Evaluation of event related potentials in patients wi̇th progressive and stable mild cognitive impairment

Objective: Amnestic mild cognitive impairment (MCI) is considered as the prodromal stage of Alzheimer's disease (AD) and the conversion rate from MCI to AD is high. There is a need for a marker to predict the conversion from MCI to AD. The aim of the study is to investigate the utility of P300 component of event related potentials as a marker for conversion from MCI to AD. Method: The study included 14 progressive MCI, 14 stable MCI and age, education, gender matched 29 healthy controls with baseline and follow-up neurological examinations, neuropsychological tests and EEG recordings. The average P300 amplitude values, which elicited by a visual oddball paradigm, were measured automatically from the Fz, Cz and Pz electrodes at a time interval of 280-550 ms. Correlations between P300 amplitude values and neuropsychological test scores were examined. ROC curve analyzes were performed to determine the sensitivity and specificity of mean P300 amplitude values. Results: The baseline P300 amplitudes of the progressive and stable MCI were lower than healthy controls and P300 amplitudes of progressive MCIs were lower than those with stable MCIs (F2,54=14,942; p<.001). Follow-up P300 amplitude values were lower in patients with progressive and stable MCI compared to healthy controls (F2,54=12,288; p<.001). In addition, baseline and follow-up Fz P300 amplitude was higher than the Cz and Pz. Several correlations were found between P300 amplitudes and neuropsychological test scores. ROC analysis showed that the baseline P300 amplitude can distinguish between progressive and stable MCI with 85.7% sensitivity and %71.4 specifity. Conclusion: The findings of the study support the use of P300 amplitude values as a marker for predicting the progression of the disease and discriminating between progressive and stable MCI. Keywords: Mild Cognitive Impairment, Alzheimer's Disease, Event Related Potentials, P300