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Alzheimer's disease dementia (ADD) is the most diffuse neurodegenerative disorder belonging to mild cognitive impairment (MCI) and dementia in old persons. This disease is provoked by an abnormal accumulation of amyloid-beta and tauopathy proteins in the brain. Very recently, the first disease-modifying drug has been licensed with reserve (i.e., Aducanumab). Therefore, there is a need to identify and use biomarkers probing the neurophysiological underpinnings of human cognitive functions to test the clinical efficacy of that drug. In this regard, event-related electroencephalographic potentials (ERPs) and oscillations (EROs) are promising candidates. Here, an Expert Panel from the Electrophysiology Professional Interest Area of the Alzheimer's Association and Global Brain Consortium reviewed the field literature on the effects of the most used symptomatic drug against ADD (i.e., Acetylcholinesterase inhibitors) on ERPs and EROs in ADD patients with MCI and dementia at the group level. The most convincing results were found in ADD patients. In those patients, Acetylcholinesterase inhibitors partially normalized ERP P300 peak latency and amplitude in oddball paradigms using visual stimuli. In these same paradigms, those drugs partially normalize ERO phase-locking at the theta band (4–7 Hz) and spectral coherence between electrode pairs at the gamma (around 40 Hz) band. These results are of great interest and may motivate multicentric, double-blind, randomized, and placebo-controlled clinical trials in MCI and ADD patients for final cross-validation. United States Department of Health & Human Services National Institutes of Health (NIH) - USA

Objective. In the last decades, machine learning approaches have been widely used to distinguish Parkinson’s disease (PD) and many other neuropsychiatric diseases. They also speed up the clinicians and facilitate decision-making for several conditions with similar clinical symptoms. The current study attempts to detect PD with dementia (PDD) by event-related oscillations (EROs) during cognitive processing in two modalities, i.e. auditory and visual. Approach. The study was conducted to discriminate PDD from healthy controls (HC) using event-related phase-locking factors in slow frequency ranges (delta and theta) during visual and auditory cognitive tasks. Seventeen PDD and nineteen HC were included in the study, and linear discriminant analysis was used as a classifier. During classification analysis, multiple settings were implemented by using different sets of channels (overall, fronto-central and temporo-parieto-occipital (TPO) region), frequency bands (delta-theta combined, delta, theta, and low theta), and time of interests (0.1–0.7 s, 0.1–0.5 s and 0.1–0.3 s for delta, delta-theta combined; 0.1–0.4 s for theta and low theta) for spatial-spectral-temporal searchlight procedure. Main results. The classification performance results of the current study revealed that if visual stimuli are applied to PDD, the delta and theta phase-locking factor over fronto-central region have a remarkable contribution to detecting the disease, whereas if auditory stimuli are applied, the phase-locking factor in low theta over TPO and in a wider range of frequency (1–7 Hz) over the fronto-central region classify HC and PDD with better performances. Significance. These findings show that the delta and theta phase-locking factor of EROs during visual and auditory stimuli has valuable contributions to detecting PDD.

Cerebrospinal and structural-molecular neuroimaging in-vivo biomarkers are recommended for diagnostic purposes in Alzheimer’s disease (AD) and other dementias; however, they do not explain the effects of AD neuropathology on neurophysiological mechanisms underpinning cognitive processes. Here, an Expert Panel from the Electrophysiology Professional Interest Area of the Alzheimer’s Association reviewed the field literature and reached consensus on the event-related electroencephalographic oscillations (EROs) that show consistent abnormalities in patients with significant cognitive deficits due to Alzheimer’s, Parkinson’s (PD), Lewy body (LBD), and cerebrovascular diseases. Converging evidence from oddball paradigms showed that, as compared to cognitively unimpaired (CU) older adults, AD patients had lower amplitude in widespread delta (>4 Hz) and theta (4–7 Hz) phase-locked EROs as a function of disease severity. Similar effects were also observed in PD, LBD, and/or cerebrovascular cognitive impairment patients. Non-phase-locked alpha (8–12 Hz) and beta (13–30 Hz) oscillations were abnormally reduced (event-related desynchronization, ERD) in AD patients relative to CU. However, studies on patients with other dementias remain lacking. Delta and theta phase-locked EROs during oddball tasks may be useful neurophysiological biomarkers of cognitive systems at work in heuristic and intervention clinical trials performed in AD patients, but more research is needed regarding their potential role for other dementias. European Committee (H2020-EU.1.3.1.H2020-MSCA-ITN-ETN-2016 project)

