Objective voice analysis of boys with profound hearing loss

A critical factor that affects human voice production is hearing because it provides necessary feedback for control of speech. Vocal quality of profoundly hearing-impaired children is often considered deviant from both perceptual and acoustic perspectives. The present study compares selected vocal acoustic parameters of a profound hearing loss group of boys with normal peers.

The subjects were 15 Iranian boys with profound bilateral sensorineural hearing loss and 15 Iranian normal hearing participants matched according to age and sex. The age range of the children with hearing loss was 61-81 months (M=72.26) (ie, 5.1-6.75 years, M=6.02 years) and for the normal group the age range was 61-80 months (M=71.47) (5.08-6.67 years, M=5.96 years). Each subject phonated 10 /â/ vowels with constant pitch and loudness for maximal phonation times. The mid 3-second portion of each token was analyzed using Dr. Speech 4.3u software (subprogram: Vocal Assessment; Dr. Speech, Tiger Electronics, Seattle, WA).

There was a statistically significantly higher fundamental frequency (F0), jitter, and shimmer in the productions of the hearing loss boys compared with the normal hearing boys. Consistent with these findings was a significantly lower value for the harmonics-to-noise ratio measure for the boys with hearing loss.

The results of the present study suggest that profoundly deaf children present with greater phonatory instability and spectral noise, with the possible inference of reduced laryngeal control relative to vocal quality. The finding of higher F0 for the boys with profound hearing loss suggests that they use a different control strategy for pitch, an area needing further study. These findings of acoustic and F0 differences of the hearing-impaired boys should be kept in mind for intervention practices especially when the social impact of deafness is considered.