Browsing by Author "Yerlikaya, Deniz"

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Citation - WoS: 2
Citation - Scopus: 2
Age-Related Aspects of Sex Differences in Event-Related Brain Oscillatory Responses: a Turkish Study
(Mdpi, 2024) Yener, Görsev; Kıyı, İlayda; Düzenli-Öztürk, Seren; Yerlikaya, Deniz
Earlier research has suggested gender differences in event-related potentials/oscillations (ERPs/EROs). Yet, the alteration in event-related oscillations (EROs) in the delta and theta frequency bands have not been explored between genders across the three age groups of adulthood, i.e., 18-50, 51-65, and >65 years. Data from 155 healthy elderly participants who underwent a neurological examination, comprehensive neuropsychological assessment (including attention, memory, executive function, language, and visuospatial skills), and magnetic resonance imaging (MRI) from past studies were used. The delta and theta ERO powers across the age groups and between genders were compared and correlational analyses among the ERO power, age, and neuropsychological tests were performed. The results indicated that females displayed higher theta ERO responses than males in the frontal, central, and parietal regions but not in the occipital location between 18 and 50 years of adulthood. The declining theta power of EROs in women reached that of men after the age of 50 while the theta ERO power was more stable across the age groups in men. Our results imply that the cohorts must be recruited at specified age ranges across genders, and clinical trials using neurophysiological biomarkers as an intervention endpoint should take gender into account in the future.
Citation - WoS: 1
Citation - Scopus: 1
Attitudes Toward Pre-Symptomatic Screening for Alzheimer's Dementia in Five European Countries: a Comparison of Family Members of People With Alzheimer's Dementia Versus Non-Family Members
(Frontiers Media Sa, 2023) Angelidou, Ioanna A.; Makri, Marina; Beyreuther, Konrad; Rovira, Merce Boada; Despoti, Akyllina; Engelborghs, Sebastiaan; Miguel, Andrea; Yener, Görsev; Yerlikaya, Deniz
Introduction: Pre-symptomatic screening is getting more attention in healthcare as it detects the risk for developing neurodegenerative diseases like Alzheimer's disease (AD), which is very useful for treatment or prevention. AD screening could play an important role in individuals with at least one affected first-degree relative, but also without family history. As the demand for screening is rising worldwide, it is important to consider possible cross-cultural differences in attitudes toward pre-symptomatic screening in order to tailor healthcare services to the needs of each country.Objective: This study aims to investigate the attitudes of family members and non-family members of people with dementia toward pre-symptomatic screening and explore possible differences in attitudes across five European countries (Belgium, Germany, Greece, Spain, Turkey) using translated versions of the Perceptions regarding pRE-symptomatic Alzheimer's Disease Screening questionnaire (PRE-ADS).Methods: The multicultural sample (N = 650) was recruited from samples that were previously used in validation studies of the translated PRE-ADS versions. The subscale Acceptability of Screening, consisting of five PRE-ADS items to specifically explore willingness to undergo screening, was created. Iota nternal consistency was measured, and structural validity was determined using Confirmatory Factor Analysis (CFA). Group comparisons were performed to investigate differences in attitudes toward pre-symptomatic AD screening regarding family history and country of origin using the PRE-ADS and the Acceptability of Screening mean scores.Results: Construct validity was acceptable for the PRE-ADS. Both the PRE-ADS (alpha = 0.76) and its subscale Acceptability of Screening (alpha = 0.90) had good internal consistency. Overall, 56.9% of the total sample expressed a positive intention toward pre-symptomatic AD screening. T-tests showed significantly higher mean scores of participants with an affected family member. An international comparison revealed differences in the Acceptability of Screening mean score across the five European countries. No cross-cultural differences were found for the PRE-ADS mean score after adjusting for confounding variables.Conclusion: The PRE-ADS and its subscale are reliable tools for assessing pre-symptomatic AD screening attitudes. Variations in the acceptability of screening seem to be linked to family history and cultural influences. Further research with larger samples is needed to explore underlying relationships.
Citation - WoS: 12
Citation - Scopus: 13
Coherence in Event-Related Eeg Oscillations in Patients With Alzheimer's Disease Dementia and Amnestic Mild Cognitive Impairment
(Springer, 2022) Fide, Ezgi; Yerlikaya, Deniz; Guntekin, Bahar; Babiloni, Claudio; Yener, Görsev
Objectives Working memory performances are based on brain functional connectivity, so that connectivity may be deranged in individuals with mild cognitive impairment (MCI) and patients with dementia due to Alzheimer's disease (ADD). Here we tested the hypothesis of abnormal functional connectivity as revealed by the imaginary part of coherency (ICoh) at electrode pairs from event-related electroencephalographic oscillations in ADD and MCI patients. Methods The study included 43 individuals with MCI, 43 with ADD, and 68 demographically matched healthy controls (HC). Delta, theta, alpha, beta, and gamma bands event-related ICoh was measured during an oddball paradigm. Inter-hemispheric, midline, and intra-hemispheric ICoh values were compared in ADD, MCI, and HC groups. Results The main results of the present study can be summarized as follows: (1) A significant increase of midline frontal and temporal theta coherence in the MCI group as compared to the HC group; (2) A significant decrease of theta, delta, and alpha intra-hemispheric coherence in the ADD group as compared to the HC and MCI groups; (3) A significant decrease of theta midline coherence in the ADD group as compared to the HC and MCI groups; (4) Normal inter-hemispheric coherence in the ADD and MCI groups. Conclusions Compared with the MCI and HC, the ADD group showed disrupted event-related intra-hemispheric and midline low-frequency band coherence as an estimate of brain functional dysconnectivity underlying disabilities in daily living. Brain functional connectivity during attention and short memory demands is relatively resilient in elderly subjects even with MCI (with preserved abilities in daily activities), and it shows reduced efficiency at multiple operating oscillatory frequencies only at an early stage of ADD.
