Cortical Sources of Resting State EEG Rhythms are Sensitive to the Progression of Early Stage Alzheimer's Disease

Article type: Research Article

Authors: Babiloni, Claudio^{a; b; *} | Lizio, Roberta^b | Del Percio, Claudio^b | Marzano, Nicola^c | Soricelli, Andrea^{c; d} | Salvatore, Elena^e | Ferri, Raffaele^f | Cosentino, Filomena I.I.^f | Tedeschi, Gioacchino^e | Montella, Patrizia^e | Marino, Silvia^g | De Salvo, Simona^g | Rodriguez, Guido^h | Nobili, Flavio^h | Vernieri, Fabrizioⁱ | Ursini, Francescaⁱ | Mundi, Ciro^j | Richardson, Jill C.^k | Frisoni, Giovanni B^l | Rossini, Paolo M.^{b; m}

Affiliations: [a] Department of Molecular Medicine, University of Rome “Sapienza”, Rome, Italy | [b] IRCCS San Raffaele Pisana, Roma, Italy | [c] IRCCS “SDN”, Naples, Italy | [d] Department of Studies of Institutions and Territorial Systems, University of Naples Parthenope, Naples, Italy | [e] Department of Neurological Sciences, University of Naples Federico II Naples, Italy | [f] IRCCS Oasi, Troina (Enna), Italy | [g] SICILIA- IRCCS Centro Neurolesi “Bonino-Pulejo” – Messina, Italy | [h] Service of Clinical Neurophysiology (DiNOG; DipTeC), Hospital-University of Genoa S. Martino, Genoa, Italy | [i] Neurology, University “Campus Biomedico”, Rome, Italy | [j] Department of Neuroscience, United Hospitals of Foggia, Foggia, Italy | [k] GlaxoSmithKline R&D China Group, Gunnels Wood Road, Stevenage, Hertfordshire, UK | [l] IRCCS “S. Giovanni di Dio-FBF.”, Brescia, Italy | [m] Department of Geriatrics, Neuroscience and Orthopedics, Institute of Neurology Catholic University “Sacro Cuore” Rome, Italy

Correspondence: [*] Correspondence to: Prof. Claudio Babiloni, Ph.D., Department of Molecular Medicine, University of Rome “Sapienza”, P.le A. Moro 5, Rome I-00185, Italy. Tel./Fax: +39 06 49910989 0917; E-mail: claudio.babiloni@uniroma1.it.

Abstract: Cortical sources of resting state electroencephalographic (EEG) rhythms are abnormal in subjects with Alzheimer's disease (AD). Here we tested the hypothesis that these sources are also sensitive to the progression of early stage AD over the course of one year. The resting state eyes-closed EEG data were recorded in 88 mild AD patients at baseline (Mini Mental State Evaluation, MMSE I = 21.7 ± 0.2 standard error, SE) and at approximately one-year follow up (13.3 months ± 0.5 SE; MMSE II = 20 ± 0.4 SE). All patients received standard therapy with acetylcholinesterase inhibitors. EEG recordings were also performed in 35 normal elderly (Nold) subjects as controls. 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), beta 2 (20–30 Hz), and gamma (30–40 Hz). Cortical EEG sources were estimated by low-resolution brain electromagnetic tomography (LORETA). Compared to the Nold subjects, the mild AD patients were characterized by a power increase of widespread delta sources and by a power decrease of posterior alpha sources. In the mild AD patients, the follow-up EEG recordings showed increased power of widespread delta sources as well as decreased power of widespread alpha and posterior beta 1 sources. These results suggest that the resting state EEG sources were sensitive, at least at group level, to the cognitive decline occurring in the mild AD group over a one-year period, and might represent cost-effective and non-invasive markers with which to enrich cohorts of AD patients that decline faster for clinical studies.

Keywords: Alzheimer's disease, disease progression, electroencephalography, low resolution brain electromagnetic tomography (LORETA)

DOI: 10.3233/JAD-121750

Journal: Journal of Alzheimer's Disease, vol. 34, no. 4, pp. 1015-1035, 2013