in exercise adherence, with shorter disease duration and less pain the strongest predictors (both predictors standardized ß = -0.2; P = 0.04). CONCLUSION: Disease duration and pain are likely to negatively influence exercise participation in people with PD. Given that most of the variance in adherence is unexplained, further work is required to determine other predictors of adherence to long-term exercise programs.

Leg muscle power is enhanced by training in people with Parkinson's disease: a randomized controlled trial.

OBJECTIVE: To determine the effects of leg muscle power training in people with Parkinson's disease. DESIGN: Randomized controlled trial. SETTING: University laboratory (outcome measures and experimental intervention), community (control intervention). SUBJECTS: Community-dwelling people with Parkinson's disease. INTERVENTIONS: Leg muscle power training using pneumatic variable resistance equipment (experimental) was compared with low intensity sham exercise (control). Both groups exercised twice weekly for 12 weeks. MAIN MEASURES: Primary outcomes were peak power of four leg muscle groups. Secondary outcomes were measures of muscle strength, mobility, balance and falls. RESULTS: Exercise adherence was high in both groups. Leg muscle power was significantly better in the experimental group than the control group in all four primary outcome measures at 12 weeks after adjusting for baseline values: leg extensors (57.9 watts, 95% confidence interval (CI) 22.0-93.7, p = 0.002); knee flexors (29.6 watts, 95% CI 7.4-51.8, p = 0.01); hip flexors (68.1 watts, 95% CI 19.6-116.5, p = 0.007); and hip abductors (37.4 watts, 95% CI 19.9-54.9, p < 0.001). The experimental group performed significantly better on tests of leg muscle strength (p < 0.001 to 0.07) and showed trends toward better performance in the Timed Up and Go (p = 0.13) and choice stepping reaction time (p = 0.11). There was a non-significant reduction in the rate of falls in the experimental group compared with the control group (incidence rate ratio 0.84, p = 0.76). CONCLUSIONS: This programme significantly improved muscle power in all trained muscle groups.

Treadmill exercise elevates striatal dopamine D2 receptor binding potential in patients with early Parkinson's disease.

We have previously demonstrated changes in dopaminergic neurotransmission after intensive exercise in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-lesioned mouse model of Parkinson's disease (PD), including an increase in the dopamine D2 receptor (DA-D2R), using noninvasive PET imaging with the radioligand [18F]fallypride. The purpose of this feasibility and translational study was to examine whether intensive exercise leads to similar alterations in DA-D2R expression using PET imaging with [18F]fallypride in individuals with early-stage PD. In this pilot study, four patients with early-stage PD were randomized to receive intensive exercise (treadmill training sessions three times/week for 8 weeks) or no exercise. Two healthy age-matched individuals participated in treadmill training. Alterations in the DA-D2R binding potential (BP) as a marker for receptor expression were determined using PET imaging with [18F]fallypride. Turning performance in the patients with PD as a measure of postural control and the Unified Parkinson's Disease Rating Scale scores pre-exercise and postexercise were determined. Our data showed an exercise-induced increase in [18F]fallypride BP as well as improved postural control in patients with PD who exercised. Changes in DA-D2R BP were not observed in patients with PD who did not exercise. These results suggest that exercise can lead to neuroplasticity in dopaminergic signaling and contribute to improved function that may be task specific (postural control) in early-stage PD.

Altered Dynamic Postural Control during Step Turning in Persons with Early-Stage Parkinson's Disease.

Persons with early-stage Parkinson's disease (EPD) do not typically experience marked functional deficits but may have difficulty with turning tasks. Studies evaluating turning have focused on individuals in advanced stages of the disease. The purpose of this study was to compare postural control strategies adopted during turning in persons with EPD to those used by healthy control (HC) subjects. Fifteen persons with EPD, diagnosed within 3 years, and 10 HC participated. Participants walked 4 meters and then turned 90°. Dynamic postural control was quantified as the distance between the center of pressure (COP) and the extrapolated center of mass (eCOM). Individuals with EPD demonstrated significantly shorter COP-eCOM distances compared to HC. These findings suggest that dynamic postural control during turning is altered even in the early stages of PD.

