1 Data of Medical historyrn The patient,a male of 67 years,was admitted because of “ imobilization in the right limbs and aphasis” .His past history included 5 years of hypertension,large area cerebral infarction in left frontal,temporal,capular corteces confirmed by CT after admission,discharge when turning better after expectant treatment.Left mobilization of the right limbs,1 month later,the patient had a general tetany,unconsiousness,cyanosis of lips for 1min.Then these manifestations relieved and the consciousness became clear but polydipsia apperared and could not be tolerated.The patient began to drink water at once.More than 1 500 ml of water was drank and large amount of urine was passed then.The polydipsia persisted 10 minutes each time,then recovered completely.The symptoms recurred once every 2～3 days or 2～3 times a day.Specific gravity of urine was between 1.001～1.005 on attack.No new locus was found in CT reexamination.EEG showedθwave or accidentalδwaves at frontal,temporal,copular areas,and fulminant δ waves on hyperventilation.The patient turned normal after the attacks.Specific gravity of urine was 1.010.None of the above mentioned symptoms occurred after antiepileptic treatment of sodium propovalerate. rn