Amanda L. Penko

It is not about the bike, it is about the pedaling: forced exercise and Parkinson's disease.

Forced exercise has resulted in neuroprotective effects and improved motor function in animal studies. These promising results have not yet been translated fully to humans with Parkinsons disease (PD), as traditional exercise interventions have not yielded global improvements in function. A novel forced exercise intervention is described that has resulted in improved motor function and central nervous system function in PD patients.

Asymmetrical pedaling patterns in Parkinson's disease patients.

BACKGROUND Approximately 1.5 million Americans are affected by Parkinsons disease (Deponti et al., 2013) which includes the symptoms of postural instability and gait dysfunction. Currently, clinical evaluations of postural instability and gait dysfunction consist of a subjective rater assessment of gait patterns using items from the Unified Parkinsons Disease Rating Scale, and assessments can be insensitive to the effectiveness of medical interventions. Current research suggests the importance of cycling for Parkinsons disease patients, and while Parkinsons gait has been evaluated in previous studies, little is known about lower extremity control during cycling. The purpose of this study is to examine the lower extremity coordination patterns of Parkinsons patients during cycling. METHODS Twenty five participants, ages 44-72, with a clinical diagnosis of idiopathic Parkinsons disease participated in an exercise test on a cycle ergometer that was equipped with pedal force measurements. Crank torque, crank angle and power produced by right and left leg were measured throughout the test to calculate Symmetry Index at three stages of exercise (20 W, 60 W, maximum performance). FINDINGS Decreases in Symmetry Index were observed for average power output in Parkinsons patients as workload increased. Maximum power Symmetry Index showed a significant difference in symmetry between performance at both the 20 W and 60 W stage and the maximal resistance stage. Minimum power Symmetry Index did not show significant differences across the stages of the test. While lower extremity asymmetries were present in Parkinsons patients during pedaling, these asymmetries did not correlate to postural instability and gait dysfunction Unified Parkinsons Disease Rating Scale scores. INTERPRETATION This pedaling analysis allows for a more sensitive measure of lower extremity function than the Unified Parkinsons Disease Rating Scale and may help to provide unique insight into current and future lower extremity function.

The cyclical lower extremity exercise for Parkinson’s trial (CYCLE): methodology for a randomized controlled trial

BackgroundMotor and non-motor impairments affect quality of life in individuals with Parkinson’s disease. Our preliminary research indicates that forced exercise cycling, a mode of exercise in which a participant’s voluntary rate of exercise is augmented on a stationary cycle, results in global improvements in the cardinal symptoms of Parkinson’s disease. The objective of the Cyclical Lower Extremity Exercise (CYCLE) trial for Parkinson’s disease is to determine the effects of forced exercise cycling on motor and non-motor performance when compared to voluntary rate cycling and a non-exercise control group. Additionally, we plan to identify any associated changes in neural activity determined by functional magnetic resonance imaging.Methods/DesignA total of 100 individuals with mild to moderate idiopathic Parkinson’s disease will participate in a single-center, parallel-group, rater-blind study. Participants will be randomized 2:2:1 into a forced exercise, voluntary exercise, or no-exercise control group, respectively. Both exercise groups will cycle 3 times per week for 8 weeks at identical aerobic intensities for 40 minutes, but participants in the forced exercise group will cycle 30% faster than their voluntary rate by means of an augmented motorized bicycle. Neuroimaging, clinical, and biomechanical assessments of motor and non-motor performance will be made at baseline both ‘on’ and ‘off’ medication, after four weeks of exercise (midpoint), end of treatment, 4 weeks after end of treatment, and 8 weeks after end of treatment.DiscussionCYCLE trial will play a critical role in determining the effectiveness of two different types of aerobic exercise, forced and voluntary, on motor and non-motor performance in individuals with Parkinson’s disease. Additionally, the coupling of clinical, biomechanical, and neuroimaging outcomes has the potential to provide insight into mechanisms underlying change in function as a result of exercise.Trial registrationClinicaltrials.gov registration number NCT01636297.

Dual-task Interference Disrupts Parkinson's Gait Across Multiple Cognitive Domains

Gait dysfunction, a hallmark of Parkinsons disease, contributes to a relatively high incidence of falling. Gait function is further diminished during the performance of a motor-cognitive task (i.e., dual-task). It is unclear if Parkinsons disease-related dual-task deficits are related to a specific area of cognitive function or are the result of a more global decline in executive function. The aim of this project was to systematically evaluate gait performance to determine if gait dysfunction is restricted to certain types of executive function or a global phenomenon in individuals with Parkinsons disease. Twenty-three individuals with mild-moderate Parkinsons disease completed a series of dual-task conditions in which gait was paired with cognitive tasks requiring: working memory (0, 1, and 2-back), attention and problem solving (serial-7 subtraction), verbal memory (digit recall), semantic memory (Controlled Oral Word Association) and information processing speed (visual Stroop test). The results demonstrate that individuals with mild-moderate Parkinsons disease have a generalized worsening of spatial-temporal gait parameters regardless of the specific cognitive demand being performed concurrently. Overall, gait velocity decreased (p < 0.01) and stride and stance time both increased (p < 0.01) across all cognitive conditions. The attention and problem solving task resulted in the greatest number of gait parameter decrements. Results indicated that performance on cognitive tasks remained unchanged from single-task to dual-task conditions. Diminished gait performance under dual-task conditions across different cognitive function domains suggests a global Parkinsons disease-related deficit in information processing and regulation of gait.