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Vecchio F.,AFaR | Tombini M.,Biomedical University of Rome | Buffo P.,University of Rome La Sapienza | Assenza G.,Biomedical University of Rome | And 4 more authors.
International Journal of Psychophysiology | Year: 2012

It has been reported that GSM electromagnetic fields (GSM-EMFs) of mobile phones modulate - after a prolonged exposure - inter-hemispheric synchronization of temporal and frontal resting electroencephalographic (EEG) rhythms in normal young and elderly subjects (Vecchio et al., 2007, 2010). Here we tested the hypothesis that this can be even more evident in epileptic patients, who typically suffer from abnormal mechanisms governing synchronization of rhythmic firing of cortical neurons. Eyes-closed resting EEG data were recorded in ten patients affected by focal epilepsy in real and sham exposure conditions. These data were compared with those obtained from 15 age-matched normal subjects of the previous reference studies. The GSM device was turned on (45. min) in the "GSM" condition and was turned off (45. min) in the other condition ("sham"). The mobile phone was always positioned on the left side in both patients and control subjects. Spectral coherence evaluated the inter-hemispheric synchronization of EEG rhythms at the following frequency bands: delta (about 2-4. Hz), theta (about 4-6. Hz), alpha1 (about 6-8. Hz), alpha2 (about 8-10. Hz), and alpha3 (about 10-12. Hz). The effects on the patients were investigated comparing the inter-hemispheric EEG coherence in the epileptic patients with the control group of subjects evaluated in the previous reference studies. Compared with the control subjects, epileptic patients showed a statistically significant higher inter-hemispheric coherence of temporal and frontal alpha rhythms (about 8-12. Hz) in the GSM than "Sham" condition. These results suggest that GSM-EMFs of mobile phone may affect inter-hemispheric synchronization of the dominant (alpha) EEG rhythms in epileptic patients. If confirmed by future studies on a larger group of epilepsy patients, the modulation of the inter-hemispheric alpha coherence due to the GSM-EMFs could have clinical implications and be related to changes in cognitive-motor function. © 2012 Elsevier B.V..

Tombini M.,Biomedical University of Rome | Pellegrino G.,Biomedical University of Rome | Pasqualetti P.,AFaR | Assenza G.,Biomedical University of Rome | And 3 more authors.
Brain Stimulation | Year: 2013

Background: Electromagnetic fields (EMFs) emitted by mobile phones had been shown to increase cortical excitability in healthy subjects following 45 min of continuous exposure on the ipsilateral hemisphere. Objective: Using Transcranial Magnetic Stimulation (TMS), the current study assessed the effects of acute exposure to mobile phone EMFs on the cortical excitability in patients with focal epilepsy. Methods: Ten patients with cryptogenic focal epilepsy originating outside the primary motor area (M1) were studied. Paired-pulse TMS were applied to the M1 of both the hemisphere ipsilateral (IH) and contralateral (CH) to the epileptic focus before and immediately after real/sham exposure to the GSM-EMFs (45 min). The TMS study was carried out in all subjects in three different experimental sessions (IH and CH exposure, sham), 1 week apart, according to a crossover, double-blind and counter-balanced paradigm. Results: The present study clearly demonstrated that an acute and relatively prolonged exposure to GSM-EMFs modulates cortical excitability in patients affected by focal epilepsy; however, in contrast to healthy subjects, these effects were evident only after EMFs exposure over the hemisphere contralateral to the epileptic focus (CH). They were characterized by a significant cortical excitability increase in the exposed hemisphere paired with slight excitability decrease in the other one (IH). Both sham and real EMFs exposure of the IH did not affect brain excitability. Conclusion: Present results suggest a significant interaction between the brain excitability changes induced by EMFs and the epileptic focus, which eliminated the excitability enhancing effects of EMFs evident only in the CH. © 2013 Elsevier Inc. All rights reserved.

