Performance on the ITPA following cerebral commissurotomy and hemispherectomy

Abstract

Patients with complete cerebral commissurotomy, partial cerebral commissurotomy, and right and left hemispherectomy all show subnormal and erratic mental age and scaled score profiles on the Illinois Test of Psycholinguistic Abilities. Lateralized testing of the visual channel subtests in two complete commissurotomy patients shows bilateral deficit and generally superior left hemisphere scores. Free-vision scores in these patients are often superior to either hemisphere alone. This suggests interhemispheric interaction on some tests, especially the Visual Sequential Memory, even in the absence of the neocortical commissures. Left as against right hemispherectomy, as well as early vs late right hemispherectomies, have some differential patterns and divergent longitudinal changes of ITPA profiles. But the ITPA subtests did not receive a natural hemispheric interpretation. The ITPA deficit of the disconnected and isolated left hemispheres which appear to have no dysphasia suggest that the psycholinguistic abilities assessed by the ITPA subtests may be irrelevant to mature language processing even if they are prerequisites to normal language development.