In the present study we introduce a sensitive video-based test for the evaluation of subtle mindreading difficulties: the Movie for the Assessment of Social Cognition (MASC). This new mindreading tool involves watching a short film and answering questions referring to the actors' mental states. A group of adults with Asperger syndrome (n = 19) and well-matched control subjects (n = 20) were administered the MASC and three other mindreading tools as part of a broader neuropsychological testing session. Compared to control subjects, Asperger individuals exhibited marked and selective difficulties in social cognition. A Receiver Operating Characteristic (ROC) analysis for the mindreading tests identified the MASC as discriminating the diagnostic groups most accurately. Issues pertaining to the multidimensionality of the social cognition construct are discussed.

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This multicenter study examined 18 F-FDG PET measures in the differential diagnosis of Alzheimer's disease (AD), frontotemporal dementia (FTD), and dementia with Lewy bodies (DLB) from normal aging and from each other and the relation of disease-specific patterns to mild cognitive impairment (MCI). Methods: We examined the 18 F-FDG PET scans of 548 subjects, including 110 healthy elderly individuals (''normals'' or NLs), 114 MCI, 199 AD, 98 FTD, and 27 DLB patients, collected at 7 participating centers. Individual PET scans were Z scored using automated voxelbased comparison with generation of disease-specific patterns of cortical and hippocampal 18 F-FDG uptake that were then applied to characterize MCI. Results: Standardized diseasespecific PET patterns were developed that correctly classified 95% AD, 92% DLB, 94% FTD, and 94% NL. MCI patients showed primarily posterior cingulate cortex and hippocampal hypometabolism (81%), whereas neocortical abnormalities varied according to neuropsychological profiles. An AD PET pattern was observed in 79% MCI with deficits in multiple cognitive domains and 31% amnesic MCI. 18 F-FDG PET heterogeneity in MCI with nonmemory deficits ranged from absent hypometabolism to FTD and DLB PET patterns. Conclusion: Standardized automated analysis of 18 F-FDG PET scans may provide an objective and sensitive support to the clinical diagnosis in early dementia.

The DemTect is short (8-10 minutes), easy to administer, and its transformed total score (maximum 18) is independent of age and education. The DemTect helps in deciding whether cognitive performance is adequate for age (13-18 points), or whether MCI (9-12 points) or dementia (8 points or below) should be suspected.