Perception of verticality after recent cerebral hemispheric stroke.
OBJECTIVE
Perception of the subjective visual vertical (SVV) is affected by cerebral hemispheric lesions. Knowledge of this disturbance is of interest for the study of its possible relation to balance disturbances. There is still uncertainty about the possible effects of a visual field defect and of the side and site of the lesion. This study was conducted to assess SVV with the head upright or tilted and to explore its relation to a visual field defect, visuospatial neglect, and the site of lesion.


METHODS
Forty patients with hemiplegia after a recent hemispheric stroke (20 with left and 20 with right stroke) were studied. The site of the lesion was determined on CT scan, with special attention focused on the vestibular cortex. A neurological examination with determination of the visual field and visual neglect was conducted before SVV was tested. Subjects sat in a dark room and adjusted a luminous rod to the vertical position. Measures were repeated with binocular and monocular vision and with the head upright or tilted to the right or left.


RESULTS
SVV was abnormally deviated in 23 of 40 patients (57%). The deviation was significantly greater among patients with a right or left hemispheric lesion than among healthy controls (-2.2 degrees and 1.5 degrees versus 0.2 degrees ); the same applied to the range of uncertainty (7.6 degrees and 4.7 degrees versus 1.9 degrees ). SVV deviation was not significantly related to the location of the lesion but was closely related to visuospatial neglect. The "E" effect observed in controls with the head tilted, ie, an SVV shift in the direction opposite to the head tilt, was not observed in hemiplegic patients with the head tilted toward the nonparetic side.


CONCLUSIONS
Recent hemispheric stroke affects SVV perception, which is closely correlated to visuospatial neglect. It is suggested that the E effect might be mediated by the stretching of the somatosensory structure of the neck.
Yelnik
Alain P
AP
Physical Medicine and Rehabilitation Department, GH Lariboisiere-F. Widal, Paris, France. alain.yelnik@lrb.ap-hop-paris.fr
Lebreton
Frederique O
FO
Bonan
Isabelle V
IV
Colle
Florence M C
FM
Meurin
Francesca A
FA
Guichard
Jean Pierre
JP
Vicaut
Eric
E
D001921:Brain / Q000000981:diagnostic imaging / Q000503:physiopathology; D005260:Female; D007839:Functional Laterality; D006429:Hemiplegia / Q000209:etiology / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D010468:Perceptual Disorders / Q000175:diagnosis / Q000503:physiopathology; D010775:Photic Stimulation / Q000379:methods; D012016:Reference Values; D013028:Space Perception; D020521:Stroke / Q000150:complications / Q000000981:diagnostic imaging / Q000503:physiopathology*; D014057:Tomography, X-Ray Computed; D015348:Vision, Binocular; D015349:Vision, Monocular; D014794:Visual Fields