Usefulness of Spectral Range Profile in Quantitative Assessment of Voice Quality in Adults and Children

Objectives: This study aims to assess the usefulness of spectral range profile (SRP) for quantitative assessment of voice quality in vocally healthy singers and non-singers groups differentiated by age and gender. Study Design: Prospective study. Methods: SRP in combination with voice range profile (VRP) using standard singing voice protocols were derived from 57 vocally healthy adults (13 trained choir singers, 44 non-singers) and from 23 vocally healthy prepubescent children (12 choir singers, 11 non-singers). Spectral voice quality parameter - coefficient of sound was calculated as the percent ratio of the sound pressure level (SPL) in the singer's formant frequency region between 2.6 and 3.7 kHz and the SPL of fundamental frequency for fortissimo singing. Results: When compared with non-singers, both genders of adult singers demonstrated a significantly greater average values of coefficient of sound (P<0.05), while no statistically significant differences were found for this parameter in the children groups. The logistic regression analysis revealed that coefficient of sound for adults and pitch range for children were selected as the key predictors of well-equipped voice. The limiting score of the coefficient of sound of ≥ 84.5 % distinguishing singers and non-singers according to ROC curve, has the sensitivity of 100% and specificity of 90.9%. Conclusions: Our study suggests that measurement of spectral range profile may be helpful for quantitative assessment of voice quality in adults, and could be recommended for phoniatricians and speech-language pathologists in their clinical practice.