Study on Delayed Auditory Feedback (DAF) with Filtered Speech

Abstract

The present study was aimed to evaluate the speech behaviors of normal young adults under DAF condition with an audiofilter.The feedback speech was distorted with a lowpass and a high-pass filter. The subjects were 21 young adults, 18 males and 13 females. Each subject read 100-word passages under DAF (delay time 200 msec) with all-pass filtering, low-pass filtering above 1, 200, 1, 700 and 2, 400Hz, and high-pass filtering below 1, 200, 1, 700 and 2, 400Hz. The feedback level was 65dB above each hearing threshold, and the sound was delivered to both ears. The speech behaviors were analysed with reference to reading time ratio and articulatory error, comparing with those under normal auditory feedback (NAF).The results were as follows:1. The speech behaviors were mostly disturbed under all-pass filtering.2. The speech behaviors under low-pass filtering were more disturbed than those under highpass filtering.3. There were little differences among speech behaviors under three conditions of filtering; 1, 200, 1, 700 and 2, 400Hz for low-pass and high-pass respectively.4. In general, the DAF effects on the male were greater than the female.5. It was concluded that the low frequency range of speech sound was mostly responsible for DAF effect.