Self-duplication shifted in time: A particular form of delusional misidentification syndrome

Abstract

Reduplicative paramnesia refers more often to places than to time or to persons. We report here the case of a 16-year-old student who, after a severe brain injury, presented the delusion of a double who was I year younger than himself and with no physical impairment. This patient presented a severe memory deficit, particularly in the verbal modality, uninhibited behaviour, decreased self awareness, difficulties in planning and impaired mental flexibility. There were no visuo-spatial or autotopognosic deficits. His delusion diminished over 2.5 years and, at the same time, learning and executive functions returned to normal. However, a retrograde amnesia of 1 year persisted. This observation is in line with Staton et al.'s(Cortex 1982; 18: 23-36) hypothesis about reduplicative paramnesia being a functional disconnection between past mnesic information and the ability to integrate it with actual experiences. Magnetic resonance imaging showed bilateral frontal contusions more severe on the left side, a small left anterior thalamic contusion, and a secondary atrophy of the left hippocampus and the left anterior temporal pole. The role of the left temporal paralimbic posttraumatic lesions in relation to reduplication of self is discussed.

Key Words:

• delusional misidentification syndrome
• paramnesia
• Capgras syndrome
• brain injury