High-Intensity Exercise Acutely Increases Substantia Nigra and Prefrontal Brain Activity in Parkinson's Disease.

BACKGROUND Pathologic alterations in resting-state brain activity patterns exist among individuals with Parkinson's disease (PD). Since physical exercise alters resting-state brain activity in non-PD populations and improves PD symptoms, we assessed the acute effect of exercise on resting-state brain activity in exercise-trained individuals with PD. MATERIAL AND METHODS Resting-state functional magnetic resonance imaging (fMRI) was collected twice for 17 PD participants at the conclusion of an exercise intervention. The acute effect of exercise was examined for PD participants using the amplitude of low frequency fluctuation (ALFF) before and after a single bout of exercise. Correlations of clinical variables (i.e., PDQ-39 quality of life and MDS-UPDRS) with ALFF values were examined for the exercise-trained PD participants. RESULTS An effect of acute exercise was observed as an increased ALFF signal within the right ventromedial prefrontal cortex (PFC), left ventrolateral PFC, and bilaterally within the substantia nigra (SN). Quality of life was positively correlated with ALFF values within the vmPFC and vlPFC. CONCLUSIONS Given the role of the SN and PFC in motor and non-motor symptoms in PD, the acute increases in brain activity within these regions, if repeated frequently over time (i.e., exercise training), may serve as a potential mechanism underlying exercise-induced PD-specific clinical benefits.

Two-Year Trajectory of Fall Risk in People With Parkinson Disease: A Latent Class Analysis.

OBJECTIVE: To examine fall risk trajectories occurring naturally in a sample of individuals with early to middle stage Parkinson disease (PD). DESIGN: Latent class analysis, specifically growth mixture modeling (GMM), of longitudinal fall risk trajectories. SETTING: Assessments were conducted at 1 of 4 universities. PARTICIPANTS: Community-dwelling participants with PD of a longitudinal cohort study who attended at least 2 of 5 assessments over a 2-year follow-up period (N=230). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Fall risk trajectory (low, medium, or high risk) and stability of fall risk trajectory (stable or fluctuating). Fall risk was determined at 6 monthly intervals using a simple clinical tool based on fall history, freezing of gait, and gait speed. RESULTS: The GMM optimally grouped participants into 3 fall risk trajectories that closely mirrored baseline fall risk status (P=.001). The high fall risk trajectory was most common (42.6%) and included participants with longer and more severe disease and with higher postural instability and gait disability (PIGD) scores than the low and medium fall risk trajectories (P<.001). Fluctuating fall risk (posterior probability <0.8 of belonging to any trajectory) was found in only 22.6% of the sample, most commonly among individuals who were transitioning to PIGD predominance. CONCLUSIONS: Regardless of their baseline characteristics, most participants had clear and stable fall risk trajectories over 2 years. Further investigation is required to determine whether interventions to improve gait and balance may improve fall risk trajectories in people with PD.

Capturing ambulatory activity decline in Parkinson's disease.

BACKGROUND AND PURPOSE: Relatively little is known about the natural evolution of physical activity-related participation restrictions associated with Parkinson's disease (PD). We examined this issue prospectively, using continuous monitoring technology to capture the free-living ambulatory activity of persons with PD engaging in life situations. We specifically sought (1) to explore natural, long-term changes in daily ambulatory activity and (2) to compare the responsiveness of ambulatory activity parameters to clinical measures of gait and disease severity. METHODS: Thirty-three persons with PD participated (Hoehn and Yahr range of 1-3). Participants wore a step activity monitor for up to 7 days at baseline and again at 1-year follow-up. Mean daily values were calculated for parameters indicative of amount, intensity, frequency, and duration of ambulatory activity. Clinical measures included the Unified Parkinson Disease Rating Scale, the 6-Minute Walk, and Maximal Gait Speed. Parametric tests for paired samples were used to investigate changes in ambulatory activity parameters and clinical measures. RESULTS: Participants had significant declines in the amount and intensity of daily ambulatory activity but not in its frequency and duration (P < 0.007). Declines occurred in the absence of changes in clinical measures of gait or disease severity. The greatest 1-year decline occurred in the number of daily minutes participants spent engaging in at least moderate-intensity ambulatory activity. CONCLUSION: Continuous monitoring of ambulatory activity beyond mere step counts may serve as a distinct and important means of quantifying declining ambulatory behavior associated with disease progression or improved ambulatory behavior resulting from rehabilitation and medical and/or surgical interventions in persons with PD.

