Audiology glossary A–Z

Definition

Auditory neuropathy is a hearing disorder that means sufferers have many problems understanding what is being said to them, particularly in noisy surroundings. This is the case even though individuals can usually understand speech in quiet surroundings.

Cause

The cause of AN is thought to be a problem with the transmission of sound from the inner ear to the brain. It can affect people of all ages. For some people, it could involve damage to the ear’s inner hair cells. These cells convert sounds into electrical impulses that travel to the brain via nerves. Other causes can include faulty connections between the inner hair cells and the nerve leading from the inner ear to the brain, or damage to the nerve itself. Sometimes a combination of these problems occurs.

Symptoms

People with AN may have a range of hearing abilities. Some have normal hearing, others have a mild to severe hearing loss identified during a hearing test. Frequently, their ability to perceive speech does not reflect the amount of identified hearing loss. They may hear the sounds but not be able to unscramble them into understandable speech. Speech may seem out of sync, muddled, and/or fades in and out. Symptoms can vary; they may stay the same, fluctuate or worsen.

Diagnosis

A combination of tests are carried out to diagnose AN, including testing the brain’s response to sounds and how the inner ear reacts to sound. The classic result of these tests is an abnormal brain reaction and a normal inner ear reaction.

Impact

This disorder can have a huge impact on an individual’s relationships and social life, as the problem of clearly hearing speech in noise can be so great. It may lead to an individual ceasing normal social activities and withdrawing into themselves. Being born with this disorder, can seriously harm the development of speech and language skills.

Treatment

A number of treatments are available, but opinions differ as to how effective each one is. Hearing aids, cochlea implants and personal listening devices are amongst those most often used.

Auditory processing disorder (APD) is a listening problem caused by the brain not processing sounds in the normal way. Your inner ear is responsible for converting sound waves into electrical signals that are sent to your brain.

APD is a problem converting these electrical impulses into meaning. APD can affect both children and adults, whether they have any hearing impairment or not. This means that although the ears are working fine, the brain cannot process what it hears.

Definition

More commonly known as AIED, this syndrome is caused by the body’s immune system and antibodies. The immune system sends antibodies to parts of the body it believes to be under attack from a virus or bacteria. In this case, it is healthy skin cells in the ear that are attacked.

Cause

The cause is unclear at present, but there is some evidence to suggest a link to Meniere’s disease. Other researchers believe it is an allergic reaction to certain foods, but evidence is not yet clear. Research continues into this recently identified disorder. Once causes are confirmed, better treatments are likely to be developed.

Symptoms

AIED symptoms often appear in one ear before the other. Common symptoms include a reduced ability to hear, sound disturbances like tinnitus, or a hissing noise. Some people also experience dizziness and feel unbalanced.

Diagnosis

Diagnosis can be difficult as these symptoms occur with many ear complaints. Once symptoms have progressed to both ears, a blood test can conform the disorder.

Treatment

The most common treatments for AEID are drugs used to suppress the immune system. These drugs affect the body as a whole and as such need to be prescribed with care. They include steroids, chemotherapy drugs, anti-transplant rejection drugs, and some new anti-tumour and necrosis drugs. Some treatments are injected directly into the ear under local anaesthetic by a skilled physician. Many of these drugs have serious side effects, especially if used over a long period of time.

Hearing aids and more invasive treatments such as cochlea implants have also been used if other treatments fail to make an improvement in the condition. Cochlear implants are fitted to the cochlea under general anaesthetic. They do not recreate normal hearing, they transmit signals to the brain that the user has to learn to interpret.

Barotrauma refers to any medical problems that arise from the pressure differences between areas of the body and the environment. This can occur as a result of flying, as you ascend the air pressure decreases or as a result of diving, where the opposite happens, as you descend the pressure increases. All involve air being trapped in an enclosed area where the pressure cannot be equalized. As air pressure decreases the volume of gases naturally in the body increase, this can happen in the middle ear which is an air filled chamber separating the outer ear from the fluid filled cochlea or inner ear.

