Why and how it works
Vestibular Rehabilitation has emerged over the past several years as an exciting and successful alternative treatment for patients with chronic non-resolved motion intolerance and imbalance problems. This management strategy is being utilized by some of the leading medical and university facilities in the country. Patients are getting better and returning to normal lives because of this treatment.
Although Vestibular Rehabilitation has only recently gained wide attention, the concept of head, body and coordinated eye exercises as a treatment for vestibular disorders is actually over 50 years old. As far back as the mid 1940's, an English otolaryngologist, Cawthorne, observed that some dizzy patients did better or recovered sooner when performing rapid head movements. In cooperation with a physiotherapist, Cooksey, they developed a regimen of exercises which are still used today, with some modification.
Since the resurgence of interest and research in vestibular rehabilitation in the mid 1980's, hundreds of articles have been published in otolaryngology, neurology, and physical therapy
journals. The overwhelming conclusion of these research studies has documented the benefits of this management strategy for vestibular dysfunction patients.
In order to understand how Vestibular Rehabilitation works and the underlying corrective mechanisms, it is important to remember that the primary role of the vestibular system is to tell the brain where the head is. Quite simply, the vestibular system is our internal reference telling the brain how our head is orientated in space. The visual and somatosensory systems, on the other hand, are external references, providing our brain with information about the movement and stability of the world around us. Working together in agreement, it is the harmonious integration of these sensory modalities that provides us with normal equilibrium.
When there is a conflict between internal and external references, the result is the brain's inaccurate perception or hallucination of motion. An example of this occurring in everyday life is the feeling of moving forward when stopped at a traffic light, when a larger vehicle in your peripheral vision has rolled backward. Another example of conflict occurs when you are parked in a carwash as the brushes pass by your car. The natural reaction is to hit your brakes to stop your car tram rolling forward, but you hadn't moved at all. There was simply a conflict between the three sensory modalities." The input from the motion detector aspect of the visual system overrode the input from the vestibular and somatosensory systems creating the hallucination or perception of motion.
There are three generally accepted models to explain why therapy works
Adaptation: The central vestibular system and brain learns to adapt to the imbalanced signal coming in from the impaired peripheral vestibular sensory receptors. The role of the vestibulo-ocular reflex is to keep the eyes focused on a target during head movement. If the incoming signal from the two internal head movement sensors is not in synchrony, the result is a sense of "after-motion" with head movement. A primary component of the equilibrium system adversely effected by the imbalance from the two peripheral vestibular mechanisms is the vestibulo-ocular reflex.
Gaze stabilization exercises work to "return" the vestibulo-ocular reflex to eliminate the retinal slippage and the patient's perception of this "after motion. II Another easily understood example is that of the two propeller airplane with one propeller operating at only half the Rpm's of the other. There is no way to increase the damaged or reduced propeller's output, so the on-board computer is programmed to accept or adapt to the imbalanced signal and maintain the plane's trajectory and course.
Substitution: The role of compensatory shift when one or more sensory systems is lost or damaged is well known. The visually impaired individual does not develop better hearing acuity, nor does the deafened individual gain better vision. They simply utilize their remaining senses more efficiently. The redundancy of multiple sensory inputs allows the fully intact individual to waste much of the input. So, for the individual who has lost vestibular function, dependency on the remaining equilibrium sensory components, e.g. vestibulo-spinal, cervico-spinal and visual inputs, must be made trustworthy.
Liberatory/Repositioning/Desensitization: There are several different approaches in the management of otolith dysfunction, commonly referred to as Benign Positioning Vertigo. They include procedures in which the otoliths which have escaped from the utricle and are now floating in the semicircular canals are loosened, dislodged, removed or ignored through a single or repetitive positioning maneuver(s).
TYPES OF THERAPY
There are four general ways in which programs may be implemented. One or more of the approaches may be used as well as one or more of the models outlined above. The goal is always to make the patient better as quickly as possible in a safe and caring manner.
Self Directed: This approach is most commonly used with patients who do not require supervision during their exercises) are not in an acute state) or whose lives do not allow weekly visits. Following a one) one-hour training or instructional session, the patient is provided with a set of protocols within a self-directed program. Best results occur when the patient spends 20-30 minutes per session two to three times a day. Most patients report a significant reduction or elimination of their symptoms within a three to four week time span.
Vestibular Rehabilitation: This program is designed for patients whose symptoms may be acute and who may require supervision during their exercises. Therapy sessions usually incorporate use of a variety of special vestibular therapy apparatus which most patients find enjoyable using. There is also an emphasis on fall prevention for older patients. Typically) the patient participates in one or two 60 minute sessions per week, with an average program of eight to ten sessions. AB the patient progresses and gains confidence) they will also be given self-directed protocols to quicken their improvement.
Balance Retraining: This therapy approach is for individuals who have a loss of balance) unsteadiness or loss of surefootedness. Most of these patients do not report dizziness or vertigo. There is an emphasis on practical solutions to the common problems of difficulty getting around in the dark) walking on uneven surfaces) such as thick carpeting or lawns) and negotiating steps and curbs. Fall prevention) movement coordination and improved participation in everyday activities are all high priorities of the program.
Liberatory/RepositioninglDesensitization: Specifically for patients with a diagnosis of Benign Paroxysmal Positioning Vertigo (BPPV), it may consist of one or more visits utilizing the clinician's choice of approach for management of the otolith originated positional vertigo.