Publications by authors named "Derya Durusu Emek-Savas"

Semantic and phonemic verbal fluency tests are widely used neuropsychological assessments of executive functions and language skills and are easy to administer. The aim of this study was to determine the impact of age, education, and gender on semantic and phonemic verbal fluency tests and to establish normative data for Turkish adults aged between 18 and 86 years. The results revealed significant main effects of age and education on all subscores of verbal fluency tests.

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Background/aim: Amnestic mild cognitive impairment (aMCI) is a risk factor for dementia, and thus, it is of interest to enlighten specific brain atrophy patterns in aMCI patients. We aim to define the longitudinal atrophy pattern in subcortical structures and its effect on cognition in patients with aMCI.

Materials And Methods: Twenty patients with aMCI and 20 demographically matched healthy controls with baseline and longitudinal structural magnetic resonance imaging scans and neuropsychological assessments were studied.

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Objective: The objective of this study was to investigate the functional changes associated with mild cognitive impairment (MCI) using independent component analysis (ICA) with the word generation task functional magnetic resonance imaging (fMRI) and resting-state fMRI.

Methods: In this study 17 patients with MCI and age and education-matched 17 healthy individuals as control group are investigated. All participants underwent resting-state fMRI and task-based fMRI while performing the word generation task.

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Background: Amnestic mild cognitive impairment (aMCI) is a transitional state between normal aging and dementia, and identifying early biomarkers is crucial for disease detection and intervention. Functional magnetic resonance imaging (fMRI) has the potential to identify changes in neural activity in MCI.

Methods: We investigated neural activity changes in the visual network of the aMCI patients (n:20) and healthy persons (n:17) using resting-state fMRI and visual oddball task fMRI.

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Semantic priming in Turkish was examined in 36 right-handed healthy participants in a delayed lexical decision task via taxonomic relations using EEG. Prime-target relations included related- unrelated- and pseudo-words. Taxonomically related words at long stimulus onset asynchrony (SOA) were shown to modulate N400 and late positive component (LPC) amplitudes.

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Extending Başar'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.

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Article Synopsis
  • The study investigates how resting state EEG rhythms differ among patients with dementia with Lewy bodies (DLB), focusing on their clinical symptoms compared to Alzheimer's disease (AD) and healthy elderly individuals.
  • It involved analyzing EEG data from matched groups, revealing greater delta activities in DLB compared to AD and highlighting differences in alpha activities related to cognitive impairments among DLB patients.
  • The findings suggest that specific clinical symptoms in DLB correlate with distinct EEG patterns, which could serve as potential biomarkers for future research on the disorder.
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Objective: The Stroop test Çapa version does not have normative data, despite its extensive use in clinical and research settings to assess executive functions. The aim of the present study was to test the validity and reliability of the Stroop test Çapa version and to establish stratified normative data in individuals aged between 18-83 years.

Method: The norm determination phase of the study included 541 healthy participants, stratified by age, education, and gender.

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Compared with Alzheimer's disease (AD), Parkinson's disease (PD) shows peculiar clinical manifestations related to vigilance (i.e., executive cognitive deficits and visual hallucinations) that may be reflected in resting-state electroencephalographic rhythms.

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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.

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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.

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Objective: Functional and structural brain alterations of cognitively normal Parkinson's disease (PD-CN) and Parkinson's disease mild cognitive impairment (PD-MCI) patients were investigated using event-related potentials (ERP) P300 and volumetric magnetic resonance imaging (MRI) parameters.

Methods: Twenty three patients with PD-CN, 21 with PD-MCI, and 23 demographically-matched healthy controls were included. EEGs were recorded using a visual oddball task and mean amplitude and peak latency values of P300 were measured.

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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.

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Previous evidence has shown different resting-state eyes-closed electroencephalographic delta (<4 Hz) and alpha (8-10.5 Hz) source connectivity in subjects with dementia due to Alzheimer's (ADD) and Lewy body (DLB) diseases. The present study tested if the same differences may be observed in the prodromal stages of mild cognitive impairment (MCI).

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We hypothesized that dopamine neuromodulation might affect cortical excitability in Parkinson's disease (PD) patients set in quiet wakefulness, as revealed by resting state eyes-closed electroencephalographic (rsEEG) rhythms at alpha frequencies (8-12 Hz). Clinical and rsEEG rhythms in PD with dementia (N = 35), PD with mild cognitive impairment (N = 50), PD with normal cognition (N = 35), and normal (N = 50) older adults were available from an international archive. Cortical rsEEG sources were estimated by exact low-resolution brain electromagnetic tomography.