Pittaccio S.,CNR Institute for Energetics and Interphases | Zappasodi F.,University of Chieti Pescara | Viscuso S.,CNR Institute for Energetics and Interphases | Mastrolilli F.,AFaR | And 7 more authors.
Human Brain Mapping | Year: 2011

This study investigates cortical involvement during ankle passive mobilization in healthy subjects, and is part of a pilot study on stroke patient rehabilitation. Magnetoencephalographic signals from the primary sensorimotor areas devoted to the lower limb were collected together with simultaneous electromyographic activities from tibialis anterior (TA). This was done bilaterally, on seven healthy subjects (aged 29 ± 7), during rest, left and right passive ankle dorsiflexion (imparted through the SHADE orthosis, O-PM, or neuromuscular electrical stimulation, NMES-PM), and during active isometric contraction (IC-AM). The effects of focussing attention on ankle passive movements were considered. Primary sensory (FSS1) and motor (FSM1) area activities were discriminated by the Functional Source Separation algorithm. Only contralateral FSS1 was recruited by common peroneal nerve stimulation and only contralateral FSM1 displayed coherence with TA muscular activity. FSM1 showed higher power of gamma rhythms (33-90 Hz) than FSS1. Both sources displayed higher beta (14-32 Hz) and gamma powers in the left than in the right hemisphere. Both sources displayed a bilateral reduction of beta power during IC-AM with respect to rest. Only FSS1 beta band power reduced during O-PM. No beta band modulation was observed of either source during NMES-PM. Mutual FSS1-FSM1 coherence in gamma2 band (61-90 Hz) showed a slight trend towards an increase when focussing attention during O-PM. Somatosensory and motor counterparts of lower limb cortical representations were discriminated in both hemispheres. SHADE was effective in generating repeatable dorsiflexion and inducing primary sensory involvement similarly to voluntary movement. Hum Brain Mapp, 2010. © 2010 Wiley-Liss, Inc.

Vernieri F.,Biomedical University of Rome | Assenza G.,Biomedical University of Rome | Maggio P.,Biomedical University of Rome | Tibuzzi F.,AFaR | And 8 more authors.
Stroke | Year: 2010

Background and Purpose-: Cerebral vasomotor reactivity (VMR) is a capability of cerebral vessels to dilate in response to hypercapnia. Transcranial direct current stimulation (tDCS) effects on cerebral hemodynamics have been poorly studied. Methods and Results-: Ten healthy subjects underwent anodal/cathodal tDCS on the left motor cortex. Before and after tDCS, VMR assessment by transcranial Doppler and an electrocardiogram were performed. Normalized low-frequency band power of heart rate variability and its reactivity from basal to VMR condition (LFNreact) were estimated as relative markers of sympathetic activation. tDCS exerted a polarity-specific effect on both VMR (P=0.0001) and LFNreact (P=0.001). Anodal tDCS decreased VMR by 3.4%/mm Hg CO2 bilaterally and increased LFNreact, whereas cathodal tDCS increased VMR by 0.8%/mm Hg CO2 bilaterally and reduced LFNreact. Conclusions-: Cerebral VMR is modified by tDCS. Based on the consensual changes with heart rate variability, we can hypothesize that the sympathetic nervous system could modulate the bihemispheric modification of VMR. Further studies are needed to confirm this hypothesis. © 2010 American Heart Association, Inc.

Vecchio F.,A.Fa.R. | Babiloni C.,University of Foggia | Lizio R.,IRCCS San Raffaele Pisana | De Vico Fallani F.,IRCCS Fondazione Santa Lucia | And 5 more authors.
Supplements to Clinical Neurophysiology | Year: 2013

The human brain contains an intricate network of about 100 billion neurons. Aging of the brain is characterized by a combination of synaptic pruning, loss of cortico-cortical connections, and neuronal apoptosis that provoke an age-dependent decline of cognitive functions. Neural/synaptic redundancy and plastic remodeling of brain networking, also secondary to mental and physical training, promote maintenance of brain activity and cognitive status in healthy elderly subjects for everyday life. However, age is the main risk factor for neurodegenerative disorders such as Alzheimer's disease (AD) that impact on cognition. Growing evidence supports the idea that AD targets specific and functionally connected neuronal networks and that oscillatory electromagnetic brain activity might be a hallmark of the disease. In this line, digital electroencephalography (EEG) allows noninvasive analysis of cortical neuronal synchronization, as revealed by resting state brain rhythms. This review provides an overview of the studies on resting state eyes-closed EEG rhythms recorded in amnesic mild cognitive impairment (MCI) and AD subjects. Several studies support the idea that spectral markers of these EEG rhythms, such as power density, spectral coherence, and other quantitative features, differ among normal elderly, MCI, and AD subjects, at least at group level. Regarding the classification of these subjects at individual level, the most previous studies showed a moderate accuracy (70-80%) in the classification of EEG markers relative to normal and AD subjects. In conclusion, resting state EEG makers are promising for large-scale, low-cost, fully noninvasive screening of elderly subjects at risk of AD. © 2013 Elsevier B.V.

