Multi-approach comparative study of EEG patterns associated with the most common forms of dementia.

Electroencephalography's (EEG) sensitivity in discriminating dementia syndromes remains unclear. This study aimed to investigate EEG markers in patients with major cognitive disorders. The studied population included 4 groups of patients: Alzheimer's disease with associated vascular lesions, Alzheimer's disease without vascular lesions (AD-V), Lewy body disease and vascular dementia (VaD); and completed by a control group composed by cognitively unimpaired patients.

Sleep deprivation and Modafinil affect cortical sources of resting state electroencephalographic rhythms in healthy young adults.

Objective: It has been reported that sleep deprivation affects the neurophysiological mechanisms underpinning the vigilance. Here, we tested the following hypotheses in the PharmaCog project (www.pharmacog.

Attention modulation during motor preparation in Parkinsonian freezers: A time-frequency EEG study.

Objective: To investigate the cortical integration of attentional stimuli during motor preparation in parkinsonian patients with freezing of gait (FoG, n=12) or without freezing of gait (n=13), and in aged-matched healthy controls (n=13). We hypothesized that interference between attention and action in freezers would be revealed by differences in cortical modulation during this dual task.

Methods: Attention during step preparation was modulated by means of an auditory oddball discrimination task.

Effects of Stimulus-Driven and Goal-Directed Attention on Prepulse Inhibition of Brain Oscillations.

Objective: Prepulse inhibition (PPI) is an operational measure of sensory gating. PPI of cortical response to a startling pulse is known to be modulated by attention. With a time-frequency analysis, we sought to determine whether goal-directed and stimulus-driven attention differentially modulate inhibition of cortical oscillations elicited by a startling pulse.

Impulse Control Disorders in Parkinson's Disease are Associated with Alterations in Reward-Related Cortical Oscillations.

Background: Impulse control disorders (ICDs) in Parkinson's disease (PD) are related to treatment with dopamine agonists, which is thought to deregulate the dopaminergic mesolimbic pathway and impair reward evaluation. EEG studies in healthy controls (HCs) have suggested that the increase in theta power observed after negative outcome is a marker of reward processing.

Objective: To compare outcome-locked, event-related spectral perturbation in a gambling task in PD patients with and without ICDs and in HCs.

A 15-day course of donepezil modulates spectral EEG dynamics related to target auditory stimuli in young, healthy adult volunteers.

Objective: To identify possible electroencephalographic (EEG) markers of donepezil's effect on cortical activity in young, healthy adult volunteers at the group level.

Methods: Thirty subjects were administered a daily dose of either 5mg donepezil or placebo for 15days in a double-blind, randomized, cross-over trial. The electroencephalogram during an auditory oddball paradigm was recorded from 58 scalp electrodes.

Impaired Early Attentional Processes in Parkinson's Disease: A High-Resolution Event-Related Potentials Study.

Introduction: The selection of task-relevant information requires both the focalization of attention on the task and resistance to interference from irrelevant stimuli. A previous study using the P3 component of the event-related potentials suggested that a reduced ability to resist interference could be responsible for attention disorders at early stages of Parkinson's disease (PD), with a possible role of the dorsolateral prefrontal cortex (DLPFC).

Methods: Our objective was to better determine the origin of this impairment, by studying an earlier ERP component, the N2, and its subcomponents, as they reflect early inhibition processes and as they are known to have sources in the anterior cingulate cortex (ACC), which is involved together with the DLPFC in inhibition processes.

The spatiotemporal dynamics of early attention processes: a high-resolution electroencephalographic study of N2 subcomponent sources.

The N2 subcomponents of event-related potentials are known to reflect early attentional processes. The anterior N2 may reflect conflict monitoring, whereas the posterior N2 may be involved in target detection. The aim of this study was to identify the brain areas involved in the generation of the N2 subcomponents, in order to define the spatiotemporal dynamics of these attentional processes.

Effects of stimulus-driven and goal-directed attention on prepulse inhibition of the cortical responses to an auditory pulse.

Objective: Inhibition by a prepulse (prepulse inhibition, PPI) of the response to a startling acoustic pulse is modulated by attention. We sought to determine whether goal-directed and stimulus-driven attention differentially modulate (i) PPI of the N100 and P200 components of the auditory evoked potential (AEP) and (ii) the components' generators.

Methods: 128-channel electroencephalograms were recorded in 26 healthy controls performing an active acoustic PPI paradigm.

Attention modulates step initiation postural adjustments in Parkinson freezers.

Background: In view of freezing of gait's circumstances of occurrence in Parkinson's disease, attentional resources appear to be involved in step initiation failure. Anticipatory postural adjustments (APAs) are essential because they allow unloading of the stepping leg and so create the conditions required for progression. Our main objective was to establish whether or not a change in attentional load during step initiation modulates APAs differently in patients with vs.

Stimulus-driven attention modulates the release of anticipatory postural adjustments during step initiation.

Objective: Step initiation can be modified by environmental stimulations, suggesting the involvement of stimulus-driven attention. Therefore, we assessed the influence of attentional status during step preparation.

Methods: Fourteen healthy, young subjects were presented with an auditory oddball paradigm in which an infrequent "target" stimulus was presented among frequent "standard" stimuli.

Motor cortex stimulation modulates defective central beta rhythms in patients with neuropathic pain.

Objective: Motor cortex stimulation therapy (MCS) is increasingly used to control refractory neuropathic pain. Post-movement beta synchronization (PMBS) is defined as a sharp increase in beta-frequency electroencephalographic power following movement offset and may reflect sensorimotor cortex inhibition induced, at least in part, by cortical processing of movement-related sensory afferent inputs. PMBS pattern is then often altered in case of neuropathic pain.

