Title

Perceptual and acoustic voice characteristics of children with anhidrotic ectodermal dysplasia

Date of Completion

January 2002

Keywords

Health Sciences, Speech Pathology

Degree

Ph.D.

Abstract

This investigation examined perceptual and acoustic voice characteristics in the speech of 13 pre-pubescent children (6 males, 7 females) who were diagnosed with anhidrotic ectodermal dysplasia (ED) (mean age = 6 years, 2 months) and in the speech of 13 normal peers (6 males, 7 females) identified as the control group (mean age = 5 years, 4 months). For each subject, acoustic measurements of mean fundamental frequency (FO), mean jitter ratio, harmonics-to-noise ratio (HNR), maximum phonation duration (MPD), and bandwidth values for the first and second formants (BW F1 & BW F2) were extracted from spontaneous speech samples and/or the midportion of 3 vowels in isolation (/a, i, u/) and embedded in the carrier phrase “Say ha&barbelow;d again, Say hi&barbelow;d again, Say hu&barbelow;d again”. Speech samples were then presented to 5 experienced listeners for the perceptual task where they rated two parameters: (1) voice quality on a 4-point categorical scale (“normal, hoarse, breathy” and “rough”), and (2) severity on a 7-point equal-appearing interval scale. Significant differences between the two groups were found for mean jitter ratio, HNR, MPD, and perceptual ratings. Results of the perceptual task indicated that listeners perceived subjects diagnosed with ED as having voices characterized as “breathy” (36%), “hoarse” (32%), “rough” (24%) and “normal” (8%). Correlation analysis between voice category groups revealed a significant correlation between acoustic variables (mean jitter ratio and HNR) and the voice category groups “breathy” and “hoarse”. Within voice category groups, only the “breathy” group yielded a significant inverse correlation between average jitter ratio values and HNR. ^