Recovery of Visual Acuity in People With Vestibular Deficits
Recovery of Visual Acuity in People With Vestibular Deficits
The purpose of this study is to determine whether exercises relieve the symptoms of dizziness
 and imbalance in people with vestibular deficits and improves the ability to see clearly
 during head movements. We hypothesize that the performance of specific adaptation and
 substitution exercises will result in an improvement in visual acuity during head movements
 while those patients performing placebo exercises will show no improvement.
Decrements in visual acuity during head movement in patients with vestibular hypofunction are
 potentially serious problems. This deficit could contribute to decreased activity level,
 avoidance of driving with resultant diminished independence and, ultimately, limited social
 interactions and increased isolation. Oscillopsia occurs because of inadequate
 vestibulo-ocular reflex (VOR) gain and suggests that compensation for the vestibular loss has
 not occurred. The purpose of this study was to examine the effect of an exercise intervention
 on visual acuity during head movement in patients with unilateral and bilateral vestibular
 hypofunction. We hypothesized that 1) patients performing vestibular exercises would have
 improved visual acuity during head movement compared to patients performing placebo
 exercises; 2) there would be no correlation between dynamic visual acuity (DVA) and the
 patients' subjective complaints of oscillopsia; and 3) improvement in DVA would be reflected
 by changes in residual vestibular function as indicated by an increase in VOR gain.

 Patients are assigned randomly to either the vestibular exercise or placebo exercise group.
 The randomization schedule is generated using a computer program for 2-sample randomization.
 The sequence was not concealed from the investigator who obtained consent from the subjects
 and supervised the exercises (SJH). The group assignment (vestibular exercise or placebo
 exercise) was concealed from the participants and from the investigator who performed the
 outcome measures.

 The vestibular exercise group practiced exercises that consisted of adaptation exercises and
 eye-head exercises to targets (Table 1), which were designed to improve gaze stability 16.
 They also performed gait and balance exercises. The placebo exercise group performed
 exercises designed to be 'vestibular-neutral'.
Inclusion Criteria:

 -  Patient had to have either a unilateral vestibular or bilateral vestibular
 hypofunction defined as follows: Unilateral vestibular deficits were defined by a >
 25% difference in slow phase eye velocity between right and left sides on either the
 caloric or rotary chair test. Bilateral vestibular deficits were defined included
 refixation saccades made in response to unpredictable head thrusts to the right and
 left, a gain < .1 on rotary chair step test and a peak slow phase eye movement of <5
 degrees/sec during irrigation of each ear on bithermal water caloric testing

 -  Healthy subjects with normal vestibular function test results

 -  must be able to complete DVA test

 Exclusion Criteria:

 -  Patients with central lesions will be omitted from the study because vestibular
 adaptation or other compensatory mechanisms may be compromised and

 -  Patients with visual acuity when the head is stationary of 20/60 or worse.

 -  Patients on medication that suppress or facilitate vestibular function will not be
 excluded from the study but data will be analyzed to assess the effect of medication.

 -  Patient who do not understand the purpose of the study and what it involves