DISORDERS OF VISUAL PERCEPTION IN PATIENTS WITH LOCALISED CEREBRAL LESIONS

A consecutive series of 65 patients with unilateral cortical lesions was given 3 tests of visual recognition and one of immediate visual retention, together with the W.A.I.S. [Wechsler Adult Intelligence Scale]. The right parietal group showed a deficit on all tests of visual perception. Test stimuli, which were both verbal and familiar, were graded in difficulty on a perceptual dimension, and discriminated between right and left hemisphere lesions. Evidence for some degree of differentiation of function within the right hemisphere is presented. The test of visual retention was associated with constructional impairment in the right hemisphere group, but not in the left hemisphere group. The relationship between perceptual disorders following right hemisphere lesions and visual object agnosia is discussed.