ID 292 – Attention modulation during motor preparation in elderly subjects, freezers and non-freezers patients with Parkinson‘s disease: A time-frequency EEG study

Abstract

Objective Freezing of gait in Parkinson’s disease seems to result from different factors including attention disorders. Our objective was to explore cortical integration of attentional stimulus during motor preparation. Methods Three groups were recruited: older people (n = 6) and parkinsonian patients with (n = 7) or without (n = 7) freezing of gait. Attention was modulated during postural preparation of the step by an auditory oddball discrimination task consisting in discriminating a target sound among a series of standard ones. The primary endpoint was quantification of EEG oscillations following the attentional stimulus. Results An increase of power in low frequencies (delta and theta bands) occurred during the 500 msec following the target stimulus, followed by a decrease in mild frequencies (alpha and beta bands). For freezers patients, early event-related synchronization after the attention stimulus was preserved, whereas EEG oscillations in alpha and beta band were impaired, with a specific impairment to generate an event-related desynchronization after the perception of an attentional stimulus. Conclusions Early attentional discrimination was efficient in freezers patients. At the opposite, further mechanisms reflecting post-discrimination processing were deficient in those patients. Key message Cortical modulations during the attention – motor preparation coupling are different in parkinsonian patients with freezing of gait.