The evaluation of visual event related potentials, Parkinson's disease and healthy elderly subjects

Objective: The purpose of this study was to research changes in brain dynamics of Parkinson's Disease patients and healthy elderly by using event-related potentials (ERP) and to evaluate a relationship with neuropsychological tests (NPT). Method: Eighteen PD patients (mean age: 65.30) and 18 age, gender and education matched healthy elderly (mean age:69.10) were included. NPT applied to all participants. "Peak" amplitude and latency of P300 and N200 target ERP responses were measured and their relationship with NPT were investigated. EEG was recorded from the F3, Fz, F4, C3, Cz, C4, P3, Pz, P4, O1, Oz and O2 by using classical visual oddball paradigm. Repeated measures of ANOVA, post-hoc t-test and partial correlation tests were used for statistical analyses. Results: Significant differences were found between groups on P300 amplitudes [F(1,31)=9.265; p=0.005]. P300 amplitudes were significantly lower in PD patients at F3, FZ, Cz, C4, Pz and P4 electrode sites than healthy controls (respectively: p=0.038, p=0.004, p=0.007, p=0.033, p=0.016, p=0.035). PD patients had lower N200 latency than healthy elderly [F (1,31)=4.186; p=0.049]. N200 latency were significantly lower in PD patients at F3, P4, O1 and OZ electrode sites than healthy controls (respectively: p=0.033, p=0.043, p=0.022). Moderate correlations were found between P300 amplitudes and N200 latency and Stroop test, digit span forward test scores. Conclusion: Electrophysiological results may showed cognitive changes which not reflect NPT in PD patients. EEG results can be useful for next studies that investigating to processes of PD. Keywords: Parkinson's Disease, Visual Event Related Potentials, visual P300/N200