Vestibular hypofunction – Symptoms and diagnosis

Vestibular dysfunction causes a disturbance in the body’s balance system due to malfunctioning of the inner ear, the central nervous system processing centers or both.

When a person has vestibular hypofunction, there will be a problem in the inner ear. The vestibular hypofunction can affect the balance part of the inner ear. It can occur either on one side or in both ears.

If the hypofunction occurs on one side of the ear, it is called unilateral hypofunction and, if it occurs on both sides, it is called bilateral hypofunction.

According to NCBI, vestibular hypofunction is a partial or complete deficit in the functions of the peripheral or central vestibular system.

Additionally, the cause of vestibular hypofunction can be due to toxic, traumatic, infectious, genetic and neurodegenerative, but in 50% of the cases, the cause is unknown.

Symptoms of Vestibular hypofunction

Dizziness is the initial symptom of vestibular hypofunction. Imbalance can be a major problem as we age.

But this condition cannot be validated as normal. There can be certain underlying conditions for vestibular hypofunction.

The ear is made up of a complex system of bone and cartilage. It contains a network of canals called semicircular canals. These canals will be filled with fluid, and the position of the fluid will change depending on the movement.

When there is a change in the misplacement of fluid, a sensor present inside the ear will send a signal to the brain. As a result, the brain will contribute to balance.

There are certain causes that can affect the brain signals and lead to vestibular hypofunction and its symptoms.

The common symptoms of vestibular hypofunction are

• Dizziness,
• Blurred vision,
• Feeling off-balance,
• A feeling of the world is spinning,
• A feeling of floating,
• Disorientation,
• Stumbling,
• Falling,
• Nausea,
• Vomiting,
• Anxiety,
• Fear,
• Diarrhoea and Changes in heart rhythm.

Case study of Vestibular hypofunction

Varun Dhawan, a 35-year-old male, is affected with vestibular hypofunction. It is a rare condition and can affect anyone.

The cause of the disease is not known, and it can cause symptoms like frequent trips and falls. The diagnostic and treatment option are discussed below.

Diagnosis of Vestibular hypofunction

The diagnosis of vestibular hypofunction will be made elaborately by an ear, nose and throat specialist (ENT specialist). The diagnosis process can help to rule out the condition of vestibular hypofunction. However, after full diagnosis, the condition can be finalised.

A full medical history of the patient will be taken before coming to the conclusion of vestibular hypofunction. The common tests used are discussed below.

ELECTRO/VIDEO-NYSTAGMOGRAPHY (ENG OR VNG)

Electronystagmography (ENG) is a group of tests that uses small electrodes. These electrodes will be placed over the skin around the eyes. This is also called a test battery and is placed around the eyes during testing.

Videonystagmography (VNG) is also the same as the test battery, which runs using goggles with video cameras that monitor the eyes. With the help of video cameras and electrodes, eye movement can be measured. This will evaluate vestibular dysfunction or neurological problems and plays a key step in diagnosing vestibular disorders.

The test will be carried out in a room that is dark or with low lighting. The examiner will be present along with the patient and ask random questions that will occupy the person and keep them alert. ENG/VNG tests are one of the common tests recommended to people with vertigo, dizziness and imbalance.

These tests follow a different pattern to target the movement of the eyes. The other parts of the test’s help observe eye movements as the head is placed in different positions.

The caloric test is also an important part of the ENG/VNG test. The caloric test detects the changes in temperature within the ear canal to stimulate a part of the vestibular system. Water or air may be used to regulate the ear canal temperature, which may be cooler or warmer than the body temperature. This test will provoke jerking eye movements for a short time.

ROTATION TESTS

Rotation tests will help evaluate how well a person’s eyes and inner ear work together. The rotation test is another key element in diagnosing vestibular disorders.

The rotation test also uses electrodes or video goggles to observe eye movements. The head will be rotated side to side at slow or moderate speeds, and the eye movements will be analysed.

