Functionally deaf patients can gain normal hearing with a new implant that replaces the middle ear. The unique invention has been approved for a clinical study, and the first operation was performed on a patient in December 2012.
With the new hearing implant, the patient has an operation to insert an implant slightly less than six centimetres long just behind the ear, under the skin and attached to the skull bone itself. The new technique uses the skull bone to transmit sound vibrations to the inner ear, so-called bone conduction.
Unlike the type of bone-conduction device used today, the new hearing implant does not need to be anchored in the skull bone using a titanium screw through the skin. The patient has no need to fear losing the screw and there is no risk of skin infections arising around the fixing.
The technique has been designed to treat mechanical hearing loss in individuals who have been affected by chronic inflammation of the outer or middle ear, or bone disease, or who have congenital malformations of the outer ear, auditory canal or middle ear. Such people often have major problems with their hearing. Normal hearing aids, which compensate for neurological problems in the inner ear, rarely work for them. On the other hand, bone-anchored devices often provide a dramatic improvement.
In addition, the new device may also help people with impaired inner ear.
If the technique works, patients have even more to gain. Earlier tests indicate that the volume may be around 5 decibels higher and the quality of sound at high frequencies will be better with BCI than with previous bone-anchored techniques.
Two parts – one exterior processor and one implant
The implant is slightly less than six centimetres long. By a surgical procedure, it is inserted just behind the ear, under the skin, into the bone itself. The coil at the upper end operates using magnetic induction with the outer, visible component, a sound processor that the patient easily can attach to or remove from the head.
The external sound processor is held in place using two magnets. The titanium screw through the skin, used in other techniques, is replaced by an inductive link that transmits sound from the patient’s surroundings through the intact skin to an internal receiver. The audio signal is transmitted to a tiny quadratic loudspeaker anchored to the bone near the auditory canal. The speaker generates sound vibrations which reach the sensory organs of the cochlea.
Deaf people will gain normal hearing and function
Hearing impairments are the most common physical disability in the industrialized world. If the problem originates in the mechanism required to conduct the sound to the inner ear – for example, in the ear canal or the small bones in the middle ear – the skull bone can be used instead. Soon, functionally deaf people will gain normal hearing with the implant pictured, known as the Bone Conduction Implant (BCI).
The project in media:
PRESS RELEASE: New implant replaces impaired middle ear
New Implant Replaces Impaired Middle Ear (Science Daily 2013-01-14)
Hörseln tillbaka med implantat (Göteborgs Posten, 2013-02-18) GP 2013-02-18 LK1-2.pdf
Ny uppfinning kan ge hörseln åter (SVT Rapport 2013-03-09)