ON THE SIMPLIFIED AVERAGING METHOD UTILIZED IN THE EEG-AUDIOMETRY OF INFANTS AND ITS REACTIVE TYPES

Abstract

Monopolar EEGs of eighty-five sleeping infants tnder sound stimulation of 500, 1000, 2000 and 4000 ps.were recorded.The subjects were introducedo our Hearing Speech Clinic for testing their heaing impairment and speech disorders.Despite no auditory response was able to visuaize in the EEGs themselves, clear-cut ones were coated out in some subjects by applying the Simpliied Averaging Method for the average response ime-pattern(Sato et al.1962) to the EEGs, wheeas no response was obtained in other subjects. Hence, it was obvious that auditory system would not be impaired in the former infants, but be donen the latter.The above responses were classified in the following five types:1.large negative response with or without preceded small positive ones.2.large negative response with preceded and followed small positive ones.3.large negative response with longer duration than the above two types.4.large negative shift with a notch suggesting two responses.5.very slight or suggested negative response.From the above evidences, it would not be impossible to achieve the audimetry of child by obtaining the average response time pattern to auditory stimulation.