The middle ear relies on the eustachian tube (a small canal that connects the middle ear to the back part of the nasal cavities) to equalise pressure and will do this effectively unless there is a blockage. If this cannot happen, a build up of negative pressure in the middle ear will cause the tympanic membrane (ear drum) to retract causing pain and discomfort and if not resolved the tympanic membrane (eardrum) may rupture/perforate. Even worse is that the thin membrane between the tympanic membrane (middle ear) and the cochlea (inner ear) called the round window, may also retract and if this perforates, would lead to leakage of inner ear fluid (perilymph).

Decompression sickness is often more commonly referred to as "the bends”. This disorder is due to the effects of water pressure, the body absorbs nitrogen gas faster as a diver descends than when they are ascending to the surface, therefore if a diver ascends too quickly, nitrogen gas bubbles will form in body tissue rather than being exhaled. The nitrogen bubbles cause decompression sickness and may cause severe pain.

There are several types of Decompression Sickness:

• Type I Decompression Sickness is the least serious form of Decompression Sickness. It normally involves only pain or discomfort around the body and joints, this is not immediately life threatening. It is important to note that symptoms of Type I Decompression Sickness may be warning signs of more serious problems.
• Type II Decompression Sickness is the most serious and can be immediately life-threatening. The main effect is on the nervous system.

Decompression Sickness can manifest itself in many different ways and has many different symptoms, medical attention should always be sought as soon as possible. The most common symptoms are:

• Hearing loss
• Extreme Fatigue
• Joint and Limb Pain
• Tingling / Numbness
• Respiratory Problems
• Vertigo / Dizziness
• Blurred Vision / Headaches
• Confusion Unconsciousness
• Ringing of the Ears
• Nausea / Vomiting / Sickness

Immediate treatment may be necessary and may consist of recompression treatment in a recompression chamber. When treating Decompression Sickness the delay in beginning recompression treatment can be the biggest single cause of residual effects.

There are two types of cholesteatoma, congenital cholesteatoma (present at birth) where some skins cells grow in the wrong place behind the eardrum and develop into a cholesteatoma over time and acquired cholesteatoma (develops later in life). A cholesteatoma is an accumulation of dead skin that occurs and grows in the middle ear behind the tympanic membrane (eardrum).

A cholesteatoma usually occurs because of eustachian tube dysfunction and or chronic (longstanding) infection of the middle ear. (Otitis media). When working correctly the eustachian tube (the tube connecting the middle ear to the back of the throat), aerates the middle ear and equalises pressure between the outer and middle ear. If this function stops working, the air in the middle ear is absorbed, resulting in a buildup of negative pressure. This negative pressure may cause the tympanic membrane to retract and if there are any areas of weakness (usually from previous infections) a pocket or sac may be formed by the weakened area being sucked inwards. In this pocket or sac skin cells get trapped, being unable to disperse and continue to multiply, effectively growing in the middle ear cavity. A cholesteatoma can increase in size over time and may destroy the surrounding ossicular bones (malleus, incus and stapes) of the middle ear, affect the facial nerve, in extreme cases it can impair the cochlea (inner ear) causing deafness and the infection can even reach the brain. Hearing loss, dizziness, and facial muscle paralysis are rare but can result from cholesteatomas.

A foul smelling discharge may be one of the first symptoms noticed and as the cholesteatoma enlarges, it can cause a feeling of fullness in the ear, along with hearing loss, tinnitus and earache, usually behind the ear. It can also cause vertigo, dizziness and muscle weakness on the infected side of the face. (facial palsy).

After assessment, initial treatment may consist of a careful cleaning of the ear and antibiotics to clear up any infection but some cholesteatomas will require surgical intervention to remove the cholesteatoma and any infection but also to preserve hearing ability.

Treatment: Tympanomastoidectomy: This is removal of the tympanic membrane (ear drum) and all or part of the mastoid bone of the skull, (this is the rounded bone you can feel behind your ears) depending on the size and spread of the cholesteatoma. It is a common procedure but the remaining cavity left in the ear will require regular assessment and cleaning (removal of wax).Tympanoplasty: This is a less invasive technique usually with a better cosmetic appearance post surgery. However, it is associated with a higher risk of recurrence of cholesteatoma. Avoiding surgery the cholesteatoma may be treated with the aid of 'aural toilet'. This involves washing out the ear canal and sucking out any debris. This however has to be done on a regular basis and does not prevent growth of the cholesteatoma.