Over the past few years, it has become standard to describe brain anatomical and functional organisation in terms of complex networks, wherein single brain regions or modules and their connections are respectively identified with network nodes and the links connecting them. Often, the goal of a given study is not that of modelling brain activity but, more basically, to discriminate between experimental conditions or populations, thus to find a way to compute differences between them. This in turn involves two important aspects: defining discriminative features and quantifying differences between them. Here we show that the ranked dynamical stability of network features, from links or nodes to higher-level network properties, discriminates well between healthy brain activity and various pathological conditions. These easily computable properties, which constitute local but topographically aspecific aspects of brain activity, greatly simplify inter-network comparisons and spare the need for network pruning. Our results are discussed in terms of microstate stability. Some implications for functional brain activity are discussed., This work was supported by TÜBİTAK and French Ministry of Foreign Affairs PHC-Bosphore Program (respectively projects no: 218S314 and 42558YL). This project has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (Grant agreement No 851255). M.Z. acknowledges the Spanish State Research Agency, through the Severo Ochoa and María de Maeztu Program for Centers and Units of Excellence in R&D (MDM-2017-0711).

Background Recognition of facial expressions (FEs) plays a crucial role in social interactions. Most studies on FE recognition use static (image) stimuli, even though real-life FEs are dynamic. FE processing is complex and multifaceted, and its neural correlates remain unclear. Transitioning from static to dynamic FE stimuli might help disentangle the neural oscillatory mechanisms underlying face processing and recognition of emotion expression. To our knowledge, we here present the first time–frequency exploration of oscillatory brain mechanisms underlying the processing of dynamic FEs. Results Videos of joyful, fearful, and neutral dynamic facial expressions were presented to 18 included healthy young adults. We analyzed event-related activity in electroencephalography (EEG) data, focusing on the delta, theta, and alpha-band oscillations. Since the videos involved a transition from neutral to emotional expressions (onset around 500 ms), we identified time windows that might correspond to face perception initially (time window 1; first TW), and emotion expression recognition subsequently (around 1000 ms; second TW). First TW showed increased power and phase-locking values for all frequency bands. In the first TW, power and phase-locking values were higher in the delta and theta bands for emotional FEs as compared to neutral FEs, thus potentially serving as a marker for emotion recognition in dynamic face processing. Conclusions Our time–frequency exploration revealed consistent oscillatory responses to complex, dynamic, ecologically meaningful FE stimuli. We conclude that while dynamic FE processing involves complex network dynamics, dynamic FEs were successfully used to reveal temporally separate oscillation responses related to face processing and subsequently emotion expression recognition.

In normal old (Nold) and Alzheimer’s disease (AD) persons, a high cognitive reserve (CR) makes them more resistant and resilient to brain neuropathology and neurodegeneration. Here, we tested whether these effects may affect neurophysiological oscillatory mechanisms generating dominant resting state electroencephalographic (rsEEG) alpha rhythms in Nold and patients with mild cognitive impairment (MCI) due to AD (ADMCI). Data in 60 Nold and 70 ADMCI participants, stratified in higher (Edu+) and lower (Edu–) educational attainment subgroups, were available in an Italian–Turkish archive. The subgroups were matched for age, gender, and education. RsEEG cortical sources were estimated by eLORETA freeware. As compared to the Nold-Edu– subgroup, the Nold-Edu+ subgroup showed greater alpha source activations topographically widespread. On the contrary, in relation to the ADMCI-Edu– subgroup, the ADMCI-Edu+ subgroup displayed lower alpha source activations topographically widespread. Furthermore, the 2 ADMCI subgroups had matched cerebrospinal AD diagnostic biomarkers, brain gray–white matter measures, and neuropsychological scores. The current findings suggest that a high CR may be related to changes in rsEEG alpha rhythms in Nold and ADMCI persons. These changes may underlie neuroprotective effects in Nold seniors and subtend functional compensatory mechanisms unrelated to brain structure alterations in ADMCI patients.

