Sensorineural Hearing Loss
Sensorineural Hearing Loss occurs when there is damage to the inner ear or the nerves that carry sound from the inner ear to the brain. The average age at which a person starts to experience sensorineural hearing loss varies. Still, it typically occurs in the later stages of life. Age-related hearing loss, or presbycusis, is the most common cause of sensorineural hearing loss. By current estimates, one in three people over 65 has some degree of hearing loss.
Several possible causes of sensorineural hearing loss include age-related changes in the inner ear, exposure to loud noise over time, certain medications, infections, and genetics. Some people may experience a combination of these factors.
Symptoms of sensorineural hearing loss can include:
- Difficulty hearing certain sounds.
- Need help understanding speech (especially in noisy environments).
- Tinnitus (ringing or buzzing in the ears).
- Sensitivity to loud noises.
Causes of Sensorineural Hearing Loss
Age-related hearing loss:As we age, the hair cells in our inner ear that help us hear begin to deteriorate, known as age-related hearing loss or presbycusis.
Noise-induced hearing loss:
Prolonged exposure to loud noise can damage the hair cells in the inner ear, leading to hearing loss. Working in a noisy environment, listening to loud music, or attending loud events can lead to Noise-induced hearing loss. For example, law enforcement officers typically have more significant hearing loss on their dominant side due to firearm practice.
Illness or injury:
Certain diseases, such as meningitis or autoimmune disorders, can damage the inner ear or auditory nerve, leading to hearing loss. Injuries to the head or ear can also cause sensorineural hearing loss.
Ototoxic medications:Certain medicines can cause damage to the inner ear, leading to hearing loss, tinnitus (ringing in the ears), or balance problems. Here are some examples of ototoxic medications:
Aminoglycoside antibiotics:This group of antibiotics includes gentamicin, tobramycin, and amikacin. These medications, used to treat severe bacterial infections, can cause hearing loss and balance problems, especially with prolonged or high-dose use.
These medications treat conditions such as high blood pressure, heart failure, and kidney disease. Examples include furosemide (Lasix), bumetanide (Bumex), and torsemide (Demadex). They can cause hearing loss or tinnitus, especially at high doses. Nonsteroidal anti-inflammatory drugs (NSAIDs): This group of pain relievers includes drugs such as aspirin, ibuprofen, and naproxen. These medications can cause temporary hearing loss and tinnitus in high doses for prolonged periods.
Some chemotherapy drugs, such as cisplatin and carboplatin, can cause hearing loss and tinnitus as a side effect.
When taken in high doses, Quinine, used to treat malaria, can cause hearing loss and tinnitus.
Illnesses and infections:
Various illnesses or injuries that affect the inner ear or the nerves that transmit sound to the brain can cause sensorineural hearing loss. Here are some examples of conditions that can lead to sensorineural hearing loss:
- Ménière disease This inner ear disorder can cause vertigo, tinnitus, and hearing loss. It may be caused by a buildup of fluid in the inner ear.
- This noncancerous tumor develops on the nerve that connects the inner ear to the brain. The growing tumor can cause hearing loss, tinnitus, and balance problems.
- Head injury: A severe blow to the head or trauma to the ear can cause damage to the inner ear or auditory nerves, leading to hearing loss.
- Viral infections: Some viral infections, such as measles, mumps, and cytomegalovirus, can cause hearing loss, particularly in infants and young children.
- Autoimmune disorders: Certain autoimmune disorders, such as rheumatoid arthritis or lupus, can cause inflammation that can damage the inner ear and lead to hearing loss.
- Otosclerosis: This condition in which abnormal bone growth in the middle ear can lead to hearing loss. Tumors: Other tumors that affect the auditory nerve or the brain can also cause hearing loss.
There are several genetic causes of sensorineural hearing loss, which means the condition is inherited and passed down from parents to their children. Here are some of the most common genetic causes of sensorineural hearing loss:
- Connexin 26 gene mutations are the most common genetic cause of sensorineural hearing loss, accounting for about 50% of cases. The modifications affect the gene that provides instructions for making a protein crucial for hearing.
- Mitochondrial DNA mutations are mutated structures within cells responsible for producing energy. Mutations in mitochondrial DNA can cause sensorineural hearing loss and other health problems.
- Usher syndrome is a rare genetic disorder affecting hearing and vision. Mutations cause it in one of several genes that play a role in the development and function of the inner ear and retina.
