Hearing is one of the five senses that we humans are gifted with. Hearing impairment means partial or complete loss of ability to hear. Before we get into the types and causes of hearing loss, it is important to understand the anatomy of our ear. The ear has 3 mains parts, the outer ear, middle and the inner ear.
The outer ear constitutes the pinna (auricle) and ear canal. Then comes the middle ear, which constitutes of the tympanic membrane, the 3 ossicles (these are the 3 ear bones namely malleus, incus and stapes) and also the opening of the Eustachian tubes (connecting the middle ear to the pharynx). The last or the inner most is the inner ear which comprises of cochlea, vestibular system and auditory nerve. Hearing loss is of two basic types – Conductive and Sensorineural hearing impairment.
The conductive hearing impairment is usually improper conduction of sound waves from the outer ear to the middle ear. These can be treated medically and sometimes surgically. Some of the common causes for conductive loss of hearing are wax in the ear, Otitis media, URTI (Upper respiratory Tract infection like common cold) etc. any congenital anomaly in the external ear or middle ear.
Sensory neural hearing impairment refers to inner ear and to the auditory nerve. Exposure to loud sound or infectious diseases like meningitis, measles rubella, mumps etc cause this type of hearing loss. This condition is sometime caused due to conditions during pregnancy and childbirth too. Some common causes are premature birth, asphyxia during child birth, Jaundice, use of certain ototoxic antibiotic during pregnancy etc. Head injury or accident or trauma near the ear can also sometimes cause hearing deficiency.
Hearing is a basic necessity or a prerequisite for speech development. A child learns to speak by hearing language, sounds and correlating what he sees with what is heard. Deafness, whether partial or complete, affects the development of child and progress in school. Prevention of causative factors, early detection, and management of the symptoms, is effective to prevent further impairment. Effective care can be taken by immunizing children and pregnant women timely, avoiding exposure to loud sounds, and managing the impaired with hearing aids.