title: A study of plane bisection in four cases of visual neglect.
abstract: We report four case studies of bisection performance in patients with severe left neglect consequent upon right hemisphere lesion. The stimuli to be bisected range from a horizontal line through horizontally oriented rectangles to a square; the stimuli are displayed on a VDU and bisections made by moving a 'mouse' that controls a cursor line on the screen. For one of the patients, both the starting position of the cursor (left or right) and the shape of the stimulus have a major effect upon bisection accuracy. One patient shows an effect of starting position but not stimulus geometry; two patients show an effect of stimulus geometry but not starting position. For 3 out of 4 patients, the estimated midpoint of a line is thus not equivalent to that of a plane with the same horizontal extent. A putative 'attentional' interpretation of the results is provided.
authors.affiliation: University Department of Clinical Neurology, Radcliffe Infirmary, Oxford.
authors.forename: J C
authors.initials: JC
authors.lastname: Marshall
authors.forename: P W
authors.initials: PW
authors.lastname: Halligan
mesh_terms: D001925:Brain Damage, Chronic / Q000175:diagnosis / Q000503:physiopathology / Q000523:psychology*; D002540:Cerebral Cortex / Q000503:physiopathology; D002561:Cerebrovascular Disorders / Q000175:diagnosis / Q000503:physiopathology / Q000523:psychology; D004292:Dominance, Cerebral / Q000502:physiology*; D005260:Female; D006423:Hemianopsia / Q000175:diagnosis / Q000503:physiopathology / Q000523:psychology; D006429:Hemiplegia / Q000175:diagnosis / Q000503:physiopathology / Q000523:psychology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D009949:Orientation / Q000502:physiology*; D011597:Psychomotor Performance / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology*