Variability in voice fundamental frequency of sustained vowels in speakers with sensorineural hearing loss

In a previous study, the low-frequency modulation extent (LFP) of the vocal fundamental frequency (F ₀) showed a significant increase in the presence of binaural noise masking for the healthy individuals. This study was to investigate the F ₀ of subjects with sensorineural hearing loss (SNHL) using sustained phonations to explore the changes of F ₀ modulations in SNHL. Twenty-three SNHL subjects and 14 age-matched subjects without hearing loss were enrolled in the study. Sustained vocalizations of vowel /a/ for more than 5 seconds were digitally recorded. The F ₀ contour of each phonation was acquired using digital signal processing. The modulation extent at different frequencies was obtained using Fourier transformation of F ₀ contour. The LFP of F ₀ (<3 Hz) was significantly greater for the SNHL subjects (P < 0.001, independent samples t test). Although the correlation analysis was limited to the auditory-evoked brainstem response (ABR) thresholds because of their disagreement with the pure-tone thresholds in some subjects with functional hearing disorder, the correlation between LFP and ABR thresholds was significant (ρ = 0.45, P = 0.03, Spearman's correlation analysis). The LFPs of F ₀ were significantly greater for the SNHL subjects and the changes of F ₀ modulations could be detected using power spectral analysis of F ₀. The method may be used for evaluation of audio-vocal feedback in SNHL.