Visual and tactile size distortion in a patient with right neglect.
One typical feature of the neglect syndrome in patients with right hemisphere damage is that they bisect horizontal lines to the right of centre. It has been argued that to a large extent these bisection errors can be attributed to a perceptual change whereby the patient experiences the left half of a line as shorter than the right half, causing them to set the midpoint of the line towards the right. We describe here a patient with a left hemisphere lesion and rightward neglect, who consequently makes bisection errors in a leftward direction. We carried out a series of tests which confirmed that he shows a subjective visual distortion in the converse direction, i.e. a perception of horizontal extents on the right as shorter than extents on the left. We also found that he shows a similar distortion in his tactile perception. The association of visual and tactile distortions in this patient is compatible with the view that the distortion effects have a rather high-level origin. Multiple single-case studies will, however, be required to establish whether this association of deficits is typical, or whether visual and tactile size distortions are separable symptoms associated with neglect.
Pritchard
C L
CL
School of Psychology, University of St Andrews, St Andrews, UK.
Dijkerman
H C
HC
McIntosh
R D
RD
Milner
A D
AD
D001288:Attention / Q000502:physiology; D001931:Brain Mapping; D004292:Dominance, Cerebral / Q000502:physiology*; D005625:Frontal Lobe / Q000503:physiopathology; D006801:Humans; D020244:Infarction, Middle Cerebral Artery / Q000175:diagnosis / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D009949:Orientation / Q000502:physiology; D010296:Parietal Lobe / Q000503:physiopathology; D010364:Pattern Recognition, Visual / Q000502:physiology*; D010468:Perceptual Disorders / Q000175:diagnosis / Q000503:physiopathology*; D010469:Perceptual Distortion / Q000502:physiology*; D011597:Psychomotor Performance / Q000502:physiology; D012858:Size Perception / Q000502:physiology*; D014110:Touch / Q000502:physiology*