CSD 5400 REHABILITATION PROCEDURES FOR THE HARD OF HEARING Amplification Implantable Hearing Aids

What Are Implantable Hearing Aids? These are hearing aids that involve some degree of surgery to internally place the device somewhere in the auditory system They were developed to address specific needs of special populations of deaf and hard of hearing listeners not able to obtain benefit from more conventional amplification

Types of Implantable Hearing Aids There are four major types of implantable hearing aids: 1.Bone anchored hearing aids Conductive/mixed hearing loss 2.Middle ear implants Moderate/severe SNHL and mixed HLs 3.Cochlear implants Profound SNHL 4.Brain stem implants VIII N. loss

Bone Anchored Hearing Aids This hearing aid provides stimulation of the cochlea by causing the mastoid bone to vibrate Here the vibrator is surgically affixed into the temporal bone

Bone Anchored Hearing Aids These hearing aids are used for patients that have malformation or atresia of the outer ear or patients who have unresolvable chronic otitis media Currently has market approval in the US Cleared for market use by the FDA

Middle Ear Implants Directly stimulates the ossicular chain by way of a magnet attached to the TM, ossicular chain or round window and a magnetic coil

Middle Ear Implants Targeted primarily for patients with moderate/severe degree of SNHL dissatisfied with conventional air conduction hearing aids Feedback Distortion Occlusion effects Currently undergoing FDA clinical trials Not marketed yet

Cochlear Implants Available for about 20 years and the treatment of choice for profoundly deaf adults and kids who obtain little or no benefit from traditional amplification Over 3000 patients have been implanted worldwide as of 1991 More information on cochlear implants specifically will come later

Brain Stem Implants Consists of an electrode array that provides electrical stimulation of the cochlear nucleus These devices are used for patients who have lost auditory nerve function Currently undergoing FDA clinical trials First recipients were implanted last year

Advantages to Implantable Hearing Aids Nothing is worn in the earcanal Discomfort of wearing earmold, or hearing aid shell is avoided (BAHA, MI implants) Elimination of occlusion effect (BAHA) Middle and outer ear problems are decreased (BAHA) Better impedance matching with the middle ear (MI implants) More efficient energy transmission to the cochlea Improved fidelity and reduced distortion Elimination of feedback Only option for any kind of amplification benefit (cochlear and BS implants)

Disadvantages to Implantable Hearing Aids Surgery is required Risk of infection Risks of anesthesia More so when close to the cranial nerves Fatigue from constant skull vibration (BAHA) Device failure (MI, cochlear, BS(?) implants) additional surgeries Electrical stimulation of the cochlear or cochlear nucleus doesn’t provide normal auditory sensation Electrical stimulation (longterm) of the auditory system isn’t well understood