Hearing is a remarkable ability and the result of tiny and delicate instruments within the ears working in conjunction with larger parts in order to produce electrical signals that are interpreted as a myriad of sounds by the brain. The brain is of prime importance in sorting and categorizing these sounds. Interestingly enough how well the brain functions may also be tied in with the level of sound the ears deliver.
A limiting of sounds to the brain, as in untreated hearing loss, seems to have long term consequences for cognitive abilities. Studies suggest the brain's plasticity is intricately woven with the amount of sound stimulation it is asked to decipher, so much so that hearing loss greatly increases the likelihood of dementia and Alzheimer's if left untreated. So how do hearing and the brain work together and where can things go wrong?
Outer Ear—the biggest part of the ear, the part typically decorated with earrings, is called the auricle or pinna. The auricle attaches to the external auditory canal. These two sections make up what is referred to as the outer ear. The auricle captures sound and funnels it through the auditory canal to the middle ear. An inability of sound to travel down the auditory canal interferes with hearing, denying sound to the brain and causing atrophy. This hearing loss is referred to as conductive hearing loss. The outer ear can be blocked for different reasons or damaged from trauma or genetics.
Middle Ear—consists of the eardrum (tympanic membrane) and three small bones, hammer (malleus), anvil (incus), and the stirrup (stapes). Collectively these small bones are known as the ossicles. Sound waves funneled from the outer ear strike the eardrum causing it to vibrate, amplifying the sound and setting into motion the three flexible bones of the ossicles. The amplified sound is then transformed into energy delivered to the inner ear as fluid vibrations. Hearing loss in the middle ear can be due to, among other things, infection or a build up of fluid. This hearing loss, also called conductive, can result in an inability to hear faint sounds. The result is not only an impact on hearing, but how the brain functions.
Inner Ear— has sections for hearing and balance. The auditory nerve and the cochlea are the parts responsible for hearing. Fluid within the snail shaped cochlea react to the vibrations sent from the ossicles, activating thousands of tiny hair cells contained within the cochlea. The activity of these cells creates chemical-electrical signals and conveys them to the auditory nerve which transmits them to the central auditory systems of the brain. Damage to hair cells in the inner ear is called sensorieneural hearing loss and is most commonly caused by noise. This type of hearing loss cannot be medically or surgically corrected, but can be treated with hearing aids.
Brain (central auditory system)--the brain through its central auditory system interprets and decodes the electrical signals sent from inner ears through the auditory nerves. This complex ability is one of the reasons hearing sound can keep your brain healthy. Sound provides a constant source of stimulation for the brain. If no attempt to correct hearing loss is made, the lack of stimulation results in a slow decline and eventually atrophy of parts of the brain.
The brain is essential in how hearing works, but hearing is also an important part of how the brain functions. Exciting new studies indicate that hearing keeps the brain nimble by stimulating parts of the brain with sound. Not only have studies shown that the brain denied these signals are more like to demonstrate atrophy, but the reintroduction of sound, as Dr. Kevin Munro discovered in his research, reported on in the The Hearing Journal,"showed changes in the auditory brainstem response (ABR) in adult hearing aid users." The results of these early tests suggest those with hear loss can rejuvenate their brains and hearing through the use of a hearing aid. To keep your hearing strong and your brain healthy call your hearing health provider today!