Tone identification in Mandarin-speaking children with profound hearing impairment

Little is known about the tone identification ability of Mandarin-speaking children with profound hearing impairment (HI) and fitted with hearing aids (HAs). The present study aimed to evaluate the Mandarin tone identification ability in children with profound HI and fitted with HAs, and explore the effects of hearing thresholds, the age of first HA fitting and the duration of HA use on Mandarin tone identification ability.

Subjects were Mandarin-speaking children aged 5;4-12;6 years with profound HI (n=41). The Mandarin Tone Identification Test was administered in five test conditions: in -10, -5, 0 and 5dB signal-to-noise ratios (S/Ns) and quiet. Hearing aids were in the usual user's settings, optimized for the best speech reception, and the volume was set to comfortable listening level.

Two-way repeated measures ANOVA showed significant effects of test conditions and tone contrasts in Mandarin tone identification. Post-hoc pairwise comparisons showed significant difference in performance among the five test conditions. Results also indicated that, among the six tone contrasts, the Tone 1/Tone 2 and Tone 2/Tone 3 contrasts were the most difficult tone contrasts in quiet. No significant difference in performance was found among the six tone contrasts in noise. Pearson product-moment correlation showed that the age of first HA fitting, the duration of HA use, aided and unaided average thresholds as well as the aided hearing thresholds in the low frequency region were not significantly correlated with tone identification ability in the five test conditions.

Consistent with previous findings, the Tone 1/Tone 2 and Tone 2/Tone 3 contrasts were the most difficult to identify in quiet; but the presence of noise resulted in these tone contrasts being equally difficult. Findings also suggest that the tone identification ability of children with profound HI needs to be improved. Although the age of first HA fitting and the duration of HA use were not significantly correlated with tone identification performance in children with profound HI, this finding does not preclude the importance of early HA fitting.