Advisor

James F. Maurer

Date of Award

2-1974

Document Type

Thesis

Degree Name

Master of Science (M.S.) in Speech: Emphasis in Speech Pathology/Audiology

Department

Speech and Hearing Sciences

Physical Description

1 online resource (ix, 51 pages)

Subjects

Intelligibility of speech -- Testing, Hearing aids -- Evaluation

DOI

10.15760/etd.1965

Abstract

Hearing aid manufacturers commonly engineer automatic gain control (AGC) circuits which are aimed at reducing'sound tolerance problems and improving speech intelligibility among wearers. The most common type of AGC engineered is one utilizing a fast attack time. The present study was designed to evaluate the effects of both fast and slow attack times on the intelligibility of speech. Twenty-four normal hearing subjects listened to sixty pre-recorded sentences through two types of hearing aid circuits. Thirty sentences were modified by a fast attack AGC circuit, and thirty sentences were modified by a slow attack AGC. The subjects marked one of four multiple~choice answers for each sentence.

The mean number of sentences answered incorrectly when heard through fast attack AGC was 8.25. When heard through slow attack AGC, the mean was 6.67. The performance differences which exist between these two modes of signal modification suggest that the fast attack does not improve intelligibility as significantly as slow attack time among normal listeners. Further investigation into the effects of slow attack AGC circuits on the user's ability to understand speech are recommended.

Persistent Identifier

http://archives.pdx.edu/ds/psu/12552

Share

COinS