You might be referring to a cochlear implant -- a device designed for people with severe to profound hearing loss in both ears. A cochlear implant consists of an electrode array that is surgically inserted into the inner ear, a small microphone, and a speech processor.
The goal of cochlear implantation is to restore hearing to people who are functionally deaf. Tinnitus is a common perception among deaf people. If a cochlear implant is successful and allows the patient to hear some external sounds, this usually reduces the perception of tinnitus, especially on the implanted side. Numerous studies reported that cochlear implants reduced or suppressed tinnitus for a majority of patients who experienced tinnitus prior to implantation (Brackmann, 1981; Tyler & Kelsay, 1990; McKerrow et al, 1991; Souliere et al, 1992; Ito, 1997; Dauman, 2000; Ruckenstein et al, 2001).
Other types of implants to restore hearing include:
The auditory brainstem implant, a device designed for
patients without a functional cochlea or auditory nerves (Toh & Luxford, 2002).
- An implant that stimulates the auditory nerve directly with a 3-dimensional array of electrodes is being developed by a group of researchers at the University of Utah (Badi et al, 2003).
- A variety of middle ear implants.
Most cases of tinnitus are associated with some degree of hearing loss. If any amount of hearing can be restored, the patient's perception of tinnitus usually decreases. The devices described above can reduce the patient's perception of tinnitus by increasing their perception of external sounds. However, only a small percentage of tinnitus patients are candidates for any of these implants.
Do not despair. The good news is that many tinnitus patients benefit from more conventional in-the-ear devices such as hearing aids, sound generators, or combination instruments (hearing aid + sound generator in one unit). Even if the tinnitus does not disappear completely while these devices are in use, most patients can obtain significant relief from the symptom. For maximum effect, acoustic therapy should be used within the framework of a comprehensive tinnitus management program.
One other type of implant has been proposed to relieve tinnitus. Shi & Martin (1999) hypothesized that tinnitus generation and maintenance shares mechanisms with other neurological symptoms such as chronic pain and movement disorders including Parkinson's Disease. A procedure called deep brain stimulation (DBS) is sometimes used to treat patients with Parkinson's Disease or chronic pain who do not receive sufficient relief from medications. DBS involves brain surgery: a small hole is drilled in the patient's skull and a thin electrode is advanced slowly through the hole to a particular location within the brain.
A small amount of electrical current is turned on and conducted through the electrode to surrounding neural tissue. If the electrode placement is accurate, patients experience immediate relief from their symptoms. A battery-powered stimulus generator is connected to the electrode and implanted under the skin near the patient's collar bone. The patient can then control the current delivered to the electrode.
Martin et al (1999) conducted a study of seven patients who experienced tinnitus and also had deep brain stimulators implanted for movement disorders. All of the patients experienced hearing loss and tinnitus prior to DBS implantation. Three of the patients reported a reduction in tinnitus when their stimulator was turned on compared to when it was off. This result led Shi & Martin (1999) to suggest that a stimulating electrode implanted in a particular auditory region of the brain might be even more effective for reducing the perception of tinnitus. To date, DBS surgery has not been performed for tinnitus. Before DBS surgery for tinnitus is attempted, many questions need to be answered, including:
1) Exactly where in the brain should a stimulating electrode be placed to maximize tinnitus relief?
2) Which tinnitus patients, if any, should be considered candidates for this procedure?
3) Do potential benefits from the procedure outweigh its inherent risks?
Fortunately, the vast majority of tinnitus patients can obtain relief from the symptom without resorting to any type of surgical implantation. Even though a true ''cure'' for most cases of chronic tinnitus is not yet available, effective tinnitus management tools and strategies are available to help patients now (Folmer, 2002).
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