Extending Basar's theory of event-related EEG oscillations, here we hypothesize that even in quiet wakefulness, transient increases in delta rhythms may enhance global cortical arousal as revealed by the desynchronization of alpha rhythms in normal (Nold) seniors with some derangement in Alzheimer's disease dementia (ADD).Clinical and EEG datasets in 100 ADD and 100 Nold individuals matched as demography, education, and gender were taken from an international archive. Standard delta (< 4 Hz) and alpha1 (8-10.5 Hz) bands were used for the main analysis, while alpha2 (10.5-13 Hz), theta (4-8 Hz), beta1 (13-20 Hz), beta2 (20-35 Hz), and gamma (35-40 Hz) served as controls. In the interpretation, the higher the alpha1 power (density), the lower that arousal. As expected, when compared to the Nold group, the ADD group showed higher global (scalp) power density at the delta-theta band and lower global power density at the alpha-beta bands. As novel findings, we observed that: (1) in the Nold group, the global delta and alpha1-2 power were negatively and linearly correlated; (2) in the ADD group, this correlation was just marginal; and (3) in both Nold and AD groups, the EEG epochs with the highest delta power (median value for stratification) were associated with the lowest global alpha1 power. This effect was related to eLORETA freeware solutions showing maximum alpha1 source activations in posterior cortical regions.These results suggest that even in quiet wakefulness, delta and alpha rhythms are related to each other, and ADD partially affects this cross-band neurophysiological mechanism. Ministry of Health, Italy ; Ministry of Health Italy - Ricerca Corrente (MOH-RC) ; H2020 Marie S. Curie ITN-ETN project with the short title "BBDiag" ; H2020-TWINN-2015 project with the short title "SynaNet"

The healthy maturation of the brain is one of the intriguing topics that need to be investigated to understand human brain and child development. The present study aimed to investigate the development of memory processes both for auditory and visual memory using electroencephalography (EEG)-Brain Dynamics methodologies. Sixteen healthy children between the ages of 6 and 7 years and eighteen healthy young adults (age: 21.32 ± 3.28 years) were included in the study. EEG was recorded from 18 channels during the visual and auditory memory paradigms. Two different subtests of the WISC-IV IQ test were applied to all children. Event-related theta (4-7 Hz), alpha (8-13 Hz) power and phase-locking were analyzed. The young adults had higher memory performance than the children for both auditory and visual paradigms. The children had increased theta phase-locking and left alpha power in response to the remembered objects in comparison to the forgotten objects. The young adults had higher theta and alpha phase-locking than the children over the frontal and central locations (p 0.05), and the children had higher parietal-occipital alpha phase-locking than the young adults. There was an increase in alpha power in children, whereas young adults had decreased post-stimulus alpha power in response to memory paradigms. The present study showed that frontocentral theta and alpha phase-locking had an essential role in brain maturation and successful memory performance. Event-related theta and alpha responses could be one of the important indicators of the mature and healthy brain, and these responses could change depending on the maturation state and age.

The research on the abnormalities of event-related oscillations in Parkinson's disease (PD) was mostly studied with cognitively normal patients. The present study aims to show the adverse effects of cognitive decline in PD patients via the EEG-Brain Oscillations approach by comparing the electrophysiological responses in two modalities, i.e. auditory, and visual in which PD group show deficit. We conducted a study in which we analyzed event-related theta power and phase-locking during auditory and visual oddball paradigm. Cognitively normal PD (PDCN) patients (N = 15), PD with mild cognitive impairment (PDMCI) patients (N = 22), PD dementia (PDD) patients (N = 11) and healthy controls (HC) (N = 17) were included in the study. Neuropsychological assessments were applied to all participants. There was a gradual decrease in scores of neuropsychological tests (HC, PDCN, PDMCI, PDD, respectively). Most of the neuropsychological test scores of the participants were highly correlated with the theta power and theta phase locking values, especially over frontal-central areas. HC had higher theta phase-locking and power in comparison to PDMCI and PDD. The differentiation between HC and PDCN was specific to frontal-central areas. Theta power and theta phase-locking were decreased overall locations in PDMCI and PDD both during visual and auditory oddball paradigms compared with PDCN. The results indicate that theta responses in PD patients decreased gradually as the cognitive decline increased. We can conclude that complex abnormalities in their neurotransmitter and neuronal signal systems that occur with the progression of the disease could be responsible for these results.

