Abstract
Background and Purpose: Persons with Parkinson disease (PD) are unable to modify their postural responses, and show an associated increase in cortical preparatory activity for anticipated postural perturbations.1 In this study we asked whether participants with PD could modify their postural responses and cortical preparatory activity when cued to focus on increasing movement amplitude before a series of predictable postural perturbations.
Methods: Twelve participants with PD performed postural responses to 30 identical backward surface translations. We cued participants to focus on increasing movement amplitude, and examined the effects of cueing by measuring postural responses (center-of-pressure initial rate of change, automatic postural response stability, peak trunk flexion, peak ankle extension) and preparatory cortical activity (electroencephalographic measures of contingent negative variation, alpha and beta event-related desynchronization).
Results: Participants with PD modified their postural responses during the amplitude trials by increasing trunk flexion, slowing center-of-pressure initial rate of change, and decreasing automatic postural response stability. However, no significant differences in contingent negative variation amplitude or alpha or beta event-related desynchronization were observed with versus without amplitude cueing.
Discussion and Conclusions: Persons with PD were able to modify their feet-in-place postural responses with amplitude cueing. These changes were not associated with changes in cortical preparation during amplitude cue trials, suggesting that other regions or measures of brain function were responsible for changes in postural responses. Future studies are needed to determine the effects of long-term amplitude-cueing practice on cortical preparation and postural stability.
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