Also called progressive multifocal leukoencephalopathy, this syndrome causes weakness, dysphagia, and aphasia. It may also lead to dementia and blindness. It typically affects patients over the age of 40, and generally those with chronic disease or immune system disorders such as lymphoma and AIDS. Death generally follows within two to six months after the onset of the syndrome, which is caused by a viral infection that inhibits the brain's ability to produce myelin.

The syndrome is named for Karl Erik Åström, neurology professor Elliot Mancall, and neuropathologist Edward Peirson Richardson Jr. Together they produced the report Progressive multifocal leukoencephalopathy: A hitherto unrecognised complication of chronic lympathic leukemia and Hodgkin's disease in 1958 for the Oxford journal Brain.

Sources:
http://kobiljak.msu.edu/cai/pathology/CNS_Infections_F/CNS_1h.html
http://chorus.rad.mcw.edu/doc/01081.html
http://www.whonamedit.com/synd.cfm/1786.html

more eponymous syndromes