Charting the progression of disability in Parkinson disease: study protocol for a prospective longitudinal cohort study.

BACKGROUND: People with Parkinson disease (PD), even in the presence of symptomatic relief from medical, surgical, and rehabilitative interventions, face a persistent worsening of disability. This disability is characterized by diminished quality of life, reduced functional mobility, declining performance in activities of daily living and worsening neurological impairments. While evidence has emerged supporting the clinically meaningful benefits of short-term exercise programs on these underlying factors, assertions regarding the effects of sustained programs of exercise and physical activity on the trajectory of disablement in PD are made in the absence of direct evidence. Indeed, the natural decline in quality of life and functional mobility in people diagnosed with PD is poorly understood. Moreover, outcome measures commonly used in clinical exercise trials typically do not capture the full spectrum of disability as defined by the World Health Organization (WHO). METHODS/DESIGN: The objective of this multicenter prospective study will be to examine the 2-year trajectory of disablement in a cohort of persons with PD. Two hundred sixty participants will be recruited to produce an expected final sample size of 150 individuals. Participants will be included if they are greater than 40 years of age, have a neurologist confirmed diagnosis of idiopathic PD, and are at Hoehn and Yahr stages 1 through 4. Data will be collected every 6 months during the study period. Primary outcome measures reflecting a broad spectrum of disablement will include, but will not be limited to, MDS-UPDRS, Timed Up and Go, Berg Balance Test, Nine Hole Peg Test, PDQ-39, and directly monitored ambulatory activity. Self-reported exercise and physical activity data also will be recorded. Statistical analyses will be used to characterize the trajectory of disablement and examine the influence of its underlying contributing factors. DISCUSSION: Tertiary prevention is an important component of contemporary healthcare for individuals living with degenerative disease. For individuals with PD, there is growing recognition that exercise and/or physical activity efforts to slow the rate of functional mobility decline, in particular, may be critical for optimizing quality of life. By describing the natural trajectory of disablement, exercise habits, and physical activity in a cohort of persons with PD, this investigation will establish an important foundation for future intervention research. Specifically, through the evaluation of the influence of sustained exercise and physical activity on disablement, the study will serve as a preliminary step toward developing a randomized controlled trial of long-term exercise in persons with PD.

Gait training with progressive external auditory cueing in persons with Parkinson's disease.

OBJECTIVE: To investigate the progressively increasing external auditory cues during mobility training with persons with Parkinson's disease (PD). DESIGN: Experimental. SETTING: General community. PARTICIPANTS: Convenience sample of persons with PD (N=12) who walked independently. INTERVENTIONS: Gait training to external auditory cues was based on a participant's comfortable walking pace. Training external auditory cues rates were increased if patients were able to maintain or increase stride length with increasing external auditory cues rate. Movement synchronization was not monitored during training. Participants trained for 30min/session, 3 sessions/wk, for 8 weeks. MAIN OUTCOME MEASURES: Walking velocity, stride length, and cadence. RESULTS: Participants trained at a mean maximal rate of 157bpm. They showed a significant (P<.01) increase in walking velocity, stride length, and cadence after 8 weeks of training. CONCLUSIONS: Walking velocity, stride length, and cadence can significantly improve when community-dwelling persons with PD participate in progressive mobility training.

Predictors of self-perceived stigma in Parkinson's disease.

