Does reduced frequency selectivity in children with mild to moderate sensorineural hearing loss affect frequency discrimination in Mismatch Negativity and Pitch Pattern Sequence Tests?

Objective: Sensorineural hearing loss (SNHL) results in reduced sensitivity, abnormal growth of loudness, reduced frequency selectivity and reduced temporal resolution (1). Our aim was to study frequency discrimination abilities in children with SNHL using the psychophysical Pitch Pattern Sequence Test (PPST) and an electrophysiological measure, the Mismatch Negativity Test (MMN). Methods: This is a cross-sectional study that included 90 children, ages ranging from 6 - 12 years, divided into a study group of 60 children with mild to moderate SNHL and a control group of 30 normal hearing children. Both groups were subdivided into 3 subgroups according to age. Results: Subgroups of children with SNHL showed statistically significant poorer scores on the PPST than their well-matched controls. Although MMN can be elicited in children with mild to moderate degree of SNHL, its latency was prolonged. The older control subgroups did not show any statistically significant better scores on the PPST; MMN latencies were longer with increased duration of hearing loss. Degree of hearing loss, gender and side had no effect on PPST or MMN. There was no statistically significant correlation between the results of the PPST and MMN. Conclusion: SNHL affects frequency discrimination abilities demonstrated in poor scores on the PPST and prolonged MMN latency.