CONDITIONS
Hearing Loss
What is hearing loss?
Hearing loss is a reduced ability to hear sounds, partially or completely. It can affect one or both ears. Hearing loss can make it difficult to understand speech, follow conversations, and participate in daily activities.
What are types of hearing loss, and what are their causes?
There are three types of hearing loss.
Conductive hearing loss: Conductive hearing loss occurs when sound is not efficiently conducted through the outer or middle ear and is not reaching the inner ear. It can often be treated surgically or with medicine. Some causes of conductive hearing loss are middle ear infection, perforated eardrum, impacted ear wax, presence of a foreign body, fluid in the middle ear, or poor eustachian tube function.
Sensorineural hearing loss: Sensorineural hearing loss occurs when there is damage to the inner ear or the nerve pathway from the inner ear to the brain. It is the most common type of hearing loss and can occur due to aging, loud noise exposure, injury, illnesses like meningitis, diabetes, certain medications used for high blood pressure and cancer treatment, Ménière’s disease, or genetic factors. Generally, it cannot be treated with medicine or surgery, but many people with this hearing loss find hearing aids helpful.
Mixed hearing loss: Sometimes, individuals may experience sensorineural and conductive hearing loss. They might initially have sensorineural hearing loss and develop an additional conductive component.
What are the symptoms of hearing loss?
Most people lose their hearing gradually. In general, signs of developing hearing loss include:
- Asking people to repeat themselves often.
- Need help following conversations, especially on the phone or in noisy places like restaurants.
- Thinking people are mumbling.
- Difficulty hearing certain high-pitched sounds, such as birds singing.
- There is a need to increase the volume of electronic devices like TVs, computers, or tablets.
- Experiencing tinnitus (ringing in the ears).
- Feeling pressure or fluid inside the ear.
- Balance problems or dizziness.
What are the symptoms of hearing loss in babies and children?
Symptoms in babies:
- Does not react to loud noises.
- Does not turn toward the source of a sound after six months.
- Does not say single words like “dada” or “mama” by one year.
- Does not turn heads when called by name.
Symptoms in children:
- Delayed speech.
- Unclear speech.
- Difficulty following directions, which might be due to hearing loss.
- Frequently asks, “Huh?”
- Raises the TV volume too high
What are different degrees of hearing loss?
The severity of hearing loss determines how much difficulty someone may have in hearing sounds. According to the American Speech-Language-Hearing Association, hearing loss is classified into several degrees: Slight, Mild, Moderate, Moderately Severe, Severe, and Profound.
- Slight: Difficulty hearing very soft sounds like leaves rustling, a whisper, or a pin dropping.
- Mild: Trouble understanding soft conversation, like whispered talk, bird chirping, or gentle stream sounds, especially in noisy environments.
- Moderate: Difficulty understanding normal speech, especially in background noise. Sounds like noise from a distance electrical transformer, light traffic, and conversations at home may not be heard.
- Moderately severe: Normal conversations are not audible; only shouting is partially distinguishable. Vowels may be heard, but consonants may not. Hearing aids are usually necessary.
- Severe: Even loud speech may be not audible. People with severe hearing loss often require others to speak loudly or shout to be heard. Children may need speech therapists to develop language, speech, and social skills.
- Profound: Even loud speech may not be heard. Children may require auditory training, auditory verbal therapy, and other interventions like sign language, lip-reading, and speech therapy. Hearing aids designed for profound loss are recommended.
How is hearing loss diagnosed?
Hearing loss is typically diagnosed through medical history, physical examination, and specialized tests.
Medical history: The doctor will ask about symptoms, any past medical conditions, medications, and exposure to loud noise.
Physical examination: The doctor will examine ears using an otoscope to look for any visible problems in the ear canal or eardrum.
Hearing tests: These tests can include:
- Pure-tone audiometry: A pure-tone test is the most common screening test for hearing loss. It assesses the quietest sounds detectable at various pitches. During the test, a series of high and low tones will be played through headphones. Some will be loud, and some will be very soft. Each time a tone is heard, the person will raise their hand, push a button, or indicate hearing the sound.
