Abstract
Objective: The relationship between pre- and postimplantation monaural auditory performance in patients undergoing bilateral sequential cochlear implantation (SCI) has not been clearly defined. A greater understanding of this relationship could potentially affect preoperative counseling to patients regarding choice of initial side to implant.
Method: Retrospective review was performed of monaural auditory performance pre- and postimplantation in 90 SCI recipients between 1997 and 2011 at Vanderbilt University. A “better-hearing ear” had lower pure tone average or speech awareness threshold by at least 10 dB, or open/closed-set speech perception score at least 10% higher.
Results: A difference in preimplantation hearing status was identified in 35 patients. The first-implanted ear was better-hearing in 11 and worse-hearing in 24. 28/35 patients had available data on post-implantation monaural auditory performance. At last follow-up (mean 24 months, range 1-69), the first-implanted ear exhibited better closed/open-set speech perception scores in 19/28 (68%) patients. There were no differences when comparing patients grouped according to preimplantation hearing status (Fisher’s exact test, P < .05). Median time between implant activations was 31 months when the first-implanted ear exhibited better performance, and 17 when the second-implanted ear performed better (difference NS, rank sum test).
Conclusion: A relationship between pre- and postimplantation monaural auditory performance in SCI recipients was not identified. The first implanted ear is more likely to exhibit better monaural auditory performance, even if this ear had worse pre-implantation hearing. This finding highlights the plasticity of central auditory pathways in cochlear implant recipients.
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