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.