Behavioral studies have shown that the recognition of facial expressions may be impaired in patients with Alzheimer's disease (AD). The identification and recognition of a facial expression might be represented by event-related brain oscillations. The present study aims to analyze EEG event-related oscillations and determine the electrophysiological indicators of impaired facial expression recognition in AD patients. EEGs of 30 healthy controls and 30 AD patients were recorded during their perception of three different facial expressions (angry, happy, neutral). Event-related power spectrum and phase locking were analyzed in the theta (4-7) and alpha (8-13 Hz) frequency bands with the EEGLAB open toolbox. There was a significant facial Expression × Group interaction (p < 0.05) for the theta power spectrum; the healthy control group had higher theta power than the AD group during the perception of angry facial expressions (p < 0.05). There was a significant hemisphere difference between the two groups (p < 0.05). There was a right hemisphere alpha power dominance in healthy subjects. However, AD patients did not have this alpha power asymmetry. The present study, for the first time in the literature, presents the electrophysiological indicators of impaired recognition of facial expression in AD patients. The current study could be a basis for future studies that will analyze emotional processing in different kinds of dementia patients, and this study may have provided indicators of electrophysiological correlates of behavioral problems observed in clinical practice.

Characterizing brain activity at rest is of paramount importance to our understanding both of general principles of brain functioning and of the way brain dynamics is affected in the presence of neurological or psychiatric pathologies. We measured the time-reversal symmetry of spontaneous electroencephalographic brain activity recorded from three groups of patients and their respective control group under two experimental conditions (eyes open and closed). We evaluated differences in time irreversibility in terms of possible underlying physical generating mechanisms. The results showed that resting brain activity is generically time-irreversible at sufficiently long time scales, and that brain pathology is generally associated with a reduction in time-asymmetry, albeit with pathology-specific patterns. The significance of these results and their possible dynamical etiology are discussed. Some implications of the differential modulation of time asymmetry by pathology and experimental condition are examined.

Facial Expression (FE) recognition is a major marker of emotional ability. Behavioral studies show that FE recognition ability decreases with aging. Studying how event-related brain oscillations change with normal aging is important to better understand the underlying mechanisms of emotional processes. The aim of this study is to investigate changes in FE recognition due to normal aging using the EEG-Brain Oscillations approach. Fifteen young and fifteen elderly healthy subjects were included in the study. 15 photographs were used with 5 different FEs (angry, happy, neutral, sad, fearful). After each EEG recording session, subjects were asked to identify the FEs that were presented. Event-related delta, theta and, alpha phase-locking and frequency-band responses were analyzed. In the FE recognition part of the study, young subjects obtained better scores than the elderly subjects. There was a significant result regarding the locationXgroup comparison in the delta response; the young group had a higher delta response than the elderly group over the occipital area. There were significant locationXgroup differences in the theta and alpha phase locking values; the elderly group had higher theta and alpha phase locking values than the young group in the frontal area. Group differences were significant in the theta response and theta phase locking; the elderly individuals' theta response and phase locking values were higher compared to those of the young individuals. In elderly individuals, FE recognition impairment has been observed. It has been shown that the impairment may be characterized by decreased occipital delta responses and phase locking. This can be interpreted to mean that elderly individuals may have developed different brain dynamics as a compensating mechanism since they are not as efficient as young individuals in performing these functions.

Guntekin, Bahar/0000-0002-0860-0524 WOS: 000498325100052 PubMed: 31477464 We have evaluated an 82 years old PD patient who has acutely developed VH secondary to acute visual loss that was associated with increased electroencephalographic activity in the gamma range over the parietal, occipital and frontal regions. In this respect, we have tested the therapeutic effect of occipital lobe oriented rTMS application and its electrophysiological correlates that led to significant improvement in the hallucinatory symptomatology of the patient after two weeks. We have revealed that the improved hallucinatory symptoms after rTMS application resolved completely after switching from the pramipexole treatment to L-Dopa indicating that there could be a combined therapeutic effect of L-Dopa and rTMS. Furthermore, Quantitative-Electroencephalography analysis has shown that the therapeutic effects of rTMS and L-Dopa were seen with the improvement of impaired gamma power spectrum. Although the main limitation of this report is that this a single case study and that these findings need to be replicated in a larger sample, e.g., as part of a controlled trial, our present findings help us to enlighten the unknown pathophysiological overlapping between the visual hallucinations in PD and Charles Bonnet Syndrome. Finally, our study revealed increased gamma coherence and power spectrum which is seen with visual hallucinations and improved after the application of 1 Hz rTMS on the occipital lobe. These findings together suggest that rTMS could be used as a therapeutic tool for parkinsonian complex VH and probably due affecting gamma coherence and power spectrum. (C) 2019 Elsevier Ltd. All rights reserved.

