What kind of inner ear problems cause hearing loss?
There are many conditions that cause the delicate sensorineural mechanism to function abnormally. Otosclerosis, discussed above, can also affect the cochlea and cause sensorineural hearing loss in some patients. In a small percentage, the sensorineural hearing loss can be severe.
The natural aging process also causes sensorineural hearing loss. Beginning shortly after birth, we begin to lose hair cells and nerve endings in the basal turn of the cochlea (the region that hears very high frequencies). As this loss pattern progresses over a lifetime, a sensorineural hearing loss develops. There are also other age-related causes of hearing loss including stiffening of the cochlear partition in the inner ear and loss of nerve endings in the acoustic nerve.
A fistula (opening) is an abnormal connection between the inner ear and the middle ear. The inner ear is filled with fluid, and the middle ear is filled with air. If a fluid leak occurs allowing the inner ear fluids out, hearing loss and dizziness commonly result. This kind of sensorineural hearing loss can often be cured by surgically repairing the fistula. Such leaks are usually caused by trauma. The trauma may be direct, such as a blow to the ear or a head injury in a car accident. However, it may also be the result of barotraumas caused by an airplane trip, a forceful sneeze, or lifting a heavy object.
Direct head trauma, particularly trauma severe enough to cause unconsciousness, can cause inner ear concussions and sensorineural hearing loss.
Ménière’s syndrome is a condition characterized by fluctuating sensorineural hearing loss (usually more prominent in the lower frequencies where we hear speech), episodic vertigo, fluctuating ear pressure, and tinnitus (usually of a seashell variety). It is due to endolymphatic hydrops, which is a swelling and fluid overload of the middle compartment of the inner ear.
There are many treatable causes of Ménière’s syndrome. So, exhaustive evaluation in search of them is recommended. When all tests have revealed none of the known causes, the condition is classified as Ménière’s Disease.
Infections involving the inner ear and hearing nerve can also produce deafness. Middle ear infections can spread to the inner ear causing loss of hearing, and usually dizziness. Viral infections may also involve the hair cells or auditory nerve causing hearing loss and even sudden total deafness.
Noise is an important cause of hearing loss. It is estimated that there are 7 to 10 million people in American industry with noise-induced hearing loss, virtually all of which was preventable. In addition to industrial noise, recreational noise can damage hearing. Such noise is encountered commonly from gunfire, power tools, snow blowers, motorcycles, loud music (especially with insert earphones) and other causes. In some cases, the playing of musical instruments can damage hearing. This has been reported not only with loud, electrical rock and roll instruments, but also with classical music performance such as violin playing and flute playing. One can minimize such problems by using ear protection whenever practical, such as during selected practice sessions.