How Do We Hear?
Sound waves enter the ear canal and cause the eardrum and middle ear bones to vibrate. This sends an electrical signal from the inner ear, via the hearing nerve to the brain.
Types Of Hearing Loss
Conductive hearing loss
Conductive hearing loss occurs when there is an obstruction in the outer or middle ear, impeding the sound waves from passing through the auditory pathway. Ear wax, infections, fluid behind the eardrum, perforations of the eardrum and otosclerosis (a stiffening of the bones in the middle ear) are the most common types of conductive hearing loss. Most outer and middle ear problems can be effectively managed with medical intervention.
Sensorineural hearing loss
Sensorineural hearing loss occurs when the hair cells in the hearing organ (cochlea) become damaged and affect the transmission of signals to the auditory part of the brain via the auditory nerve. The most common cause is aging, but loud noise, some types of medication, and genetics can also affect hearing. Inner ear hearing loss cannot be reversed with medication or surgery.
Mixed hearing loss is a combination of both conductive and sensorineural hearing loss. This type of hearing loss can range from mild to profound.
Hearing loss in everyday life
Hearing loss can range from mild to profound. This graph shows which sounds can or cannot be heard depending on the degree of hearing loss. For example, someone with a severe hearing loss can hear an airplane or a motorbike close-by (Very loud, hence lower end of the graph). However they will not be able to hear normal-level speech or birdsong.
Frequency and amplitude of a variety of common sounds
A birdtweet is a high-pitched tone, therefore on the right of the graph; low-pitched tones are on the left.