Lateralisation of speech centre in left-handedness due to cerebral and extracerebral lesions.

Abstract

This report is based on a study of a small sample of five patients who were initially right-handed and became left-handed due to loss of function in the right arm after extracerebral causes such as polio or injury. Carotid amytal tests in these patients showed that all of them still had the speech centre in the left hemisphere. As expected, lateralised neuropsychological brain function tests showed no significant differences between right and left brain. In infantile right hemiplegia due to atrophic left brain lesions, the speech centre had shifted to right side in 10 out of 15 patients. Neuropsychological tests showed sparing and protection of dominant left brain functions.