[Physiologic and clinical manifestations of brain-dominance (author's transl)].

The effects of brain-dominance in psychology, electrophysiology and the axial muscles are described. 1. Left-sided vascular hemispheric brain-distrubances, with or without aphasia, reduce, compared with arteriosclerotics, without focal signs, verbal, action-and total IQ, those on the right side only the action and total IQ. When comparing right- and left-sided frontal, frontoparietal and frontotemporal vascular disturbances - with or without a aphasia-, the left-sided frontotemporal lesions had a lower action- and verbal IQ, even if there were no signs of aphasia. In children aged between 12 and 40 months we found no correlation between the degree of motor dominance and mental development. Among children with delayed speech development--and therefore also in children with subnormal development--the number of lefthander was significantly higher than with the other children. 2. One can show electromyographically that, when a muscle is voluntarily contracted, there is simultaneous contraction of the same muscle on the other side. This contralateral motorspread happens more often from the stimulation of the dominant side to the subordinated side than vice versa. Ipsilateral somato-sensory cortical response is more common when stimulating the dominant than the subordinated ulnar nerve and develops ontogenetically parellel with right- or left-handedness. 3. Stabilographic registration can show a right-sided prevalence of swing of the vertical axis of the body, which probably is related to a lower irritability of the vestibular apparatus on galvanic stimulation. With the eyes open, the right-sided deviation of the bodyaxis increases which can be explained by greater functional strength of the right visuomoto system, which itself can be shown by the higher frequency of right-sided optocinetic nystagmus.