Objectives: The present study aims to evaluate the amplitude and latency of event-related potentials (ERPs) P100, N170, VPP and N230 in individuals with Alzheimer's disease (AD) compared to healthy elderly controls, using a passive viewing task of emotional facial expressions. Methods: Twenty-four individuals with mild to moderate AD and 23 demographically matched healthy elderly controls were included in the study. ERP P100, N170, VPP and N230 amplitude and latency values were compared between groups. Results: The categorization of emotional facial expressions was intact; yet, increased P100 amplitude and latency, decreased N170 amplitude, and increased VPP amplitude were observed in AD compared to controls. Increased N230 amplitude and latency were observed in response to angry expressions, while neutral expressions elicited decreased amplitude and latency. Conclusions: Increased P100 amplitude and latency may reflect reduced amygdala volume and disruptions in the visual system, while decreased N170 and increased VPP amplitudes may reflect impaired perceptual processing, mitigated by a greater involvement of prefrontal areas for task performance in AD. Significance: This study is the first to report a complex pattern of ERPs to emotional facial expressions in individuals with AD. (C) 2019 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.

WOS: 000466619600006 PubMed ID: 30851280 Event-related oscillatory responses reflect the cognitive status in many neuropsychiatric conditions including mild cognitive impairment (MCI). In this study, a total of 30 patients with amnestic MCI (aMCI) and 25 patients with MCI of Parkinson's disease (PD-MCI) were compared with 28 aged-, gender-, education-matched healthy control (HC) participants using visual event-related delta, theta, alpha oscillatory responses by methods of event related spectral perturbation and inter-trial coherence. PD-MCI and aMCI groups commonly share a decreased theta power, but all electrophysiological deviations from the controls were more prominent in PD-MCI than aMCI in all frequency bands. Additionally, decreased phase-locking in all studied frequency bands was encountered only in PD-MCI group, but it was preserved in aMCI. These findings indicate that visual networks in PD-MCI are more severely affected than aMCI. Reduced phase-locking in PD-MCI may possibly relate to dysfunctioning subcortical modulating centers that take a role in the generation of event-related responses. Scientific and Technological Research Council of Turkey-TUBITAK [112S459] This study was supported by the Scientific and Technological Research Council of Turkey-TUBITAK (Project number: 112S459).

Hallucinations in Parkinson ‘s disease (PD) could affect about one-quarter of the patients. There are limited studies on how the hallucinations effect cognitive states of the patients with Parkinson’s disease.

Introduction: Cognitive Impairment in Parkinson’s disease could occur by the progression of the disease. Event-related theta responses in the frontal region is strongly connected with cognitive processes. Increase of theta response during increased cognitive load is a robust finding. The decrease theta phase-locking and theta power was found in the patient groups which had cognitive decline. The aim of the present study is to investigate the event-related theta responses in Parkinson Patients with and without cognitive deficits during auditory and visual cognitive paradigms. Methods: Three different group of Parkinson’s disease patients were included in the study. 15 PD patients without cognitive deficits, 23 PD patients with mild cognitive impairment (MCI), 11 PD patients with dementia, and 18 aged-matched healthy controls (HC) were included in the study. The mean of Mini Mental State Examination (MMSE) scores was 28,00±1,25 for the HC group, 26,80±1,90 for the PD group, 22,56±5,32 for the PD-MCI group, and 18,82±3,74 for the PD-Dementia group. EEG was recorded at 8 different frontal locations (F3-F4, F7-F8, FC3-FC4, and FT7-FT8). Auditory and visual oddball paradigms were applied during EEG recordings. Phase-locking analysis (Inter-trial coherence) and event related power spectrum were analyzed for theta (4-7 Hz) frequency band for all subject groups for both “target” and non-target” stimulations. Results: In accordance with the previous studies target stimulation elicited higher theta phase-locking and theta power than the non-target stimulation (p

Background Studies on Event Related EEG Brain Oscillations presented essential results on the understanding of cognitive brain function and cognitive decline in different pathologies. Event related oscillatory dynamics in Parkinson’s disease (PD) have not been studied comprehensively. In the last three years, our group aimed to fulfill this critical gap. Material and methods 27 PD patients without cognitive deficits, 34 PD patients with Mild Cognitive Impairment, 22 patients with PD Dementia and 33 healthy controls were included in the study.EEG was recorded during visual and auditory oddball paradigEvent related power spectrum, phase locking, event related coherence were evaluated in delta, theta, alpha, beta and gamma frequency bands for all group of subjects. Results Event related delta, theta, alpha and beta power and phase locking increased with a cognitive load in healthy subjects but these responses decreased in PD patients who have mild cognitive impairment and dementia. Event related delta, theta, and alpha coherence values were also lower in PD patients with cognitive deficits. The most differentiated results were found in the theta frequency band, frontal theta responses were the lowest in PD patients with dementia especially during the visual paradigm rather than the auditory paradigm. Conclusions Comprehensive analysis of Event-related oscillatory dynamics could successfully differentiate the cognitive decline in Parkinson’s disease patients. The differentiation between subject groups did not just appear in local circuits, but long distance connections were also impaired in PD patients with cognitive decline. Acknowledgments This work (Grant No. 214S111 ) was supported by TUBITAK .

