Spatial hearing in a child with auditory neuropathy spectrum disorder and bilateral cochlear implants

Abstract

Objective: The neural dys-synchrony associated with auditory neuropathy spectrum disorder (ANSD) causes a temporal impairment that could degrade spatial hearing, particularly sound localization accuracy (SLA) and spatial release from masking (SRM). Unilateral cochlear implantation has become an accepted treatment for ANSD but treatment options for the contralateral ear remain controversial. We report spatial hearing measures in a child with ANSD before and after receiving a second cochlear implant (CI). Study sample: An 11-year-7-month old boy with ANSD and expressive and receptive language delay received a second CI eight years after his first implant. Design: The SLA and SRM were measured four months before sequential bilateral CIs (with the contralateral ear plugged and unplugged), and after nine months using both CIs. Results: Testing done before the second CI, with the first CI alone, suggested that residual hearing in the contralateral ear contributed to sound localization accuracy, but not word recognition in quiet or noise. Nine-months after receiving a second CI, SLA improved by 12.76° and SRM increased to 3.8–4.2 dB relative to pre-operative performance. Results were compared to published outcomes for children with bilateral CIs. Conclusions: The addition of a second CI in this child with ANSD improved spatial hearing.

Key Words::

• Medical audiology
• pediatric
• cochlear implant
• behavioral measures

Acknowledgements

We are grateful to the patient's family for giving consent to publish this case study. We wish to thank Lynzee Alworth for assisting with data collection prior to the patient's second CI. We also thank two anonymous reviewers for their thoughtful comments on an earlier version of this paper. Portions of this study were presented at the 2012 annual conference of the American Speech-Language Hearing Association in Atlanta, Georgia, USA.

Declaration of interest: The authors report no conflict of interest. The authors alone are responsible for the content and writing of the paper.