Basal ganglia damage and subcortical dementia after possible insidious Coxsackie virus encephalitis

Two patients with a chronic non-progressive illness beginning with undue sleepiness and personality change are described. Both have an atypical movement disorder, clearly distinct from Parkinson's disease. Each has an impairment of memory and learning with relative preservation of arithmetical, language and visuospatial tasks, suggesting a subcortical dementia. Both have atrophy of deep structures on their CT scans, and elevated antibodies to one of the Coxsackie viruses. It is suggested that insidious virus encephalitis (perhaps cases that would previously have been described as encephalitis lethargica) still occurs, and is among the causes of subcortical dementia.