Joe R. Nocera

Effects of home-based exercise on postural control and sensory organization in individuals with Parkinson disease

Loss of function and postural instability occur in Parkinson disease (PD). Dynamic exercise interventions are successful in improving motor control and physical function. However, most programs are based in a health facility or physical therapy setting and involve travel. With the limitations associated with PD (e.g. health care and medication cost as well as travel limitations) these therapies may be inaccessible and exclude some individuals from maintaining or increasing their function. The purpose of this study was to evaluate the effectiveness of a home-based exercise intervention on postural control in individuals with PD. Multivariate analysis of covariance was performed on individuals with PD (N = 10) and healthy aged-matched controls (N = 10). Participants were assessed utilizing computerized dynamic posturography (CDP) before and after a 10-week exercise intervention. Participants were instructed on proper technique prior to the intervention, were given an illustrated home program, and were monitored weekly concerning their progress. Pre-intervention assessment demonstrated that individuals with PD had statically lower scores on a Sensory Organization Test (p < .05). Following the intervention, results indicated no statistical difference between individuals with PD and aged match controls (p > .05). This initial study indicates that a home exercise intervention is an effective method of improving postural control in individuals with PD. Results from this investigation support further study to determine the extent to which both preventative and restorative home-based programs can improve postural control.

Knee extensor strength, dynamic stability, and functional ambulation: are they related in Parkinson's disease?

OBJECTIVE To evaluate the relationship between knee extensor strength, postural stability, functional ambulation, and disease severity in Parkinsons disease (PD). DESIGN A cohort study. SETTING University research laboratory. PARTICIPANTS Patients (N=44) with idiopathic PD. INTERVENTION Not applicable. MAIN OUTCOME MEASURES Participants were evaluated on their isokinetic knee extensor strength. Additionally, participants completed an assessment of their postural stability (Functional Reach Test for static stability and a dynamic postural stability assessment as measured by the center of pressure-center of mass moment arm during gait initiation). Participants also underwent an evaluation of their functional ambulation as measured by a 6-minute walk test. Lastly, participants were evaluated by a neurologist specially trained in movement disorders to assess neurologic status and disease severity using the Unified Parkinsons Disease Rating Scale and the Hoehn and Yahr disability score. RESULTS Knee extensor strength positively correlated with dynamic postural stability and negatively correlated with disease severity. Further, dynamic postural stability was negatively correlated to disease severity and positively correlated with functional ambulation in this cohort of patients with PD (P<.05). The results also suggest that the Functional Reach Test may be a valuable assessment tool to examine postural stability in PD. CONCLUSIONS These findings suggest a malleable relationship between knee extensor strength, dynamic stability, and disease severity in PD. Although strength is only one piece of the puzzle in the functional outcome of PD, these findings may assist clinicians in designing appropriate interventions aimed at increasing function and decreasing fall risk in PD.

Spatiotemporal variability during gait initiation in Parkinson's disease

During gait initiation (GI), consistency of foot placement while stepping is important in making successful transitions from a state of stable static posture to an unstable state of dynamic locomotion. In populations characterized by gait dysfunction and postural instability, such as persons with Parkinsons disease (PD), the ability to generate a consistent stepping pattern during GI may be essential in the prevention of falls. However, little is known about GI variability in persons with PD as compared to their healthy elderly peers. Therefore, this study investigated spatiotemporal variability during the first two steps of GI in 46 persons with idiopathic PD and 49 healthy age-matched adults. Stepping characteristics, including the length, width, and time of the first two steps of GI as well as their coefficients of variation (CV) were compared between groups. Persons with PD initiated gait with significantly shorter steps (swing step length=.463 vs. .537 m, stance step length=.970 vs. 1.10 m) and higher variability in step length (swing step CV=8.82 vs. 5.45, stance step CV=6.76 vs. 3.61). Persons with PD also showed significantly higher variability in the time of the swing step (swing step CV=10.0 vs. 7.4). GI variability did not differ significantly between disease stages in persons with PD. Because greater variability in these measures during gait is related to an increased risk of falls, we propose that higher GI variability may play a considerable role in falls frequently observed during transitions from quiet standing in PD.

Can exercise improve language and cognition in Parkinson's disease? A case report

Parkinsons disease is commonly accompanied by cognitive issues that limit participation in activities of daily living. Unfortunately, most current treatment paradigms and pharmacotherapeutics fail to address the cognitive impairment demonstrated in this population. Mounting evidence in healthy older adults suggests that aerobic exercise may improve cognitive function. This article describes a patient with Parkinsons disease prescribed 8 weeks of aerobic exercise. Despite very high performance at baseline, the participant improved on several cognitive measures post exercise. The results of this investigation mimic the research in healthy older adults. We therefore suggest that future large scale randomized trials are warranted to evaluate the efficacy of aerobic exercise for ameliorating declines in cognitive performance in persons with PD.

