NIRS Signal Analysis using Variance Plot for Auditory Selective Attention

Abstract

In near-infrared spectroscopy (NIRS), there is optical pathlength problem. Thus, NIRS measurements cannot be compared between subjects and or regions within a subject. In this study, we propose a separation method for the optical pathlength influence by the variance plot analysis using the variance of the sample mean to NIRS time series signal. As a validation example, we conducted variance plot analysis on auditory selective attention by 10 subjects of normal adult males. As a result, in 8 subjects out of 10 subjects for auditory area on the left side and 7 subjects out of 10 subjects on the right side for auditory area, channels corresponded which are activated concentrating on listening to music.