EVALUATION BY OCTAVE ANALYSIS

摘要

A method of examining a bodily function. A first set of frequency characteristics and amplitude characteristics of a first electrical signal deriving from rhythmic activity of a nerve in a living body is detected at a first condition. The nerve is stimulated to a second condition and a second set of frequency characteristics and amplitude characteristics of a second electrical signal deriving from the rhythmic activity of said nerve is detected. The fundamental frequency present in the frequency characteristics is identified. From the fundamental frequency the frequencies corresponding to a plurality of octaves of said fundamental frequency are calculated. The amplitude of said electrical signals at said octaves is identified. For said first signal a first amplitude ratio is calculated being the ratio of the amplitude difference between a first pair of said octaves, and the amplitude difference between a second pair of said octaves. For said second signal a second amplitude ratio is calculated being the ratio of the amplitude difference between said first pair of octaves, and the amplitude difference between said second pair of octaves. An octave ratio is calculated being the ratio of said first amplitude ratio to said second amplitude ratio. The octave ratio is used as a measure of said bodily function.