PAROXYSMAL ALIEN HAND SYNDROME

Four patients are described who presented with a paroxysmal form of th e alien hand syndrome. Two patients with damage to one frontomedial co rtex had brief episodes of abnormal motor behaviour of the contralater al arm that featured groping, grasping, and apparently purposeful but perseverative movements, which both patients interpreted as alien or f oreign. The other two patients, with posterior parietal damage, report ed a paroxysmal feeling of unawareness of the location of the contrala teral arm, lack of recognition of the arm as their own, purposeless mo vements, and personification of the arm. These cases represent a new f orm of the alien hand syndrome manifested by brief, paroxysmal episode s, which may be due to ictal mechanisms.