Acoustic Trauma occurs by experiencing a sudden and powerful sound like an explosion, gunshots, firecracker or even head trauma (hitting the side of the head).These events often lead to damaged ear drums and consequently conductive hearing loss.  Many people have experienced a period of reduced hearing after exposure to loud sounds; for example after a concert, a sporting event or a visit to a dance club. This kind of hearing impairment is often temporary and after some time the trauma will stop.  It is crucial to contact the physicians at Oklahoma Otolaryngology Associates immediately once Acoustic Trauma has occurred for the best chance of recovery.  Some medications can reverse hearing loss in the first few days.  However, upon waiting, the conditions may become irreversible.

Normally, the brain processes sound through a “domino” effect.  Sound travels along a pathway from air to inside the brain and if any piece of the path is injured, for example due to a loud noise, hearing loss results.  In a normal working system, sound first is collected by the pinna, which is the cartilage portion of the ear that is visible on the outside. The sound waves then travel through the ear canal to the eardrum and cause it to vibrate. The vibrations are sent to three smaller bones called Ossicles within the ear; the malleus, incus and stapes. These small bones send the vibrations to the cochlea, which is a snail shaped sac of fluid.  The vibrations cause tiny hair cells in the cochlea to bend. These tiny hair cells are attached to nerves and when they bend, it produces an electrical signal which is carried to the brain. The brain recognizes these signals as sound.  When the vibrations sent to the inner ear are too strong (loud noises) it can damage the eardrum, ossicles or the cochlea.

If the acoustic trauma continues, such as loud machinery in a workplace environment, it will typically lead to hearing impairment within a relatively narrow frequency around 4 kHz.  The person withAcoustic Trauma will not be able to hear within a certain range of high frequency tones.  It is important to understand that the hearing loss may be irreversible and untreatable.  The person suffering from Acoustic Trauma may require surgery to resolve the condition. Sometimes a hearing aid or other treatment can be helpful for people suffering from permanent acoustic trauma and prevent further loss of hearing.

Others may have experienced Acoustic Shock, which is a condition when exposed to unexpected loud sounds via telephones. Employees at call centers who work with headsets on are particularly at risk.  Sounds which can trigger acoustic shock can stem from feedback oscillation, FAX tones or signaling tones.  Listening to callers at a high level can contribute to the risk of acoustic shock.

Acoustic Shock is when there is a strong muscle contraction in the middle ear after exposure. The Acoustic Shock can also cause a tearing of the inner membrane in the ear.  People suffering from an Acoustic Shock can experience other symptoms such as:  headache, tinnitus, ear pain, nausea, jaw and neck pain, a hollow feeling or fluttering noises in the ear, poor balance, anxiety, hypersensitivity and unexplainable fatigue.  If the symptoms continue without treatment, permanent tinnitus and/or hearing loss may occur.

Sources:  www.medlineplus.gov; www.hear-it.org; www.ohniww.org