Hyperfamiliarity in Dementia and Mild Cognitive Impairment.

INTRODUCTION Hyperfamiliarity, a phenomenon in which feelings of familiarity are evoked by novel stimuli, is well described in epilepsy and the lesioned brain. Abnormality of familiarity in Alzheimer's disease (AD) and mild cognitive impairment (MCI) have also been described in the literature, but more from a neuropsychological approach perspective. Currently, there is a lack of study on the real-life experience of familiarity abnormality in dementia and MCI. Our aim was to compare the occurrence of hyperfamiliarity among dementia and MCI. MATERIALS AND METHODS We recruited 73 participants, 29 with AD, 10 with vascular dementia, 7 with MCI and 27 healthy controls, and administered a questionnaire to assess hyperfamiliarity frequency. RESULTS Hyperfamiliarity was observed in real-life in cognitive impairment, but was unrelated to its severity or underlying aetiology. CONCLUSION This study highlights the similar rate of occurrence of hyperfamiliarity in the daily life of individuals with cognitive impairment. Future research should examine neuropsychological correlations and mechanisms that contribute to such observations.