Temporal gradient in confabulation.

Abstract

We report on a patient, PL, who developed an amnesic confabulatory syndrome following heart arrest. PL's confabulation occurred both in episodic and semantic memory tasks. In a task in which she was asked to identify photographs of people and events highly familiar to her, a temporal gradient on her performance emerged. Confabulation was massive for the recognition of photographs from the eighties and decreased consistently for the recognition of photographs representing people and events from earlier decades. Correct responses, in contrast, were distributed according to an opposite pattern. Correct recognition was very high for photographs from the fifties but consistently decreased for photographs from the following decades. These results are discussed in terms of the co-occurrence and interaction of preserved awareness of the personal past and impaired ability to access less stable memories. These results also suggest that memories are not stored randomly but according to a temporal criterion that presumably reflects the relative strength and stability of stored episodic memories.