The ear is made up of three parts: the outer ear, the middle ear, and the inner ear. Hearing loss can occur from damage or obstruction to any of these components.

The outer ear is made up of the auricle (or pinna), the auditory canal and the eardrum. The function of the outer ear is to funnel sound from the outside to the hearing system.

The middle ear is an air-filled chamber that houses the smallest bones in the body - the incus, malleus and stapes. The function of the middle ear is to match the impedance of the outer ear to that of the inner ear. The middle ear is attached to the outer ear on one side and to the inner on the other.

The inner ear structure houses the sensory organs for hearing and balance, including the cochlea, vestibules, and semicircular canals. Sound is processed by the fluid-filled cochlea and information regarding balance is handled by the semicircular canals. Motion from the middle ear causes the fluid in the cochlea to move, which triggers small hair cells, located along the entire length of the cochlea, to bend. This action of the hair cells produces a chemical response, which in turn stimulates the corresponding nerve endings to send signals to the area of the brain that processes auditory input.

Some Typical Causes of Hearing Loss:
A reduction in hearing sensitivity may result from a problem in the outer ear, middle ear, and/or inner ear.

Outer ear hearing loss may result from a build up of wax in the ear canal or infection of the ear canal (e.g., swimmer's ear).

Typical causes of hearing loss in the middle ear are fluid trapped in the middle ear cavity, a perforated eardrum, and otosclerosis (calcification around the stapes, which significantly reduces its mobility).

Outer ear and inner ear hearing loss may be treated medically, either with drugs and/or surgery. If these are not an option, hearing aids are an excellent alternative.

Inner ear damage is considered the most common cause of hearing loss. Common causes of inner ear hearing loss are:
• Normal aging process
• Exposure to noise for long periods of time and/or at loud levels
• Head injuries
• Ototoxic medication (that which damages the auditory system)

Inner ear hearing loss, commonly referred to as sensorineural hearing loss, results from the damage to the tiny hair cells that line the cochlea, which ultimately affects the transfer of information from the ear to the brain. Surgical intervention is typically not an option with this type of hearing loss. Rather, hearing aids are most often recommended for sensorineural hearing loss.