The concept of prescribing exercise for persons with dizziness was first described by Cooksey and Cawthorne in the 1950s (Cawthorne, 1944; Cooksey, 1946). Today, exercise for persons with vestibular disorders is considered to be the standard of care (Cowand et al., 1998; Herdman, 1990; Herdman, 1992; Herdman et al., 1995; Herdman and Whitney, 2000). Exercises are specifically prescribed that help the person with a vestibular disorder either compensate for or adapt to the impairment (Shepard and Telian, 1993). Knowledge of vestibular anatomy, physiology, pathologies involved, and an in-depth understanding of how various interventions can affect outcome is very important for effective treatment of persons with vestibular disorders. Exercises to decrease the risk of falling, improve balance and postural control, improve confidence, and decrease the subjective feelings of dizziness also seem to decrease a patient's anxiety (Jacob et al., 2000). Vestibular exercise programs have been shown to enhance the speed and degree of recovery (Herdman et al., 1995; Horak et al., 1992; Krebs et al., 1993; Strupp et al., 1998; Yardley et al., 1998).

Common conditions often referred for vestibular physical and occupational therapy include benign paroxysmal positional vertigo (BPPV) (Blakely, 1994; Herdman et al., 1993; Lynn et al., 1995), bilateral vestibulopathy (Brown et al., 2001; Krebs et al., 1993; Telian et al., 1991), endolymphatic hydrops, labyrinthine concussion (Cowand et al., 1998; Fujino et al., 1996; Horak et al., 1992; Shepard et al., 1990; Shepard et al., 1993; Smith-Wheelock et al., 1991), labyrinthitis (Cowand et al., 1998; Fujino et al., 1996; Shepard et al., 1990; Shepard et al., 1993; Smith-Wheelock et al., 1991), Ménière's disease (Cowand et al., 1998; Fujino et al., 1996; Shepard et al., 1990; Shepard et al., 1993; Smith-Wheelock et al., 1991), perilymph fistula, and vestibular neuritis. Central diagnoses include cervicogenic dizziness, brainstem hemorrhage (Cowand et al., 1998; Horak et al., 1992; Shepard et al., 1990; Shepard et al., 1995; Smith-Wheelock et al., 1991), posttraumatic anxiety symptoms, stroke/transient ischemic attacks (TIA), traumatic head injury (Cowand et al., 1998; Horak et al., 1992; Shepard et al., 1990; Shepard et al., 1993), and migraine-related vestibulopathy (Cass et al., 1997; Whitney et al., 2000). Psychiatric disorders that have been reported to manifest with a component of dizziness include panic disorders (Jacob et al., 2000), agoraphobia (Jacob et al., 2000), and hyperventilation syndrome. The most common nonvestibular causes of dizziness are low blood pressure and medication-induced dizziness (Furman and Whitney, 2000).

Persons with vestibular disorder present with various complaints, and often report experiencing balance dysfunction, dizziness, vertigo, anxiety about their symptoms, space and motion complaints (symptoms elicited by a specific visual stimulus pattern (Furman and Cass, 1996), and fear of falling. They may describe visual disturbances, dysequilibrium, and dizziness occurring while they are at work, at home, or engaged in leisure activities. Common visual problems experienced include difficulty focusing while reading, “bouncing” of the visual world as they move (oscillopsia), impaired smooth pursuit, saccades, and vergence. Balance problems frequently noted include increased sway while standing, an inability to stand still, walking with a wide-based gait, veering during walking, adduction or crossing their legs during gait, difficulty walking in the dark or on uneven surfaces, bumping into things, or falling.

Tinnitus, difficulty hearing, and aural fullness are related cochlear signs reported by persons with vestibular disorders. Descriptions of problems related to the head include dizziness, spinning, headache, pressure, neck pain, a swimming sensation, and heaviness. Often, persons with vestibular disorders report fatigue and difficulty concentrating. All of these problems contribute to making vestibular disorders difficult to treat, as affected individuals may have multiple symptoms and frequently have more than one diagnosis.

A physical therapy evaluation provides information on impairments and functional deficits so that appropriate intervention can be determined. A thorough workup by the physician and vestibular function tests help direct the physical therapy evaluation and intervention. The patient history should include goals of treatment, premorbid health, current and premorbid activity level, and a description of the onset, frequency, duration, and severity of the dizziness and imbalance. Not all persons with vestibular disorders experience both dizziness and imbalance. Identifying the positions or situations that exacerbate or relieve the symptoms can afford valuable insight into the cause of the problem. Gaining an understanding of the magnitude of the functional deficits is very important. The intensity and duration of symptoms, the degree to which symptoms impede activities of daily living, and how symptoms affect social activities help to determine intervention.

A thorough exploration of the individual's history of falling can also provide insight into the physiology of the condition and the necessary treatment (Herdman et al., 2000; Whitney, Hudak, and Marchetti, 2000). Not simply the number of falls but also the conditions of the fall, the frequency of falling, and whether medical treatment was necessary are all important in the assessment of the person with a vestibular disorder. Fear of falling in individuals who have fallen may constrict their willingness to move (Tinetti and Powell, 1993).

The patient's medical and surgical history will affect the prescription of an exercise program. Persons with premorbid orthopedic and cardiac limitations need to be carefully monitored to ensure that they are safe with the exercise program. Frail, older adults may need to be seen more frequently in order to ensure compliance and safety with their exercises.

Typically, the range of motion of the joints, muscle strength, sensation, vision, motions that provoke symptoms, balance, and gait are all determined before an exercise program is started. Because of the influence of somatosensation on balance, it is important to assess range of motion and sensation, particularly in the ankles and cervical region. The visual assessment includes testing the function of the ocular muscles, including saccades and smooth pursuit, as well as the function of the vestibular ocular reflex.

