SUBACUTE SCLEROSING PANENCEPHALITIS (SSPE) - EARLY DIAGNOSIS, PROGNOSTIC FACTORS AND NATURAL-HISTORY

We studied the value of long video-split electroencephalographic monit oring (VSEEG) in detecting myoclonus in early SSPE and evaluated the n atural history and outcome-affecting factors. The 32 newly diagnosed p atients had VSEEG to detect myoclonus and its correlations with EEG pe riodic complexes. Disease progression was monitored by a special 'outc ome score'; the chi-square test and multi-variable statistics analysed the outcome score in relation to different variables, such as age at onset, sex, duration of symptoms at presentation, CSF measles antibody titre, type and interval between periodic complexes (EEG discharges). Myoclonus or atonia occurred in all patients and was time-related to the EEG periodic complexes; in 32% of patients, myoclonus or atonia we re not clinically evident. The EEG periodic complexes were of 3 types: Type I (16 patients) periodic giant delta waves; Type TI(IO patients) periodic giant delta waves intermixed with rapid spikes or fast activ ity; and Type III (6 patients), long spike-wave discharges interrupted by giant delta waves. Outcome score was associated with symptoms dura tion (P < 0.01) and EEG periodic complexes (P < 0.05). Symptom duratio n was inversely related to final outcome (multi-variable analysis). Lo ng VSEEG monitoring greatly improves early diagnosis and detection of subtle atonia or segmental myoclonus. Prognostic factors were the type of EEG periodic complexes and duration of symptoms at presentation.