ABSTRACT
The dementia that can occur in Parkinson’s disease (PD) and other movement
disorders has been characterized as a subcortical dementia (1-3). The subcortical
dementias are in contrast to the more well-known cortical dementias, the proto-
type being Alzheimer’s disease (AD). Many have debated the appropriateness of
the cortical/subcortical dichotomy in terms of the exclusivity of pathological changes to these regions. Recent research on neuropathology of these dementias
reveals less of a dichotomy and more of a continuum from relatively more cor-
tical pathology in the dementias, such as AD, to mixed cortical and subcortical
pathology in the case of Dementia with Lewy bodies (DLB), to relatively more
subcortical pathology in dementias associated with parkinsonian disorders,
such as PD. While the traditional designation of cortical and subcortical may
not accurately reflect the underlying pathology of the dementias in question,
the concepts are a useful heuristic when applied to the behavioral manifestations
of these dementias. Subcortical dementias are characterized behaviorally by
slowed mental processing speed (bradyphrenia), attentional and executive defi-
cits, mild retrieval-based memory problems, and neuropsychiatric changes,
such as apathy and depression. This contrasts with the deficits in memory and
cortical association functions, including aphasias, apraxias, and agnosias,
typical of cortical dementias.
