There are many different causes of hearing loss. The following are the general categories into which hearing loss falls:

• Otosclerosis – is a disease that causes bony growth on the ossicles and causes the stapes to become immobile, thus not allowing sound to be transferred into the cochlea. This is the result of a disease that affects the movement of the stapes, located in the middle ear.
• Meniere’s disease – is a problem involving fluid pressure within the cochlea. It causes the sufferer to experience intermittent episodes of hearing loss, dizziness, and tinnitus. These episodes can occur anytime and for varying amounts of time. They are often associated with stress.
• Drug induced – some medications can result in damage to the auditory system with prolonged use. They are called ototoxic. Here are a few drugs that are known to cause hearing loss: aminoglycoside antibiotics (such as streptomycin, neomycin, kanamycin); salicylates in large quantities (aspirin), loop diuretics (lasix, ethacrynic acid); and drugs used in chemotherapy regimens (cisplatin, carboplatin, nitrogen mustard).
• Tumors – one of the common tumors in the ear is called a vestibular schwannoma. These tumors develop around the 8th cranial nerve, which is also known as the auditory nerve.
• Trauma – trauma to the ear can include fractures of the temporal bone, puncture of the eardrum by foreign objects, sudden changes in air pressure, and very loud noises.
• Presbycusis – this hearing loss is caused by natural aging of the human body and begins after age 20, but often it is not noticed until the ages of 55 to 65. Presbycusis affects the high frequencies in the speech range, making understanding and hearing speech difficult.
• Noise-induced hearing loss (NIHL) – this is hearing loss due to exposure to either a sudden, loud noise or exposure to loud noises for a period of time. A dangerous sound is anything that is 85 dB (sound pressure level – SPL) or higher.

Dangerous Decibels focuses on Noise-induced hearing loss.