OBJECTIVE: The burden of PD extends beyond physical limitations and includes significant psychosocial adjustments as individuals undergo changes to their self-perception and how others perceive them. There is limited quantitative evidence of the factors that contribute to self-perceived stigma, which we addressed in the present study. METHODS: In 362 individuals with PD (157 women, 205 men), self-perceived stigma was measured by the four-item stigma subscale of the Parkinson's Disease Questionnaire (PDQ-39). Hierarchical linear modeling was used to assess predictors of stigma including demographics (age, gender) and disease characteristics: duration, stage (Hoehn & Yahr Scale), motor severity (Unified Parkinson's Disease Rating Scale, UPDRS, Part 3), activities of daily living (UPDRS Part 2), and depression (Geriatric Depression Scale). Predictor variables were chosen based on their significant correlations with the stigma subscale. Further analyses were conducted for men and women separately. RESULTS: For the total sample, the full model accounted for 14% of the variance in stigma perception (p < .001). Younger age and higher depression scores were the only significant predictors (both p < .001). This pattern was also seen for the men in the sample. For the women, only depression was a significant predictor. Depression mediated the relation between stigma and activities of daily living. CONCLUSIONS: Younger age (men) and depression (men and women) were the primary predictors of self-perceived stigma in PD. Disease characteristics (motor and ADL) did not contribute to stigma perception. Depression is a potential treatment target for self-perceived stigma in PD.

The effects of auditory rhythms and instruction on walking patterns in individuals post stroke.

The objective was to investigate the effects of auditory rhythms and arm movement on inter-segmental coordination during walking in persons who have suffered a stroke. Eleven subjects walked on a treadmill: (1) during systematic increases in velocity (0.22-1.52 m/s), (2) with instructions to 'step to the beat' during systematic increases in metronome frequency (1-2.2 Hz), and (3) with instructions: 'move the arms and legs to the beat' during systematic increases in metronome frequency (1-2.2 Hz). Movement amplitude of upper and lower body segments, frequency coordination between arm and leg movements, phase relation between upper and lower body segments were measured. Moving the arms and legs to the beat resulted in increased arm swing along with 1:1 frequency coordination between the arm and leg, and a more out-of-phase relation between transverse pelvic and thoracic rotation was observed with larger pelvic and thoracic rotations. Verbal instructions to move the arms to the beat of a metronome leads to increased arm swing, increased stride length, but further study is needed to examine the dynamics of the changes in arm movement, to enhance understanding of how upper extremity movement dysfunction affects inter-segmental coordination during walking.

Arm constraint and walking in healthy adults.

The aim of the present study was to examine the functional adaptations in inter-segmental coordination when constraining one arm in healthy adults during treadmill walking at different velocities. Subjects were instructed to walk on a motorized treadmill at different walking velocities (range: 0.22-1.52 m/s) during three experimental conditions, i.e.: (1) no arm constraint, (2) dominant arm constrained, and (3) non-dominant arm constrained. Movements of body segments were recorded with a 3D motion analysis system. A comparison between walking with one arm constrained and normal walking revealed decreased, transverse pelvic, thoracic, and trunk rotation, however there were slight increases in non-constrained arm movement amplitude. Reduced arm movement amplitude did result in altered frequency and phase relations between the arm and leg. Persons with upper extremity movement dysfunction may walk slower due to atypical coordination between upper and lower body movement at higher walking velocities. Future studies should focus on examining the underlying dynamics of adaptations in inter-limb and trunk coordination during walking in both healthy adults and persons with upper extremity movement disorders.

Are the average gait speeds during the 10meter and 6minute walk tests redundant in Parkinson disease?

We investigated the relationships between average gait speed collected with the 10Meter Walk Test (Comfortable and Fast) and 6Minute Walk Test (6MWT) in 346 people with Parkinson disease (PD) and how the relationships change with increasing disease severity. Pearson correlation and linear regression analyses determined relationships between 10Meter Walk Test and 6MWT gait speed values for the entire sample and for sub-samples stratified by Hoehn & Yahr (H&Y) stage I (n=53), II (n=141), III (n=135) and IV (n=17). We hypothesized that redundant tests would be highly and significantly correlated (i.e. r>0.70, p<0.05) and would have a linear regression model slope of 1 and intercept of 0. For the entire sample, 6MWT gait speed was significantly (p<0.001) related to the Comfortable 10 Meter Walk Test (r=0.75) and Fast 10Meter Walk Test (r=0.79) gait speed, with 56% and 62% of the variance in 6MWT gait speed explained, respectively. The regression model of 6MWT gait speed predicted by Comfortable 10 Meter Walk gait speed produced slope and intercept values near 1 and 0, respectively, especially for participants in H&Y stages II-IV. In contrast, slope and intercept values were further from 1 and 0, respectively, for the Fast 10Meter Walk Test. Comfortable 10 Meter Walk Test and 6MWT gait speeds appeared to be redundant in people with moderate to severe PD, suggesting the Comfortable 10 Meter Walk Test can be used to estimate 6MWT distance in this population.

