Recovery of Visual Acuity in People With Vestibular Deficits

July 16, 2015 updated by: Susan Herdman, Emory University

Recovery of Visual Acuity in 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.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

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'.

Study Type

Interventional

Enrollment (Actual)

23

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United States
    • Georgia
      • Atlanta, Georgia, United States, 30322
        • Center for Rehabilitation Medicine, Emory University

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

16 years to 78 years (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

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

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Single

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: exercises for gaze stabilization
Experimental group performed vestibular adaptation and substitution exercises
Other: gaze stabilization exercises
adaptation and substitutin exercises encorporating retinal lsip and head movements
Placebo Comparator: Control exercises
Saccadic eye movements against a Ganzfeld to prevent retinal slip error signal; no head movements
Other: Control exercises
saccadic eye movements against a plain background; no head movements

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in Visual Acuity During Head Movement From Baseline to Discharge
Time Frame: pre-intervention and at discharge

visual acuity is measured using a computerized system first with the head stationary and then with the head moving in yaw plane. Head velocity is measured using a rate sensor and optotype is displayed only when head velocity is between 120 and 180 degrees per second.

The change in visual acuity was calculated from subtracting the discharge measurement from the baseline measurement (pre-intervention).
pre-intervention and at discharge
Subjective Complaints: (All Pre- and Post-intervention):
Time Frame: pre-intervention, 2 weeks, 4 weeks and at discharge
questionnaire
pre-intervention, 2 weeks, 4 weeks and at discharge

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Disability Scale
Time Frame: pre-intervention, 2 weeks, 4 weeks and at discharge
questionnaire
pre-intervention, 2 weeks, 4 weeks and at discharge
Activities Specific Balance Confidence Scale
Time Frame: pre-intervention, 2 weeks, 4 weeks and at discharge
questionnaire
pre-intervention, 2 weeks, 4 weeks and at discharge
Symptoms Intensity for Dizziness, Oscillopsia, Disequilibrium
Time Frame: pre-intervention, 2 weeks, 4 weeks and at discharge
visual analoque scales
pre-intervention, 2 weeks, 4 weeks and at discharge
Balance and Gait
Time Frame: pre-intervention, 2 weeks, 4 weeks and at discharge
gait speed
pre-intervention, 2 weeks, 4 weeks and at discharge
Fall Risk (Dynamic Gait Index)
Time Frame: pre-intervention, 2 weeks, 4 weeks and at discharge
performance test
pre-intervention, 2 weeks, 4 weeks and at discharge
Eye Movements: Scleral Search Coil
Time Frame: pre- and post-treatment
eye movements are measured by having the participant sit within an electromagnetic field while wearing a scleral coil (like a contact lens but only in contact with the sclea, not the cornea); te coil moves with eye movement and distorts the electrimagnetic field
pre- and post-treatment

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Emory University

Collaborators

National Institute on Deafness and Other Communication Disorders (NIDCD)

Investigators

  • Principal Investigator: Susan J Herdman, PhD, Emory University

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

August 1, 2000

Primary Completion (Actual)

December 1, 2004

Study Completion (Actual)

December 1, 2004

Study Registration Dates

First Submitted

December 12, 2006

First Submitted That Met QC Criteria

December 12, 2006

First Posted (Estimate)

December 13, 2006

Study Record Updates

Last Update Posted (Estimate)

August 7, 2015

Last Update Submitted That Met QC Criteria

July 16, 2015

Last Verified

July 1, 2015

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • IRB00000336
  • R01DC003196 (U.S. NIH Grant/Contract)

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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