Article

Patients with vestibular dysfunction, migraine and/or anxiety may experience
visual vertigo (VV), whereby symptoms are provoked by disorienting visual
environments (e.g. supermarkets). Patients with VV over rely on vision for
balance (i.e. visually dependent). Visual vertigo significantly improves when
vestibular rehabilitation incorporates exposure to optokinetic stimulation (OKS).
However, whether OKS exposure induces a reduction in visual dependency is
unknown. This study investigated this issue by measuring visual dependency before
and after repeated OKS exposure. Twenty-six healthy subjects (10 males; mean age
29.8 years, range 20-42 years) were randomly allocated into an OKS group who
underwent graded OKS exposure for five consecutive days, or a no intervention
control group. Assessment included the 'Rod and Frame' and 'Rod and Disc' tests
where subjects set the subjective visual vertical in darkness, facing a tilted
luminous frame or luminous rotating disc, respectively. Postural sway measures
were obtained with eyes open, closed and facing the rotating disc. Results showed
significant reductions in subjective vertical tilt with the frame and rotating
disc for the OKS group only (p</=0.01). Total sway path and mean deviation
induced by the rotating stimulus decreased significantly only for the OKS group
(p<0.01), as did the Kinetic Quotient (disc rotation/eyes open sway path ratio;
p=0.04). The Romberg Quotient (eyes closed/eyes open ratio) showed no change.
Findings suggest visual dependency, both at a perceptual and a postural level,
can be reduced with short-term graded OKS exposure in healthy subjects. This has
important implications for treatment of patients with VV and balance disorders.
CI - Crown Copyright (c) 2010. Published by Elsevier B.V. All rights reserved.

Langue : ANGLAIS