The spectrum of MRI findings in subacute sclerosing panencephalitis with clinical and EEG correlates

Reports of magnetic resonance imaging (MRI) findings in subacute sclerosing panencephalitis (SSPE) with clinical and electroencephalography (EEG) correlation are few. To describe the MRI features of SSPE and correlate with its clinical features and EEG. Clinical, MRI and EEG data of 33 patients (male/female 19/14; age: 11.4 ± 5.3 yr) were reviewed. All patients had raised IgG anti-measles antibody (≥ 1:625) in cerebrospinal fluid. Their clinical features were myoclonus (100%), seizures (42%), visual disturbances (18%), pyramidal signs (30%), extrapyramidal symptoms (27%), and cognitive impairment (79%) and behavioral changes (21%). EEGs were universally abnormal: diffuse slowing of background activity-all; periodic complexes-27 (symmetrical): High voltage delta waves (55%) and sharp & slow wave discharges (45%). MRI findings included – normal (9%), cerebral atrophy (78%), white matter (76%) and basal ganglia (6%) changes. Restricted diffusion in periventricular/subcortical region was noted in 4/23 patients (stage 2). Magnetic resonance spectroscopy showed decreased N-acetyl aspartate peaks and elevated choline peaks in 75% and lactate peak in 25% (stage 3) of patients. Correlation of background delta activity among patients with MRI signal abnormalities and those without any signal change was noted (P=0.02). There was significant correlation between visual deficits and bilateral parieto-occipital white matter signal changes (P=0.03). There was no other EEG-MRI or clinical-MRI correlation. MRI abnormalities in SSPE are diverse and may or may not reflect underlying pathology. Visual deficits were observed in patients with parieto-occipital white matter signal change. Restricted diffusion of signal abnormalities and lactate peak in magnetic resonance spectroscopy were uncommon and it may add to better understanding.