Adults with unilateral congenital ear canal atresia – sound localization ability and recognition of speech in competing speech in unaided condition

Abstract

Background Individuals with unilateral hearing loss show poor spatial hearing, but individual variability is high. Aims/objectives To investigate if the degree of hearing loss in unilateral ear canal atresia affects horizontal sound localization and speech recognition. Materials and methods Twelve subjects with unilateral ear canal atresia without childhood hearing intervention. Previously published data from eight normal-hearing subjects in normal binaural as well as experimentally induced unilateral hearing loss served as a reference. Horizontal sound localization and recognition of speech in spatially separate competing speech were assessed. Results Linear regression analysis demonstrated a relationship between sound localization accuracy (SLA) and the air conduction pure tone average of the atretic ear (r = 0.85, p=.007). The large proportion of variability in SLA (72%) explained by the degree of hearing loss of the atretic ear indicates that binaural processing is possible. SLA was worse than for normal hearing individuals (p<.0001), and comparable to moderate simulated unilateral hearing loss (p=.13). Speech discrimination was significantly worse than normal (p<.0001) and not dependent on degree of hearing loss of the atretic ear. Conclusions and significance Individuals with congenital unilateral ear canal atresia show impaired horizontal SLA and recognition of speech in competing speech.