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Abstract Details

Cortical Responses to Balance Perturbation are Abnormal in Parkinson’s Disease
Movement Disorders
P4 - Poster Session 4 (5:30 PM-6:30 PM)
3-002
We aimed to identify an electrophysiological biomarker of attention-dependent compensation for impaired balance in Parkinson’s disease (PD).
PD increases fall risk, but clinical balance tests fail to identify balance impairments when those at risk of falling use attentional mechanisms to compensate for impaired automatic balance control. Brain activity may reveal a biomarker for such compensation. Using electroencephalography (EEG), we recently showed that young adults with worse balance have a larger supplementary motor area evoked potential (N1, 100-200ms) that we hypothesize reflects attentional control of balance. We therefore tested whether cortical responses during balance recovery were altered in people with PD, and associated with worse balance.
We recruited 15 people with PD (4F/11M, 71±6 years, MDS-UPDRS III 30±4, OFF dopamine medications) and 17 control subjects (noPD, 5F/12M, 71±7 years). Balance ability was assessed using the MiniBESTest. Cortical responses were evoked by sudden translations of the floor (unpredictable forward/backward, 5-10cm). Cortical Cz-EEG responses were time-locked to perturbation and averaged across trials within subjects. Two negative peaks were observed and quantified as the N1 (100-200ms) and N2 (200-300ms). T-tests compared balance ability and cortical responses between groups. Linear regressions tested associations between balance ability and cortical response amplitudes within groups.

Although the N1 was similar across groups (p=0.20, PD: 27±17μV, noPD: 32±16μV), the N2 was smaller in PD (p=0.0004, PD: 14±9μV, noPD: 26±9μV). Balance was worse in PD (p=0.010, PD: 20±7, noPD: 25±2), but cortical responses were not associated with balance ability in either group (p>0.05).
Cortical evoked activity during balance recovery is abnormal in PD. The N2 is not evoked by perturbations in young adults and thus has not been widely studied like the N1. Abnormal N2 activity in PD warrants further study of cortical activity during balance recovery in older populations.
Authors/Disclosures
Aiden Payne, PhD (Emory University)
PRESENTER 		No disclosure on file
No disclosure on file