Adult‐Onset Subacute Sclerosing Panencephalitis Presenting With Subacute Cognitive Deficits

We describe the case of a 41-year-old man diagnosed with adult-onset subacute sclerosing panencephalitis (SSPE). The patient presented with subacute progressive cognitive deficits and a neuropsychological profile indicating predominant frontoparietal dysfunction. MRI showed only mild parietal-predominant cerebral atrophy. The patient later developed periodic myoclonic jerks with time-locked periodic slow wave complexes on electroencephalography. Evidence of intrathecal synthesis of anti-measles IgG was identified in the cerebrospinal fluid. The patient satisfied modified Dyken diagnostic criteria and was diagnosed with SSPE. A frontoparietal pattern of deficits on neuropsychological assessment may be an early clue to the diagnosis of adult-onset SSPE.