The Bone Anchored Hearing Aid or BAHA is a type of hearing aid used in the management of bilateral conductive hearing loss. It is widely accepted as an alternative if an air-conduction hearing aid is contraindicated. It uses a surgically implanted titanium connection used to attach prosthetics to an implant to transmit sounds by directly conducting from the bone to the inner ear, therefore bypassing the external auditory canal and the middle ear. Externally visible is a surgically embedded titanium post. This titanium post consists of a sound processor that transmits vibration of sounds to the post. It then vibrates the skull and the inner ear, stimulating the nerve fibers to allow the sound to be heard.

Usually for BAHA's, the hearing aid can only be used once the titanium fixture bonds with the surrounding tissue. It usually takes place within two to six months after implantation. This is more commonly termed as Osseointegration.

Patients that usually benefit and entertain the use of BAHA's are those with chronic supporative otitis media and those with congenital atresia of the external auditory canal, which is exacerbated severely by the presence of conventional air conduction hearing aids. Several trials have shown its efficiency in patients with a conductive or mixed hearing loss. In recent clinical trials though, the usage of BAHA's are already extended to patients with unilateral hearing loss. Potential candidates for the Bone Anchored Hearing Aid are patients who experiences from skin reaction to any type of ear mold. For some patients, it is not necessary that the benefits relate to hearing ability but for cosmetic or comfort improvements. The highest priority is given to children with congenital bilateral atresia of the external auditory canal and other congenital illness like the Down's syndrome. It also is a suitable prescription for people who have malformed ears or non protruding outer ear and ear canals such as Treacher Collins Syndrome or Microtia.

BAHA's are indicated for hearing loss from congenital hearing problems, Chronic Supporative Otitis Media, and otosclerosis for those who will not undergo stapedectomy but as a third treatment option. Pre-operative assessment of the air-bone gap size is very helpful in predicting if speech recognition will improve or otherwise with the BAHA in comparison to the air-conduction hearing aid.

There are several potential health benefits in using Bone Anchored Hearing Aids though; it is very strict that patients meet the criteria to maximize the clinical benefit. But priority is given to congenital cases in line with the results on research nowadays. However, there is a slight disadvantage in speech recognition and sound localization in noisy backgrounds for patients with unilateral hearing loss. The benefits for this are still inconclusive.

Although benefits are visible, there are also potential side effects to this procedure. Soft tissue damage is the commonest and the loss of fixture in the skull from its position as well. The titanium post is screwed from the outside and into the bone and due to the open wound, infections will always be a risk. A requirement to prevent these would be focused daily care. Use of ointments and antibiotics may help in minimizing infections.

There are improvements and innovations to the surgical procedures in recent years therefore resulting in being capable to have a single stage procedure done using local anesthesia. The day after the procedure has been done or even a few hours after, patients may be able to leave the hospital not even requiring analgesia in the succeeding days. The patient will also be given time to heal or for the Osseointegration process to take place. This is where caution is expected. Infection will prevent osseointegration to succeed. On the other hand, small children or babies sometimes require a double stage procedure to be carried out.

There are different models of the BAHA systems. The BAHA Cordelle, BAHA Divino and BAHA Intenso are the ones available today. The BAHA Cordelle is a body worn BAHA for those people needing more amplification. The BAHA Divino has a built-in directional microphone. The BAHA Intenso has more power and sound quality is clearer in all listening environments. The BAHA Classic and BAHA Compact will not be manufactured anymore as per February 2007 and July 2007 respectively.

In most countries, the cost of the Bone Anchored Hearing Aid ranges from USD4000 to USD4500. Surgery can cost as much as USD25000. These prices vary depending on the type of procedure and the hospital itself. Today, there is only one known manufacturer of bone-anchored hearing aids and it has registered the acronym BAHA as a trademark to its own.