Bone Anchored Hearing Systems/ Aids (BAHS/ BAHA)
The BAHS/ BAHA has been used for conductive, mixed and single-sided sensorineural hearing loss for more than 30 years. The titanium implant is osseo-integrated into the skull bone, and an external sound processor transmits sound through direct bone conduction via an external abutment to the cochlear. Brands available include the Cochlear BAHA and Oticon Medical Ponto. For young children under 4-5 years of age, a soft band is usually used to hold the BAHS/ BAHA device whilst awaiting skull growth to accommodate surgical implantation.
Typically, patients have chronically draining ears, external otitis, atresia ear canal with normal cochlear hearing. Patients with single sided deafness (SSD) usually lose hearing from birth, sudden sensorineural hearing loss, post acoustic nerve tumor affliction or surgery. Even in SSD, speech discrimination in group conversations and noisy environments are improved when both ears can hear. Localisation of sound is better with 2 ears. Realistic patient expectations are important.
Non-surgical options of using a bone conduction hearing aid or CROS hearing aid is sometimes not as well tolerated due to significant pressure on the scalp, less cosmesis and the need for 2 hearing aids (CROS).
Concerns about BAHS/ BAHA include skin infections and overgrowth around the titanium abutment. In response to this, there are now systems that do not penetrate the skin, like the MEDEL BONEBRIDGE Conduction Implant. The Bonebridge offers the first active conduction implant system with intact skin. It allows direct stimulation of the skull bone instead of vibration through an implanted titanium screw, without osseo-integration lag time. The internal implant is larger than the BAHA however, and thus more challenging for very young children.