Subcortical dementia.
BACKGROUND: Drawing a distinction between cortical and subcortical dementias seems both useful and justified. Recent research has, however, cast doubt on the clinical, neuropsychological, neuroimaging and neuroanatomical basis of the distinction. AIMS: To arrive at a reasoned conclusion about the relationship between the two types of dementia and the validity of distinguishing between them. METHOD: The historical and recent clinical and scientific literature on subcortical dementia was reviewed. RESULTS: The traditional claim that subcortical dementia has distinct clinical manifestations, neuroimaging findings and a neuropathological profile is not altogether borne out by the literature. Some studies show that frontal executive dysfunction and the profile of memory deficits are not significantly different from those seen in Alzheimer's disease. Neuropathological findings also overlap. CONCLUSIONS: The category of subcortical dementia may be clinically useful in highlighting the likelihood that an individual with dementia is more likely to suffer from bradyphrenia and motor difficulties. As neuroscience advances a preoccupation with the distinction may hinder the assessment and treatment of individual cases.