EEG Coherence in Alzheimer s Disease

J Korean Neurol Assoc > Volume 21(2); 2003 > Article

Journal of the Korean Neurological Association 2003;21(2): 163-168.

알쯔하이머병에서 뇌파 C o h e r e n c e

곽용태 , 함동석 한일우 백종삼

효자병원 신경과,인제대학교 의과대학 상계백병원 신경과학교실

EEG Coherence in Alzheimer s Disease

Yong Tae Kwak

"Department of Neurology, Hyoja Geriatric Hospital Department of Neurology, Sanggye Paik Hospital, Inje University College of Medicine"

Abstract

"Background : EEG coherence can be used to evaluate the functional cortical connections and to get information about the synchronization of the regional cortical activity. We studied EEG coherence in patients affected by clinically probable Alzheimer s disease (AD) in order to quantify the modifications in the cortico-cortical or cortico-subcortical connections. Methods : The EEGs were recorded in 62 AD patients and in 30 normal age-matched subjects from 16 electrodes with linked-ears reference. Spectral parameters and coherence were calculated by a multichannel autoregres-sive model using 20 artifact-free 2-sec epoch in normal controls and AD patients. Results : In AD patients, alpha coher-ence in frontal field and theta, alpha interhemispheric coherence was significantly decreased, whereas alpha, beta coher-ence in posterior field was significantly increased. Some electrodes in the anterior field showed significant negative cor-relation with MMSE, whereas other electrodes in the posterior field showed significant positive correlation with MMSE. Conclusions : This study suggests that coherence is a useful tool for understanding electrophysiologic change of AD and for correlating with the severity of cognitive dysfunction. And these coherence changes can be interpreted as the effects of neuronal loss and neocortical disconnection.Key Words : EEG, Coherence, Alzheimer s disease"