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Obstructive sleep apnea syndrome (OSAS) is a sleep disorder characterized with upper airway obstructions. Some studies showed cognitive and electrophysiological changes in patients with OSAS; however, contradictory results were also reported. The purpose of the present study was twofold: (1) to investigate cognitive changes in severe OSAS patients by using neuropsychological tests and electrophysiological methods together, (2) to investigate influence of hypoxemia levels on cognition.

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Objective: This study tested the hypothesis that markers of functional cortical source connectivity of resting state eyes-closed electroencephalographic (rsEEG) rhythms may be abnormal in subjects with mild cognitive impairment due to Alzheimer's (ADMCI) and Parkinson's (PDMCI) diseases compared to healthy elderly subjects (Nold).

Methods: rsEEG data had been collected in ADMCI, PDMCI, and Nold subjects (N = 75 for any group). eLORETA freeware estimated functional lagged linear connectivity (LLC) from rsEEG cortical sources.

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The present study tested the hypothesis that cortical sources of resting state eyes-closed electroencephalographic (rsEEG) rhythms reveal different abnormalities in cortical neural synchronization in groups of patients with mild cognitive impairment due to Alzheimer's disease (ADMCI) and dementia with Lewy bodies (DLBMCI) as compared to cognitively normal elderly (Nold) subjects. Clinical and rsEEG data in 30 ADMCI, 23 DLBMCI, and 30 Nold subjects were available in an international archive. Age, gender, and education were carefully matched in the three groups.

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Article Synopsis
  • This study investigates resting-state EEG rhythms in Alzheimer's Disease (ADD), Parkinson's Disease with Dementia (PDD), and Lewy Body Dementia (DLB) to evaluate functional cortical connectivity abnormalities.
  • Results indicated that ADD patients showed significantly higher delta connectivity and reduced alpha connectivity compared to PDD and DLB participants, suggesting distinct neurophysiological disruptions in ADD.
  • The study found better classification accuracy in differentiating ADD patients from healthy older individuals compared to those with DLB or PDD, highlighting a compromised neurophysiological reserve in ADD.
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Article Synopsis
  • This study explored differences in brain activity patterns between patients with Alzheimer's disease (ADMCI), Parkinson's disease (PDMCI), and healthy elderly individuals using resting state electroencephalography (rsEEG).
  • Researchers found that the source activities of certain brain wave frequencies (alpha and delta) were significantly different in the ADMCI and PDMCI groups compared to healthy subjects, indicating distinct neural synchronization abnormalities.
  • The findings suggest that these brain wave patterns could potentially help in diagnosing and understanding cognitive impairments, and future studies are needed to validate their clinical usefulness.
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Introduction: Parkinson's disease (PD) is the second most common neurodegenerative disease after Alzheimer's disease. Cognitive changes in PD are less observable than motor symptoms; thus, research on cognitive processes, which are known to be impaired from the early stages of PD, is minimal. The purpose of this study is to research the brain dynamics of cognitively normal PD patients and healthy elderly controls using event-related potentials (ERPs) and to evaluate their relationships with neuropsychological tests.

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Article Synopsis
  • The study examined how resting state electroencephalographic (rsEEG) rhythms may indicate brain arousal in different types of dementia: Alzheimer's (ADD), Parkinson's (PDD), and Lewy body (DLB) dementia.
  • Data from 158 subjects, including healthy elderly individuals, revealed that patients showed significant differences in brain wave patterns, particularly in alpha and delta activities, compared to healthy individuals.
  • The findings suggest that specific rsEEG markers can help distinguish between the types of dementia and may have future applications in clinical settings and drug discovery.
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Background: Brain oscillatory responses can be used for non-invasive analyses of cortico-cortical connectivity, local neuronal synchronization, and coherence of oscillations in many neuropsychiatric conditions including Alzheimer's disease (AD). In the present paper, we examine sensory-evoked and event-related gamma coherences elicited by visual stimuli in three sub-gamma bands in two sub-groups of patients with AD (i.e.

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Introduction: Hippocampal volume is a core biomarker of Alzheimer's disease (AD). However, its contribution over the standard diagnostic workup is unclear.

Methods: Three hundred fifty-six patients, under clinical evaluation for cognitive impairment, with suspected AD and Mini-Mental State Examination ≥20, were recruited across 17 European memory clinics.

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