Like the ENG/VNG test, the rotation test will also be carried out in a dark room, with the medical professional asking random questions during testing. However, rotation tests provide extra information beyond the ENG/ VNG, like how well the balance organs are functioning. The different types of rotation tests are

• Auto head rotation,
• A screening test and
• Computerised rotary chair.

In auto head rotation, the person tested will be asked to look at a fixed target and move their head back and forth for short periods of time.

In computerised rotary chair tests, the patient sits in a motorised chair that rotates side to side at a controlled rate. Screenings will be performed with a professional watching the eyes while turning the patient side to side in a swivel chair. However, not all people will require rotation tests.

VIDEO HEAD IMPULSE TESTING (VHIT)

The diagnostic method evaluates how well the eyes and inner ears coordinate. A small set of glasses with a camera will be used to monitor eye movements.

Video head impulse testing is similar to rotational testing. The head will be moved to evaluate the vestibulo-ocular reflex. However, the test uses a very small and quick movement of the head to evaluate the reflex function. However, this test is less common.

Audiometry (Hearing Tests)

The audiometry test measures hearing function. Hearing evaluations play an important role in vestibular diagnostics because the inner ear contains both balance and hearing organs.

More than one test may be required when a person is affected with vestibular dysfunction, especially when there is evidence of hearing loss.

The audiometric test battery will be carried out in a sound-treated room. Earphones will be used to present the words and tones to the patient at different pitches and levels. A response will be recorded when the sound is heard by the person. Testing with words will be repeated in a quiet room.

Another part of the hearing test is tympanometry. The test will help to detect problems between the eardrum and the inner ear.

Tympanometry uses a small earpiece which creates pressure and plays sound in the ear canal. The tympanometry will also be used for acoustic-reflex testing. The equipment will help measure the reflex of muscles in the middle ear as a response to pressure and loud sound.

Imaging tests

MAGNETIC RESONANCE IMAGING (MRI)

MRI will use radio waves and a magnetic field to produce cross-sectional images of body tissues. An MRI of the brain will reveal the presence of tumours, stroke damage and other soft-tissue abnormalities that can lead to dizziness or vertigo.  

MRI in and around the inner ear will help in the diagnosis of vestibular disorders in some instances.

COMPUTERIZED AXIAL TOMOGRAPHY

A CT scan adopts the technique of X-ray, which is one of the best for studying bony structures. The inner ear is present inside the skull’s temporal bone on each side. These scans are often used to look for abnormalities around the inner ear, such as fractures or areas with thinning bone, which can lead to vestibular hypofunction.

Treatments

There is a single specialised treatment for vestibular dysfunction. Treatments can vary depending on diagnosis, as well as individual factors like age. Treatments will aim at correcting the problem, minimising symptoms and promoting overall wellness. Some of the treatments handled are

• Vestibular rehabilitation therapy (VRT)
• Complementary and alternative medicine (CAM)
• Surgery
• Medication.

Complications

A person with vestibular hypofunction will often trip or fall due to the condition. The complications of vestibular hypofunction include

• Discomfort,
• Reduced quality of life and
• Injury from falling.

Living with vestibular dysfunction

The symptoms of vestibular dysfunction can interfere with regular daily activities. This can impact your driving skills, work or enjoy recreational activities.

This can lead to symptoms like depression and frustration. Counselling will help a person cope with the disorder and lifestyle impacts.

When should I call my healthcare provider?

Consult your doctor if you have symptoms like

• Feeling light-headed
• Dizziness
• Disorientation
• Blurred vision
• Stumbling and
• A feeling of floating.

These symptoms can affect your quality of life. In such cases, you should contact your healthcare provider immediately.

Conclusion

Vestibular hypofunction can affect the quality of life. The term vestibular disorder is an umbrella term used to define many inner ear conditions and other parts of the central nervous system.

There are twenty-five types of known vestibular disorders, and each disorder requires unique testing and treatment. Apart from treatment, there will be certain lifestyle changes required to handle the disorder.

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