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Cognitive impairment and EEG background activity in adults with Down's syndrome: A topographic study

Authors

  • Svetla Velikova,

    1. Department of Neurology, Clinical Neurophysiology, Neurorehabilitation, Institute of Experimental Neurology-INSPE, IRCCS University Hospital, San Raffaele, Milan 20132, Italy
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  • Giuseppe Magnani,

    1. Department of Neurology, Clinical Neurophysiology, Neurorehabilitation, Institute of Experimental Neurology-INSPE, IRCCS University Hospital, San Raffaele, Milan 20132, Italy
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  • Claudia Arcari,

    1. Department of Neurology, Clinical Neurophysiology, Neurorehabilitation, Institute of Experimental Neurology-INSPE, IRCCS University Hospital, San Raffaele, Milan 20132, Italy
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  • Monica Falautano,

    1. Department of Neurology, Clinical Neurophysiology, Neurorehabilitation, Institute of Experimental Neurology-INSPE, IRCCS University Hospital, San Raffaele, Milan 20132, Italy
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  • Massimo Franceschi,

    1. Department of Neurology, IRCCS Multimedica, Santa Maria, Castellanza (VA) 21053, Italy
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  • Giancarlo Comi,

    1. Department of Neurology, Clinical Neurophysiology, Neurorehabilitation, Institute of Experimental Neurology-INSPE, IRCCS University Hospital, San Raffaele, Milan 20132, Italy
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  • Letizia Leocani

    Corresponding author
    1. Department of Neurology, Clinical Neurophysiology, Neurorehabilitation, Institute of Experimental Neurology-INSPE, IRCCS University Hospital, San Raffaele, Milan 20132, Italy
    • Department of Clinical Neurophysiology, Hospital of San Raffaele, Via Olgettina 60, Milan 20132, Italy
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Abstract

Objective: Studies correlating electroencephalographic (EEG) data and cognitive performance in Down's syndrome (DS) showed conflicting results. The aims of this study were to investigate the sources of EEG rhythms in adults with DS at three dimensional representation of current source density (CSD) using exact/standard Low Resolution Electromagnetic Tomography (e/sLORETA), and their correlation with cognitive performance. Methods: Twenty-five adults with DS underwent a neuropsychological battery and 5 min of resting, eye-closed 29-channel EEG were recorded. After e/sLORETA analysis, data were compared with those from age and gender-matching control subjects as following: absolute and relative power in delta (1–3 Hz), theta (4–7 Hz), alpha1 (8–9 Hz), alpha2 (10–12 Hz), beta1 (13–18 Hz), beta2 (19–21 Hz), beta3 (22–30 Hz); alpha and theta bands adjusted to individual alpha peak frequency (IAF). Current source activities in DS group in regions showing significant differences compared with controls underwent correlation analysis with psychometric scores. Results: In DS, IAF was shifted to lower frequencies and correlated positively with Wechsler Adult Intelligence Scale and Mini-Mental State examination. Compared with controls, DS showed increased CSD in: theta, alpha-1, and beta1 classical bands and in IAF-adjusted bands, while relative alpha2 was decreased. A negative correlation between cognitive performance and theta/alpha CSD in the right frontal lobe and right posterior cingulate cortex was found. The relative alpha2 correlated positively with cognitive tests. Conclusions: Increased CSD in DS, correlating with cognitive performance, for both slow and fast rhythms suggests involving of cortical and subcortical mechanisms. LORETA might be useful for objective measure of cognitive decline in DS. Hum Brain Mapp, 2011. © 2010 Wiley-Liss, Inc.

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