title: Mild cognitive impairment: same identity for different entities.
abstract: This study investigates whether different patterns of grey matter (GM) loss may account for the different neuropsychological profiles observed in patients with amnestic (a-) and non-amnestic (na-) mild cognitive impairment (MCI), and may predict patients' clinical evolution. Fifty-five consecutive individuals complaining of cognitive dysfunction (referred to specialist dementia clinics) were screened and included in the study if they met the diagnostic criteria for MCI on a neurodegenerative basis. After an extensive neuropsychological assessment, patients were classified as suffering from a-MCI or na-MCI. Twenty-eight healthy individuals were also recruited and served as controls. All participants underwent magnetic resonance imaging at 3T, including conventional images and volumetric scans. Volumetric data were processed using voxel-based morphometry to assess between-group differences in regional GM volumes and correlations with neuropsychological performances. When compared to controls, a-MCI patients showed prominent GM volume reductions in the medial temporal lobes, while those with na-MCI showed reduced GM volumes in the orbito-frontal cortex and basal ganglia. In a-MCI patients, significant associations were found between verbal long-term memory performance and GM volumes in the hippocampus. Conversely, in na-MCI patients, associations were found between scores at tests exploring executive functions and GM volumes in the orbito-frontal cortex. At one-year follow-up, conversions were recorded exclusively toward Alzheimer's disease (AD) in the a-MCI group, and toward non-AD dementia in the na-MCI group. This study confirms that MCI is a heterogeneous clinical identity including different neurodegenerative entities; specific patterns of regional GM loss appear to account for specific neuropsychological features and are likely to predict patients' clinical evolution.
authors.affiliation: Neuroimaging Laboratory, Santa Lucia Foundation, IRCCS, Rome, Italy.
authors.forename: Laura
authors.initials: L
authors.lastname: Serra
authors.forename: Giovanni
authors.initials: G
authors.lastname: Giulietti
authors.forename: Mara
authors.initials: M
authors.lastname: Cercignani
authors.forename: Barbara
authors.initials: B
authors.lastname: Spanò
authors.forename: Mario
authors.initials: M
authors.lastname: Torso
authors.forename: Diana
authors.initials: D
authors.lastname: Castelli
authors.forename: Roberta
authors.initials: R
authors.lastname: Perri
authors.forename: Lucia
authors.initials: L
authors.lastname: Fadda
authors.forename: Camillo
authors.initials: C
authors.lastname: Marra
authors.forename: Carlo
authors.initials: C
authors.lastname: Caltagirone
authors.forename: Marco
authors.initials: M
authors.lastname: Bozzali
mesh_terms: D000368:Aged; D060825:Cognitive Dysfunction / Q000145:classification* / Q000175:diagnosis* / Q000523:psychology; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D019636:Neurodegenerative Diseases / Q000145:classification / Q000175:diagnosis / Q000523:psychology; D009483:Neuropsychological Tests