Biased postural vertical in humans with hemispheric cerebral lesions.
This study was aimed at demonstrating the existence of a biased postural vertical in humans with a recent cerebral lesion. The postural vertical of patients and controls was analysed comparatively using a self-regulated balancing task, performed in sitting posture. Patients displayed a quite constant (19/22) contralesional tilt of the postural vertical (mean -2.6 degrees), varying with the severity of their spatial neglect and hemianaethesia. Eight of them showed a pathological contralesional bias (mean -5.5 degrees) as compared to normals. This result indicates an asymmetric process of somatic graviceptive information due to some cerebral lesions. When patients were subjected to a transcutaneous electrical stimulation applied onto the contralesional side of the neck, body verticality was especially improved in those who showed a pathological bias in the postural vertical. This effect could thus be due to a reduced distortion in the egocentric co-ordinate system for spatial information processing.
Pérennou
D A
DA
Département de Médecine Physique et Réadaptation du C.H.U. de Nîmes, Unité de Rééducation Neurologique, Centre Médical 30240, Le Grau du Roi, France. perenn@iurc1.iurc.montp.inserm.fr
Amblard
B
B
Leblond
C
C
Pélissier
J
J
D002540:Cerebral Cortex / Q000098:blood supply / Q000502:physiology*; D002561:Cerebrovascular Disorders / Q000503:physiopathology*; D005260:Female; D018466:Gravity Sensing / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D004856:Postural Balance / Q000502:physiology*; D011187:Posture / Q000502:physiology*; D004561:Transcutaneous Electric Nerve Stimulation; D014796:Visual Perception / Q000502:physiology