Effects of acetylcholinesterase inhibitors and memantine on resting-state electroencephalographic rhythms in Alzheimer's disease patients.

Acetylcholinesterase inhibitors (AChEIs) are the most widely used symptomatic treatment for mild to severe Alzheimer's disease (AD) patients, while N-methyl-d-aspartic acid (NMDA) receptor antagonist memantine is licensed for use in moderate to severe AD patients. In this article, the effect of these compounds on resting state eyes-closed electroencephalographic (EEG) rhythms in AD patients is reviewed to form a knowledge platform for the European Innovative Medicine Initiative project "PharmaCog" (IMI Grant Agreement No. 115009) aimed at developing innovative translational models for drug testing in AD.

Anticipatory postural adjustments during step initiation: elicitation by auditory stimulation of differing intensities.

Step initiation is associated with anticipatory postural adjustments (APAs) that vary according to the speed of the first step. When step initiation is elicited by a "go" signal (i.e.

Role of basal ganglia circuits in resisting interference by distracters: a swLORETA study.

Background: The selection of task-relevant information requires both the focalization of attention on the task and resistance to interference from irrelevant stimuli. Both mechanisms rely on a dorsal frontoparietal network, while focalization additionally involves a ventral frontoparietal network. The role of subcortical structures in attention is less clear, despite the fact that the striatum interacts significantly with the frontal cortex via frontostriatal loops.

Movement preparation and cortical processing of afferent inputs in cortical tremor: an event-related (de)synchronization (ERD/ERS) study.

Objective: We sought to characterize cortical activity related to motor control in patients presenting with isolated cortical tremor, in order to determine whether or not myoclonus-related impairments are a source of event-related desynchronization/synchronization (ERD/ERS) disruption.

Methods: Nine patients presenting with isolated cortical tremor were compared with controls. Mu and beta ERD/ERS were computed over the scalp and brain surfaces using 128-channel electroencephalographic (EEG) recording during voluntary and passive finger extensions.

Deficit of sensorimotor integration in normal aging.

Sensorimotor performance declines with normal aging. The present study explored age-related changes in sensorimotor integration by conditioning a supra-threshold transcranial magnetic stimulation pulse with a peripheral nerve shock at different interstimulus intervals. Cortical motor threshold of the abductor pollicis brevis muscle, intracortical inhibition and facilitation were measured.

Use of swLORETA to localize the cortical sources of target- and distracter-elicited P300 components.

Objective: Cognitive event-related potentials (especially P300) have long been used to explore attentional processes. The aim of this study was to identify the cortical areas involved in P300 generation during a selective attention task.

Methods: 128 channel electroencephalograms were recorded in 15 healthy controls performing a three-stimulus visual oddball paradigm, in order to identify distracter- and target-elicited P300 components.

Cortical involvement in the sensory and motor symptoms of primary restless legs syndrome.

Background: Restless legs syndrome (RLS) is characterized by closely interrelated motor and sensory disorders. Two types of involuntary movement can be observed: periodic leg movements during wakefulness (PLMW) and periodic leg movements during sleep (PLMS). Basal ganglia dysfunction in primary RLS has often been suggested.

Deficient "sensory" beta synchronization in Parkinson's disease.

Objective: Beta rhythm movement-related synchronization (beta synchronization) reflects motor cortex deactivation and sensory afference processing. In Parkinson's disease (PD), decreased beta synchronization after active movement reflects abnormal motor cortex idling and may be involved in the pathophysiology of akinesia. The objectives of the present study were to (i) compare event-related synchronization after active and passive movement and electrical nerve stimulation in PD patients and healthy, age-matched volunteers and (ii) evaluate the effect of levodopa.

Attention impairment in temporal lobe epilepsy: a neurophysiological approach via analysis of the P300 wave.

Purpose: Attention is often impaired in temporal lobe epilepsy (TLE). The P300 wave (an endogenous, event-related potential) is a correlate of attention which is usually recorded during an "oddball paradigm," where the subject is instructed to detect an infrequent target stimulus presented amongst frequent, standard stimuli. Modifications of the P300 wave's latency and amplitude in TLE have been suggested, but it is still not known whether the source regions also differ.

Kinematic angular parameters in PD: reliability of joint angle curves and comparison with healthy subjects.

Background: Most previous biomechanical studies of Parkinson's disease (PD) have been restricted to the description of spatiotemporal parameters and certain peak values for angular parameters. The reliability of joint angle curves and comparisons with control data are of major interest in PD, since variability in gait cycle timing is a feature of this pathology.

Methods: We used a video motion analysis system to record kinematic, spatiotemporal and angular parameters in 32 'off-drug' PD patients.

Post-movement beta synchronization in subjects presenting with sensory deafferentation.

Objective: We studied the time course and location of post-movement beta synchronization (PMBS) in patients presenting with sensory deafferentation, in order to assess the hypothetical relationship between the PMBS and the cortical processing of movement-related somatosensory afferent inputs.

Methods: We used the event-related synchronization (ERS) method. EEG activity was recorded (via a 128-electrode system) during brisk, unilateral right and left index finger extension by 10 patients presenting with neuropathic pain related to sensory deafferentation.

Anticipatory postural adjustments associated with arm movement in Parkinson's disease: a biomechanical analysis.

Objective: To study anticipatory postural adjustments (APAs) in Parkinson's disease (PD) via a biomechanical analysis, including vertical torque (Tz).

Methods: Ten patients with PD (in the "off-drug" condition) and 10 age matched controls were included. While standing on a force platform, the subject performed a right shoulder flexion in order to grasp a handle in front of him/her, under three conditions (all at maximal velocity): movement triggered by a sound signal and loaded/non-loaded, self-paced movement.