Unexpected Dual Task Benefits on Cycling in Parkinson Disease and Healthy Adults: A Neuro-Behavioral Model

Abstract

BackgroundWhen performing two tasks at once, a dual task, performance on one or both tasks typically suffers. People with Parkinson’s disease (PD) usually experience larger dual task decrements on motor tasks than healthy older adults (HOA). Our objective was to investigate the decrements in cycling caused by performing cognitive tasks with a range of difficulty in people with PD and HOAs.MethodsTwenty-eight participants with Parkinson’s disease and 20 healthy older adults completed a baseline cycling task with no secondary tasks and then completed dual task cycling while performing 12 tasks from six cognitive domains representing a wide range of difficulty.ResultsCycling was faster during dual task conditions than at baseline, and was significantly faster for six tasks (all p<.02) across both groups. Cycling speed improved the most during the easiest cognitive tasks, and cognitive performance was largely unaffected. Cycling improvement was predicted by task difficulty (p<.001). People with Parkinson’s disease cycled slower (p<.03) and showed reduced dual task benefits (p<.01) than healthy older adults.ConclusionsUnexpectedly, participants’ motor performance improved during cognitive dual tasks, which cannot be explained in current models of dual task performance. To account for these findings, we propose a model integrating dual task and acute exercise approaches which posits that cognitive arousal during dual tasks increases resources to facilitate motor and cognitive performance, which is subsequently modulated by motor and cognitive task difficulty. This model can explain both the improvement observed on dual tasks in the current study and more typical dual task findings in other studies.

Improved cognition while cycling in Parkinson’s disease patients and healthy adults

“…Simpler tasks were interspersed among difficult tasks in order to avoid possible cognitive fatigue. For a breakdown of dependent variables by cognitive task see Table 2 (See also Table 2, Altmann et al, 2015). …”

“…More specifically, considering previous findings of greater visual-spatial than verbal impairments in PD (Cooper et al, 2009; Uc et al, 2005), we predicted that group differences in performance would be disproportionately found in visual-spatial tasks. Further, based on our previous findings (Altmann et al, 2015), we predicted that any dual task benefits experienced by the HOA group would be reduced in the PD group.…”

“…We have recently reported unexpected dual task benefits on cycling during a range of cognitive tasks in both HOAs and people with PD (Altmann et al, 2015). In that study, participants performed a large battery of cognitive tasks while sitting in a quiet room or while pedaling a stationary bicycle.…”

Retraining Automaticity: Recovering the Procedural Memory of Walking after Stroke

“…As yet, our science for rehabilitative "loading" and expectations to improve DT tolerance and automaticity in gait, is imperfect and developing [55]. Here is where the science of neuroplasticity and motor learning -including intensity and task specificity more than any other concepts -have been incompletely applied in most of the research on dual task training to date.…”

“…The limitations have been in training. Research that has been designed to investigate retention of motor learning through dual task trainingessentially toward a dual task development of a procedural memory or to show greater automaticity after training [55], has largely been poorly designed. Methods in these studies have included sufficient numbers of repetitions, yet have not applied sufficient intensity.…”