VISUAL-PATTERN RECOGNITION MEMORY AND LEARNING-DEFICITS IN SENILE DEMENTIAS OF ALZHEIMER AND LEWY BODY TYPES

Senile dementia of Alzheimer's type (SDAT) and the recently described senile dementia of Lewy body type (SDLT) are both characterized by marked cognitive deterioration. In this study we compare and contrast neuropsychological profiles in the two disorders. The tests described include some well-known standard psychometric tests as well as pattern recognition (PR) and conditional learning paired associate (CLPA) tasks taken from the computerised Cambridge Neuropsychological Test Automated Battery. Most of the standard tests were unable to distinguish between SDAT and SDLT. The SDLT patients were more severely impaired on the computerised CLPA task, and generally took longer to respond. It is suggested that the severe mnemonic deficiencies seen in SDLT result from relatively marked neurodegeneration of temporal and possibly frontal lobe structures, and that response deficiencies could reflect involvement of motor areas.