Deaf relates to a person who is partially or completely lacking in the sense of hearing.  A hearing impairment is a decrease in one's ability to hear (i.e. perceive auditory information). While some cases of hearing loss are reversible with medical treatment, many lead to a permanent disability (often called deafness).

Ear- a sensitive organ

Sound consists of vibrations of air in the form of waves. The ear is able to pick up these vibrations and convert them into electrical signals that are sent to the brain. In the brain, these signals are translated into meaningful information, such as language or music with qualities like volume and pitch. The volume of sound is measured in decibels (dB). The ear consists of three parts:

1) The Outer Ear: It is the visible portion of the ear on either side of the head and includes the ear canals that go into the head. The fleshy parts of the outer ear act as collectors of sound waves, which then travel down the ear canal to the eardrum. This is a membrane of tissue that separates the outer ear from the middle ear.
2) The Middle ear: The sound waves cause the eardrum to vibrate. This vibration is passé on to the middle ear, which consists of bones called ossicles. These amplify and conduct the vibrations of the eardrum to the inner ear.
3) The Inner ear: The inner ear consists of an organ called the cochlea, which is shaped like a snail’s shell. The cochlea contains tiny cells called hair cells which move in response to the vibrations passed from the ossicles. The movement of these hair cells generates an electrical signal that is transmitted to the brain through the auditory nerve.

Causes of hearing loss. These can be divided into two basic types:

1) Conductive hearing loss: It is caused by anything that interferes with the transmission of sound from the outer ear to the inner ear. Possible causes can be middle ear infections, collection of fluid in the middle ear, blockage of the outer ear, damage to the ear drum by infection or an injury, and growth of the surrounding bone.

2) Sensorineural hearing loss: It is caused due to damage to the pathway for sound impulses from the hair cells of the inner ear to the auditory nerve and the brain. Possible causes includes age-related hearing loss, acoustic trauma, viral infections of the inner ear, Meniere’s disease, certain drugs affecting the hair cells, viral infections, brain tumor, and a stroke.

If the hearing loss occurs at a young age, it may interfere with the acquisition of spoken language. Hearing aids and cochlear implants may alleviate some of the problems caused by hearing impairment, but are often insufficient. People who have hearing impairments, especially those who develop a hearing problem later in life, often require support and technical adaptations as part of the rehabilitation process.

Dogs helping their deaf owners

Nearly nine million of the UK population experiences some degree of hearing loss. That’s one person in every seven. Over 650,000 of these people are severely or profoundly deaf and could benefit from a hearing dog. Hearing dogs change lives. They alert their deaf owners to sounds we take for granted, providing greater independence, confidence and security. Most are selected from rescue centres or donated as unwanted pets. We rely totally on the generosity of individuals and organisations to continue transforming the lives of deaf people and unwanted puppies. Thank you for your interest in our work.

University helping the deaf

Gallaudet university leads the world in undergraduate liberal arts education, carrer development, and outstanding, and outstanding graduate programs for deaf, hard-of-hearing. It is also provides courses for the normal students. One more institute namely, the Texas School for the deaf are working for the deaf education, their rights and all the issues related to them. They provide all this in order to create an optmal enviornment for the deaf educationan and a community which respects their culture. The Deaf Association of New Zealand defines deaf by two approaches. One based on a cultural/linguistic view and the other on a medical view. The word Deaf spelt with a capital D denotes a culture and a community. This descriptionn of deafness is most commonly applied to those who are deaf at birth or in very childhood. With the small d, deaf refers simply to hearing loss . The medical view is due to the lack of hearing in the range of sound common to most people.