Explicit memory and repetition priming in dementia: evidence for a common basic mechanism underlying conscious and unconscious retrieval deficits.
The present study was designed to assess performance of Alzheimer's (AD) and Multi-infarct (MID) demented patients on the explicit and implicit versions of two memory tasks, namely Word-Stem Completion and Word-Pair Learning. Consistently with previous studies, the AD patients were deficient on the explicit and implicit versions of both tasks. In MID patients, a dissociation emerged between normal implicit and deficient explicit Word-Stem Completion. Two multiple regression analyses were performed to evaluate patients' ability on measures of lexical-semantic competence, explicit memory, and global intellective efficiency in predicting level of repetition priming. The results demonstrate a close association between explicit and implicit memory performance in AD patients but no relation between repetition priming level and measures of lexical-semantic competence or general intelligence. Overall, the results of the present study do not support previous conceptualizations suggesting that a breakdown in the structure of semantic memory is at the root of deficient priming in demented patients. Alternative interpretations of the deficient repetition priming effect in dementia, based on a common mechanism underlying conscious and unconscious retrieval deficits, are discussed.
Carlesimo
G A
GA
Neurological Clinic, University of Rome Tor Vergata, Italy.
Fadda
L
L
Marfia
G A
GA
Caltagirone
C
C
D000368:Aged; D000544:Alzheimer Disease / Q000175:diagnosis* / Q000523:psychology; D015161:Dementia, Multi-Infarct / Q000175:diagnosis / Q000523:psychology; D005260:Female; D006801:Humans; D007361:Intelligence Tests; D008297:Male; D008569:Memory Disorders / Q000175:diagnosis* / Q000523:psychology; D011939:Mental Recall; D008875:Middle Aged; D011581:Psychological Tests / Q000706:statistics & numerical data; D012044:Regression Analysis; D012660:Semantics; D013647:Task Performance and Analysis; D014473:Unconscious, Psychology