Hearing Loss in Savannah Seniors

“Hearing is the deepest, most humanizing, philosophical sense that man possesses…deafness means the loss of the most vital stimulus that brings language, sets thoughts astir, and keeps us in the company of men.”

Hearing Loss

This quote from Helen Keller, who was both blind and deaf, emphasizes the importance of the sense of hearing. For her, vision connected her to things, whereas hearing connected her to people.

Hearing is arguably our most important sense of orientation to our world. It is omni directional and it occurs during sleep. Hearing is the watchman that alerts our detective sense of vision to the warning signals within our environment. It is interesting to note that deaf animals do not survive in the wild. Most importantly, hearing affords us the opportunity for language, which defines us as a species.

Hearing impairment leads to loss of communication with resultant social isolation and frustration. Fortunately, there is now a great deal we can do to improve hearing, even with the deafest of patients.

This treatise provides an overview of how the ear works with respect to hearing. We will then touch upon some of the important ways hearing loss can be remedied.

How the Ear Works

Basically, the hearing part of the ear functions to convert the mechanical vibrations of sound to electrical impulses that can be interpreted by the brain. The ear is composed of three parts, generally known as the external, middle, and inner ears.

The external ear consists of the cartilaginous outer ear, or pinna, and the ear canal. Together these structures function like a megaphone, collecting and funneling sound to the tympanic membrane, or eardrum.

The middle ear consists of the tympanic membrane and the three ear bones, or ossicles. The middle ear functions as an amplifier that magnifies and focuses the sound waves upon the inner ear, or cochlea. The cochlea is a transducer that changes the mechanical energy of sound to electrical impulses, which are sent via the cochlear nerve to the brain for interpretation.

Types of Hearing Loss

Hearing loss can be divided into two basic types, depending upon which part of the ear is affected. Factors that impede conduction of sound through the external and middle ears produce a so-called conductive hearing loss. Examples would include wax impactions, middle ear fluid, eardrum perforations, and ossicular problems. The significance of conductive losses is that typically they are “fixable.”

Abnormalities of the inner ear produce so-called sensorineural hearing loss. Most commonly, this type of hearing loss is due to damage and loss of the hair cells within the cochlea. Common causes of this type of hearing loss include toxic noise exposure, the effects of aging, infection, heredity, and certain ototoxic drugs. Uncommonly, disorders affecting the cochlear nerve may be responsible for sensorineural hearing loss. Examples include acoustic tumors and multiple sclerosis.

Conductive and sensorineural hearing losses are best evaluated with an audiogram performed by a licensed audiologist. The audiogram must include tests of bone and air conduction in order to properly characterize the hearing loss. Following the audiogram, an otologist should review the data and examine the ear with a microscope. In this way, the specific type of hearing loss can be diagnosed and appropriate treatment options offered.

Treatments for Conductive Hearing Loss

With conductive hearing loss, there is something that impedes conduction of sound through the external and middle ear mechanisms to the inner ear. Causes may be as simple as a wax impaction, fluid within the middle ear space, or a hole in the eardrum. More complex causes of conductive hearing losses result from abnormalities of the ossicular chain that connects the eardrum to the inner ear. There are two basic problems that can affect the ossicular chain: stiffness and disconnection. Both are most commonly caused by the sequelae of infection, but there are hereditary and traumatic causes as well.

Treatments of conductive hearing losses generally involve surgical procedures that are performed on an outpatient basis. These procedures are typically performed with a microscope through the ear canal. The procedure typically involves reconstruction of the eardrum and/or the ossicular chain that connects it to the inner ear. Generally speaking, conductive hearing losses can be restored to within 10-20% of normal.

Bone Anchored Hearing Aids

Relatively recently, a novel approach to the restoration of conductive hearing loss was developed in Scandinavia. The bone anchored hearing aid, or BAHA, is based on the premise that bone does not significantly reduce the intensity of sound transmission. Therefore, a titanium screw can be placed behind the ear to which a hearing aid is attached. The amplified sound is transmitted through the titanium screw and skull bone directly to the inner ear, bypassing the normal conductive anatomy of the middle ear. Hearing is reportedly very clear and the restoration of the conductive loss is uniformly quite successful with the BAHA.

The BAHA has recently been used for single sided profound deafness as well. This application of the BAHA involves contra lateral routing of stimulus, or CROS. That is to say, the BAHA is implanted on the deaf side and the signal is transferred to the opposite “hearing” ear.