Re: Bone-anchored hearing aids for people with bilateral hearing impairment: a systematic review

Abstract

The improvement in quality of life from bone-anchored hearing aids Sir, Colquitt et al.’s 1 comprehensive review of bone-anchored hearing aids (BAHAs) emphasized the overall lack of evidence on quality of life (QoL). They reported just one study 2 of the effects on QoL, when measured using generic instruments (a further study was found, but was not reported because of limited data). This study compared BAHAs to both previously-worn air-conduction hearing aids (36 patients) and previously-worn bone-conduction hearing aids (20 patients). With all patients combined, a statisticallysignificant effect of BAHAs was found in only one of the 8 domains (mental health) of the SF-36 questionnaire; there were no effects on the EQ-5D questionnaire. When the patients were grouped by their previous aids, the only statistically-significant effect found was on one of the five dimensions (anxiety/depression) of the EQ-5D in the air-conduction group. We had independently conducted a survey of QoL with bone-anchored hearing aids. We found two other papers 3, 4 that considered the SF-36 questionnaire. The SF-36 which has 8 scales (physical functioning, physical limitation, bodily pain, general health, vitality, social functioning, emotional limitation, and mental health), each of which are measured on a scale from 0 to 100. Neither study found any statistically significant effects of BAHA fitting, either for BAHAs vs. previously worn air-conduction hearing aids (1213 patients) 3 , or for BAHAs vs. pre-fitting in previously-unaided patients (8 patients) 4 . We found no studies that have used the other common generic measure of QoL, the Health Utilities Index. In general, these results support Colquitt et al.’s review. We conclude that there is an absence of evidence that BAHAs lead to any improvement in QoL — when measured with generic instruments. That does not necessarily mean that there is no effect, as no evidence of difference does not imply evidence of no difference. The qualification 'when measured with generic instruments' is crucial here: the problem is that the generic instruments themselves are mostly insensitive to either hearing impairment or its management. The HUI-3 is the most responsive, but there are only minimal changes in EQ-5D scores as a result of cochlear implantation, 5 even though it is self-evident that a cochlear implant often leads to a dramatic improvement in a patient’s life. We therefore agree with Colquitt et al. in their call for more research on the potential benefits of BAHAs on quality of life.