Hearing Health

How We Hear

Hearing is a fascinating multistage process in which the brain receives signals from the ear giving us the perception of sound. Sounds start as vibrations that travel through the air. As these vibrations or pulses in air molecules travel down the ear canal they vibrate the tympanic membrane, or ear drum. These acoustical vibrations are then transferred from the air to the bones of the middle ear, or the ossicles, turning them into mechanical movements. As these bones move they help to increase the strength of the vibrations to account for the loss of energy when the vibrations transfer to the fluid of the inner ear, or the cochlea. Once the vibrations leave the bones of the middle ear and are transferred to the cochlea, a wave is generated in the fluid that stimulates receptor cells in the hearing organ called hair cells. The hair cells are sensitive to specific tones or frequencies and will only respond to their corresponding wave. When the hair cell responds it sends a neural signal through the auditory nerve that is in turn sent to the brain, specifically the auditory cortex, for processing. Through this process, complex vibrations and signals are transmitted to the brain and processed near instantaneously allowing us to hear and comprehend speech and sounds that surround us in our environment.

Hearing Loss

There are three types of hearing loss, each originating at different points along the auditory pathway from the ear canal up to the brain.

Conductive hearing loss: A conductive hearing loss is a loss that originates as an obstruction of some sort to the vibrations that are trying to reach the inner ear. This can occur as either a blockage of the ear canal, or as some condition affecting the movement or vibration of the tympanic membrane (eardrum) or ossicles (middle ear bones). One common obstruction of the ear canal is the excessive buildup of cerumen (ear wax). Other blockages of the ear canal include foreign objects, bony growths, and tumors. Other causes of conductive hearing loss can include perforation of the eardrum, fluid build-up in the middle ear space, dislocation of the ossicles, and stiffening of the joints that connect the ossicles to one another. In many cases, conductive hearing losses can be medically resolved, or in other cases treated using hearing devices.

Sensorineural hearing loss: A sensorineural hearing loss is a loss typically related to the function of the inner ear and/or in the auditory portion of the brain. The most common cause of sensorineural hearing loss is the loss of function of the hair cells (receptors) within the inner ear. The loss of function of these cells cannot, unfortunately, be reversed. For nearly all people, sensorineural hearing loss will occur as function of aging, a condition called presbycusis. This age-related loss of hearing is thought to be genetically influenced as to when and how rapidly the loss will develop. Loss of hair cell function can also occur as a side-effect of oto-toxic (damaging to the ear) drugs, including certain antibiotics and chemotherapy agents. Noise-induced hearing loss is yet another cause of sensorineural hearing loss that is cumulative (adds up) over time after repeated exposures. It is this reason that everyone is encouraged to protect their ears when exposed to loud noise. Loss of hair cell function can also occur as the result of reduced blood flow to the inner ear or exposure to certain bacteria or viral infections of the inner ear. Other less common causes of sensorineural hearing loss include certain tumors of the auditory nerve and degradation of certain elements of the auditory nervous system. Sensorineural hearing loss in many people is the result of multiple causes such as aging and previous noise exposure. This type of hearing loss is most often treated through the use of hearing devices, although some persons with severe to profound sensorineural hearing loss find help using a cochlear implant.

Mixed hearing loss: A mixed hearing loss is one in which there is a component of both conductive and sensorineural hearing losses together. This means that there is some obstruction keeping sound from reaching the inner ear at appropriate levels, but also having reduced hearing as a result of damage to the inner ear or auditory nerve. While sometimes complex, these cases are often managed with medical treatment along with hearing devices.

Tinnitus

Tinnitus is the perception of sound by some sort of signal being generated within the auditory system, almost always inaudible to other listeners. This can be perceived as humming, clicking, buzzing, ringing, chirping and other various forms of sound. In some cases tinnitus or the ringing in the ears, fluctuates and is only noticeable at certain times. While there are many different causes of tinnitus, such as medications and various disorders, the most common cause of tinnitus is a result of a reduction in hearing. It is thought that when the brain is not receiving a certain level of stimulation, it will attempt to fill in the gaps with a perceived signal which is only audible to the individual. In most cases tinnitus is very mild and not bothersome, but can be very traumatic and disturbing for others. In some cases, persons who suffer from tinnitus report that they feel the tinnitus impedes their abilities to communicate in many different listening situations. Other report difficulties concentrating, reading, or falling asleep.

Unfortunately at that point in time there is no known cure for tinnitus, however, there are several options for alleviating its effects. White noise generators, tinnitus maskers, and even hearing aids have been shown to decrease the presence and effects of tinnitus in those who suffer from it.

Tinnitus can also be caused by a more serious medical condition. If you or a loved one suffers from tinnitus, contact your primary care physician or your audiologist to help identify the possible causes and treatment options for alleviating these issues.

