Focusing on finger moving from three feet to one foot away from face B. Head movements Turning from side to side 2. Sitting A. Eye and head movements, as 1 B. Shrug and circle shoulders C.
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Abstract Background and Purpose The efficacy of both habituation and adaptation exercise interventions in the treatment of unilateral vestibular hypofunction has been demonstrated by prior studies. The purpose of this paper is to describe the preliminary results of an ongoing study that compares the effects of these two different exercise approaches on outcomes related to vestibular function.
Methods Seven participants with unilateral vestibular hypofunction have completed a 6-week exercise intervention after randomize assignment to either habituation H exercises, or gaze-stability GS adaptation exercises. The following measures were taken pre-treatment and post-treatment: Dizziness Handicap Inventory DHI to measure the symptom impact, motion sensitivity quotient MSQ to assess sensitivity to head movements, and the dynamic visual acuity test DVA as a measure of gaze-stability during head movements.
Head movement, which is required by both exercise interventions, rather than the specific type of exercise may be the critical factor underlying the observed improvements in motion sensitivity and dynamic visual acuity. The adaptation exercises are based on the demonstrated ability of the vestibular system to modify the magnitude of the vestibulo-ocular reflex VOR in response to a given input head movement.
The adaptation of the VOR has been demonstrated in individuals with normal vestibular function and those with unilateral vestibular hypofunction. These exercises require the individual to perform rapid, active head rotations while watching a visual target, with the stipulation that the target remains in focus during the head movements. If the target is moving in the opposite direction of the head movement, then these exercises are referred to as x2 viewing exercises. While these exercises have been shown to improve dynamic visual acuity, the actual mechanism behind this improvement is not known.
In contrast with adaptation exercises, habituation exercises are based on the idea that repeated exposure to a provocative stimulus e. While there is support for the two different intervention approaches, there are no studies to date that have compared the two interventions in terms of changes in symptoms, motion sensitivity, and dynamic visual acuity.
What is reported herein are the preliminary results of a study designed to investigate this issue in individuals with an identified unilateral vestibular loss.
The underlying hypotheses for this study are that: 1 individuals who perform gaze stability exercises will have a greater improvement in dynamic visual acuity compared to those who perform the habituation exercises, and 2 individuals who perform habituation exercises will have a greater reduction in their motion sensitivity compared to those who perform the gaze stability exercises.
All participants had a documented unilateral vestibular hypofunction based on surgical history, caloric test results, or clinical examination, and had an abnormal clinical dynamic visual acuity test. Informed consent was obtained, and the institutional review board for human subjects protection at Duke University approved all aspects of the study. The computerized Dynamic Visual Acuity Testing apparatus was similar to devices reported previously in the literature.
The orientation of the optotype was randomly altered, and the size of the optotype was progressively decreased in 0. For each optotype size, five orientations of the optotype were presented. Static visual acuity was determined first.
When the participant was unable to correctly identify all trials at a given acuity level, the test was stopped, and the number of missed optotypes was recorded.
When the participant was unable to correctly identify all trials at a given acuity level, the test was stopped. The DVA test was performed under both active self-generated head movements and passive examiner generated head movements conditions.
The test was performed separately for ipsilesional and contralesional head rotation. Since the ipsilesional DVA test was the item of interest in this study, the contralesional passive DVA test was always run first to account for any learning effects that might occur. This method of DVA testing has been shown to be reliable with good sensitivity and specificity.
The MST measures the perceived intensity and duration of symptoms provoked by16 rapid changes in head or body position. An overall score, the motion sensitivity quotient MSQ , is determined from the results of each of the movements. The MST has been shown to be both a reliable and valid measure of motion-provoked dizziness.
The participants in the GS group performed a series of exercises designed to improve gaze-stability during head movements Table 1 as well as balance and gait exercises.
The participants in the H group performed a series of exercises designed to decrease their sensitivity to head movements Table 1 , as well as balance and gait exercises similar to those performed by the GS group. The exercises used in each group are used routinely in clinical practice and are often referred to as either adaptation exercises the GS group , or habituation exercises the H group.
The participants were instructed to perform the exercises three times a day over a 6-week period. The participants returned to the lab once a week for clinical assessment and progression of the exercise program. The exercise progression was based on clinical experience treating patients with acute and subacute vestibular disorders.
The exercise program was devised so that the participants could successfully complete each phase of the program. Static and dynamic visual acuity tests, MST, and the DHI were administered at the start of the program and at the end of the 6-week intervention period.
The author performed all testing and treatment interventions. Table 1.
Vestibular Rehabilitation Therapy (VRT)
These are the problems that rehabilitation aims to address. Symptoms due to vestibular disorders can diminish quality of life and impact all aspects of daily living. They also contribute to emotional problems such as anxiety and depression. Additionally, one of the consequences of having a vestibular disorder is that symptoms frequently cause people to adopt a sedentary lifestyle in order to avoid bringing on, or worsening, dizziness and imbalance.
Virtual Reality -- for most head-mounted implementations, this is an irrational idea. Somatosensory dependence training Convergence exercises and prisms. These are often recommended by optometrists. Follow the link above for some more ususual protocols.
Vestibular rehabilitation exercises
Vestibular disorders[ edit ] The term "vestibular" refers to the inner ear system with its fluid-filled canals that allow for balance and spatial orientation. Vestibular dysfunction can exist unilaterally, affecting only one side of the body, or bilaterally, affecting both sides. The BPPV is characterized by temporary dizziness feeling associated with blurred vision in relation to certain head positions. BPPV may affects anterior, posterior or horizontal vestibular canals. Several positional tests such as Hall-bike dix test, supine roll test, and head shaking nystagmus test may indicate which canal is affected by BPPV. Although the body naturally compensates for vestibular dysfunction as it does for the dysfunction or deficiency of any sense , vestibular rehabilitation furthers the compensation process to decrease both primary and secondary symptoms.