Graduation Year

2002

Document Type

Dissertation

Degree

Au.D.

Degree Granting Department

Audiology

Major Professor

Gans, Richard E.

Keywords

Dynamic Visual Acuity, Oscillopsia, Vestibulo-Ocular Reflex

Abstract

Patients with non-compensated vestibular dysfunction frequently complain of the ability to maintain dynamic visual acuity during activities which require the movement of the head. When this occurs the patient is experiencing oscillopsia, which is the symptom resulting from a non-functional vestibulo-ocular reflex (VOR). To measure the presence of oscillopsia, tests of dynamic visual acuity (DVA) may be used.A recent test of DVA has been reported which is administered while patients are walking on a treadmill. Although this test has been shown to be useful in evaluating DVA in patients, there are several disadvantages to treadmill use. These include physical space, cost and accessibility. Additionally, walking at the required treadmill speed to produce sufficient head movement may pose difficulties and be medically contraindicated for patients with certain health risks. The purpose of this study was to evaluate a different method to measure DVA in patients which would not require the use of the treadmill, but instead utilize a volitional head movement to reveal oscillopsia. In this study, patients performed the DVA test in two conditions: (1) walking on a treadmill, and (2) seated on a chair volitionally moving the head.In this study, DVA was tested in both conditions with 15 adults with normal vestibular function, and 16 adults with vestibular impairment. Results revealed that both methods, treadmill walking and volitional head movement, appeared equivalent for measuring DVA in normal subjects and vestibular impaired subjects. The lack of finding a significant main effect of method, and interactions that include method, supports the equivalence of volitional head movement to a treadmill approach for the measurement of DVA.

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