Hyperacusis is a medical term used to describe any abnormal discomfort caused by sounds that are tolerable to listeners with ordinary hearing.

It’s often viewed as a phenomenon – because it’s a subjective experience, it cannot be measured directly and is, consequently, very difficult to study and to diagnose.

Mastoiditis is an uncommon bacterial infection of the mastoid bone located behind the ear. It is usually seen in children, although adults can also be affected. The mastoid bone has a honeycomb-like structure, it contains air spaces called mastoid cells, which help maintain the air space in the middle ear. Mastoiditis can develop when the mastoid cells become infected or inflamed, often as a result of a persistent middle ear infection as bacteria from the middle ear can travel into the air cells of the mastoid bone. Another cause is any abnormal collection of skin cells which prevent drainage of the ear and cause infection (Chlesteatoma)

Mastoiditis typically causes fever, irritability and tiredness, swelling behind the ear, redness /tenderness or pain behind the ear, a creamy discharge from the ear, headaches and a hearing loss. Most ear infections are due to an Otitis Media (middle ear infection). Mastoiditis is treated with antibiotics, sometimes surgery (Myringotomy) may be required to drain the ear and to have the infected mastoid bone removed. A small hole is made in the eardrum to drain the fluid and relieve pressure from inside your ear. A small tube may be inserted into the middle ear to provide ventilation and prevent fluid building up inside it. This tube will typically fall out naturally after 6-12 months. An operation to remove the infected mastoid bone is known as a mastoidectomy - this is only usually needed if the infection is severe.

With early antibiotic treatment, most people recover quickly with no complications however, treatment is not always easy and the condition may come back. It is important that any infected bone is removed thereby preventing further complications or the infection reaching the brain.

Ménière's disease is a rare disorder that affects the inner ear. It can cause vertigo, tinnitus, hearing loss, and often a feeling of pressure deep inside the ear. In the UK, it is estimated that around 1 in 1,000 people have Ménière's disease. It can occur at any age, but it most commonly affects people aged 40-60 years and is more common in women than in men.

Sometimes there may be a family history of the disease. The cause of Ménière's disease is not known, although it is thought to be caused by a problem with the pressure in the inner ear. The inner ear is made up of the cochlea (coiled tube responsible for hearing) and the vestibular system (semi-circular canals) that control balance. The inner ear is fluid filled and the fluid is called endolymph. If the pressure of this fluid changes - for example, because there is too much fluid - it can result in symptoms such as vertigo and tinnitus. In most cases, the cause of the fluid pressure change is unknown, but it may be due to an allergy, Autoimmunity (immune system starts producing antibodies that attack your own tissues and organs), Genetic factors, or a chemical imbalance in the fluid (too little or too much sodium/potassium). Each individual may present differing symptoms.

The symptoms can appear as sudden attacks without warning, often lasting several hours. The symptoms may take a few days to disappear after each attack. Vertigo is one the most common and noticeable symptoms of Ménière's disease and is the sensation that you or the environment is moving or spinning. A vertigo attack can last for just a few minutes, but could last for two to three hours. You may also feel dizzy, sick and off-balance. You may have difficulty standing or walking during an attack. Tinnitus is the perception of noise with no external source. The noise comes from inside your body and is usually more noticeable when you are tired or when it is quiet, i.e. just before sleeping, as there is less background noise to distract you. The sounds that you can hear may be ringing, buzzing, humming, whistling, even music.

Ménière's disease progresses through different stages:

Early stage: Consists of sudden unpredictable attacks of vertigo, usually accompanied by nausea, vomiting and dizziness. Some loss of hearing is experienced often with tinnitus at the same time. Your ear/s may also feel blocked, with a sense of fullness. Attacks of vertigo at this stage can last anything from 20 minutes to 24 hours and the length of time between attacks can also vary. Your hearing and the full sensation in your ear will usually return to normal between attacks.
Middle stage: Consists of continuing attacks of vertigo, but less severe. Tinnitus and hearing loss often become worse. You may have times where the symptoms go away for several months at a time.