Dizziness

There are many medical conditions that can cause what people describe as “dizziness”, including certain neurological, cardiovascular, and musculoskeletal conditions. In some cases, dizziness can be linked to a dysfunction of the labyrinth, the balance portion of the inner ear. Dizziness linked to the inner ear or vestibular (balance) nervous system can often be treated or managed with proper diagnosis. It is important to seek medical care from one’s primary care physician or ear nose and throat physician to determine the cause of dizziness and imbalance issues.

Dizziness issues related to the inner ear include (But are not limited to):

Hearing Aids

Hearing aids can be a great tool in alleviating the symptoms of hearing loss. The purpose of hearing aids is to provide an increase in the acoustical signal to overcome the effects of hearing loss. In many cases, persons with hearing loss have great difficulty conversing in social situations, especially those with background noise such as parties, family gatherings, church or religious gatherings, restaurants, business meetings and many others. If nothing is done to alleviate these struggles, persons with hearing loss tend to find themselves pulling away from these type gatherings and even loved ones as hearing and the ability to communicate in these settings becomes very taxing and difficult to maintain. The goal of hearing aids is to increase the signal of conversational speech in order to help those with hearing loss improve their ability to hear and understand what people are saying. The ultimate goal in this is to improve that person’s quality of life. Unfortunately, hearing aids can never restore hearing to that of a normal functioning ear. Hearing aids can, when properly chosen, tuned, and maintained, can maximize what that person’s remaining hearing will allow.

There are many different types and styles of hearing aids, and not all are appropriate for each person. The process for the appropriate selection of hearing aids is very individually specific and should take into account the patient’s type and severity of hearing loss, personal lifestyle, communication needs, as well as budget. While there may be many people with an identified hearing loss, hearing aids may not be appropriate for everyone. A consultation with a licensed audiologist following an appropriate audiological evaluation can help determine if hearing aids are right for you, and if so, what specific hearing aids are most appropriate for you.

Hearing aid fitting: Once appropriate devices have been selected, the fitting and fine-tuning procedures are performed. Based on one’s hearing loss, the audiologist is able to make calculations to determine the amount of amplification needed for appropriate reception of conversational speech. These levels must be verified at the level of the eardrum to ensure that the person is receiving the correct amount of amplification. Using verification measures such as Live Speech Mapping, an audiologist can fine-tune one’s hearing aids to each individuals hearing loss across the various frequencies related to conversational speech. When settings are verified in this way, the guesswork in adjusting hearing devices is almost eliminated.

Hearing Aid Technology/Accessories: In today’s technological age, hearing aids have become very sophisticated microcomputers that process sound in real time and adjust the auditory signal to accommodate an individual’s hearing loss. Latest technology devices make ongoing and simultaneous adjustments in response to changes in the sound within the environment. In addition to the amazing processing abilities of a hearing aid, other features such as wireless streaming and the use of accessories are also features on today’s hearing devices. Such accessories include wireless microphones, which allows the hearing aid user to have an increased reception of another speaker’s voice over excessive background noise. Bluetooth capabilities in today’s hearing devices allow them to connect wirelessly to cell phones, tablets, and other media players for hands free cellphone communication as well as wireless streaming of music and movie audio. Other accessories include television streamers, which allow the television signal to be transmitted wirelessly to the hearing aid and adjusted to one’s hearing loss to further improve one’s abilities to understand television programming. More in-depth information on these types of accessories and features can be obtained through a consultation with your audiologist.

Protecting Your Hearing: One major cause of hearing loss seen today is a result of repeated noise exposure. When loud sounds enter the ear, the hair cells responsible for the transmission of sound can be damaged. This can include exposure to loud sounds such as industrial noise, power tools, lawn equipment, loud music, and firearms. Following each incident of exposure, a threshold shift (reduction in hearing) occurs. This threshold shift occurs as the result of overstimulation of the hair cells, including the overextension of the cilia on the tops of these cells. Some of these cells recover from the exposure, while others are permanently damaged. That is why some of the threshold shift is temporary (hearing gets better) while a small portion is permanent. The permanent portion is not usually noticed after each exposure, but over time, the permanent portion accumulates until hearing loss becomes noticeable and irreversible.

For this reason, it is important to protect your ears and hearing from loud sounds by using hearing protection devices. A hearing loss which is caused as a result of loud noise exposure is called a noise-induced hearing loss and is categorized as a permanent sensorineural hearing loss. If you already have a hearing loss as a result of noise exposure, it is important to use hearing protection so as to preserve the function of the hair cells that remain.

There are many types of hearing protection devices ranging from the small foam ear plugs, custom ear plugs, over the ear muffs, and even electronic hearing protection. These later devices allow the user to maintain conversation abilities and hear “normally” until the sound levels reach a point where protection is necessary. If you find yourself exposed to various types of loud noise, it is imperative to find ways to protect your hearing. For more information contact your audiologist to discuss options that fit your needs.