hearing loss types
Conductive hearing loss -
Wherein sound is not conducted efficiently through the outer and middle ears due to :
- Impacted wax in the ear canal
- Perforation of the ear drum
- Fluid in the middle ear
- Discontinuity or fixation of the tiny bones or ossicles of the middle ear.
It can often be corrected through medicine, surgery, hearing aid or a middle ear implant as in a stapedectomy or ossicular replacement prostheses.
Sensorineural hearing loss -
Is caused by
- Damage to the inner ear (cochlea)
- Birth injury (neonatal jaundice or hypoxia) to the nerve pathways from the inner ear to the auditory centers in brain.
- Drugs that are toxic to the auditory system, genetic syndromes, noise exposure / viruses / hear trauma / aging and tumors.
People with sensorineural hearing loss experience a reduction in sound level, speech understanding and hearing clarity. It cannot be corrected medically or surgically and is a permanent loss, but hearing clarity can be improve by the use of hearing aids and more recently with Cochlear Implant.
Mixed hearing loss -
Sometimes a sensorineural hearing loss occurs in combination with a conductive hearing loss were in there may be damage in the outer or the middle ear and the cochlea or auditory nerve. In these cases a combination of surgery and hearing aids can alleviate the problem.
Degree of hearing loss
- Normal hearing ( 0 to 25 dB HL)
- Mild hearing loss ( 26 to 40 dB HL)
- Moderate hearing loss ( 41 to 70 dB HL)
- Severe hearing loss ( 71 to 90 dB HL)
- Profound hearing loss (greater than 91 dB HL)
"ABOUT 3 OUT OF EVERY 1000 NEW BORN BABIES ARE BORNED WITH SOME FORM OF HEARING IMPAIREMENT WHICH MAKES IT ONE OF THE MOST COMMON BIRTH DEFECTS IN THE WORLD."