Exercise and motor training in people with Parkinson's disease: a systematic review of participant characteristics, intervention delivery, retention rates, adherence, and adverse events in clinical trials.

There is research evidence that exercise and motor training are beneficial for people with Parkinson's disease (PD), and clinicians seek to implement optimal programs. This paper summarizes important factors about the nature and reporting of randomized controlled trials of exercise and/or motor training for people with PD which are likely to influence the translation of research into clinical practice. Searches identified 53 relevant trials with 90 interventions conducted for an average duration of 8.3 (SD 4.2) weeks. Most interventions were fully supervised (74%) and conducted at a facility (79%). Retention rates were high with 69% of interventions retaining ≥85% of their participants; however adherence was infrequently reported, and 72% of trials did not report adverse events. Overall, the labor-intensive nature of most interventions tested in these trials and the sparse reporting of adherence and adverse events are likely to pose difficulties for therapists attempting to balance benefits and costs when selecting protocols that translate to sustainable clinical practice for people with PD.

The relationships between the unified Parkinson's disease rating scale and lower extremity functional performance in persons with early-stage Parkinson's disease.

BACKGROUND: The Unified Parkinson's Disease Rating Scale (UPDRS) is the "gold standard" assessment tool for characterizing impairments in persons with Parkinson's disease (PD); however, this scale's ability to predict functional capabilities across different functional tasks has not been adequately assessed in persons with early-stage PD. METHODS: Thirty persons with PD within 3 years of diagnosis and without motor fluctuation performed self-selected walking, fast walking, and sit-to-stand and stair-climbing tasks. Pearson's correlation coefficients were used to calculate correlations with a standard UPDRS examination (P<.05). Simple linear regression models were used to fit each functional performance outcome measure with the UPDRS total predictor scores. RESULTS: The correlations between the UPDRS motor (section III), UPDRS total scores, and all timed functional performance measures were fair to good (range, 0.45-0.57). Conversely, only greater self-selected time to walk 50 ft correlated with a higher UPDRS activities of daily living (II) score (r=.386; P<.05). CONCLUSIONS: The UPDRS motor (III) and total scores may be good predictors of overall lower extremity function in persons with early-stage PD. Understanding the relationships between UPDRS scores and functional capabilities may allow clinicians to better quantify early physical functioning, longitudinally assess disease progression, and assess the efficacy of interventions.

The effect of exercise training in improving motor performance and corticomotor excitability in people with early Parkinson's disease.

OBJECTIVES: To obtain preliminary data on the effects of high-intensity exercise on functional performance in people with Parkinson's disease (PD) relative to exercise at low and no intensity and to determine whether improved performance is accompanied by alterations in corticomotor excitability as measured through transcranial magnetic stimulation (TMS). DESIGN: Cohort (prospective), randomized controlled trial. SETTING: University-based clinical and research facilities. PARTICIPANTS: Thirty people with PD, within 3 years of diagnosis with Hoehn and Yahr stage 1 or 2. INTERVENTIONS: Subjects were randomized to high-intensity exercise using body weight-supported treadmill training, low-intensity exercise, or a zero-intensity education group. Subjects in the 2 exercise groups completed 24 exercise sessions over 8 weeks. Subjects in the zero-intensity group completed 6 education classes over 8 weeks. MAIN OUTCOME MEASURES: Unified Parkinson's Disease Rating Scales (UPDRS), biomechanic analysis of self-selected and fast walking and sit-to-stand tasks; corticomotor excitability was assessed with cortical silent period (CSP) durations in response to single-pulse TMS. RESULTS: A small improvement in total and motor UPDRS was observed in all groups. High-intensity group subjects showed postexercise increases in gait speed, step and stride length, and hip and ankle joint excursion during self-selected and fast gait and improved weight distribution during sit-to-stand tasks. Improvements in gait and sit-to-stand measures were not consistently observed in low- and zero-intensity groups. The high-intensity group showed lengthening in CSP. CONCLUSIONS: The findings suggest the dose-dependent benefits of exercise and that high-intensity exercise can normalize corticomotor excitability in early PD.

