Interaural Asymmetry, Not Hearing Thresholds, Predicts Diotic Frequency Modulation Sensitivity in Children With...

Sensory deprivation during childhood not only disrupts sound perception but may also alter central auditory processing and auditory development. While the effects of severe hearing loss in childhood are relatively well recognized, the impact of minimal-to-mild sensorineural hearing loss remains less clear. Animal models suggest that even transient auditory deprivation during development can impair central mechanisms that support perceptual skills. This study examined how minimal-to-mild sensorineural hearing loss affects temporal processing in children.

In a case-control design, children (4 to 12 years; n = 121) participated in psychoacoustic tasks using a three-alternative forced-choice adaptive procedure to assess sensitivity to amplitude modulation and frequency modulation in a diotic mode. Amplitude modulation detection thresholds were measured using a 20-Hz modulation rate, and frequency modulation detection thresholds were obtained at 2 and 20 Hz. Statistical analyses included between-group comparisons (normal hearing, unilateral hearing loss, and bilateral hearing loss) and regression modeling with age, pure-tone average, and interaural asymmetry entered as continuous independent variables.

Analyses revealed that children with minimal-to-mild hearing loss did not exhibit deficits in amplitude or frequency modulation sensitivity. However, interaural asymmetry in hearing sensitivity was associated with reduced sensitivity to frequency modulation.

These findings indicate that asymmetric hearing loss within the minimal-to-mild hearing loss range has an adverse effect on basic measures of auditory perception. This study underscores the need for early identification and intervention, as even minimal hearing loss during childhood can disrupt auditory perception in subtle yet developmentally significant ways.