Obtaining Reliable Estimates of Ambulatory Physical Activity in People with Parkinson's Disease.

We determined the number of days required, and whether to include weekdays and/or weekends, to obtain reliable measures of ambulatory physical activity in people with Parkinson's disease (PD). Ninety-two persons with PD wore a step activity monitor for seven days. The number of days required to obtain a reliable estimate of daily activity was determined from the mean intraclass correlation (ICC2,1) for all possible combinations of 1-6 consecutive days of monitoring. Two days of monitoring were sufficient to obtain reliable daily activity estimates (ICC2,1 > 0.9). Amount (p = 0.03) but not intensity (p = 0.13) of ambulatory activity was greater on weekdays than weekends. Activity prescription based on amount rather than intensity may be more appropriate for people with PD.

Identifying clinical measures that most accurately reflect the progression of disability in Parkinson disease.

INTRODUCTION: The temporal relationship between disease and disability progression in Parkinson disease (PD) is not well understood. Our objective was to describe the natural, multidimensional trajectory of disability in persons with PD over a two-year period. METHODS: We conducted a multi-center, prospective cohort study involving four institutions. Data were collected at baseline and at 6-month intervals over 2 years using standardized clinical tests representing three World Health Organization defined disability domains: impairment, activity limitation, and participation restriction. Unadjusted mixed effects growth models characterized trajectories of disability in the three disability domains. The data set was analyzed using restricted maximum likelihood (REML) estimation. Standardized estimates of change were also computed using Cohen's d for each measure. RESULTS: Of the 266 enrolled participants, we analysed data from individuals who participated in at least 3 assessments (n = 207, 79%). Rates of disability progression over the 2-year period differed across domains. Moderate effects were detected for motor impairment (d = .28) and walking-related activity limitation (gait-related balance (d = .31); gait speed (d = .30)). Marginal effects were noted for upper extremity-related activity limitation (d = .11) and health-related quality of life participation restriction (d = .08). CONCLUSIONS: The natural trajectory of walking-related activity limitation was the most potent indicator of evolving disability, suggesting that routine assessment of walking and periodic rehabilitation is likely to be warranted for many persons with PD. Natural trajectories of disability provide important comparison data for future intervention studies.

Toward Understanding Ambulatory Activity Decline in Parkinson Disease.

BACKGROUND: Declining ambulatory activity represents an important facet of disablement in Parkinson disease (PD). OBJECTIVE: The primary study aim was to compare the 2-year trajectory of ambulatory activity decline with concurrently evolving facets of disability in a small cohort of people with PD. The secondary aim was to identify baseline variables associated with ambulatory activity at 1- and 2-year follow-up assessments. DESIGN: This was a prospective, longitudinal cohort study. METHODS: Seventeen people with PD (Hoehn and Yahr stages 1-3) were recruited from 2 outpatient settings. Ambulatory activity data were collected at baseline and at 1- and 2-year annual assessments. Motor, mood, balance, gait, upper extremity function, quality of life, self-efficacy, and levodopa equivalent daily dose data and data on activities of daily living also were collected. RESULTS: Participants displayed significant 1- and 2-year declines in the amount and intensity of ambulatory activity concurrently with increasing levodopa equivalent daily dose. Worsening motor symptoms and slowing of gait were apparent only after 2 years. Concurrent changes in the remaining clinical variables were not observed. Baseline ambulatory activity and physical performance variables had the strongest relationships with 1- and 2-year mean daily steps. LIMITATIONS: The sample was small and homogeneous. CONCLUSIONS: Future research that combines ambulatory activity monitoring with a broader and more balanced array of measures would further illuminate the dynamic interactions among evolving facets of disablement and help determine the extent to which sustained patterns of recommended daily physical activity might slow the rate of disablement in PD.

