The FDA today approved a new brain stem implant designed to restore some hearing in people who
experience total hearing loss when the removal of tumors damages their cranial hearing nerves.
The device, made by Cochlear Corporation of Englewood, Colo., restores the ability to detect certain
sounds and speech, although it does not restore normal hearing. In clinical studies, the device worked for
most, but not all, patients.
FDA expedited review of the product, the first of a kind, and approved it within six months of receipt
of the manufacturer's application.
The product is an auditory brain stem implant system. It is surgically implanted into the brain and
electrically stimulates the area that normally receives the electrical signal from the ear. The patient wears a
pocket-size speech processor that picks up sound and changes it into electrical pulses that are transmitted to
The device was approved for use in teenagers and adults who have a rare disease called
neurofibromatosis type 2 in which tumors growing on cranial nerves need to be surgically removed. Removal
of tumors on the auditory nerve requires severing or cutting the nerve, which results in total loss of hearing.
These patients cannot be helped by hearing aids or cochlear implants.
Approval was based on a review of clinical studies of safety and effectiveness conducted by Cochlear
Corp. and on the recommendation of the Ear, Nose and Throat Devices Panel of FDA's Medical Devices
Advisory Committee which met in July to evaluate the device.
In the studies, the device was implanted in some 90 people between the ages of 12 and 67 with
neurofibromatosis type 2. The device was implanted during surgery to remove auditory nerve tumors. Sixty
patients were evaluated for effectiveness after six months of use. (The remaining 30 had yet to reach their
Results varied: 82% of the 60 patients were able to detect certain familiar sounds, such as honking
horns and ringing doorbells; 85% were able to hear and understand conversation with the aid of lip reading;
and 12% were able to hear well enough to use the phone.
Of the 90 patients who received this implant, 18% were not able to hear any sound. This was due
either to migration of the implant after surgery or misplacement of the device during surgery.