Causes Of Hearing Loss In Adults by Harvik Speech & Hearing Clinic

Loss may be associated with different types of health problems, but the end effect is one of two basic types of hearing loss; Sensorineural and Conductive.
Sensorineural hearing loss
Sensorineural hearing loss is an interference in the transmission of sound impulses from the inner ear to the brain. It is most often not reversible, but can be most can helped with amplification. Some of the important causes of sensorineural hearing loss include:
Major illness during childhood
Common childhood diseases, such as mumps, measles, scarlet fever, whooping cough, meningitis, and extended high fevers can cause hearing loss. Having these diseases does not guarantee hearing loss, but these should be followed up with a hearing test.
Aging
A decrease in hearing is common with age. This condition is called presbycusis. Age-related hearing loss is generally thought to be a decline in the nerve function of the ear as a person ages. The main area of injury in age-related hearing loss is in the cochlea, a snail-shell-shaped structure that generates the first electrical impulse for hearing. There is usually a loss of cells that pick up the tones, particularly in the high-frequency portion of the cochlea. As these cells are damaged, the cells lose their ability to transmit sound in the form of pitches. The degeneration may progress to involve the nerve fibers that connect the ear and brain. The loss is so gradual that a person may not know that it has happened. Most people over the age of 65 have some hearing loss and by age 80, almost everyone does.
Noise-induced hearing loss
Intense sounds of greater than 75 decibels cause damage to the inner ear. Damage may occur because of a single exposure or from many exposures over months or years. Typically, noise produced by machines or weapons is the most damaging.. If a sound reaches 85 dB or stronger, it can cause permanent damage to your hearing. The amount of time you listen to a sound affects how much damage it will cause. The quieter the sound, the longer you can listen to it safely. If the sound is very quiet, it will not cause damage even if you listen to it for a very long time; however, exposure to some common sounds can cause permanent damage. With extended exposure, noises that reach a decibel level of 85 can cause permanent damage to the hair cells in the inner ear, leading to hearing loss. Many common sounds may be louder than you think… A typical conversation occurs at 60 dB - not loud enough to cause damage. A bulldozer that is idling (note that this is idling, not actively bulldozing) is loud enough at 85 dB that it can cause permanent damage after only 1 work day (8 hours). When listening to music on earphones at a standard volume level 5, the sound generated reaches a level of 100 dB, loud enough to cause permanent damage after just 15 minutes per day! A clap of thunder from a nearby storm (120 dB) or a gunshot (140-190 dB, depending on weapon), can both cause immediate damage. Some examples of noises that can cause noise-induced hearing loss include: motorcycles, lawnmowers, wood working tools, loud rock music, firecrackers, and gun fire.
Medications
It is also called as "vestibular schwannoma" - An acoustic neuroma is a tumor which is located between the ear and the brain, and which usually affects balance as well as hearing. In 95 percent of cases the tumor affects only one ear, and in 5 percent of cases the problem is linked to an inherited syndrome called neurofibromatosis type 2. The possibility of an acoustic neuroma should be considered when there is a hearing loss in one ear only.