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October 1966

Bilateral CROS: Two-Sided Listening With One Hearing Aid

Author Affiliations

From Northwestern University Hearing Clinic, Evanston, Ill.

Arch Otolaryngol. 1966;84(4):426-432. doi:10.1001/archotol.1966.00760030428011

IN RECENT months several articles1-4 have been published on the use of a hearing aid for persons with good (normal or near normal) hearing in one ear and with poor or unaidable hearing in the opposite ear. Harford and Barry1 refer to this principle of hearing-aid use as "contralateral routing of signals" (CROS). Extensive clinical application of CROS has provided the impetus for its modification to benefit persons with hearing impairment in both ears, but with one ear unaidable. The purpose of this article is to present a preliminary report on this modification with some evidence of its clinical value. Since this hearing aid is basically a CROS with two microphones, we differentiate it from the classic CROS by calling this the bilateral CROS, or BICROS.

A candidate for a BICROS hearing aid is one who has a poor ear which is "unaidable" and a better ear which