Whаt is Vestibular Rehabilitaton?
Vestibular compensation is a process that allows the brain to regain balance control and minimise dizziness symptoms when there is damage to, or an imbalance between, the right and left vestibular organs (balance organs) in the inner ear.
Essentially, the brain copes with the disorientating signals coming from the inner ears by learning to rely more on alternative signals coming from the eyes, ankles, legs and neck to maintain balance.
Treatment of vestibular hypofunction
Vestibular hypofunction can be a unilateral or bilateral vestibular loss. There are three types of vestibular rehabilitation exercises to reduce symptoms in cases where physical dysfunction cannot be reduced. The category of exercises chosen by a vestibular therapist depends on the problems reported by the patient. The following exercises can be used to treat dizziness with fast movements or exposure to intense visual stimuli, difficulty seeing (appearance of bouncing or jumping visual field) with head movement, and trouble with balance.
Canalith repositioning treatments:
- Premedication of the patient
- Specific positions
- Timing of shifts between positions
- Use of vibration
- Post-maneuver instructions
Because the methods of vestibular rehabilitation therapy differ for different disorders, the form of vestibular dysfunction, ability level, and history of symptoms, each patient must be carefully assessed in order to diagnose vestibular dysfunction and to choose the correct exercises for treatment. In some cases, vestibular rehabilitation may not be the appropriate treatment at all. Vestibular disorders can be diagnosed using several different kinds of assessments, some of which include examination of an individual’s ability to maintain posture, balance, and head position. Some diagnostic tests are more easily performed in a clinical setting than others but relay less specific information to the tester, and vice versa.
- Caloric reflex test
The caloric reflex test is designed to test the function of the vestibular system and can determine the cause of vestibular symptoms. The reflex test consists of pouring water into the external auditory canal of a patient and observing nystagmus, or involuntary eye movement. With normal vestibular function, the temperature of the water has an effect on the direction of eye movement. In individuals with peripheral unilateral vestibular hypofunction, nystagmus is absent.
- Rotational chair testing
This test is used to test bilateral vestibular hypofunction and the degree of central nervous system (CNS) compensation that results. Movement of fluid within the inner ear, known as endolymph, is responsible for the relationship between eye movement and head velocity. The test consists of seating a patient in a rotating chair, rotating the chair to specific velocity, and observing eye movement. In individuals with normal vestibular function, the velocity of eye movement should be equal and opposite that of head movement.
- Visual perception testing
Visual perception testing can assess a patient’s ability to determine vertically- and horizontally-oriented objects, but with a limited degree of specificity. When asked to align a bar to horizontal or vertical, an individual with normal vestibular function can align the bar within 2.5 degrees of horizontal or vertical. An inability to do so indicates vestibular dysfunction. In some cases, the direction of tilt away from the desired orientation is on the same side as the dysfunction, while in some cases the opposite is true.
Using various technologies to assess a person’s ability to maintain posture and balance, different patterns of posturography can be determined. Once a pattern is determined, the modalities and inputs that the person relies on to maintain balance can be inferred. Knowing what systems and structures influence a person’s stance can suggest different areas of dysfunction and preference.
- Non-vestibular dizziness
In some cases, the results of vestibular tests are normal, yet the patient experiences vestibular symptoms, especially balance issues and dangerous falls. Some diagnoses that result in non-vestibular dizziness are concussions, Parkinson’s disease, cerebellar ataxia, normal-pressure hydrocephalus, leukoaraiosis, progressive supranuclear palsy, and large-fiber peripheral neuropathy. There are also several disorders known as chronic situation-related dizziness disorders. For example, phobic postural vertigo (PPV) occurs when an individual with obsessive-compulsive characteristics experiences a sense of imbalance, despite the absence of balance issues.