Although hearing loss often affects both ears it is not uncommon that only one side is affected or that the two sides are affected to different degrees.

If hearing loss is present in one ear only, it is called single-sided hearing loss or unilateral hearing loss - or single-sided deafness (SSD) If the hearing loss is profound.

The distinction between unilateral and bilateral hearing loss is important as hearing loss in one ear can be treated differently than hearing loss that affects both ears.

Hearing aids for single-sided hearing loss

CROS (and BICROS) hearing aids make use of the fact that a person with hearing loss in one ear still hears well (or better) with the other ear.

CROS stands for ‘Contralateral Routing of Signal’ and consists of two parts:

• the CROS device with a microphone to pick up sounds and voices from the non hearing ear and wirelessly transmit them to the hearing aid
  
• the hearing aid to receive the signal from the non hearing ear and play it to your good ear
  

A CROS hearing aid will transmit sound and voices to let your good ear hear for both your ears. If you have good hearing in one ear and impaired hearing in the other, then a CROS hearing aid will work for you.