Apoorva Prathibha K. S. 1 , K. V. Nisha1, Ajith U. Kumar 1
1 Department of Audiology, All India Institute of Speech and Hearing (AIISH), Naimisham Campus, Manasagangothri, Mysuru, 570006, India
The variability in rehabilitative outcomes of children with ANSD has intrigued Audiologists over past two decades. The current study aimed to compare the hearing aid outcomes in children with ANSD and SNHL. Retrospective data collected from medical reports of 24 participants, aged 1-4.9y was taken for the study. The participants were 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). While the group equivalency in HA functional benefit (aided hearing aid scores within speech banana) and data at 3 evaluations (baseline, follow up-1, & follow up-2) was considered preliminary criteria for inclusion of both groups, the diagnosis of the former was based on the recommendations of Staar et al. (2000) and the latter group comprised on SNHL children who were age-matched to the former group. The hearing aid benefit was quantified as difference between unaided and aided thresholds of the better ear were obtained at three evaluations for 4 frequencies (500, 1000, 2000 and 4000 Hz). The results of two-way repeated measure ANOVA (4 frequencies × 3 evaluations) revealed significant no main effect of frequency [F(3,66)=0.12, p>0.05] and follow up [F(2,44)=0.61, p>0.05], but the significant effect of group [F(1,66)=0.12, p=0.001] and significant interaction effects [group*followup: F(2,44)=8.31, p=0.001, ηp2 =0.03; group*frequency: F(3,66)=5.17, p=0.003, ηp2 =0.19; group*frequency*follow up:F(6,132)=4.11, p=0.001, ηp2 =0.16] were seen. On post-Hoc independent t-tests, the hearing aid benefit in SNHL group was statistically higher (p<0.05) than ANSD group in 500, 1000 & 2000 Hz frequencies at baseline, and at 500 Hz in follow up 1. This disparity in hearing aid benefit (despite group equivalency age, degree and functional outcomes of hearing aid) between the groups can be traced to the neural asynchrony in ANSD, leading to variable outcomes in them.