Types and Degrees of Hearing Loss

Types of Hearing Loss

Conductive hearing loss involves the outer and middle ear and may be caused by a wax blockage, punctured eardrum, birth defects, ear infection or heredity, and often can be effectively treated medically or surgically.

Sensorineural hearing loss or nerve-related deafness, is the most common type of hearing loss. It involves damage to the inner ear caused by aging, pre-natal and birth-related problems, viral and bacterial infections, heredity, trauma, exposure to loud noise, fluid backup or a benign tumour in the inner ear.

Mixed hearing loss refers to a combination of conductive and sensorineural loss and means that a problem has occured in both the outer or middle and the inner ear.

Central hearing loss results from damage or impairment to the nerves or nuclei of the central nervous system, either in the pathways to the brain or in the brain itself. This is a rare type of hearing loss.

Degrees of Hearing Loss

Decibel Loss Hearing Loss
16 – 25 Slight – Problems if listening conditions are poor (i.e. a noisy party)
26 – 40 Mild – Difficulty hearing soft or distant speech in church or theatre; may benefit from a hearing aid
41 – 55 Moderate – Conversation heard from 1-2 metres, but understanding speech is a strain, especially with background noise; hearing aids required
56 – 70 Moderately severe – Conversation must be loud and nearby; hearing aids should be complemented by other devised and speech reading instruction
71 – 90 Severe – Cannot hear loud speech or understand speech on the telephone; besides hearing aids, other technology and speech reading, counseling and speech therapy may be required
91 + Profound – Some very loud sounds may be heard or felt through vibration. Speech reading training, speech therapy and counseling are essential (this is the level of hearing loss for a late deafened person)