Audiological and Language Outcomes in Children Using Hearing Aids: A Retrospective Comparative Study of ANSD and Cochlear Hearing Loss

Abstract

The current study aimed to compare the hearing aid (HA) outcomes and speech and language outcomes in children with Auditory neuropathy spectrum disorder (ANSD) and Sensorineural hearing loss (SNHL). The retrospective data collected from medical reports of 24 participants, aged 1-4.9y was categorized into two groups based on the patho-physiology of the deficit: ANSD (n = 12, mean age:2.43±1.21 SD) and SNHL (n = 12, mean age:2.43±1.21y SD). The group equivalency in HA benefit (aided hearing aid scores within speech banana) and audiological data (PTA, degree of HL, Symmetry, SRT, ABR, OAEs, CM, aided and unaided free-field thresholds, and language scores) at 3 evaluations (baseline, follow up-1, & follow up-2) was considered preliminary criteria for inclusion of both groups. The hearing aid benefit (functional gain) was quantified as difference between free-field unaided and aided thresholds obtained at three evaluations for 4 frequencies (500, 1000, 2000 and 4000 Hz), while speech and language outcome was quantified as difference of chronological and language age on the three measures [receptive (RLA) and expressive (ELA) language age, combined (C-LA) language age]. For hearing aid benefit, the results of two-way repeated measure ANOVA revealed significant main effect of groups, frequencies and significant interaction effects between them. Follow up test t-test revealed functional gain of hearing aid in SNHL group was significantly greater than ANSD group at all frequencies in the baseline, while the similar group differences confined to only 500 Hz at follow up 1. No group differences in functional gain were seen in follow up 2. This disparity in hearing aid benefit (despite group equivalency in age, degree and configuration) in baselines but not follow-up can be traced to the acclimatization differences between groups, with ANSD group requiring greater acclimatization period for the realization of hearing aid benefits. With respect to speech and language outcomes, repeated measure revealed significant main effect of timeline and language score and significant interaction effects. On post-Hoc independent t-tests, significantly higher language scores on all measures (RLA, ELA & C-LA) were observed for SNHL compared to ANSD at baseline. In contrast, at follow up 1 and follow up 2, SNHL had significantly better language scores over ANSD only on C-LA as the test SECS considers not only verbal reception and expression, but also non-verbal part of it. Although both the groups have equivalent functional hearing aid benefit, the differences seen in C-LA at the follow up 2 implies non-verbal language perception advantage of SNHL children, despite similar hearing aid acclimatization impact on verbal language reception (RLA) and expression (ELA).