Summary:To resolve the controversy about whether there are two fundamental categories of dementia, we selected the presence or absence of motoric disturbance in dementia patients as an external criterion reflecting putative subcortical and cortical pathology. Dementia patients with motoric disturbance (DEM M+ group) and dementia patients without motoric disturbance (DEM M− group) matched on global dementia severity, age, and education were compared on operational measures of bradyphrenia, naming disturbance, and amnesia. The data revealed that (a) patients with dementia and movement disorder were more bradyphrenic, (b) bradyphrenia was not accounted for by severity of primary motor disturbance, (c) naming disturbance was equally frequent and severe but qualitatively different, and (d) no differences were found in either the frequency and severity of memory disorder in free or cued recall. These preliminary data provide tentative support to the idea of two fundamental classes of dementia.