title: Attention and Working Memory-Related EEG Markers of Subtle Cognitive Deterioration in Healthy Elderly Individuals.
abstract: Future treatments of Alzheimer's disease need the identification of cases at high risk at the preclinical stage of the disease before the development of irreversible structural damage. We investigated here whether subtle cognitive deterioration in a population of healthy elderly individuals could be predicted by EEG signals at baseline under cognitive activation. Continuous EEG was recorded in 97 elderly control subjects and 45 age-matched mild cognitive impairment (MCI) cases during a simple attentional and a 2-back working memory task. Upon 18-month neuropsychological follow-up, the final sample included 55 stable (sCON) and 42 deteriorated (dCON) controls. We examined the P1, N1, P3, and PNwm event-related components as well as the oscillatory activities in the theta (4-7 Hz), alpha (8-13 Hz), and beta (14-25 Hz) frequency ranges (ERD/ERS: event-related desynchronization/synchronization, and ITC: inter-trial coherence). Behavioral performance, P1, and N1 components were comparable in all groups. The P3, PNwm, and all oscillatory activity indices were altered in MCI cases compared to controls. Only three EEG indices distinguished the two control groups: alpha and beta ERD (dCON >  sCON) and beta ITC (dCON <  sCON). These findings show that subtle cognitive deterioration has no impact on EEG indices associated with perception, discrimination, and working memory processes but mostly affects attention, resulting in an enhanced recruitment of attentional resources. In addition, cognitive decline alters neural firing synchronization at high frequencies (14-25 Hz) at early stages, and possibly affects lower frequencies (4-13 Hz) only at more severe stages.
authors.affiliation: INSERM U1039, Faculty of Medicine, La Tronche, France.|Biomarkers of Vulnerability Unit, Department of Mental Health and Psychiatry, University Hospitals of Geneva, Geneva, Switzerland.
authors.forename: Marie-Pierre
authors.initials: MP
authors.lastname: Deiber
authors.affiliation: Biomarkers of Vulnerability Unit, Department of Mental Health and Psychiatry, University Hospitals of Geneva, Geneva, Switzerland.
authors.forename: Hadj Boumediene
authors.initials: HB
authors.lastname: Meziane
authors.affiliation: Biomarkers of Vulnerability Unit, Department of Mental Health and Psychiatry, University Hospitals of Geneva, Geneva, Switzerland.
authors.forename: Roland
authors.initials: R
authors.lastname: Hasler
authors.affiliation: Division of General Psychiatry, Department of Mental Health and Psychiatry, University Hospitals of Geneva, Geneva, Switzerland.
authors.forename: Cristelle
authors.initials: C
authors.lastname: Rodriguez
authors.affiliation: Division of General Psychiatry, Department of Mental Health and Psychiatry, University Hospitals of Geneva, Geneva, Switzerland.
authors.forename: Simona
authors.initials: S
authors.lastname: Toma
authors.affiliation: Division of General Psychiatry, Department of Mental Health and Psychiatry, University Hospitals of Geneva, Geneva, Switzerland.
authors.forename: Marine
authors.initials: M
authors.lastname: Ackermann
authors.affiliation: Division of Geriatrics, Department of Internal Medicine, Rehabilitation and Geriatrics, University Hospitals of Geneva, Geneva, Switzerland.
authors.forename: François
authors.initials: F
authors.lastname: Herrmann
authors.affiliation: Division of General Psychiatry, Department of Mental Health and Psychiatry, University Hospitals of Geneva, Geneva, Switzerland.
authors.forename: Panteleimon
authors.initials: P
authors.lastname: Giannakopoulos
mesh_terms: D000368:Aged; D000375:Aging / Q000502:physiology* / Q000523:psychology*; D000513:Alpha Rhythm / Q000502:physiology; D001288:Attention / Q000502:physiology*; D001611:Beta Rhythm / Q000502:physiology; D001921:Brain / Q000503:physiopathology*; D003071:Cognition / Q000502:physiology; D060825:Cognitive Dysfunction / Q000175:diagnosis / Q000503:physiopathology; D003344:Cortical Synchronization / Q000502:physiology; D004569:Electroencephalography / Q000379:methods; D005071:Evoked Potentials; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008570:Memory, Short-Term / Q000502:physiology*; D009483:Neuropsychological Tests; D013826:Theta Rhythm / Q000502:physiology
keywords: Alzheimer’s disease; EEG; EEG phase synchronization; attention; brain waves; cognitive decline; working memory