Focal brain lesions and intelligence: a study with a new version of Raven's Colored Matrices

Abstract

Contrasting results have been obtained in previous investigations, which have used the standard version of Raven's Colored Progressive Matrices for studying the effects of localized brain lesion on visual-spatial intelligence. Some of these discrepancies might be due to the fact that specific factors, such as unilateral spatial neglect, could contribute to decreased performance obtained on Raven's test by patients with focal brain lesions. A new set of Colored Matrices, devised to minimize the influence of unilateral spatial neglect without changing the essential features of the original task, was therefore constructed. The test was administered to 76 normal controls, 74 right brain-damaged patients, 87 aphasics, and 61 nonaphasic left brain-damaged patients, in order to study the effect of laterality of lesions and of language impairment on Raven's scores. The results show that, if the influence of unilateral spatial neglect is minimized and Raven's scores are corrected in reference to age, educational level, and lesion size, then: no significant differences are observed between right and left brain-damaged patients; aphasics score worse than nonaphasic left brain-damaged patients; impairment is greater in patients with Wernicke's and Global aphasia (i.e., in patients with severe language comprehension disorders) than in patients classified as Broca's, Anomic, or Conduction aphasia; impairment is greater in patients with semantic-lexical discrimination errors than in patients free from semantic-lexical comprehension disorders.