Disturbances of the body schema in relation to language impairment and hemispheric locus of lesion.

The relationship of disturbances of the body schema to hemispheric locus of lesion and sensory aphasic disorder was assessed by giving verbal and non-verbal tests of right-left orientation, finger recognition, and autotopagnosis to patients with unilateral cerebral disease. The study was restricted to right-handed patients who were free from general mental impairment or confusion. The tests were also given to a group of control patients whose performances defined the range of normal performance in each test. A significant proportion of patients with sensory aphasic disorder performed defectively on all the tests, non-verbal as well as verbal, the relative frequency of failure in this group ranging from 10 to 67% for the different tests. There were, however, a number of patients with sensory aphasic disorder who performed adequately on most of the tests. Defective performance on the part of non-aphasic patients with lesions of either the left or the right hemisphere was quite rare in the case of 19 of the 20 tests. The exceptional test was the task of imitating lateral movements from Head's battery, on which both non-aphasic groups performed relatively poorly. The patients with lesions of the right hemisphere were significantly inferior to those with left hemisphere disease on this test. The findings are interpreted as indicating that sensory aphasic disorder is a necessary but not sufficient condition for the occurrence of some types of bilateral `body schema' disturbance in patients with unilateral disease. It is postulated that the sufficient condition is a combination of aphasic disorder with somatosensory impairment. Bilateral impairment of the `body schema' does not appear to have a differential relationship to hemispheric locus of lesion per se.