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Type of hearing loss
 
 
 Degree of hearing loss
Damage of any part along the auditory pathway will affect our hearing ability. Normal hearing people can hear sounds as soft as 25 dB HL between 250 Hz (low pitch) and 8000 Hz (high pitch). Hearing level exceeds this normal range will be considered as hearing loss. The degree of hearing loss is universally classified into 5 categories:
   


Mild loss hearing levels between 26 to 40 dB HL: difficult to hear soft sounds & whispers.
Moderate loss hearing levels between 41 to 55 dB HL: speech must be loud to be heard; difficult to hear distant speech; some difficulties in group discussion or meeting.
Moderately severe loss hearing levels between 56 to 70 dB HL: very difficult to hear in noisy places, group discussion or meeting.
Severe loss hearing levels between 71 to 90 dB HL: extremely difficult to hear environmental sounds; unable to hear speech beyond 25 cm (12 inches) from ear.
Profound loss hearing levels below 91 dB HL: can barely hear sounds; rely on lip-reading in daily communication.
 
 
Types of hearing loss
There are three general types of hearing loss:
 
1.
 Conductive hearing loss
 
Caused by outer and/or middle ear problems, such as malformation of the ear structure, outer ear infection, earwax impaction, perforated eardrum, middle ear infection and otosclerosis.
   
 
2.
 Sensori-neural hearing loss
 
Caused by damage or degeneration of the inner ear hair cells, and/or by auditory pathway damage or pathology, such as aging, prolonged noise exposure, head trauma, post-chemotherapy and tumor.
   
 
3.
 Mixed hearing loss
 
Mixture of conductive and sensori-neural hearing loss.
   
 
 
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