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

Reduplicative paramnesia refers more often to places than to time or to per sons. 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 1 year younger tha n 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 fle xibility. There were no visuo-spatial or autotopognosic deficits, His delus ion diminished over 2.5 years and, at the same time, learning and executive functions returned to normal, However, a retrograde amnesia of 1 year pers isted. This observation is in line with Staton et al.'s (Cortex 1982; 18: 2 3-36) hypothesis about reduplicative paramnesia being a functional disconne ction between past mnesic information and the ability to integrate it with actual experiences, Magnetic resonance imaging showed bilateral frontal con tusions more severe on the left side, a small left anterior thalamic contus ion, and a secondary atrophy of the left hippocampus and the left anterior temporal pole, The role of the left temporal paralimbic post-traumatic lesi ons in relation to reduplication of self is discussed.