Mechanism of dynamic visual acuity recovery with vestibular rehabilitation.
OBJECTIVE
To determine why dynamic visual acuity (DVA) improves after vestibular rehabilitation in people with vestibular hypofunction.


METHODS
Combined descriptive and intervention study.


METHODS
Outpatient department in an academic medical institution.


METHODS
Five patients (age, 42-66 y) and 4 age-matched controls (age, 39-67 y) were studied. Patients had vestibular hypofunction (mean duration, 177+/-188 d) identified by clinical (positive head thrust test, abnormal DVA), physiologic (reduced angular vestibulo-ocular reflex [aVOR] gain during passive head thrust testing), and imaging examinations (absence of tumor in the internal auditory canals or cerebellopontine angle).


METHODS
Vestibular rehabilitation focused on gaze and gait stabilization (mean, 5.0+/-1.4 visits; mean, 66+/-24 d). The control group did not receive any intervention.


METHODS
aVOR gain (eye velocity/head velocity) during DVA testing (active head rotation) and horizontal head thrust testing (passive head rotation) to control for spontaneous recovery.


RESULTS
For all patients, DVA improved (mean, 51%+/-25%; range, 21%-81%). aVOR gain during the active DVA test increased in each of the patients (mean range, 0.7+/-0.2 to 0.9+/-0.2 [35%]). aVOR gain during passive head thrust did not improve in 3 patients and improved only partially in the other 2. For control subjects, aVOR gain during DVA was near 1.


CONCLUSIONS
Our data suggest that vestibular rehabilitation increases aVOR gain during active head rotation independent of peripheral aVOR gain recovery.
Schubert
Michael C
MC
Department of Otolaryngology Head and Neck Surgery, Johns Hopkins School of Medicine, Baltimore, MD 21287-0910, USA. mschube1@jhmi.edu
Migliaccio
Americo A
AA
Clendaniel
Richard A
RA
Allak
Amir
A
Carey
John P
JP
D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D016022:Case-Control Studies; D015331:Cohort Studies; D005081:Exercise Therapy / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D011336:Probability; D020127:Recovery of Function; D012016:Reference Values; D012027:Reflex, Vestibulo-Ocular / Q000502:physiology*; D018570:Risk Assessment; D012720:Severity of Illness Index; D016896:Treatment Outcome; D014717:Vertigo / Q000175:diagnosis / Q000534:rehabilitation; D015837:Vestibular Diseases / Q000175:diagnosis / Q000534:rehabilitation*; D014724:Vestibular Function Tests; D014792:Visual Acuity / Q000502:physiology*