1-1-05. Electroencephalographic diagnosis of prion disease in Japanese CJD surveillance

The electroencephalographic finding of periodic synchronous discharges (PSDs) is a basic clue for the diagnosis of Creutzfeldt-Jacob disease (CJD). We proposed grading of PSDs. We defined grade A as typical PSDs, grade B as PSDs of relatively longer periodic intervals, grade C as PSDs of relatively rare appearance, grade D as PSDs of rudimentary appearance, and grade E as absent PSDs. The occurrence rate of PSDs in Japanese CJD surveillance was 62% in total CJD (490/794), 72% in sporadic CJD (441/610), 24% in genetic CJD (41/171), and 61% in dura CJD patients (8/13). Among 171 genetic CJD patients, the occurrence rate of PSDs was 0% in P105L mutation CJD (0/2), 3% in V180I mutation CJD (3/90), 14% in P102L mutation CJD (4/29), 70% in E200K mutation CJD (16/23), and 71% in M232R mutation CJD patients (17/24). The occurrence rate of MRI changes in both cortical and basal ganglia was significantly higher in the s-CJD group with PSDs than in the s-CJD group without PSDs. The occurrence rate of PSDs in non-CJD patients who needed differential diagnosis of CJD was 10% (37/355). Non-CJD diseases associated with PSDs were status epilepticus, diffuse Lewy disease, Hashimoto encephalopathy, Wernicke encephalopathy and uremic encephalopathy.