- Speech audiometry: This test evaluates how well individuals can hear spoken words. It provides insight into how much a hearing aid might assist. During the test, the individual listens to words presented at various volume levels, often in the presence of background noise. They are then asked to repeat or respond to the words they hear.
- Tympanometry: This test measures how well the eardrum moves in response to changes in air pressure. A small device is inserted into the ear. The device sends air and sounds into the ear, causing the eardrum to move. An individual feels changes in air pressure within the ear. Movements of the eardrum are recorded by a machine on graphs known as tympanograms.
- Otoacoustic emissions (OAE) test: This measures sound waves produced by the inner ear in response to sound stimuli. A tiny tool goes into the ear. It makes and listens to sounds. The sound it makes moves the fluid in the cochlea, making hair cells move, too. These moving hair cells create vibrations that make a sound called OAEs. OAEs are typically present when hearing is normal or near normal and are absent when there is a problem in the cochlea.
- Auditory brainstem response (ABR): ABR is a test that checks hearing sensitivity and evaluates if the neural pathways within the brainstem are transmitting sound properly. It helps in detecting auditory-neurological issues. In this test, brainwave activity in the auditory parts of the brain is recorded as a response to clicks or tones played in each ear. Electrodes are placed on the head to pick up these brain responses while an individual is resting or sleeping. This test is painless and does not cause discomfort.
Depending on the results of these tests, further evaluation by an ENT doctor (ear, nose, and throat specialist) or an audiologist may be recommended. This could include imaging tests such as CT scans or MRI scans to assess the inner ear structures.
Based on the findings from the medical history, physical examination, and test results, the doctor will diagnose the type and degree of hearing loss and its underlying cause if possible.
How is hearing loss treated?
Treatment depends on the cause and severity of the hearing loss.
Conductive hearing loss
- Medications, such as antibiotics, for treating ear infections.
- Surgeries like tympanoplasty to repair a ruptured eardrum, tympanostomy tube insertion for chronic middle ear infections, or tumour removal surgery.
- Procedures for removing earwax or other objects from the ear canal.
Sensorineural hearing loss
- Medications like corticosteroids reduce swelling in the cochlear hair cells (loud noise exposure can damage these hair cells).
- Management options such as hearing aids and cochlear implants.
- Hearing aids: A hearing aid is worn either behind or inside the ear, making sounds louder.
- Cochlear implants: These devices are surgically implanted in the ear. These are especially indicated for individuals with severe hearing loss who do not find hearing aids helpful. Cochlear implants transmit sound directly to the hearing nerve.
Mixed hearing loss
Treatments are tailored to address specific issues affecting the outer, middle, and inner ear.
Can hearing loss be prevented?
Although some causes of deafness, such as genetic factors, certain medical conditions, or aging, may not be preventable, individuals can take steps to minimize their risk of hearing loss:
- Avoid exposure to loud noise.
- Do not set the volume of TV, music players, and toys too high.
- No buds for ear cleaning.
- Protect ear from injury.
- Do not practice traditional way of pouring hot oil into the ear.
- Choose headphones or earphones that cover the ears rather than earbuds inserted directly into the ear canal when listening to music.
- Wear earplugs or earmuffs for protection when working in noisy environments like discos, nightclubs, or pubs.
References
- John Hopkins Medicine. Types of hearing loss. Available from: https://www.hopkinsmedicine.org/health/conditions-and-diseases/hearing-loss/types-of-hearing-loss . Accessed on 2nd May 2024
- Cleveland clinic. Allergic rhinitis (Hay Fever). Available from: https://my.clevelandclinic.org/health/diseases/17673-hearing-loss . Accessed on 2nd May 2024
- Hearing loss. Available from: https://www.healthdirect.gov.au/hearing-loss. Accessed on 2nd May 2024
- Centers for Disease Control and Prevention. What is hearing loss in children? Available from: https://www.cdc.gov/ncbddd/hearingloss/facts.html. Accessed on 2nd May 2024
