Acute Bouts of Passive Leg Cycling Can Improve Cognitive Function in Parkinson's Patients

Abstract

Parkinson's disease (PD) often leads to a deficit in cognitive function. Pharmacological therapies are effective in treating motor symptoms in PD, but do not slow the progression of cognitive decline. A number of studies have reported that intensive exercise can improve cognitive function. However, individuals with PD often have difficulties participating in high-intensity exercise. PURPOSE: The purpose of this study is to determine if acute bouts of passive leg cycling can improve cognitive function in PD, and if different rates of pedaling have variable effects on cognitive function. METHODS: Nineteen, mild to moderate idiopathic PD patients (12 men, 7 women, age- 63.2 ± 8.6), reported to the exercise science laboratory on four separate occasions, separated by one week. On the first visit, PD patients completed a YMCA cycling test (Excalibur 1300 W cycle ergometer) to estimate maximal oxygen consumption and a computer based psychomotor tests consisting of Trail Making Test (TMT) A and B while 'on' anti-Parkinson's medication. For the next three visits PD patients participated in passive leg cycling (MOTOmed viva2) at 60, 70 and 80 revolutions per minute (rpm) while 'off' anti-Parkinson's medications. Cycling rates were randomly administered. The TMT A and B were administered prior to and immediately after each cycling session. RESULTS: Data were analyzed using a 3 (trial) by 2 (time) analysis of variance (ANOVA) with repeated measures on both variables. TMT A scores did not differ between trials (p=0.569) or across time (p=0.207). In addition, no trial by time interaction was observed for TMT A Scores (p=0.555). TMT B scores improved across time (70.3 ± 3.7 vs. 62.4 ± 2.6 sec, p=0.003) with no difference between trials (p=0.919) or trial by time interactions observed (p=0.841). The difference in scores between TMT B and A showed a main effect of time (pre: 37.6 ± 2.6, post: 31.0 ± 1.9 sec, p=0.006). CONCLUSION: These data suggest that passive leg cycling can improve executive function in PD patients, as measured by the TMT B. Lack of improvement in the TMT A suggests that TMT B improvement is due to changes in visual search and motor speed alone. However, there is no association between cognitive improvement and passive cycling rate. Future studies will compare these results with active-assisted cycling at variable rates.