Detecting and predicting balance decline in Parkinson disease: a prospective cohort study.

BACKGROUND: The natural progression of balance decline in individuals with Parkinson disease (PD) is not well understood. OBJECTIVES: We aimed to: 1) compare the utility of three standardized clinical measures for detecting balance decline over 1-year, 2) identify components of balance susceptible to decline, and 3) identify factors useful for predicting future balance decline. METHODS: Eighty people with PD (59% male; mean age 68.2 ± 9.3; Hoehn & Yahr range I-IV) completed Balance Evaluation Systems Test (BESTest), Mini-BESTest, and Berg Balance Scale (BBS) assessments. Baseline predictor variables included the MDS-UPDRS III sub-score, presence of freezing, 6-month fall history, age, gender, and physical activity. Balance and MDS-UPDRS III assessments were repeated at 6 (n = 51) and 12 months (n = 44). RESULTS: BESTest and Mini-BESTest score declined over 6 and 12 months (P < 0.01). Postural responses, stability limits, and sensory orientation were most susceptible to decline. BBS score did not change (P > 0.01). MDS-UPDRS III score was unchanged over 6 months (P > 0.01), but declined over 12 months (P < 0.01). Change in BESTest score over 6 months was related to baseline MDS-UPDRS III, H&Y, freezing, and fall history (P < 0.05). Change in BESTest score over 12 months was related to baseline MDS-UPDRS III and freezing (P < 0.05). Change in Mini-BESTest over 12 months was related to baseline MDS-UPDRS III and age (P < 0.05). CONCLUSIONS: The BESTest and Mini-BESTest were responsive to balance decline in individuals with PD and helped to identify decline in underlying balance components. Disease severity and freezing most consistently predicted balance decline in persons with PD.

Balance differences in people with Parkinson disease with and without freezing of gait.

BACKGROUND: Freezing of gait (FOG) is a relatively common and remarkably disabling impairment associated with Parkinson disease (PD). Laboratory-based measures indicate that individuals with FOG (PD+FOG) have greater balance deficits than those without FOG (PD-FOG). Whether such differences also can be detected using clinical balance tests has not been investigated. We sought to determine if balance and specific aspects of balance, measured using Balance Evaluation Systems Test (BESTest), differs between PD+FOG and PD-FOG. Furthermore, we aimed to determine if time-efficient clinical balance measures (i.e. Mini-BESTest, Berg Balance Scale (BBS)) could detect balance differences between PD+FOG and PD-FOG. METHODS: Balance of 78 individuals with PD, grouped as either PD+FOG (n=32) or PD-FOG (n=46), was measured using the BESTest, Mini-BESTest, and BBS. Between-groups comparisons were conducted for these measures and for the six sections of the BESTest using analysis of covariance. A PD composite score was used as a covariate. RESULTS: Controlling for motor sign severity, PD duration, and age, PD+FOG had worse balance than PD-FOG when measured using the BESTest (p=0.008, F=7.35) and Mini-BESTest (p=0.002, F=10.37), but not the BBS (p=0.27, F=1.26). BESTest section differences were noted between PD+FOG and PD-FOG for reactive postural responses (p<0.001, F=14.42) and stability in gait (p=0.003, F=9.18). CONCLUSIONS: The BESTest and Mini-BESTest, which specifically assessed reactive postural responses and stability in gait, were more likely than the BBS to detect differences in balance between PD+FOG and PD-FOG. Because it is more time efficient to administer, the Mini-BESTest may be the preferred tool for assessing balance deficits associated with FOG.

External validation of a simple clinical tool used to predict falls in people with Parkinson disease.

BACKGROUND: Assessment of fall risk in an individual with Parkinson disease (PD) is a critical yet often time consuming component of patient care. Recently a simple clinical prediction tool based only on fall history in the previous year, freezing of gait in the past month, and gait velocity <1.1 m/s was developed and accurately predicted future falls in a sample of individuals with PD. METHODS: We sought to externally validate the utility of the tool by administering it to a different cohort of 171 individuals with PD. Falls were monitored prospectively for 6 months following predictor assessment. RESULTS: The tool accurately discriminated future fallers from non-fallers (area under the curve [AUC] = 0.83; 95% CI 0.76-0.89), comparable to the developmental study. CONCLUSION: The results validated the utility of the tool for allowing clinicians to quickly and accurately identify an individual's risk of an impending fall.