- Waardenburg syndrome is a rare genetic disorder that can cause sensorineural hearing loss and changes in pigmentation of the hair, skin, and eyes. Mutations in several different genes cause the condition.
- Pendred syndrome is a genetic disorder that can cause sensorineural hearing loss and an enlarged thyroid gland. Mutations in a gene that provides instructions for making a protein essential for the transport of iodine in the thyroid gland are the cause.
Sensorineural Hearing Loss DiagnosisSeveral tests can be used to diagnose sensorineural hearing loss. Below are some of the most common tests:
- Audiometry: This is the most common test for hearing loss. It involves headphones and listening to a series of tones at different frequencies and volumes. The test produces an audiogram showing the softest sounds heard by the patient at each frequency.
- Speech audiometry: This test measures the ability to hear and understand speech. It involves listening to words or sentences at different volumes and repeating them back.
- Tympanometry: This test measures the eardrum’s movement in response to changes in air pressure. It can help determine if there are any problems with the middle ear, such as fluid buildup.
Medical History And Physical Examination
When diagnosing sensorineural hearing loss, medical history and physical examination are essential factors in determining the cause and extent of the hearing loss. During the physical examination, the healthcare provider will examine the ears for signs of infection or blockage and test for other related symptoms, such as dizziness or balance problems.
The provider may also use a tuning fork to test hearing in each ear and look for any abnormalities in the ear’s structure. A thorough medical history and physical examination can help guide further testing and treatment for sensorineural hearing loss. Your healthcare provider may use some or all of the following factors in your diagnosis:
- Age: Age-related hearing loss is the most common cause of sensorineural hearing loss. The age at which symptoms start can provide important information.
- Family history: A history of hearing loss or other related conditions can suggest a genetic cause.
- Medications: Certain medications, such as aminoglycoside antibiotics or loop diuretics, can cause hearing loss as a side effect.
- Noise exposure:Exposure to loud noises from occupational or recreational sources can cause hearing loss.
- Illnesses and infections: Certain conditions or diseases, such as meningitis or mumps, can cause hearing loss.
- Tinnitus: The presence of tinnitus (ringing or buzzing in the ears) can suggest inner ear damage.
Sensorineural Hearing Loss Treatment
Hearing aids can help people with sensorineural hearing loss by amplifying sounds and making them easier to hear. Hearing aids can be programmed to amplify specific frequencies or ranges that the individual has difficulty hearing. Some hearing aids have directional microphones that can help filter out background noise and improve speech understanding in noisy environments. It’s important to note that hearing aids do not restore hearing to normal and may not be appropriate for all types or degrees of hearing loss. It’s also important to have realistic expectations about the benefits of hearing aids, which can take time to adjust to and may not work for everyone.
Cochlear implants are small electronic devices surgically implanted in the inner ear to provide a sense of sound to people with severe to profound hearing loss. Unlike hearing aids, which amplify sound, cochlear implants bypass the damaged parts of the inner ear and directly stimulate the auditory nerve. A cochlear implant consists of an external and an internal component. The outer portion includes a microphone, a speech processor, and a transmitter that sends signals to the interior part. The internal component consists of a receiver and an electrode array surgically implanted in the inner ear. The microphone picks up sound and sends it to the speech processor, which converts it into digital signals. The digital signals are then sent to the transmitter, which sends them to the receiver in the internal component. The receiver sends the signals to the electrode array, which stimulates the auditory nerve and sends them to the brain, where they are interpreted as sound.
Assistive Listening Devices
Assistive listening devices are designed to help people with hearing loss improve their ability to hear and communicate in various situations. These devices amplify or enhance sounds, making them easier to hear. Assistive listening devices can be combined with hearing aids or cochlear implants to improve communication in various situations.Here are some examples of assistive listening devices:
- FM systems are wireless devices that use radio waves to transmit sound directly from a speaker or other sound source to a receiver worn by the listener. FM systems are commonly used in classrooms, conferences, and group settings.
- Infrared systems work similarly to FM systems but use infrared light to transmit sound.
- Loop systems use magnetic fields to transmit sound directly to hearing aids or cochlear implants equipped with a telecoil.
- Telephone amplifiers can be attached to telephones to amplify the sound of the voice on the other end.
- Captioning devices display captions or subtitles for television shows, movies, and other media.