Effect of posture on the perception of verticality in neglect patients.
OBJECTIVE
The anticlockwise (ACW) deviation of the visual and visuohaptic subjective verticals (SVs), known to occur in patients with right hemisphere lesion, is amplified by spatial neglect (N). These patients have only been assessed when sitting. We investigated the hypothesis that postural changes modulate visuohaptic SV deviation.


METHODS
Eight patients presenting with a right hemisphere lesion and spatial N were compared with 6 matched control subjects (C). In the dark, they had to rotate a luminous rod to put it at the vertical in 4 conditions: (1) sitting with plantar sole support; (2) sitting without plantar sole support; (3) sitting with legs extended on a support; and (4) supine position.


RESULTS
N patients showed a significant ACW deviation (-4.5 degrees) of the SV compared with C subjects (+0.01 degrees). The effect of body position depended on the group (P=0.022) because changes had definite effects in the N but not in the C group. In fact, the former showed a reduction of the ACW deviation, from the first to the fourth condition.


CONCLUSIONS
Although the possible role of plantar and leg somaesthetic inputs remains to be thoroughly investigated, the modulation of gravitational inputs at trunk or vestibular level influences the SV deviation in N patients. This has to be put in relation with the modulation of N signs reported by other authors when passing from the sitting to the supine position.
Saj
Arnaud
A
Service de Rééducation Neurologique and EA 2691, Hôpital Swynghedauw, CHRU de Lille, France. a-saj@chru-lille.fr
Honoré
Jacques
J
Davroux
Jessy
J
Coello
Yann
Y
Rousseaux
Marc
M
D000368:Aged; D001921:Brain / Q000473:pathology; D002545:Brain Ischemia / Q000503:physiopathology*; D005260:Female; D007839:Functional Laterality; D006801:Humans; D020300:Intracranial Hemorrhages / Q000503:physiopathology*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009949:Orientation / Q000502:physiology*; D010465:Perception; D010468:Perceptual Disorders / Q000175:diagnosis / Q000503:physiopathology; D011187:Posture; D013028:Space Perception; D020521:Stroke / Q000503:physiopathology*; D016683:Supine Position; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D014796:Visual Perception / Q000502:physiology*