Vecchio F.,AFaR | Buffo P.,University of Rome La Sapienza | Sergio S.,University of Rome La Sapienza | Iacoviello D.,University of Rome La Sapienza | And 3 more authors.
Clinical Neurophysiology | Year: 2012

Objectives: It has been shown that electromagnetic fields of Global System for Mobile Communications phone (GSM-EMFs) affect human brain rhythms (Vecchio et al., 2007, 2010), but it is not yet clear whether these effects are related to alterations of cognitive functions. Methods: Eleven healthy adults underwent two electroencephalographic (EEG) sessions separated by 1 week, following a cross-over, placebo-controlled, double-blind paradigm. In both sessions, they performed a visual go/no-go task before real exposure to GSM-EMFs or after a sham condition with no EMF exposure. In the GSM real session, temporal cortex was continuously exposed to GSM-EMFs for 45. min. In the sham session, the subjects were not aware that the EMFs had been switched off for the duration of the experiment. In the go/no-go task, a central fixation stimulus was followed by a green (50% of probability) or red visual stimulus. Subjects had to press the mouse button after the green stimuli (go trials). With reference to a baseline period, power decrease of low- (about 8-10. Hz) and high-frequency (about 10-12. Hz) alpha rhythms indexed the cortical activity. Results: It was found less power decrease of widely distributed high-frequency alpha rhythms and faster reaction time to go stimuli in the post- than pre-exposure period of the GSM session. No effect was found in the sham session. Conclusions: These results suggest that the peak amplitude of alpha ERD and the reaction time to the go stimuli are modulated by the effect of the GSM-EMFs on the cortical activity. Significance: Exposure to GSM-EMFs for 45. min may enhance human cortical neural efficiency and simple cognitive-motor processes in healthy adults. © 2011 International Federation of Clinical Neurophysiology.

Babiloni C.,University of Foggia | Lizio R.,IRCCS San Raffaele Pisana | Vecchio F.,A.Fa.R. | Frisoni G.B.,IRCCS S. Giovanni di Dio F.B.F. | And 7 more authors.
Journal of Alzheimer's Disease | Year: 2010

Cortical sources of resting eyes-closed alpha rhythms are typically abnormal in mild cognitive impairment (MCI) and Alzheimer's disease (AD) subjects. Here we tested the hypothesis of a progressive impairment of cortical alpha reactivity to eye-opening across amnesic MCI and mild AD subjects, reflecting another aspect of the impairment of cortical neural synchronization. Resting electroencephalography (EEG) data were recorded in 36 normal elderly subjects (Nold), 91 amnesic MCI, and 31 mild AD subjects during eyes-closed and -open conditions. EEG sources were estimated by LORETA software. In the eye-closed condition, posterior alpha 1 (8-10.5 Hz) sources were lower in MCI and AD than Nold subjects. The opposite was true for occipital delta sources (2-4 Hz). Reactivity to the eyes-open condition showed posterior alpha 1 and alpha 2 (10.5-13 Hz) sources was high in the Nold, intermediate in the MCI, and low in the AD subjects. Furthermore, occipital alpha 1 reactivity across MCI and AD subjects was correlated to the cognitive impairment as revealed by Mini-Mental State Examination score. In conclusion, at least at group level, the continuum across amnesic MCI and mild AD status is related to an impaired reactivity of cortical neuronal synchronization to eyes opening at alpha rhythms. © 2010 - IOS Press and the authors. All rights reserved.

Moretti D.V.,IRCCS S. Giovanni di Dio Fatebenefratelli | Frisoni G.B.,IRCCS S. Giovanni di Dio Fatebenefratelli | Fracassi C.,IRCCS S. Giovanni di Dio Fatebenefratelli | Pievani M.,IRCCS S. Giovanni di Dio Fatebenefratelli | And 5 more authors.
Neurobiology of Aging | Year: 2011

