Deafness is the total inability to hear the sound and has many causes that can develop at any age of an individual. By the age of 20 years, hearing loss in people may gradually decline. Deafness can occur suddenly as the complication of an infection, as the result of an injury to the ear, genetic defects, certain diseases and nerve damage. Most common cause of deafness is associated with the noise pollution accounting for one-quarter of the affected cases. Congenital deafness occurs at the birth of an infant while deafness that develops during an individual’s life is known as adventitious. There are two types of deafness; conductive deafness and nerve deafness.
Conductive hearing loss
This occurs when there is blockage of the sound wave to the inner ear. It can develop as the result of various conditions such as middle ear infections, perforated ear drums and benign tumors. In several of the cases, treatments are available to regain the hearing.
This develops as the result of disease or trauma that affects the cochlear nerve thus interrupting the electrical impulse that reaches the brain. In some cases, this can occur with abnormalities of the brain’s ability to ‘translate’ the signal from the cochlear nerve.
- Genetic disorders can cause deafness which can occur at the time of conception and examples include osteogenesis and multiple lentigines syndrome
- Prenatal exposure to disease can result in the birth of an infant who can be deaf. This includes rubella, influenza and mumps.
- Exposure to loud noise can cause temporary hearing loss and the ringing in the ears known as tinnitus can develop. Chronic exposure to loud noise can result in deafness
- Trauma can cause deafness such as fractured skull or perforation of the ear drum
- Other cause can include various diseases such as meniere’s disease, exposure to certain chemicals, the severe case of jaundice, meningitis and mumps.
The diagnosis of ear conditions is usually examined by the use of otoscope that can identify whether the ear canal is blocked or can indicate signs of infection. Individuals may be referred to a specialist known as otologist or otolaryngologist who will conduct tests to identify the cause of deafness. The various hearing tests can include audiometry that evaluates the hearing loss, otoacoustic emission testing and auditory brainstem response can be used for infants or children. In some cases, the MRI or CT scan may be necessary to determine the presence of any abnormal tumors that can affect the auditory nerve.
When the damage to the nerves or the inner ear occurs, the deafness can be permanent. However, in such cases, the hearing aid is the only form of treatment that amplifies the sound electronically. In individuals born without the ear canal, a bone-conducting hearing aid can be beneficial that transmits the sound through the skull to the inner ear. In some cases, the cochlear implant can be helpful by the connection to the auditory nerve and is stimulated for proper transmission of impulses to the brain. Complete deaf children require special training as soon as their condition is identified that can include sign language, lip reading and speech therapy.