Resting State Cortical Electroencephalographic Rhythms in Covert Hepatic Encephalopathy and Alzheimer's Disease

Article type: Research Article

Authors: Babiloni, Claudio^{a; b; *} | Vecchio, Fabrizio^c | Del Percio, Claudio^b | Montagnese, Sara^d | Schiff, Sami^d | Lizio, Roberta^b | Chini, Giorgia^e | Serviddio, Gaetano^f | Marzano, Nicola^g | Soricelli, Andrea^{g; h} | Frisoni, Giovanni B.ⁱ | Rossini, Paolo M.^{b; j} | Amodio, Piero^e

Affiliations: [a] Department of Molecular Medicine, University of Rome Sapienza, Rome, Italy | [b] IRCCS San Raffaele Pisana, Rome, Italy | [c] AFa.R., Dip. Neurosci. Osp. FBF, Isola Tiberina, Rome, Italy | [d] Clinical and Experimental Medicine, University of Padova, Padova, Italy | [e] Department of Informatics and Systemistics, University of Rome Sapienza, Rome, Italy | [f] Department of Medical and Occupational Sciences, University of Foggia, Foggia, Italy | [g] IRCCS “SDN”, Naples, Italy | [h] Università degli Studi di Napoli Parthenope, Napoli, Italy | [i] IRCCS “S. Giovanni di Dio-F.B.F.”, Brescia, Italy | [j] Departments of Geriatrics, Neurosciences & Orthopedics, Catholic University “Sacro Cuore”, Rome, Italy

Correspondence: [*] Correspondence to: Claudio Babiloni, Ph.D., Department of Molecular Medicine, University of Rome “Sapienza”, Rome, Piazzale Aldo Moro, 5, Roma I-00185, Italy. Tel.: +39 06 49910989; Fax: +39 06 49910917; E-mail: claudio.babiloni@uniroma1.it.

Abstract: Patients suffering from prodromal (i.e., amnestic mild cognitive impairment, aMCI) and overt Alzheimer's disease (AD) show abnormal cortical sources of resting state electroencephalographic (EEG) rhythms. Here we tested the hypothesis that these sources show extensive abnormalities in liver cirrhosis (LC) patients with a cognitive impairment due to covert and diffuse hepatic encephalopathy (CHE). EEG activity was recorded in 64 LC (including 21 CHE), 21 aMCI, 21 AD, and 21 cognitively intact (Nold) subjects. EEG rhythms of interest were delta (2–4 Hz), theta (4–8 Hz), alpha 1 (8–10.5 Hz), alpha 2 (10.5–13 Hz), beta 1 (13–20 Hz), and beta 2 (20–30 Hz). EEG cortical sources were estimated by LORETA. Widespread sources of theta (all but frontal), alpha 1 (all but occipital), and alpha 2 (parietal, temporal) rhythms were higher in amplitude in all LC patients than in the Nold subjects. In these LC patients, the activity of central, parietal, and temporal theta sources correlated negatively, and parietal and temporal alpha 2 sources correlated positively with an index of global cognitive status. Finally, widespread theta (all but frontal) and alpha 1 (all but occipital) sources showed higher activity in the sub-group of LC patients with CHE than in the patients with aMCI or AD. These results unveiled the larger spatial-frequency abnormalities of the resting state EEG sources in the CHE compared to the AD condition.

Keywords: Alzheimer's disease, covert hepatic encephalopathy, electroencephalography, hepatic encephalopathy, liver cirrhosis, low resolution brain electromagnetic tomography, mild cognitive impairment, minimal hepatic encephalopathy

DOI: 10.3233/JAD-121807

Journal: Journal of Alzheimer's Disease, vol. 34, no. 3, pp. 707-725, 2013