Background Event-related beta responses are related to the visual cognitive process. Beta phase-locking had decreased in subjects with cognitive deficits. Parkinson’s disease dementia (PDD) and dementia with Lewy bodies (DLB) have similar pathophysiology and have different clinical symptoEEG event-related responses in neurodegenerative diseases are remarkable for understanding the mechanisms underlying the pathophysiology. The aim of our study was to investigate the event-related beta responses in PDD and DLB patients. Material and methods 12 DLB, 14 PDD patients and matched 15 healthy controls were included in the study. There was no significant difference for the Mini-Mental State Examination score between the patient groups. EEG recordings were performed from 32 different locations during visual oddball paradigm. Phase-locking analysis was performed for beta (15–25 Hz) frequency band for all subject groups. Repeated measures of ANOVA was used for statistical analysis (p Results Healthy controls had increased beta phase locking with increasing cognitive loading. Healthy controls had higher beta phase locking than both PDD and DLB patients. LocationXGroup effect was significant for beta phase locking (p = 0.002). DLB patients had the worst beta phase locking particularly in parietal and occipital locations in comparison to other groups. Conclusions The present study showed that dementia characterized by a cognitive decline is reflected with decreased beta phase locking in posterior areas in both Parkinson’s disease and Lewy body disease. The decreased event-related beta phase locking could be a candidate of biomarkers for dementia in PDD and DLB patients.

Introduction Subacute sclerosing panencephalitis (SSPE) is a progressive encephalitis, that rarely affects adults. The brain damage occurs in about 5 years after the patient is infected by measles virus. The survival rate is low. Spontaneous alpha activity is a sign of healthy brain. Here we aimed to present electroencephalography (EEG) power spectrum analysis of an adult-onset SSPE. Case report The patient was a 23 year-old girl with the complaint of vision loss and forgetfulness. In her neurological examination, the place and time orientation were impaired. Brain magnetic resonance imaging showed diffuse parenchymal gliosis in the bilateral parietooccipital region. The measles Ig G level was found to be high and oligoclonal band was positive in cerebrospinal fluid. The patient was diagnosed with SSPE. Isoprinosine, rivastigmine and cognitive rehabilitation were started. The patient was followed up for 2 years and a total of 6 EEG recordings were done. Alpha activity (8–13 Hz) was analysed via the power spectrum (Fast Fourier Transform) analysis. No significant alpha peak was observed in the parietooccipital region in the background activity in the first 4 quantitative (q) EEGs. The analysis of the last 2 qEEGs after cognitive rehabilitation demonstrated a significant increase in the background activity of the parietooccipital region and in 7–8 Hz slow alpha peak. Conclusion This is the first SSPE case that demonstrated the improvement in QEEG analysis parallel to the clinical improvement in long term follow-up. We think that QEEG can be used as a tool to monitor the course of the disease.

18th World Congress of Psychophysiology of the International Organization of Psychophysiology (IOP) -- AUG 31-SEP 04, 2016 -- Havana, CUBA WOS: 000382408700195 Background: In the last decade research on delta oscillatoryresponses invaded the literature. One of thefirst research on thisarea showed that delta responses increase upon cognitive load(Başar and Stampfer 1985). After this preliminary result, manyresearchers have shown that delta responses are related to attention,perception, decision making and working memory processes. Ourgroup and other groups in the literature indicated that the deltaresponses in different patient groups were decreased duringcognitive load in comparison to healthy controls. In a recent reviewwe have described that decrease of delta responses could be acandidate of a general electrophysiological biomarker for neuropsy-chiatric disorders (Güntekin and Başar 2015). Delta responses weredecreased in Alzheimer’s disease, in Mild Cognitive impairment(MCI) in bipolar disorder patients and as well as in schizophreniapatients during cognitive load in comparison to healthy controls. Inthe present study we analyze the delta responses in Parkinson’sdisease with and without cognitive deficits Int Org Psychophysiol