Unraveling delusional misidentification: A neuropsychological and experimental exploration of a new case of reduplication syndrome

Objective: Delusional syndromes of misidentification and/or reduplication (DSMRs) are based on the misidentification or duplication of people, places, objects, or events. A qualitative and comprehensive investigation was conducted to shed light on the core neurological and neuropsychological features and, neural correlates of all DSMRs, particularly Reduplicative Paramnesia for Place (RPP). Method: A detailed and systematic approach based on clinical, experimental, and neuroimaging data was carried out in a single case. We investigated the role played by the co-presence of an alteration of the sense of familiarity and damage to the critical belief evaluation system as a necessary condition for the generation of all DSMRs, and in particular for RPP. Results: Unlike most of previously described cases, RPP syndrome persists during the chronic phase in the context of a well-preserved global cognitive status whereas other forms of DSMRs tend to recover over time. In addition, there is a persistent alteration in the sense of familiarity and absence of critical evaluation of delusional beliefs. A structural disconnection analysis relates cortical-subcortical damaged areas and the corresponding white matter fasciculi with the clinical manifestation of DSMRs syndromes. Conclusions: The striato-capsular stroke coupled with subcortical damages and bifrontal cortical atrophy may explain the clinical manifestations and experimental data obtained and are in agreement with the bicomponential model hypothesis highlighting the role played by altered sense of familiarity in generating all DSMRs.