Objective:

To measure the effects of levodopa and deep brain stimulation (DBS) on response inhibition, gait speed, and event-related EEG potentials (ERPs) in people with Parkinson’s disease (PwPD) during performance of a response inhibition task while walking.

Background:

ERPs can non-invasively measure neural processes associated with cognitive-gait interactions. When performing a response inhibition task while walking, the first ERP component (N1) reflects early sensory-perceptual processes. The second component (N2) reflects subsequent “go/no-go” conflict monitoring and response selection processes. The third component (P3) reflects response inhibition processes. ERPs could reveal distinct mechanisms underlying disease and treatment-induced changes in cognitive-gait interactions, which could lead to improved outcomes in PwPD (e.g. freezing of gait, falls).

Design/Methods:

We measured response accuracy, treadmill-walking speed, and ERPs in PwPD as they completed a “go/no-go” response inhibition task while walking on a treadmill during four distinct levodopa/DBS treatment conditions (-levodopa/-DBS, -levodopa/+DBS, +levodopa/-DBS, +levodopa/+DBS). We used paired t-tests to evaluate differences among the treatment conditions with respect to response accuracy, treadmill-walking speed, and the mean amplitudes of the ERP components.

Results:

Ten PwPD (58-79 years-old, 2 females) had lower response accuracy, slower treadmill-walking speed, higher N1 mean amplitude, and lower N2 and P3 mean amplitudes during the -levodopa/-DBS condition. Response accuracy improved only during the +levodopa/+DBS condition (p=0.03). Walking speed improved during the -levodopa/+DBS, +levodopa/-DBS and +levodopa/+DBS conditions. The mean N1 amplitude improved during the +levodopa/-DBS condition (p<0.05). The mean N2 and P3 amplitudes improved during the -levodopa/+DBS condition (p<0.05).

Conclusions: