Development of a "virtual cocktail party" for the measurement of speech intelligibility in a sound field.

This technical report describes an approach to the measurement of speech intelligibility for sentences presented in a sound field in the presence of 16-talker babble. More specifically, we detail our (1) selection and preparation of target speech materials, (2) selection and preparation of experimental babble, (3) analog instrumentation, (4) software routines for attenuator control, (5) calibration, (6) experimental subjects, and (7) experimental protocol. In the final section of this report we present speech-intelligibility data from 16 young adults (21-30 yr of age) with normal hearing sensitivity for pure-tone signals.

Audiometric hearing status of individuals with and without multiple sclerosis.

The purpose of the present investigation was to determine whether differences exist in audiometric hearing status between individuals with and without multiple sclerosis (MS) and between individuals with relapsing-remitting MS (RRMS) and individuals with secondary progressive MS (SPMS). Forty-seven subjects with MS (26 with RRMS and 21 with SPMS) and forty-nine control subjects without MS completed both a comprehensive case-history questionnaire and a conventional hearing evaluation. Statistical analyses, accounting for the potential confounding factors of age, sex, noise exposure, and use of ototoxic medications, revealed significant differences in hearing thresholds between subjects with and without MS at select audiometric test frequencies (p < 0.05). At these audiometric test frequencies, the subjects with MS had poorer hearing thresholds. Additional analyses revealed significant differences in hearing sensitivity at select audiometric frequencies between the subjects with RRMS and the subjects with SPMS, such that those with SPMS had poorer hearing thresholds. These findings have significant clinical implications for practitioners working with patients with MS.