ABSTRACT
Diagnostic criteria for dementia as established by the current version of the Diagnostic and Statistical Manual of the American Psychiatric Association require “the development of multiple cognitive deficits that include memory impairment and at least one of the following: aphasia, apraxia, agnosia, or a disturbance in executive functioning”. The executive functioning is the ability to inhibit inappropriate responses and to select key information and behaviors for action. The diagnosis of early dementia rests on the informant-based clinical judgment that cognitive changes are sufficient to interfere with everyday performance. Psychosis occurring in relatively early stages of dementia has been postulated as a diagnostic feature for “diffuse Lewy body disease” or the “Lewy body variant of Alzheimer disease (AD)” but large-scale prospective studies with clinicopathological correlation will be needed to fully determine the interrelationships among Lewy body disease, Parkinson’s disease, and AD.
