On the interaction between electroencephalogram bands of normal elderly women and demented elderly women

Abstract

[Purpose] This study investigated the potential of quantitative electroencephalogram (EEG) analysis for dementia diagnosis by examining the correlation between each frequency band of EEG using a sample of normal and demented elderly women. [Subjects] Thirty-three elderly women (17 normal, 16 demented) without history of brain disease were participated in this study. [Methods] EEGs of the subjects were measured continuously for 5 minutes while subjects' eyes were closed. The AT index was defined as the ratio of the theta wave to the SMR wave; the AC index was defined as the ratio of the low beta wave to alpha wave; and the ST index was defined as the ratio of the high beta wave to the alpha wave. The differences in brain activity between normal and demented elderly women were analyzed using the Mann-Whitney test and the SPSSWIN (ver. 12.0) program. [Results] All areas showed a lower AT index among normal elderly women compared to demented elderly women. In the P4 area, the AC index and the ST index were significantly higher in normal than in demented elderly women, indicating there is a difference in brain activity between normal and demented elderly women. [Conclusion] These results show that quantitative EEG analysis can be used for dementia diagnosis.