Abstract: A study on age-related change of encephalofluctuograph was accomplished in 120 subjects aged 20 to 79 years. The results showed: (1)The activities of S-spectra moved toward low-frequency with age from 20 to 59 years,and then shifted backward high-frequency to some extent after 60 years of age. (2)There were obvious age-related changes in some spectral series,in which S17-series were the most susceptible to aging. (3)The coherence between or among different brain areas and the continuous frequencies in all brain areas enhanced in the aging process, and the power distribution was disordered gradually with age; (4)Age-related changes were displayed chiefly in the dominant brain area (left-anterior brain) and dominant brain axis (left-anterior/right-posterior brain), and the most distinct degradation of functions was observed in the left-anterior brain which is closely related to higher brain function. The results indicated that age-related changes of brain function was a nonlinear and a multi-level complex process.

Key words: Encephalofluctuograph, Brain function, Age