How do we hear?
Acoustic sound waves vibrate the tympanic membrane in the ear, which transmits vibrations through the bones of the middle ear to the cochlea (organ of hearing). Hair cells in the cochlea, in turn, transmit sound vibrations to the auditory nerve, which are received by neuronal receptors of the central nervous system in the form of chemical reactions in the brain.
Why does hearing loss occur?
Hearing loss results from failure of the physical structures in the outer and middle ear that conduct sound impulses to the nerve center in the inner ear is called a conductive hearing loss. This involves interference of any sort in the transmission of sound from the external auditory canal to the inner ear.
Hearing loss resulting from damage to the tiny hair cells that line the inner ear and transmit sound in the form of vibrations to the nerves or damage or injury to any of the structures of the inner ear of the auditory nerve is known as sensorineural hearing loss. The dysfunction may be in the inner ear, eighth cranial nerve, or in the central auditory pathways. Hearing loss resulting from damage to the physical structures of the outer and/or middle ear and damage to the cochlea or auditory nerve is called a mixed hearing loss. This involves both conductive and sensorineural components.
How do I know if I have a hearing loss?
You should have your hearing checked if
- You have to strain to hear normal conversation
- You have to watch other people's faces very carefully to follow what they are saying
- You need to ask people to repeat what they have said often
- You often misunderstand what people are saying
- You turn the volume of the television or radio up so high that others complain
- You feel that people are mumbling when they are talking to you
- You are having ear infections, dizziness, or a ringing in your ears
- You find that the effort to hear leaves you feeling tired and irritated
- You notice, when using the phone, that you hear better with one ear than the other
What causes hearing loss in children?
Hearing losses that are present at birth or that present themselves later, but are genteically present, are termed congenital. Some of the known causes of congenital hearing loss are:
- Maternal rubella
- Cytomeglovirus/maternal infection
- Ototoxic and other drugs or maternal alcoholism
- Maternal syphilis
- Parental ionizing irradiation during pregnancy
- Recessively inherited deafness
Hearing loss that occurs after birth is known as acquired. Some of the known causes of acquired hearing loss are:
- Hypoxia at birth
- Traumatic delivery
- Premature delivery
- Infection/high fevers
- Infantile measles or mumps
- Noise trauma
- Otitis media (acute, chronic, serous)
- Accidents (trauma) to the ear or head
- Ototoxic drugs
Otitis media is the most common cause of temporary hearing loss in children.
What is the effect of language development in children with hearing loss?
The acquisition of language is a time locked, auditory linked process related to early maturational periods in a child's life. It is essentially that any hearing loss be identified as early as possible to ensure optimal language development. The nature of hearing losses make it imperative that a team of professionals work together to diagnose a hearing loss and chart the management of the child with hearing loss.
Patients with suspected hearing problems must be seen by an otolaryngologist who specializes in disorders of the inner ear prior to audiologic testing or remediation. If a hearing disorder is suspected, you may call 212-979-4340 for a medical referral or to receive additional information. The Hearing Aid Dispensary is located in the Hector R. Giancarlo, M.D. Center for Communicative Sciences at The New York Eye and Ear Infirmary, 230 Second Avenue, New York City.I have a hearing loss