Self-reported benefits from successive bilateral cochlear implantation in post-lingually deafened adults: randomised controlled trial

Abstract

Adult users of unilateral Nucleus CI24 cochlear implants with the SPEAK processing strategy were randomised either to receive a second identical implant in the contralateral ear immediately, or to wait 12 months while they acted as controls for late-emerging benefits of the first implant. Twenty four subjects, twelve from each group, completed the study. Receipt of a second implant led to improvements in self-reported abilities in spatial hearing, quality of hearing, and hearing for speech, but to generally non-significant changes in measures of quality of life. Multivariate analyses showed that positive changes in quality of life were associated with improvements in hearing, but were offset by negative changes associated with worsening tinnitus. Even in a best-case scenario, in which no worsening of tinnitus was assumed to occur, the gain in quality of life was too small to achieve an acceptable cost-effectiveness ratio. The most promising strategies for improving the cost-effectiveness of bilateral implantation are to increase effectiveness through enhanced signal processing in binaural processors, and to reduce the cost of implant hardware.

• Bilateral implantation
• Cochlear implantation
• Effectiveness
• Cost-effectiveness

Sumario

Se seleccionaron aleatoriamente usuarios adultos de implante coclear (IC) Nucleus CI24 unilateral con la estrategia de procesamiento SPEAK, para recibir un segundo IC idéntico en el oído contralateral, de manera inmediata o después de 12 meses mientras actuaban como controles para observar los beneficios de aparición tardía del primer implante. Completaron el estudio 24 sujetos, 12 de cada grupo. La recepción del segundo IC condujo a una mejoría de las habilidades auto-reportadas en la audición espacial, calidad auditiva y audición del lenguaje, pero también a cambios, generalmente no significativos, en las mediciones de calidad de vida. Un análisis multivariado mostró que los cambios positivos en calidad de vida se asociaron con mejoría auditiva, pero que estos fueron contrarestados por cambios negativos asociados a un empeoramiento del tinnitus. Incluso en el mejor de los casos en el que no hubo empeoramiento del tinnitus, la ganancia en calidad de vida fue demasiado pequeña para lograr una relación costo/efectividad aceptable. Las estrategias más prometedoras para mejorar la relación costo/efectividad de la implantación bilateral deben incrementar esa efectividad mejorando el procesamiento de señales en los procesadores binaurales y reduciendo el costo del propio implante.

Notes

1. In estimating life-time costs and benefits, future costs and future benefits were discounted to reflect the usual preference of people to obtain benefits immediately but to defer expenditure. In the analyses reported by Summerfield et al. (2002), a discount rate of 6% per annum was applied, in line with economic practice at the time. Thus, if a cost of €n was to be met in y years time, it was valued as €n/(1.06)^y. Similarly, when estimating the incremental gain in QALYs from receipt of a second implant, the increase in health utility of +0.031 was accumulated with the formula: