Sound vibrations can be transmitted to the inner ear by means of bone conduction via a titanium screw anchored in the skull bone. The technique is called the bone anchored hearing aid (BAHA) and has been developed at Chalmers over many years. The first patient was treated in 1977 and the first BAHA prototype was produced as a part of Professor Bo Håkansson´s PhD project during the following years.
Since then, several PhD projects at Chalmers have been focusing on gradually refining the technique. Among those, Peder Carlsson should be mentioned, participating in the earliest stages of the project. Today, the implant has helped over 100.000 persons to better hearing and the international recognition is constantly increasing.
A BAHA device can often provide dramatic improvement for persons with mechanical hearing loss, caused by e.g. a chronic inflammation of the outer or middle ear, bone disease or congenital malformations. Normal hearing aids, which compensate for neurological problems in the inner ear, rarely work for patients suffering from these disorders.
The origin of the project is the discovery made in the 1960´s by professor Per-Ingvar Brånemark, that a titanium screw can become perfectly integrated with the surrounding bone, i.e. become osseointegrated. In the BAHA research, Professor Bo Håkansson has had a close, longstanding collaboration with docent Anders Tjellström, audiologist at Sahlgrenska University Hospital.
Figure: A titanium screw is anchored in the skull bone, transmitting sound vibrations to the inner ear. Illustration: Oticon Medical
Brånemark Osseointegration Center, Sahlgrenska University Hospital, Chalmers University of Technology