COCHLEAR IMPLANTS AND BONE ANCHORED HEARING AIDS–EARLY DETECTION AND INTERVENTION IS THE KEY TO NORMAL SPEECH AND HEARING
Have you ever had that gut–wrenching sensation of seeing something that is socially reprehensible, such as trash at the beach or a disconcerting social situation? I have that same reaction when I see children in the Valley with untreated hearing loss. Although all of the local hospitals screen newborns for hearing loss, we still see children in the Valley who go untreated. There are a couple of technologies, which are nothing short of miraculous, for children. First, and probably the most miraculous, is cochlear implantation. Also, for a select sub–set of patients, and probably equally amazing, is the bone anchored hearing aid. Each of these devices has different applications.
Cochlear implantations are useful for patients who are born with severe to profound hearing loss. In fact, cochlear implants are probably ideally suited for this category of patients. Unfortunately, these devices need to be implanted very early in life in order to function well. When we are born, we have an adequately–arborized and inter–connected neuronal tree of sorts. This tree is replete with many interconnections to neighboring neurons and allows for a fast number of connections that make it adequate for us to hear all the various sounds, tones and combination of sounds that exist.
When I see children 3–4 years old who have severe to profound hearing loss and have not had a cochlear implant by 2 years of age, it frustrates me. These children could have normal hearing if the device is implanted within the first 2–3 years of life. Unfortunately, these children often fall through the cracks. Some children are not appropriately referred to an Ear, Nose, & Throat physician in a timely fashion. Some children are referred, but the parents are scared about surgery and do not face the problem head on.
When children receive the cochlear implant at 12–months to 2–years of age, very often they do exceptionally well. Throughout their lives they can enjoy normal speech, be mainstreamed in normal classes, and have basically normal hearing sensitivity. In fact, they can even plug their cochlear implants into their iPods or cellular phones and carry on what we would consider normal activities of daily living. Often times, once they have received one cochlear implant, we will perform a second implant in order to improve sound localization.
BONE–ANCHORED HEARING AIDS
The other hearing rehabilitative method is bone–anchored hearing aid (BAHA). The bone–anchored hearing aid is a very simple device that is a metal post attached to the bone of the skull. This allows a small vibrating hearing aid to transmit sound to the bone of the head. When the skull is vibrated, although be it very minutely, it basically shakes the fluid in the cochlea, which replicates the conductive mechanism of the ear (the eardrum and the ear bones). This device bypasses the eardrum and ear bones and allows for normal hearing.
Furthermore, the device can actually be detected by the cochlea of the opposite ear, because it vibrates the entire skull. So, for example, if you had complete hearing loss in the right ear, but the hearing in the left ear was normal, a right–sided bone–anchored hearing aid would give the patient the sensation of normal hearing sensitivity in both ears and allow for enhanced sound localization.
The most useful application of the BAHA is in patients who have bilateral congenital malformations of the ear, where the ear canal is not adequately formed or the eardrum or ear bones do not move normally. In these cases, the child has profoundly muffled hearing. This can be devastating to speech and language development and limits the child’s ability to function normally in school. In these patients, when identified early, a BAHA can be inserted to restore their hearing to normal.
The motivation for writing this article is to help improve the social awareness of hearing loss in children and the opportunities that are available for treatment right here in the Valley. Hopefully, these children can be identified early in their development so that they can be adequately treated.
If you suspect that your very young child may not be hearing normally or that there may be congenital malformations of the ear, you should seek the attention of your doctor.