Facilitating the use of implicit memory and learning in the physical therapy management of individuals with Alzheimer disease: a case series.

BACKGROUND AND PURPOSE: Physical rehabilitation of individuals with Alzheimer disease (AD) is often complicated by impairments in explicit memory and learning. Rehabilitation strategies that facilitate the use of the preserved implicit memory system may be effective in treating patients with AD. The purpose of this case series is to describe the application of these strategies, including high-repetition practice, errorless learning (EL), and spaced retrieval, to the physical therapy management of individuals with moderate AD. CASE DESCRIPTION: Three women aged 89 to 95 years with moderate AD who resided in an assisted living facility participated in physical therapy to address their mobility limitations. INTERVENTION: Twelve physical therapy sessions were scheduled over a period of 4 weeks. Interventions were individually designed to address the mobility needs of each patient, and rehabilitation strategies based on implicit learning principles were integrated into the interventions. OUTCOMES: All patients participated in at least 10 of the 12 physical therapy sessions. Improvements in performance of objective measures of balance were observed in all patients, although only 1 patient's balance score exceeded the minimal detectable change. No significant clinical change was observed in any patients on the Timed Up and Go Test or self-selected gait speed. DISCUSSION: Principles of implicit learning were integrated into the interventions for these patients with moderate AD. However, the feasibility of applying the EL paradigm was limited. Further research on the effectiveness of EL, spaced retrieval, and other rehabilitation strategies that facilitate implicit learning of mobility skills in patients with AD is needed to promote optimal physical therapy outcomes in this patient population.

Locomotor requirements for bipedal locomotion: a Delphi survey.

BACKGROUND: Bipedal locomotor control requirements may be useful as classifications for walking dysfunction because they go beyond gait analysis to address all issues contributing to walking dysfunction. OBJECTIVE: The objective of this study was to determine whether locomotor experts could achieve consensus about the requirements for bipedal locomotion. DESIGN AND METHODS: Locomotor experts from physical therapy and other related professions participated in an electronic mail Delphi survey. Experts recommended additions, deletions, rewording, and merges for 15 proposed locomotor requirements in round 1. In rounds 2 and 3, panelists commented on and rated the validity, mutual exclusiveness, and understandability of each requirement. Consensus was defined a priori as: (1) 75% or more panelists agree or strongly agree that a requirement is valid, mutually exclusive, and understandable in round 3; (2) no difference between round 2 and 3 ratings with kappa coefficients ≥.60; and (3) a reduction in panelists who commented and convergence of comments between rounds 1 and 3. Content analysis and nonparametric statistics were used. RESULTS: Fifty-eight panelists reached full consensus on 5 locomotor requirements (Initiation, Termination, Anticipatory Dynamic Balance, Multi-Task Capacity, and Walking Confidence) and partial consensus for 7 other requirements. There were no significant differences in ratings between rounds 2 and 3, and there was a decrease in the percentage of panelists who commented between rounds 1 and 3. LIMITATIONS: The study's 6-month time frame may have contributed to panelist attrition. CONCLUSIONS: Locomotor experts achieved consensus on several bipedal locomotor requirements. With validation, these requirements can provide the framework for a clinically feasible and systematic diagnostic tool for physical therapists to categorize locomotor problems and standardize intervention for walking dysfunction.

Novel, high-intensity exercise prescription improves muscle mass, mitochondrial function, and physical capacity in individuals with Parkinson's disease.

