CROS is an acronym for Contralateral Routing of Signals. A CROS hearing aid is fit to a person who has normal hearing ear and one ear that is unaidable. The unaidable ear may be unaidable due to the severity of the loss, a physical malformation of the ear, a chronic medical condition which prohibits occluding the ear canal or any combination of the three. A CROS hearing aid consists of a microphone at the level of the unaidable ear which transmits via a wire or FM to a receiver in (or at) the normal hearing ear. BI CROS stands for bilateral-CROS. This refers to a hearing aid system which incorporates two microphones, one in (or at) each ear and a single amplifier and receiver. In this case the BI CROS device is fit to an individual who has a hearing loss in both ears, but one ear is unaidable, allowing the individual to receive sounds from both sides of their head in their good ear.
At Starkey Labs, we offer CROS and BI CROS systems in a choice of custom ITE or BTE with all of our circuits, both analog and digital. Our CROS/BICROS hearing aids transmit the signal via a wire. The wire is designed to run just below the hairline. A measurement should be made when ordering to ensure the proper length wire.
Other manufacturers may have different product offerings.