Pilot study on the interaction between exercise and medication in the management of Parkinson's disease symptoms
Date
2018
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
University of Delaware
Abstract
Motor symptoms of Parkinson’s disease (PD) include tremor, bradykinesia (slow movement), rigidity and impaired postural control. Symptoms are treated with dopamine replacement therapies (DRT) and it has been shown that exercise helps slow disease progression and improve mobility. In studies involving rapid isometric contractions, some have reported abnormally segmented force production that could impair multiple aspects of mobility. There has been little development of segmentation measures. Aim 1 was to determine if one bout of speed-based exercise can reduce symptoms and improve mobility at a time when the efficacy of a DRT dose is beginning to diminish. Grip strength, timed up and go (TUG), static balance, force steadiness (tremor) and isometric force pulses were measured before and after three treatment conditions in ten subjects with PD (Hoehn-Yahr ≤ 3.0): 1) no exercise, DRT only; 2) no DRT and a 30-minute high-speed low resistance (HS-LR) bicycling session; and 3) DRT plus HS-LR bicycling session. It was hypothesized that the medication plus exercise condition would result in the greatest acute improvement in function. Aim 2 was to evaluate test-retest reliability of force segmentation and time to peak force (TpF) measures. Results: Paired t-tests did not support any treatment effects (all p>.055). Delaying an afternoon dose of medication was more challenging for some subjects than others and individual exercise responses varied considerably. Segmented force pulses were observed in most subjects and the mean segmentation was strongly correlated with TpF on all three visits (r=.806-.960) suggesting that slowing in force production is related to disrupted rather than reduced neural drive. ICCs supported favorable test-re-test reliability of mean segments (r=.88) and TpF (r=.86) relative to ICCs of r=.97 and r=.82 for grip strength and TUG, respectively. The methodological approach to Aim 1 would likely require a larger sample size and individuals with a greater duration of DRT use or a more pronounced “wearing off” effect to determine whether afternoon exercise can boost function alone or with medication. Aim 2 results are promising in that mean segmentation has similar reliability to TUG, which is already accepted in rehabilitation research. Furthermore, strong correlations between segmentation and TpF support further inquiry into the role of disrupted neural drive in bradykinesia or PD subtyping.
Description
Keywords
Biological sciences