Confabulation, executive functions, and source memory in Alzheimer's disease

Most current views consider confabulation strictly related to the dysfuncti on of frontally based processes subserving the control of retrieval from lo ng-term memory. This study addresses the relationship between confabulation , source memory, and executive functions in 17 Alzheimer disease (AD) patie nts and 18 normal controls. The following tasks were used: Six tasks tappin g executive functions; a task in which subjects had to discriminate the ori gin of a given information, i.e. visual perception or imagination; a modifi ed version of the Confabulation Battery (Dalla Barba, 1993a) tapping episod ic memory, general semantic memory and personal plans; and a modified versi on of the Crovitz test, in which, in response to a cue word, subjects had t o produce a personal memory, a general semantic memory, or a personal plan. AD patients were clearly impaired on tests of executive functions, and show ed poor monitoring abilities for the source of information. AD patients con fabulated when they were required to retrieve a personal episode and also, although less frequently, when they were required to make a personal plan. Correlation studies showed that AD patients' confabulation did not correlat e with their performance on executive tasks or with their ability to discri minate the origin of information. It is suggested that confabulation reflec ts a pathological awareness of personal temporality.