Hearing impairment or Deafness is partial or complete loss of hearing.
There are two types of deafness which are not mutually exclusive:
Conductive hearing loss –
This occurs when there is a problem in the transmission of sound waves from the external ear, through the middle ear.
The disease processes, which may be congenital or acquired, can occur at any level along this part of the ear and include conditions such as excess ear wax, trauma, Otitis Externa or media with effusion, chronic ear disease or Cholesteatoma and Otosclerosis.
Sensorineural hearing loss –
This refers to problems occurring in the cochlea (most common site of disease), cochlear nerve or brain stem resulting in abnormal or absent neurosensory impulses.
There are also a number of congenital and acquired conditions resulting in sensorineural hearing loss but by far the most common is presbyacusis: age-related hearing loss which may also be associated with tinnitus (ringing, buzzing, whistling, hissing or other noise, heard in the ear in the absence of environmental noise). Acquired conditions include trauma, infections, meneire’s disease, perilymph fistula, Acoustic Neuroma, immune conditions, noise induced.
Presently there are around 60 million deaf persons in India. Around half of this is due to conductive loses mainly Cholesteatoma & Otosclerosis. Majority of the paediatric population also suffers with middle ear fluid & chronic ear disease.
Cholesteatoma is a disease of the ear in which a skin cyst grows into the middle ear and mastoid.
Otosclerosis is defined as abnormal bone growth in the ear, eventually resulting in hearing loss. It can be an inherited disorder, resulting in abnormal hardening of bone in the middle ear and sometimes inner ear.
Chronic Otitis Media
Otitis media means inflammation of the middle ear. The inflammation occurs as a result of a middle ear infection. It can occur in one or both ears. Otitis media is the most frequent diagnosis recorded for children.
What Are The Risk Factors?
Strong family history
Exposure to loud sounds
Certain ototoxic drugs
Children –high risk neonates, meningitis, antenatal infections Perinatal causes include prematurity and/or low birth weight, birth asphyxia, severe hyperbilirubinaemia and sepsis.
What Are The Current Diagnostic Tools?
After a thorough ENT examination the doctor may ask for the following diagnostic tests.
Pure tone audiometry
What Are The Options After Diagnosis?
The treatable causes will be addressed in the clinic i.e. ear wax, infections, foreign body etc.Most of conductive deafness will need surgical management i.e. Glue ear, perforations, Otosclerosis etc.
For some unrepairable conductive deafness & nerve deafness following management options are available
a. Externally worn hearing aids
They are devices that increase the volume of the sound reaching the ear (effectively, amplifiers). They sit either behind the ear (although these devices are not powerful enough for patients with severe impairment) or just inside. Hearing aids that are placed right inside the external auditory meatus are available for patients with mild hearing loss. Bone conduction hearing aids for patients with conductive hearing loss are available in the form of headbands.
b. Implantable hearing aids
1. Cochlear implants which are devices designed to stimulate the cells of the auditory spiral ganglion to provide a sense of hearing to those with neurosensory hearing loss. Traditionally, the procedure has been unilateral. It is offered to those patients who have had a minimum of 3 months hearing aid trial (unless there is an underlying ossifying aetiology) on a background of profound sensorineural hearing loss (e.g. 90db HL) and, in children, failure to develop speech, language and listening skills.8 More recently, there has been a move towards bilateral implants in a subset of these patients; the British Cochlear Implant Group has set out specific guidance as to which patients in particular should be offered this procedure.
2. Bone anchored hearing aids are reserved for patients with conductive and mixed hearing loss. Surgery involves the fixing of a titanium implant just behind the ear, to which is connected an external abutment and a sound processor. Thus, it allows sound to be conducted through the bone rather than through the middle ear (‘direct bone conduction’).
3. Auditory brain stem implants are electrodes placed in the cochlear nucleus (in the brain stem).The implant works in conjunction with an external receiver and speech processor. This device converts sounds into electrical signals, which are then sent to the implant.
Tinnitus (Ringing in the ears)
Disclaimer: The details in this section are for general information only. Always check with your own doctor.
Tinnitus is a word used by doctors to describe a condition when patients hear noises in their ears or in their heads.
Tinnitus has sometimes been described as ‘the sound of silence’ because all people, if they are seated in a completely quiet soundproofed room, will hear a type of rushing or hissing sound. Usually this noise is masked by environmental sounds. Hearing words, songs or voices is not included in the definition of tinnitus.
It is when this type of noise becomes intrusive into everyday life that it can become immensely irritating and becomes known as ‘tinnitus’. The noises of tinnitus may vary in pitch from low frequency to high frequency, they maybe intermittent or permanent and they usually vary in the intensity of sound. Some people spend a long time looking around the house for whatever it is that must be making the noise, other people fear that they may be developing a brain tumour.
Sometimes people notice that the intensity of the noises can alter according to various activities such as exercise, the drinking of coffee or wine and other stimuli.
Children can suffer from tinnitus as well as adults, which can be frightening for them when they do not understand what is happening. When tinnitus is first noticed, it can be very worrying.
Types of tinnitus
Tinnitus is generally divided into two types:
- noises that can be heard by somebody examining the patient (objective tinnitus)
- noises that can only be heard by the patient (subjective tinnitus)