Relationships among body weight, joint moments generated during functional activities, and hip bone mass in older adults.

OBJECTIVE: To investigate the relationships among hip joint moments produced during functional activities and hip bone mass in sedentary older adults. METHODS: Eight male and eight female older adults (70-85 yr) performed functional activities including walking, chair sit-stand-sit, and stair stepping at a self-selected pace while instrumented for biomechanical analysis. Bone mass at proximal femur, femoral neck, and greater trochanter were measured by dual-energy X-ray absorptiometry. Three-dimensional hip moments were obtained using a six-camera motion analysis system, force platforms, and inverse dynamics techniques. Pearson's correlation coefficients were employed to assess the relationships among hip bone mass, height, weight, age, and joint moments. Stepwise regression analyses were performed to determine the factors that significantly predicted bone mass using all significant variables identified in the correlation analysis. FINDINGS: Hip bone mass was not significantly correlated with moments during activities in men. Conversely, in women bone mass at all sites were significantly correlated with weight, moments generated with stepping, and moments generated with walking (p<0.05 to p<0.001). Regression analysis results further indicated that the overall moments during stepping independently predicted up to 93% of the variability in bone mass at femoral neck and proximal femur; whereas weight independently predicted up to 92% of the variability in bone mass at greater trochanter. INTERPRETATION: Submaximal loading events produced during functional activities were highly correlated with hip bone mass in sedentary older women, but not men. The findings may ultimately be used to modify exercise prescription for the preservation of bone mass.

Biomechanics of the heel-raise exercise.

The purpose of this investigation was to determine whether increases in internal (muscular) demand would be proportional to increases in the external demand during heel-raise exercise. Seven male (mean age 74.9 +/- 4.8 years) and 9 female (mean age 74.4 +/- 5.1 years) older adults performed both double-leg heel raises and single-leg heel raises under 3 loading conditions (no external resistance and +5% and +10% of each participant's body weight). Kinematic and kinetic dependent variables were calculated using standard inverse-dynamics techniques. The results suggest that although the single-heel raise led to increases in peak net joint moments, power, and mechanical-energy expenditure (MEE), it did so at the expense of range of motion and angular velocity. In addition, increasing the external resistance by 5% of participants' body weight did not elicit significant changes in either the power or the MEE of the ankle joint. These effects should be considered when prescribing these exercises to older adults.

Lower-extremity biomechanics during forward and lateral stepping activities in older adults.

OBJECTIVE: To characterize the lower-extremity biomechanics associated with stepping activities in older adults. DESIGN: Repeated-measures comparison of kinematics and kinetics associated with forward step-up and lateral step-up activities. BACKGROUND: Biomechanical analysis may be used to assess the effectiveness of various 'in-home activities' in targeting appropriate muscle groups and preserving functional strength and power in elders. METHODS: Data were analyzed from 21 participants (mean 74.7 yr (standard deviation, 4.4 yr)) who performed the forward and lateral step-up activities while instrumented for biomechanical analysis. Motion analysis equipment, inverse dynamics equations, and repeated measures ANOVAs were used to contrast the maximum joint angles, peak net joint moments, angular impulse, work, and power associated with the activities. RESULTS: The lateral step-up resulted in greater maximum knee flexion (P<0.001) and ankle dorsiflexion angles (P<0.01). Peak joint moments were similar between exercises. The forward step-up generated greater peak hip power (P<0.05) and total work (P<0.001); whereas, the lateral step-up generated greater impulse (P<0.05), work (P<0.01), and power (P<0.05) at the knee and ankle. CONCLUSIONS: In older adults, the forward step-up places greater demand on the hip extensors, while lateral step-up places greater demand on the knee extensors and ankle plantar flexors. RELEVANCE: Clinicians may use data from biomechanical analyses of in-home exercises to more effectively target specific lower-extremity muscle groups when prescribing exercise activities for older adults. The forward step-up is recommended for maintaining or improving hip extensor performance; whereas, the lateral step-up is recommended when targeting the knee extensors and ankle plantar flexors.