Definition

Infectious myringitis is an infection of the ear drum that causes painful blisters. Pain occurs suddenly and persists for 24 to 48 h. This infection frequently causes temporary hearing impairment and a sensation of congestion and earache: hearing loss and fever suggest a bacterial origin. The condition is most often seen in children, but it may also occur in adults.

Cause

Infectious myringitis is a form of middle ear infection that is caused by the same viruses or bacteria that cause middle ear infections. The most common of these is mycoplasma, which often accompanies a common cold or similar infection like flu. Cleaning your ear with cotton buds or similar items, suffering a head trauma, or regularly having water in your ears can make you more likely to develop Myringitis.

Symptoms

Most people go to the doctor after 2 to 3 days of their ear feeling bunged and a mild hearing loss. Other symptoms may include itching in the ear, pain, and a discharge draining from the ear. Pain usually lasts for 24 to 48 hours. The hearing loss usually disappears once the infection has been treated successfully.

Diagnosis

By examining the ear with an otoscope [specialist torch].

Treatment

Infectious myringitis is usually treated with antibiotics. These may be given by mouth or as drops in the ear. If the pain is severe, small cuts may be made in the blisters so they can drain. Pain-killing drugs may be prescribed, as well.

Otolaryngology is the study and treatment of disorders and diseases of the ear, nose and throat [ENT]. More recently it includes cancer of the throat and neck.

Otolaryngologists carry out a variety of operations such as tonsillectomy in the throat and adenoidectomy on the nose. Common ear operations they carry out include stapedectomy, mastoid surgery and myringoplasty.

Otolaryngologists are surgeons who have chosen to specialize in ENT. It takes eight years to qualify.

Otosclerosis is a rare condition that can cause gradual hearing loss. It affects the middle ear, found behind the eardrum and which is predominantly filled with air. There are three bones within the middle ear section called the malleus, the incus and the stapes.

External Otitis or "swimmer's ear" is an infection of the skin covering the outer ear and/or the ear canal. Acute external otitis is commonly caused by a bacterial infections, the swimmer's ear infection is usually caused by excessive water exposure from swimming or other water sports. When water collects in the ear canal, it can often get trapped inside and be prevented from exiting by being absorbed by earwax, then the warm moist conditions allow bacteria to grow rapidly.

Cuts or abrasions of the skin lining the ear canal can also lead to bacterial infection of the ear canal. Other causes include a spot or pimple developing inside the ear, a fungal infection or something directly irritating the ear canal, such as a hearing aid or an ear plug for example. Otitis externa is relatively common. It is estimated that around 10% of the population will be affected at some point in their lives. People with certain long-term (chronic) conditions, such as eczema, asthma or allergic rhinitis, are at greater risk of developing otitis externa. Chronic (long-term) swimmer's ear is otitis externa that persists for longer than four weeks or that occurs more than four times a year. Symptoms of otitis externa are usually a feeling of fullness and a very itchy ear. They may include ear pain, (this may range from moderate to severe pain, which may be due to the ear canal swelling. If severe this may cause the face to appear swollen too and it may not be immediately obvious that the pain is coming from the ear.

Sometimes discharge may be present from the ear and you may be noticing a temporary or fluctuating hearing loss. Often only one ear is affected and while otitis externa can clear up by itself, it can take several weeks without treatment. Antibiotics may be prescribed to treat the infection along with painkillers if necessary and sometimes ear drops. Treatment for other underlying conditions that may aggravate otitis externa, such as dermatitis, psoriasis or eczema may prove beneficial.

Moisture may prolong otitis externa so for this reason, the ear should be kept as dry as possible. While showering or swimming use an ear plug (available for water sports these are available and are designed to keep water out). Despite the temptation, scratching the inside of the ear, inserting any object including the use of cotton buds should be avoided.

This will only aggravate the irritated skin, and in most situations will make the condition worse. If a hearing aid is worn this should be left out as much as possible until any swelling, pain and discharge stops.