Quantification of the movements and positions that trigger symptoms of dizziness not only provides information on the cause of the symptoms but may also help in selecting activities for treatment. Therapists commonly ask patients to move into and out of supine and side-lying positions, and then have the patients rate their symptoms on a verbal analogue scale and indicate the duration of the symptoms (Norre and De Weerdt, 1980; Smith-Wheelock et al., 1991). Monitoring the intensity and duration of the symptoms over the length of treatment can provide information on the recovery of the patient.

Two aspects of postural control should be evaluated, the ability to move the center of gravity within the base of support and the ability to utilize available sensory information for balance. The ability to move the center of gravity within the base of support is determined by asking the person to perform tasks such as shifting his or her weight while standing and then reaching for objects. This can be quantified by measuring how far the person can reach (i.e., the Functional Reach test [Duncan et al., 1990] or the multidirectional Reach test [Newton, 2001]) or how long they can maintain a position (i.e., standing on one foot or in tandem). In addition, the clinician can ask patients to twist their trunk, pick up objects from different surfaces, or stand on a narrow base of support to determine how stable they are doing functional activities. Having the person with a vestibular disorder stand on high-density foam with the eyes open and then closed (Clinical Test of Sensory Interaction and Balance, or CTSIB) (Shumway-Cook and Horak, 1986) can help the therapist determine the fall risk (Anacker and Di Fabio, 1992), and also how well the patient uses the sensory information that he or she has available (Shumway-Cook and Horak, 1986). Scores on the CTSIB have been shown to correlate with conditions 4 and 5 of computed dynamic posturography (Anacker and Di Fabio, 1992; Weber and Cass, 1993).

Patients with vestibular disorders often describe difficulty walking, especially under varying sensory conditions such as walking with head turns, in dimmed or absent lighting, or with movement in the environment. Assessment of the person's gait during various functional tasks and under different sensory conditions is crucial. Persons with a vestibular disorder are asked to walk, walk at different speeds, walk over and around objects, and walk with various head movements in order to determine how stable they are during ambulation (Whitney et al., 2000a; Whitney and Herdman, 2000). These tasks can be quantified using the time it takes to complete a task or by qualitatively describing the movements, as in the Dynamic Gait Index (Shumway-Cook and Woollacott, 1995).

The goals of vestibular rehabilitation include decreasing the risk of falling, improving gaze stability, improving the person's dynamic and static postural control, decreasing symptoms, and enhancing the individual's ability to carry out activities of daily living and to work. The achievement of these goals is through exercise and the practice of activities in a safe environment. Customized exercise programs are better than exercise handouts provided without direction as to which exercises are most important to perform (Shepard and Telian, 1995).

Vestibular rehabilitation intervention is prescribed individually for each patient. For patients with peripheral vestibular lesions, vestibular rehabilitation exercises are thought to promote compensation or recalibration of the vestibular system, specifically the vestibulo-ocular reflex (VOR). The system appears to recalibrate because an error signal is created from the slip of an image on the retina (Robinson, 1976; Fetter and Zee, 1988). The use of eye and head movements as an exercise to change the gain of the VOR results in a change in the inhibition of the activity in the vestibular nuclei, and consequently in enhanced patient function. Recovery of the VOR is frequency specific. Stimulation of the VOR through exercises must be performed at varying frequencies for maximal functional recovery (Godaux, Halleux, and Gobert, 1983; Lisberger, Miles, and Optican, 1983).

Activity after a lesion to the vestibular system is important. Animals that moved freely after surgery had faster functional recovery (Lacour, Roll, and Appaix, 1976). Patients with vestibular disorders had faster recovery and improved function when they increased their activity early after surgery (Herdman et al., 1995).

Some persons with vestibular disorders have little or no remaining vestibular function, owing to disease or ototoxicity. These persons must learn how to use remaining sensory function such as somotosensation and vision. In addition, receptors in the neck can assist in stabilizing vision and posture, although in patients with intact vestibular systems, the cervical ocular reflex contributes little to gaze stability. The cervical ocular reflex performs maximally at lower frequencies and is accentuated in patients with bilateral vestibular loss (Kasai and Zee, 1978; Bronstein and Hood, 1986). Smooth pursuits and saccades can also assist in stabilizing vision at slow speeds (Kasai and Zee, 1978; Segal and Katsarkas, 1988; Leigh et al., 1994). Patients who have no function in the vestibular system will never be able to walk in the dark, will have great difficulty walking on uneven surfaces, and will never be able to read and walk at the same time. Driving a car without any vestibular function is impossible because the visual field jumps (oscillopsia), especially as the car goes over bumps.

Patients with balance disorders are taught to maximize the sensory function that remains, to substitute for sensory loss, and to predetermine when they will have difficulty with balance so that they can modify their behavior. Exercises are prescribed to enhance the use of vestibular, visual, and somatosensory inputs. Habituation exercises may be recommended for patients with dizziness provoked by specific position changes.

The outcomes of vestibular rehabilitation have included a decrease in dizziness and vertigo, a decrease in the number of falls, improved gait, decreased neck pain, improved VOR, greater balance confidence, decreased anxiety, improvements in activities of daily living, and improvements in the perceived disability. Generally, persons with peripheral vestibular disorders have a better prognosis than those with central vestibular disorders. Persons with both central and peripheral vestibular disorders have a poorer prognosis. All persons with vestibular disorders should have an opportunity to work with a knowledgeable physical or occupational therapist, because quality of life can be improved with vestibular rehabilitation.