Visual field dependence-independence before and after unilateral vestibular loss.

To investigate whether visual field dependence-independence changed after unilateral vestibular loss, Menière's patients were tested before and after unilateral vestibular neurotomy and compared with controls. Using the rod and frame test, visual vertical perception was tested under four visual contexts (with a frame tilted either clockwise or counterclockwise, with a vertical frame, and without visual reference). Both controls and Menière's patients before unilateral vestibular loss split into visual field dependent and independent subpopulations. Unilateral vestibular loss did not change this partition but, for both subpopulations, it induced asymmetrical visual field dependence with a reduced or abolished contralesional dependence. Finally, when vertical/horizontal references were provided, visual vertical perception was improved in both subpopulations, suggesting that all patients relied on the same allocentric strategy.