Objective Comparison of Benefits Derived From Contralateral Routing of Signal Hearing Aid and Bone Conduction Device in Noisy Surroundings in Patients With Single-Sided Deafness

Abstract

Background and Objectives Single-sided deafness (SSD) leads to non-participation of the diseased ear in generating adequate auditory input, which results in poor speech discrimination in noisy surroundings. The present study objectively compared the audiological benefits rendered by contralateral routing of signal (CROS) hearing aid and bone conduction device (BCD) in patients with SSD >70 dB HL using the modified hearing in noise test (HINT). Materials and Methods Patients with SSD >70 dB HL in poor and clinically normal hearing in the better ear were enrolled. Patients aged <18 or >70 years, with a history of neurological insult or ear infection in the last 3 months, mental retardation, psychiatric or developmental disorders, and diabetes were excluded. Modified HINT was performed with the affected ear unaided, aided with CROS hearing aid, and with BCD, generating three groups. Noise signal was presented at a fixed intensity of 65 dB at the neutral position in the center and speech signal was presented to either ear sequentially. The test was repeated with the speech signal fixed at the neutral position and the noise signal presented to either ear. Results BCD led to a better signal-to-noise ratio (SNR) than CROS hearing aid in all situations except when noise was centralized and speech was presented to the affected ear. Conclusions A benefit was observed when auditory rehabilitation was used for the affected ear as demonstrated by better SNR scores. The results showed that BCD performed better than CROS hearing aid.