According to the Merck Manual: "SSPE is suspected in young patients with dementia and neuromuscular irritability. EEG, CT or MRI, CSF examination, and measles serologic testing are done. EEG shows periodic complexes with high-voltage diphasic waves occurring synchronously throughout the recording. CT or MRI may show cortical atrophy or white matter lesions. CSF examination usually reveals normal pressure, cell count, and total protein content; however, CSF globulin is almost always elevated, constituting up to 20 to 60% of CSF protein. Serum and CSF contain elevated levels of measles virus antibodies. Anti-measles IgG appears to increase as the disease progresses. If test results are inconclusive, brain biopsy may be needed."
Subacute sclerosing panencephalitis
Progressive multifocal leukoencephalopathy
Hashimoto's encephalopathy
Hereditary diffuse leukoencephalopathy with spheroids
Intravascular lymphomas
HIV-associated nephropathy
Toxic leukoencephalopathy
Progressive rubella panencephalitis