ENT Knowledge Base
Classification of Hearing Loss
Conductive: caused by outer or / and middle ear problems, such as malformation of the outer ear, outer ear infection, blockage of earwax, perforated ear drum, middle ear infection, otosclerosis and so on.
Sensori-neural: caused by damage of the inner ear hair cells, such as aging, prolonged noise exposure, tumor and head trauma
Mixed: combination of conductive and sensori-neural hearing losses.
Decibel (dB)- Loudness of sounds
20 dB Ticking watch
30 dB Quiet whisper
40 dB Refrigerator hum
50 dB Rainfall
60 dB Sewing machine
70 sB Washing machine
80 dB Alarm clock at two feet
85 dB Average traffic
95 dB MRI
100 dB Blow dryer, subway train
105 dB Power mower, chainsaw
110 dB Screaming child
120 dB Rock Concert, thunderclap
130 dB Jackhammer, jet engine plane (100 ft. away)
140 dB Shotgun blast, airbag deployment, firecracker
How to define hearing loss?
Normal (below 25 dB HL): normal hearing
Mild (26 to 40 dB HL): difficult to hear faint and soft sounds
Moderate (41 to 55 dB HL): speech must be loud to be hear; difficult to hear distant speech; some difficulty in group discussion or meeting
Moderately severe (56 to 70 dB HL): difficult to hear in noisy background; very difficult in group discussion or meeting
Severe (71 to 90 dB HL): difficult to hear environmental sounds; unable to hearing speech more than one foot from ears
What are the common causes of hearing loss?
Middle ear infection
Prolonged noise exposure
What are the possible signs of hearing Loss in adults?
Ask people to repeat themselves frequently
Many people you talk to seem to mumble or speak unclearly
Have troubles hearing in noisy environments
Misunderstand what others are saying and respond inappropriately
Difficult to follow conversation with two or more people talking at the same time
Difficult to hear over the phone
Family members complain that you turn the TV volume up too high
What are the possible signs of hearing loss in children?
Often say "Huh?"
Do not respond when being called
Do not follow verbal instructions
Respond to sounds inconsistently
Speech is unclear
Language and speech development is not age-appropriate
Turn the TV volume up too high
What should I do if I really have hearing difficulties?
We highly recommend you to obtain a detailed hearing assessment by a qualified audiologist. Besides, ENT specialist and audiologist can offer you professional advices on hearing-related issues.
I prefer mini-sized hearing aid, can I fit one?
It depends on various factors, such as the degree of hearing loss, age, manual dexterity, ear canal condition, affordability and so on. You are highly recommended to consult an audiologist for further professional advices.
Is it necessary to fit two hearing aids?
The ability to locate sound source accurately and efficiently depends on two equally functioning ears. Since normal hearing people listen with both ears, hearing impaired people are recommended to fit hearing aids on both ears to obtain better sound localization ability. With the help of a single hearing aid, those with hearing loss in both ear are generally weak in sound localization (it can be very dangerous especially in traffic), while their hearing enhance significantly with the help of two hearing aids. Besides, listening with only one ear is physically stressful.
How much does a hearing aid cost?
Hearing aids with basic features are relatively cheaper than those equipped by advanced features. Conventional hearing aids generally cost HK$4000 - 5000, whereas digitally programmable hearing aids and fully digital hearing aids cost around HK$7000 - 8000 and HK$ 12000-29000 respectively.
Why does my hearing in noisy environment remain so poor even with the help of hearing aid(s)?
It is the most common complaint obtained from conventional hearing aid users. Since all sounds, (both speech and background noise) are collected and amplified by the hearing aid, it is very likely for the amplified speech masked by the amplified background noise. Due to technological advancement, fully digital hearing aids with adaptive directional microphones, multi-channel signal processing and noise reduction system can significantly enhance hearing ability in noise. You are recommended to contact a qualified audiologist for further information.
Can my hearing problem be treated by medication or surgery?
It will depend on which type of hearing loss you are suffering from:
Caused by outer or / and middle ear problems, such as malformation of the outer ear, outer ear infection, blockage of earwax, perforated ear drum, middle ear infection, otosclerosis and so on. Medication or surgery may help to correct your hearing. If not, fitting hearing aid will be another way to enhance your hearing ability thus speech understanding.
caused by damage of the inner ear hair cells. Aging, prolonged noise exposure, tumor and head trauma are some of the major causes of sensorineural hearing loss. Sensorineural hearing loss is a permanent loss; therefore medication and surgery cannot help. Fitting hearing aid or using assistive listening device are some ways to enhance hearing ability.