BAHA (Bone Anchored hearing Aid) is a surgically implantable system for certain types of hearing loss. The BAHA conducts sound directly through the bone, instead of the normal route through the middle ear.

Who can benefit from BAHA?
BAHA can be useful in some cases of conductive and mixed hearing loss such as congenital external ear malformations (microtia, external auditory canal atresia, etc.), chronic ear infections where the presence of persistent ear discharge makes the use of a conventional hearing aid difficult. Unlike a conventional hearing aid, BAHA does not occlude the external canal, and thus prevents aggravation of infection in persistently discharging ears. BAHA can also be used in cases of single sided sensorineural deafness, provided the better ear is functioning normally.

Components of BAHA
The BAHA consists of a titanium implant, an external abutment, and a sound processor.

The titanium component is surgically implanted in the bone behind the ear, over which the external abutment is fixed. The sound processor fits over the external abutment. Over a period of time, the titanium implant osseointegrates with the bone.
The procedure of fixing the titanium implant and the external abutment can be performed as a single staged surgery or separately, depending on the skull bone thickness.

How does BAHA work?

1. A sound processor picks up sound vibrations.
2. An abutment is attached to the sound processor and the implant. The abutment trasfers the sound vibrations from the processor to the implant.
3. A small titanium implant is placed in the bone behind the ear where it fuses with the living bone. This process is called osseointegration. The implant transfers the sound vibrations to the functioning cochlea.

The sound processor picks up sound waves and digitally analyses the sound. This digitally enhanced signal is amplified and converted into vibrations. These vibrations are then conducted directly via the bone to the inner ear bypassing the external and middle ear. In cases of single sided deafness, the implant picks up sounds from the side of the deaf ear and conducts it via the bone to the normal ear, thus bypassing the non-hearing ear. Hence it is important that a patient being considered for BAHA has a good inner ear function (in cases of conductive loss) or one ear with a completely normal function (for single sided deafness).

Surgery for BAHA
The patient is provided a BAHA trial with a soft band before going ahead with the surgery. Once the patient is satisfied with the benefit gained with BAHA, the surgery can be performed. It is usually performed under general anesthesia and can be done as a day-care procedure. Suture removal is usually done after a week and the external sound processor can be fitted once the wound heals (usually 3 weeks following the surgery).