Acoustic Voice Analysis of Prelingually Deaf Adults Before and After Cochlear Implantation

Abstract

It is widely accepted that many severe to profoundly deaf adults have benefited from cochlear implants (CIs). However, limited research has been conducted to investigate changes in voice and speech of prelingually deaf adults who receive CIs, a population well known for presenting with a variety of voice and speech abnormalities. The purpose of this study was to use acoustic analysis to explore changes in voice and speech for three prelingually deaf males pre- and postimplantation over 6 months. The following measurements, some measured in varying contexts, were obtained: fundamental frequency (F0), jitter, shimmer, noise-to-harmonic ratio, voice turbulence index, soft phonation index, amplitude- and F0-variation, F0-range, speech rate, nasalance, and vowel production. Characteristics of vowel production were measured by determining the first formant (F1) and second formant (F2) of vowels in various contexts, magnitude of F2-variation, and rate of F2-variation. Perceptual measurements of pitch, pitch variability, loudness variability, speech rate, and intonation were obtained for comparison. Results are reported using descriptive statistics. The results showed patterns of change for some of the parameters while there was considerable variation across the subjects. All participants demonstrated a decrease in F0 in at least one context and demonstrated a change in nasalance toward the norm as compared to their normal hearing control. The two participants who were oral-language communicators were judged to produce vowels with an average of 97.2% accuracy and the sign-language user demonstrated low percent accuracy for vowel production.