Noise Induced Hearing Loss

Noise and hearing loss
Sudden hearing loss produced by a sudden and very loud noise (blast injury) is called acute acoustic trauma. If the sound is loud enough, it can cause the eardrum to rupture or the person to have a complete loss of hearing. When the ears are exposed to extremely loud noises, or to prolonged loud noises, inner ear structures can be damaged. This can lead to noise-induced hearing loss.

According to the American Academy of Otolaryngology-Head and Neck Surgery, noise is damaging if:

• You have to shout to be heard.
• Your ears hurt.
• Your ears ring.
• You have difficulty hearing for a couple of hours after the exposure.

How does a loud noise cause hearing loss?

Loud noises can cause damage to the hair cells in the inner ear and to the hearing nerve, called sensorineural hearing loss or nerve deafness. Sensorineural hearing loss also can be caused by infection, head injury, aging, certain medications, birth defects, tumors, problems with blood circulation or high blood pressure, and stroke.



Damage can occur from a brief, intense noise such as an explosion, or from continuous loud noises such as noises in a loud work environment. Hearing loss from loud noises may be immediate or occur slowly over years of continuous exposure.

Immediate hearing loss is often accompanied by tinnitus, or ringing in the ears or head. Immediate hearing loss can occur in one or both ears and often involves severe damage to the inner ear structure.

Prolonged exposure to noise can actually change the structure of the hair cells in the inner ear, resulting in hearing loss. Tinnitus, which is the sound of ringing, roaring, buzzing, or clicking inside the head, often occurs with prolonged noise exposure damage, as well.

Hearing loss from noise can be permanent or temporary.
Noises that cause hearing loss

Hearing loss can occur after a one-time exposure to a loud noise or after repeated exposure to varying loud noises. Exposure to loud noises can occur at work, at home, or at play.

Diagnosis

Whenever one is exposed to very loud noise or an explosion especially if it is accompanied by a decrease in hearing (hearing loss) and ringing (tinnitus) should contact the ENT surgeon immediately. According to international guidelines the visit to the otorhinolaryngologist should
take place within 48 hours because immediate treatment is extremely important for the outcome.

The otolaryngologist will examine the ears and the hearing with otoscopy, tympanometry, sound reflexes and an audiogram in both air and bone conduction.

The objective is to determine the extent of hearing loss, to identify which frequencies are affected and to determine if the damage includes the auditory nerve. 

The main treatment of acute acoustic trauma is cortisone, which can be administered orally or intravenously and often is combined with cortisone administration into the middle ear (increases the chances of success). Usually up to  five intratympanic effusions are recommended with an interval of 3.5 days each. Intratympanic cortisone injections are administered painlessly and safely when by physician.

The prognosis is generally good if there is early diagnosis and treatment. Early treatment can save the patient's hearing!