title: The Fall of Sleep K-Complex in Alzheimer Disease.
abstract: Although a slowing of electroencephalographic (EEG) activity during wakefulness and -to some extent- sleep of Alzheimer disease (AD) patients (i.e., increased slow-frequency activity) was documented, recent findings in healthy elderly show a decreased 0.6-1 Hz slow wave activity (SWA) during NREM, which was associated to β-amyloid deposition and impaired hippocampal memory consolidation. We hypothesize that the apparent contradiction may be explained by the partial overlap between 0.6-1 Hz EEG activity and K-Complex (KC). According to this view, we studied both frontal KCs and SWA in 20 AD patients and 20 healthy age-matched controls (HC) during nightly sleep, under the hypothesis that KCs better discriminate patients from healthy elderly than ≤1 Hz SWA. A drastic decrease of KC density during stage 2 NREM was found in AD compared to HC. Patients show more than 40% reduction of the KC density, allowing a correct classification of 80%. On the other hand, ≤1 Hz SWA of AD patients is slightly (not significantly) higher in most cortical areas compared to HC. Although no significant changes of ≤1 Hz SWA are detectable over frontal areas in AD, KC density decreases over the same location, and its decrease is related to the cognitive decline.
authors.affiliation: Department of Psychology, "Sapienza" University of Rome, Rome, Italy.
authors.forename: Luigi
authors.initials: L
authors.lastname: De Gennaro
authors.affiliation: Department of Psychology, "Sapienza" University of Rome, Rome, Italy.
authors.forename: Maurizio
authors.initials: M
authors.lastname: Gorgoni
authors.affiliation: Department of Psychology, "Sapienza" University of Rome, Rome, Italy.
authors.forename: Flaminia
authors.initials: F
authors.lastname: Reda
authors.affiliation: Department of Psychology, "Sapienza" University of Rome, Rome, Italy.
authors.forename: Giulia
authors.initials: G
authors.lastname: Lauri
authors.affiliation: Department of Psychology, "Sapienza" University of Rome, Rome, Italy.
authors.forename: Ilaria
authors.initials: I
authors.lastname: Truglia
authors.affiliation: Department of Psychology, "Sapienza" University of Rome, Rome, Italy.
authors.forename: Susanna
authors.initials: S
authors.lastname: Cordone
authors.affiliation: Department of Psychology, "Sapienza" University of Rome, Rome, Italy.
authors.forename: Serena
authors.initials: S
authors.lastname: Scarpelli
authors.affiliation: Department of Psychology, "Sapienza" University of Rome, Rome, Italy.
authors.forename: Anastasia
authors.initials: A
authors.lastname: Mangiaruga
authors.affiliation: Department of Psychology, "Sapienza" University of Rome, Rome, Italy.
authors.forename: Aurora
authors.initials: A
authors.lastname: D'atri
authors.affiliation: Institute of Neurology, Catholic University of The Sacred Heart, Rome, Italy.
authors.forename: Giordano
authors.initials: G
authors.lastname: Lacidogna
authors.affiliation: Department of Biotechnological and Applied Clinical Science, University of L'Aquila, L'Aquila, Italy.
authors.forename: Michele
authors.initials: M
authors.lastname: Ferrara
authors.affiliation: Institute of Neurology, Catholic University of The Sacred Heart, Rome, Italy.
authors.forename: Camillo
authors.initials: C
authors.lastname: Marra
authors.affiliation: Institute of Neurology, Catholic University of The Sacred Heart, Rome, Italy.|IRCCS San Raffaele Pisana, Rome, Italy.
authors.forename: Paolo Maria
authors.initials: PM
authors.lastname: Rossini
mesh_terms: D000368:Aged; D000544:Alzheimer Disease / Q000503:physiopathology*; D058256:Brain Waves; D005260:Female; D005625:Frontal Lobe / Q000503:physiopathology*; D006801:Humans; D008297:Male; D012894:Sleep Stages