Usage of CROS and IROS hearing aids by patients with bilateral high-frequency hearing loss.

Responses to a hearing aid usage questionnaire were received from 128 patients with high-frequency sensorineural hearing loss fitted monaurally with contralateral routing of signals (CROS) or ipsilateral routing of signals (IROS) hearing aids. Functional benefits were demonstrated by wearing the instruments 8 to 9 hr/day, use of the aids about 60% of the time in communicative situations, subjective benefit judgements of 5 to 9 on a 10-point scale, improved subjective sound localization, and improved clarity of speech with the hearing aids. Although CROS and IROS fittings could not be separated on the basis of these factors, considerably more complaints were reported by the CROS wearers, and many of these related to auditory factors. Both CROS and IROS fittings appear to be effective approaches to the patient with high-frequency hearing loss. However in light of the fewer complaints by the IROS group, and the fact that a large proportion of the CROS complaints related to the amplified signal, IROS appears to be the preferable of the two. The exception involves cases requiring high gain so that CROS might be employed to reduce acoustic feedback.