This study was designed to determine if language, motor planning, and memory could be identified as discrete components of performance. One hundred and thirty-three control subjects and 141 subjects diagnosed as having senile dementia of the Alzheimer type (SDAT) were studied. The results suggest that the patterns of deficits in language, memory and praxis are highly individualized. Previous work has demonstrated the presence of apraxia in moderately and severely demented persons, and this study suggests that apraxia contributes, significantly to dysfunction in some persons with SDAT. The results of this investigation support the need for multidimensional assessment and individualized care planning for persons with SDAT.