Developmental Sexual Dimorphism of the Oral and Pharyngeal Portions of the Vocal Tract: An Imaging Study

Abstract

Purpose-The anatomic origin for prepubertal vowel acoustic differences between males and females remains unknown. The purpose of this study is to examine developmental sex differences in vocal tract (VT) length and its oral and pharyngeal portions.Method-Nine VT variables were measured from 605 imaging studies (MRI and CT) between birth and 19 years. Given sex differences in growth rate ), assessment of sex differences was done using a localized comparison window of 60 months. Analysis entailed applying this comparison window first to four discrete age cohorts, followed by a progressive assessment where this comparison window was moved in one month increments from birth across all ages.Results-Findings document significant postpubertal sex differences in both the oral and pharyngeal portions of the VT. Also, periods of significant prepubertal sex differences in the oral region first, followed by segments in the pharyngeal region. NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author ManuscriptConclusions-Assessment of developmental sex differences using localized age ranges is effective in unveiling sex differences that growth rate differences may conceal. Findings on the presence of prepubertal sex differences in the oral region of the VT may clarify in part the anatomic basis of documented prepubertal acoustic differences.

Toward Improved Spectral Measures of /s/: Results From Adolescents

“…Avery & Liss, 1996; Fuchs & Toda, 2010) that affect front cavity size. Given the minimal anatomical differences observed by Vorperian et al (2011) for boys vs. girls in the age range 10–14;11 years, a sociophonetic explanation appears to account best for the current data.…”

“…However, Pentz et al (1979) did not find gender differences in spectral peak frequencies for 8.5–11.3-year-olds. The anatomical data of Vorperian et al (2011) suggest that gender differences in young adolescents (ages comparable to those used here) are restricted to nasopharynx size, which should not affect the resonant frequencies of fricatives in the oral cavity; however, as with adults, gender differences in adolescents could arise from any variations in articulatory postures that affect front cavity length. Thus, we evaluated whether our proposed measures showed gender differences.…”

“…a) First, one of the main heuristic settings, the upper frequency limit of the mid-frequency band, was held constant for males and females here, given that gender differences in the upper vocal tract in this age range seem to be minimal (Vorperian et al, 2011). Yet it appears that some adolescent girls may sometimes have main front-cavity resonances higher than the current high-frequency bound of 7 kHz, especially at fricative midpoint and in nonlabial contexts.…”

Sagittal Area of the Vocal Tract in Young Female Children

“…Vorperian et al [7,16] have shown gender differences in growth rates of some aspects of the vocal tract in children of the age range studied here. Goals for future studies will include confirming present findings in a larger sample of female children, and conducting a parallel investigation of vocal tract area growth in male children.…”

“…The decision to study one sex was based on the findings of Vorperian et al [16] that there are prepubertal differences in vocal tract growth rates in boys and girls. The decision to study girls was a random choice.…”