What is Hearing Loss?

Hearing is one of the five senses.  It is a rather complex process.  The ear is divided into three main parts known as the outer ear, the middle ear and the inner ear.  They all lead to the brain.  In the outer ear, the sound travels down the ear canal, hits the eardrum and causes a vibration.  The middle ear consists of a small space with three bones called the ossicles, and is located behind the eardrum.  These little bones connect the eardrum to the inner ear and the vibration travels through them and causes movement of fluid in the inner ear.  The inner ear is also known as the cochlea.  When the fluid moves, it causes changes or movement in the hair cells and this sends an electrical signal up the auditory or hearing nerve to the brain.  Then the brain interprets these electrical signals into sounds.

There are different types of hearing loss, grouped into three basic categories.  The medical terms for these are sensorineural, conductive, and mixed hearing loss.  The group it is categorized in depends on which part of the auditory system is damaged.

Conductive hearing loss happens when sound is not conducted efficiently through the outer ear down the canal to the eardrum, and has trouble getting to the ossicles, or the little bones of the middle ear.  This makes it difficult to hear faint sounds like whispers.  It can be caused by such things as an ear infection, build up of fluid in the middle ear from a cold, build up of earwax, or allergies.

Sensorineural hearing loss is the most common permanent type of loss of hearing, and happens when there is damage to the inner ear or in the nerve pathways to the brain.  This can make even loud enough talking or sounds seem muffled, jumbled or just not heard clearly.  This could be caused from noise exposure at work from machinery, loud music at concerts, head trauma, a genetic condition, or aging.

In some cases, you can have a combination of both of these and this is referred to as mixed hearing loss.  This is where there is damage to both the outer or middle, and inner ear.