Dissociation of visual and haptic vertical in two patients with vestibular nuclear lesions.

Bronstein, A M; Pérennou, D A; Guerraz, M; Playford, D; Rudge, P · Neurology · 2003

case_series · Level IV

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Abstract

The somatosensory (haptic) vertical (HV) and visual vertical (VV) were assessed in two patients with vestibular nuclear lesions. Patient 1 had paroxysmal nystagmus, and was tested "on" and "off." The HV was normal "on" and "off" but the VV was severely tilted during vestibular paroxysms. Patient 2, with a brainstem stroke, was tested at months 1 and 6. The VV was severely tilted on both occasions (>12 degrees) but the HV was marginally tilted (4 degrees) in the acute stage only. These VV-HV dissociations suggest that vestibular nuclear lesions influence gravity perception mostly via ocular torsional effects rather than by disrupting a single, internal representation of verticality.

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