Hearing Loss
There are three different types of hearing loss:
Conductive | Sensorineural | Mixed
The degree of hearing loss is classified by the severity, measured in degrees. Please see the chart at the bottom of this page for reference.
Conductive hearing loss
A decrease in sound due to problems in the outer or middle ear. Diseases or disorders that cause conductive hearing loss limit the transmission of sound through the outer or middle ear to the inner ear. This type is often treatable with proper medical or surgical intervention. Some of the common causes include:
- Cerumen (Earwax)
- Ear infections of the outer or middle ear
- Perforation of the tympanic membrane (eardrum)
- Injury to the outer ear
- Stiffness of the middle ear bones
- Trauma to the middle ear bones
With these conditions the inner ear and hearing nerve may be completely normal. However, they are not receiving the sound properly because transmission or conduction of the sound is reduced.
Sensorineural hearing loss
This is the most common type of hearing loss. It originates in the inner ear or along the auditory nerve. In this case, sound is transmitted through the outer and middle ears, but the inner ear is less efficient in transmitting the sound. This frequently occurs due to damage to the hair cells inside the cochlea. This leads to a reduced perception of sound intensity and quality. This condition is usually compensated with hearing aids that amplify sound to overcome the decrease in hearing sensitivity. Some common causes include:
- Presbycusis (Aging)
- Excessive exposure to noise
- Ototoxic medications
- Certain genetic disorders
- Viral disease
- Ménière’s disease
- Head injury
Mixed hearing loss
Mixed hearing loss is the combination of both conductive and sensorineural at the same time. The inner ear is damaged and there is a blockage of transmission of sound in either the outer or middle ear. Many times this can be corrected. However, the sensorineural condition is permanent. Hearing aids can often be used to improve hearing in this case.
| Degrees of Hearing Loss | Hearing Threshold (in decibels, dB) | Ability to Hear Speech |
|---|---|---|
| None | 0-25 dB | No perceptible difficulty. |
| Mild | 26-40 dB | Difficulty hearing soft speech and conversations, especially in noisier or more reverberant situations, but can understand in quiet environments. |
| Moderate | 41-55 dB | Difficulties understanding speech, especially in the presence of background noise. Higher volume levels are needed for hearing TV or radio. |
| Moderate to Severe | 56-70 dB | Clarity of speech is considerably affected. Speech has to be louder than usual, difficulties in group conversations tend to occur. |
| Severe | 71-90 dB | Regular speech is inaudible. Difficulties even with loud speech. Comprehension often only possible through shouting or amplification. |
| Profound | 91+ dB | Even amplified speech is difficult to understand or even inaudible. |
Tinnitus
Tinnitus can be described as ringing, humming, buzzing, hissing, whistling or roaring sound. Usually a symptom of an underlying condition, Tinnitus can be treated. Learn more by clicking the button.