Speech-perception-in-noise and bilateral spatial abilities in adults with delayed sequential cochlear implantation

Abstract

Objective: To determine speech-perception-in-noise (with speech and noise spatially distinct and coincident) and bilateral spatial benefits of head-shadow effect, summation, squelch and spatial release of masking in adults with delayed sequential cochlear implants.

Study design: A cross-sectional one group post-test-only exploratory design was employed. Eleven adults (mean age 47 years; range 21 – 69 years) of the Pretoria Cochlear Implant Programme (PCIP) in South Africa with a bilateral severe-to-profound sensorineural hearing loss were recruited. Prerecorded Everyday Speech Sentences of The Central Institute for the Deaf (CID) were used to evaluate participants’ speech-in-noise perception at sentence level. An adaptive procedure was used to determine the signal-to-noise ratio (SNR, in dB) at which the participant’s speech reception threshold (SRT) was achieved. Specific calculations were used to estimate bilateral spatial benefit effects.

Results: A minimal bilateral benefit for speech-in-noise perception was observed with noise directed to the first implant (CI 1) (1.69 dB) and in the speech and noise spatial listening condition (0.78 dB), but was not statistically significant. The head-shadow effect at 180° was the most robust bilateral spatial benefit. An improvement in speech perception in spatially distinct speech and noise indicates the contribution of the second implant (CI 2) is greater than that of the first implant (CI 1) for bilateral spatial benefit.

Conclusion: Bilateral benefit for delayed sequentially implanted adults is less than previously reported for simultaneous and sequentially implanted adults. Delayed sequential implantation benefit seems to relate to the availability of the ear with the most favourable SNR.