We conducted, in persons with Parkinson's disease (PD), a thorough assessment of neuromotor function and performance in conjunction with phenotypic analyses of skeletal muscle tissue, and further tested the adaptability of PD muscle to high-intensity exercise training. Fifteen participants with PD (Hoehn and Yahr stage 2-3) completed 16 wk of high-intensity exercise training designed to simultaneously challenge strength, power, endurance, balance, and mobility function. Skeletal muscle adaptations (P < 0.05) to exercise training in PD included myofiber hypertrophy (type I: +14%, type II: +36%), shift to less fatigable myofiber type profile, and increased mitochondrial complex activity in both subsarcolemmal and intermyofibrillar fractions (I: +45-56%, IV: +39-54%). These adaptations were accompanied by a host of functional and clinical improvements (P < 0.05): total body strength (+30-56%); leg power (+42%); single leg balance (+34%); sit-to-stand motor unit activation requirement (-30%); 6-min walk (+43 m), Parkinson's Disease Quality of Life Scale (PDQ-39, -7.8pts); Unified Parkinson's Disease Rating Scale (UPDRS) total (-5.7 pts) and motor (-2.7 pts); and fatigue severity (-17%). Additionally, PD subjects in the pretraining state were compared with a group of matched, non-PD controls (CON; did not exercise). A combined assessment of muscle tissue phenotype and neuromuscular function revealed a higher distribution and larger cross-sectional area of type I myofibers and greater type II myofiber size heterogeneity in PD vs. CON (P < 0.05). In conclusion, persons with moderately advanced PD adapt to high-intensity exercise training with favorable changes in skeletal muscle at the cellular and subcellular levels that are associated with improvements in motor function, physical capacity, and fatigue perception.

Predictors of gait speeds and the relationship of gait speeds to falls in men and women with Parkinson disease.

Gait difficulties and falls are commonly reported in people with Parkinson disease (PD). Reduction in gait speed is a major characteristic of Parkinsonian gait, yet little is known about its underlying determinants, its ability to reflect an internal reservation about walking, or its relationship to falls. To study these issues, we selected age, disease severity, and nonmotor factors (i.e., depression, quality of life, balance confidence, and exercise beliefs and attitudes) to predict self-selected (SELF), fast-as-possible (FAST), and the difference (DIFF) between these walking speeds in 78 individuals with PD. We also examined gender differences in gait speeds and evaluated how gait speeds were related to a retrospective fall report. Age, disease severity, and balance confidence were strong predictors of SELF, FAST, and, to a lesser extent, DIFF. All three parameters were strongly associated with falling. DIFF was significantly greater in men compared to women and was significantly associated with male but not female fallers. The results supported the clinical utility of using a suite of gait speed parameters to provide insight into the gait difficulties and differentiating between fallers in people with PD.

Comparative utility of the BESTest, mini-BESTest, and brief-BESTest for predicting falls in individuals with Parkinson disease: a cohort study.

BACKGROUND: The newly developed brief-balance evaluation system test (brief-BESTest) may be useful for measuring balance and predicting falls in individuals with Parkinson disease (PD). OBJECTIVES: The purposes of this study were: (1) to describe the balance performance of those with PD using the brief-BESTest, (2) to determine the relationships among the scores derived from the 3 versions of the BESTest (i.e., full BESTest, mini-BESTest, and brief-BESTest), and (3) to compare the accuracy of the brief-BESTest with that of the mini-BESTest and BESTest in identifying recurrent fallers among people with PD. DESIGN: This was a prospective cohort study. METHODS: Eighty participants with PD completed a baseline balance assessment. All participants reported a fall history during the previous 6 months. Fall history was again collected 6 months (n=51) and 12 months (n=40) later. RESULTS: At baseline, participants had varying levels of balance impairment, and brief-BESTest scores were significantly correlated with mini-BESTest (r=.94, P<.001) and BESTest (r=.95, P<.001) scores. Six-month retrospective fall prediction accuracy of the Brief-BESTest was moderately high (area under the curve [AUC]=0.82, sensitivity=0.76, and specificity=0.84). Prospective fall prediction accuracy over 6 months was similarly accurate (AUC=0.88, sensitivity=0.71, and specificity=0.87), but was less sensitive over 12 months (AUC=0.76, sensitivity=0.53, and specificity=0.93). LIMITATIONS: The sample included primarily individuals with mild to moderate PD. Also, there was a moderate dropout rate at 6 and 12 months. CONCLUSIONS: All versions of the BESTest were reasonably accurate in identifying future recurrent fallers, especially during the 6 months following assessment. Clinicians can reasonably rely on the brief-BESTest for predicting falls, particularly when time and equipment constraints are of concern.