Correlation between Clinical Stages and EEG Findings of Subacute Sclerosing Panencephalitis

Abstract

In this retrospective study 67 patients with SSPE seen between the years 1980 and 1998 were reviewed. Using the criteria of SSPE diagnosis (clinical signs, characteristic EEG patterns, high titres of measles antibodies in the serum and CSF), the patients were divided into two groups. Group A fulfilled all criteria, however, due to the inability of measuring measles antibody before 1987, it was not possible to observe the third criterion in Group B. Among 67 patients, groups A and B consisted of 51 boys and 16 girls ranging in age between 1 to 23 years, mean age 13.1. The male/female ratio was 3.1. The periodic EEG complexes (PCs) were usually bilateral, synchronous and symmetrical. PC amplitude asymmetry was seen in 12 patients and 2 patients had no PC synchronization between the hemispheres. Six patients had more than one form of PC. Delta activity in anterior hemispheres after PC was seen in 40 patients, mostly in stage 2A. Thirty-two patients had focal epileptiform abnormalities in multiple locations at every stage but most frequently in frontal, central and temporal regions. One patient had PC over both hemispheres and periodic lateralized epileptiform discharges (PLEDs) over the right hemisphere. The EEG findings described and observed in our study do not seem to be specific to SSPE but these findings were not atypical or unusual.

Subacute sclerosing panencephalitis: clinical phenotype, epidemiology, and preventive interventions

“…32 Injection of diazepam during the EEG study increases the sensitivity of detecting the periodic complexes. 32 Injection of diazepam during the EEG study increases the sensitivity of detecting the periodic complexes.…”

“…Ancillary investigations include electroencephalography (EEG) and magnetic resonance imaging (MRI). 31,32 Neither of these tests is specific or sensitive to the diagnosis of SSPE and may correlate poorly with the clinical stage of the disease. Dyken's modified criteria, often the diagnostic tool used in medical reports, includes clinical history, elevated CSF measles antibody titres as major markers, typical EEG, increased CSF immunoglobulin G (IgG), brain biopsy, and special molecular diagnostic tests to identify measles virus mutated genome as minor markers.…”

“…28 The background activity becomes abnormal and has low amplitude as the disease stages increase. 32 Injection of diazepam during the EEG study increases the sensitivity of detecting the periodic complexes. 37 The study by Demir et al 36 comprehensively reports on the EEG evolution in SSPE, the diversity of potential EEG findings, and the overlap in features with epilepsy syndromes such as Lennox-Gastaut syndrome, electrical status epilepticus during slow-wave sleep, and epileptic spasms.…”

“…The clinical manifestations of stage 1-4 subacute sclerosing panencephalitis52 and electroencephalography correlate32 …”

Adult onset subacute sclerosing panencephalitis - Lessons learnt from an atypical presentation

“…In a study from Turkey of 67 patients of SSPE, only one had both periodic complexes over both hemispheres and PLEDS over right hemisphere. [7] Vast nontypical features have thus been reported in literature available on adult onset SSPE. Other potential mimickers are hereditary disorders such as cerebral autosomal dominant arteriopathy with sub cortical infarcts and leucoencephalopathy (CADASIL), mitochondrial encephalopathy, lactic acidosis, stroke-like episodes (MELAS), or Fabry's disease.…”