CROS Application in CI

Bilateral profound sensorineural hearing loss (PSNHL) is often treated with Cochlear
Implants. The majority of bilaterally deafened patients, however, often only receive a
unilateral cochlear implant (CI), with resultant limitations related to monaural listening.
For unilateral CI users, the deficits inherently associated with monaural listening remain
despite the considerable benefits achieved through implantation. Providing bilateral input to
monaural listeners (MLs) overcomes some of these disadvantages. Treatment by contralateral
routing of signal (CROS) hearing aids, where the signal of interest is routed from the
impaired (deaf) ear to the normal cochlea for processing is a promising alternative in
unilateral CI recipients who cannot benefit from bilateral CIs. Utilizing CROS technology
provides a less invasive alternative for patients who are unable or unwilling to undergo a
second CI surgery and offers an innovative approach to resolving the auditory deficits
associated with monaural listening. CROS technology has been used to treat traditional
monaural listeners since 1965. When applied to unilateral CI users, this novel approach can
overcome a key limitation of current treatment by restoring access to sound from the
non-implanted ear and improving speech perception in noise.