Deafness is a total loss or a large decrease (hearing loss) of the sense of hearing. The deaf person, known as verbal, hears sounds, but do not understand the meaning of language.
The degree of hearing loss is assessed in decibels. Mild deafness (20-40 dB) : speech is perceived, at least some specific sounds. Moderate hearing loss (40-70 dB) : speech to high channel is perceived with equipment. Severe deafness (70-90 dB) : speech track is very high perceived without understanding the words , essential equipment is required. Profoundly deaf (over 90 dB) : no perception of speech essential equipment is required. Deafness (over 120 dB) : sound is not perceived.
The apparatus, called the hearing aid, amplifies the sound and can hear the words or at least hear sounds depending on the severity of deafness.
The causes of deafness are multiple: hereditary deafness, infection in pregnant mothers, mumps, rubella, meningitis, chronic otitis, head trauma, injury to the ear, perforated eardrum, exposure to high decibel level, etc.. Some older people lose hair cells (tiny hairs) for recognizing sounds.
A person born deaf communicate with sign language and can generally read lips to understand some of the message, the message is filled with signs. Light signals are installed to notify the sound as a bell or the phone adapted.
Depending on the cause, it happens that we can correct, at least partially, deafness by performing surgery to repair the eardrum or ossicles. In cases of total deafness, electrodes may be located near the auditory nerve (if the nerve is used) by capturing the ambient sounds, the electrodes produce an electrical microcurrent that stimulates the auditory nerve. Statistics show that 30% of people with implant recognize speech successfully..
21 mai 2010
| The text above is for information purposes only. Only a doctor can diagnose a disease. No treatment (medication or scheme) should be undertaken without consulting a health professional. |