Quantitative Normative Gait Data in a Large Cohort of Ambulatory Persons with Parkinson's Disease

Background Gait performance is widely evaluated to assess health status in older adult populations. While several investigators have presented normative values for spatiotemporal gait parameters drawn from older adult populations, the literature has been void of large-scale cohort studies, which are needed in order to provide quantitative, normative gait data in persons with Parkinson’s disease. The aim of this investigation was to provide reference values for clinically important gait characteristics in a large sample of ambulatory persons with Parkinson’s disease to aid both clinicians and researchers in their evaluations and treatments of gait impairment. Methodology/Principal Findings Gait performance was collected in 310 individuals with idiopathic Parkinson’s disease as they walked across a pressure sensitive walkway. Fourteen quantitative gait parameters were measured and evaluated with respect to Hoehn and Yahr disease staging and gender. Disease duration and age were controlled for in all analyses. Individuals with the greatest Parkinson’s disability walked significantly slower with shorter steps and stride lengths than the mild and moderately affected groups. Further, the most affected patients spent more time with both feet on the ground, and walked with a wider base of support than the moderately disabled patients. No differences were detected between the mild and moderate disability groups on any of the gait parameters evaluated. Conclusions/Significance Reference values for 14 gait parameters in a large cohort of ambulatory patients with Parkinson’s disease are provided and these may be highly useful for assessing and interpreting an individual’s gait dysfunction. It is important for clinicians and researchers to appreciate the lack of change in quantitative parameters as PD patients move from mild to moderate gait impairment.

Tests of dorsolateral frontal function correlate with objective tests of postural stability in early to moderate stage Parkinson’s disease

A substantial number of individuals with Parkinsons disease who display impaired postural stability experience accelerated cognitive decline and an increased prevalence of dementia. To date, studies suggest that this relationship, believed to be due to involvement of nondopaminergic circuitry, occurs later in the disease process. Research has yet to adequately investigate this cognitive-posturomotor relationship especially when examining earlier disease states. To gain greater understanding of the relationship between postural stability and cognitive function/dysfunction we evaluated a more stringent, objective measure of postural stability (center of pressure displacement), and also more specific measures of cognition in twenty-two patients with early to moderate stage Parkinsons disease. The magnitude of the center of pressure displacement in this cohort was negatively correlated with performance on tests known to activate dorsolateral frontal regions. Additionally, the postural stability item of the UPDRS exhibited poor correlation with the more objective measure of center of pressure displacement and all specific measures of cognition. These results may serve as rationale for a more thorough evaluation of postural stability and cognition especially in individuals with mild Parkinsons disease. Greater understanding of the relationship between motor and cognitive processes in Parkinsons disease will be critical for understanding the disease process and its potential therapeutic possibilities.

Concurrent Word Generation and Motor Performance: Further Evidence for Language-Motor Interaction

Embodied/modality-specific theories of semantic memory propose that sensorimotor representations play an important role in perception and action. A large body of evidence supports the notion that concepts involving human motor action (i.e., semantic-motor representations) are processed in both language and motor regions of the brain. However, most studies have focused on perceptual tasks, leaving unanswered questions about language-motor interaction during production tasks. Thus, we investigated the effects of shared semantic-motor representations on concurrent language and motor production tasks in healthy young adults, manipulating the semantic task (motor-related vs. nonmotor-related words) and the motor task (i.e., standing still and finger-tapping). In Experiment 1 (n = 20), we demonstrated that motor-related word generation was sufficient to affect postural control. In Experiment 2 (n = 40), we demonstrated that motor-related word generation was sufficient to facilitate word generation and finger tapping. We conclude that engaging semantic-motor representations can have a reciprocal influence on motor and language production. Our study provides additional support for functional language-motor interaction, as well as embodied/modality-specific theories.

Exercise and Balance in Older Adults with Movement Disorders

This chapter concerns balance, gait function, exercise, and current rehabilitation options for older adults with Parkinson’s disease (PD) and stroke, within the context of normal aging. We outline the primary balance and gait deficits and their impact on fall rates for PD and stroke, with discussion regarding impairment in dual tasking and cognitive disturbances. We consider current options in physical therapy and exercise-based therapy for PD and stroke, particularly for interlimb coordination and gait function. Crossover approaches in rehabilitative techniques from PD/stroke to normal aging motor impairments often go underutilized in the clinic. Therefore, implications for older adults without movement disorders, who often have purely aging-related symptoms similar to those of PD, are discussed. Currently, research is especially engaged in investigating novel approaches to multimodal exercise, which have emerged as promising therapies for balance impairments including aerobic exercise, tai chi, and dance. Efficacy of such interventions is presented with respect to new research showing cognitive effects. We conclude the chapter by discussing hypotheses regarding mechanisms underlying deficit and recovery in these populations. Understanding the mechanisms for rehabilitative gains is crucial for developing targeted and efficient therapy for PD and stroke populations.