The theta/gamma and alpha3/alpha2 ratio were investigated as early markers for prognosticating of progression to dementia. 76 subjects with mild cognitive impairment (MCI) underwent EEG recording, MRI scans and neuropsychological (NPS) tests. After 3 years of follow-up, three subgroups were characterized as converters to Alzheimer's disease (AD, N= 18), converters to non-AD dementia (N= 14) and non-converters (N= 44). The theta/gamma and alpha3/alpha2 ratio, performance on cognitive tests and hippocampal volume, as evaluated at the time of initial MCI diagnosis, were studied in the three groups. As expected, MCI to AD converters had the smallest mean hippocampal volume and poorest performance on verbal learning tests, whereas MCI to non-AD converters had poorest cognitive performance in non-verbal learning tests, abstract thinking, and letter fluency. Increased theta/gamma ratio was associated with conversion to both AD and non-AD dementia; increased alpha3/alpha2 ratio was only associated with conversion to AD. Theta/gamma and alpha3/alpha2 ratio could be promising prognostic markers in MCI patients. In particular, the increase of high alpha frequency seems to be associated with conversion in AD. EEG markers allow a mean correct percentage of correct classification up to 88.3%. Future prospective studies are needed to evaluate the sensitivity and specificity of these measures for predicting an AD outcome. © 2009 Elsevier Inc.

Babiloni C.,University of Foggia | Vecchio F.,A.Fa.R. | Lizio R.,IRCCS San Raffaele Pisana | Ferri R.,Oasi Institute for Research on Mental Retardation and Brain Aging IRCCS | And 5 more authors.
Journal of Alzheimer's Disease | Year: 2011

Physiological brain aging is characterized by a combination of synaptic pruning, loss of cortico-cortical connections and neuronal apoptosis that provoke age-dependent decline of cognitive functions. Neural/synaptic redundancy and plastic remodeling of brain networking, also secondary to mental and physical training, promotes maintenance of brain activity in healthy elderly for everyday life and fully productive affective and intellectual capabilities. Unfortunately, in pathological situations, aging triggers neurodegenerative processes that impact on cognition, like Alzheimers disease (AD). Oscillatory electromagnetic brain activity is a hallmark of neuronal network function in various brain regions. Modern neurophysiological techniques including digital electroencephalography (EEG) allow non-invasive analysis of cortico-cortical connectivity and neuronal synchronization of firing, and coherence of brain rhythmic oscillations at various frequencies. The present review of field EEG literature suggests that discrimination between physiological and pathological brain aging clearly emerges at the group level, with some promising result on the informative value of EEG markers at the individual level. Integrated approaches utilizing neurophysiological techniques together with biological markers and structural and functional imaging are promising for large-scale, low-cost, widely available on the territory and non-invasive screening of at-risk populations. © 2011 IOS Press and the authors. All rights reserved.

Babiloni C.,University of Foggia | De Pandis M.F.,Casa di Cura San Raffaele Cassino | Vecchio F.,A.Fa.R. | Buffo P.,University of Rome La Sapienza | And 4 more authors.
Clinical Neurophysiology | Year: 2011

Objective: Here we test the hypothesis that cortical source mapping of resting state electroencephalographic (EEG) rhythms could characterize neurodegenerative disorders inducing cognitive impairment such as Parkinson's disease related dementia (PDD) and Alzheimer's disease (AD). Methods: To address this issue, eyes-closed resting state EEG rhythms were recorded in 13 PDD, 20 AD, and 20 normal elderly (Nold) subjects. Age, gender, and education were carefully matched across the three groups. Mini Mental State Evaluation (MMSE) score probed subjects' global cognitive status, and was matched between the PDD and AD groups. EEG rhythms of interest were delta (2-4. Hz), theta (4-8. Hz), alpha1 (8-10.5. Hz), alpha2 (10.5-13. Hz), beta1 (13-20. Hz), and beta2 (20-30. Hz). EEG cortical sources were estimated by low resolution brain electromagnetic source tomography (LORETA). Results: With respect to the Nold and AD groups, the PPD group was characterized by peculiar abnormalities of central delta sources and posterior cortical sources of theta and beta1 rhythms. With respect to the Nold group, the PDD and AD groups mainly pointed to lower posterior cortical sources of alpha1 rhythms, which were positively correlated to MMSE score across all PDD and AD subjects as a whole (the lower the alpha sources, the lower the MMSE score). This alpha decrease was greater in the AD than PPD patients. Conclusions: The results suggest that topography and frequency of eyes-closed resting state cortical EEG rhythms distinguished PDD and AD groups. Significance: We report the existence of different effects of neurodegeneration on the cortical neural synchronization mechanisms generating resting state EEG rhythms in PDD and AD patients. © 2011.

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