CONDITIONAL HANDEDNESS - HANDEDNESS CHANGES IN MULTIPLE PERSONALITY DISORDERED SUBJECT REFLECT SHIFT IN HEMISPHERIC DOMINANCE

This study investigates whether the host personality (Pe) and the primary alterpersonality (Pa) of a woman with multiple personality disorder are controlled by the left and right hemispheres, respectively. Results support the hypothesis. Behavioral and preference measures indicate that Pe is strongly right handed and Pa is left handed. Verbal and musical dichotic tests show significantly greater accuracy for stimuli presented to the left ear for Pa and to the right ear for Pe. It is concluded that shifts in hemisphericity involve redistribution of attentional resources and callosal suppression. "Conditional handedness" is proposed as a handedness subtype, characterizing persons who alternate personalities and consistently display alternate hand preferences linked to specific personality characteristics. © 1992.