Citation - WoS: 7
Citation - Scopus: 8
Normalized Theta but Increased Gamma Activity After Acetylcholinesterase Inhibitor Treatment in Alzheimer's Disease: Preliminary Qeeg Study
(Sage Publications Inc, 2023) Fide, Ezgi; Yerlikaya, Deniz; Öz, Didem; Öztura, İbrahim; Yener, Görsev
Acetylcholinesterase inhibitors (AChE-I) are the core treatment of mild to severe Alzheimer's disease (AD). However, the efficacy of AChE-I treatment on electroencephalography (EEG) and cognition remains unclear. We aimed to investigate the EEG power and coherence changes, in addition to neuropsychological performance, following a one-year treatment. Nine de-novo AD patients and demographically-matched healthy controls (HC) were included. After baseline assessments, all AD participants started cholinergic therapy. We found that baseline and follow-up gamma power analyzes were similar between groups. Yet, within the AD group after AChE-I intake, individuals with AD displayed higher gamma power compared to their baselines (P < .039). Also, baseline gamma coherence analysis showed lower values in the AD than in HC (P < .048), while these differences disappeared with increased gamma values of AD patients at the follow-up. Within the AD group after AChE-I intake, individuals with AD displayed higher theta and alpha coherence compared to their baselines (all, P < .039). These increased results within the AD group may result from a subclinical epileptiform activity. Even though AChE-I is associated with lower mortality, our results showed a significant effect on EEG power yet can increase the subclinical epileptiform activity. It is essential to be conscious of the seizure risk that treatment may cause.
Citation - WoS: 10
Citation - Scopus: 11
The Reliability of P300 and the Influence of Age, Gender and Education Variables in a 50 Years and Older Normative Sample
(Elsevier, 2022) Yerlikaya, Deniz; Hunerli-Günduz, Duygu; Fide, Ezgi; Özbek, Yağmur; Kıyı, İlayda; Öztura, İbrahim; Yener, Görsev
Objectives: The present study aims to investigate the effects of age, gender, and level of education on P300 in a healthy population, aged 50 years and over; and determine the reliability metrics for different conditions and measurement methods.Method: Auditory and visual oddball recordings of 171 healthy adults were investigated. A fully automated preprocessing was applied to elicit ERP P300. Maximum peak amplitude, latency and mean amplitudes were measured. Data were stratified by age, gender, and education to determine group-level differences by using repeat measures of ANOVA. The internal consistency of P300 was calculated by a split-half method using odd-even segments. Test-retest reliability was assessed by calculating the intraclass correlation coefficient (ICC).Results: Maximum peak P300 amplitudes were higher in the 50-64 years age group compared to the >65 years age group; and females showed increased P300 amplitudes compared to males. P300 measures showed fair to good internal consistency and poor to good test-retest reliability.Conclusion: Age and gender should be taken into account when designing ERP studies with elderly individuals. P300 showed good internal consistency in general, between gender groups and age groups. Long-term test-retest reliability was lower but acceptable. These findings can be interpreted as the strength of P300 by being an objective and reliable method independent of cultural differences. Here we underline several factors that may affect P300 measures and discuss other possible factors that should be standardized for P300 to be used in clinical settings.
Citation - WoS: 2
Resting-State Eeg Findings in Differentiating Alzheimer's Disease From Amnestic Mild Cognitive Impairment and Healthy Elderly Controls
(Galenos Publ House, 2021) Kayal, Ozgecan; Gunduz, Duygu Hunerli; Yerlikaya, Deniz; Yener, Görsev
Objective: We aimed at investigating alterations in Resting-State electroencephalography (rsEEG) patterns of individuals with amnestic mild cognitive impairment (aMCI), and Alzheimer's disease (AD). Materials and Methods: Twenty healthy controls (HC) with 20 aMCI, and 20 AD patients were included in the study. EEG data was recorded for 4 minutes of eyes-closed condition according to the International 10-20 system. EEG rhythms of interest were delta (0.5-3.9 Hz), theta (4-7.8 Hz), alpha 1 (8-10.4 Hz), alpha 2 (10.5-13 Hz), and beta (13-30 Hz). The discriminatory power of rsEEG between groups was evaluated using the receiver operating characteristic analysis. Correlations among cognitive scores and power values of rsEEG were analyzed using Pearson correlation analysis. Results: We observed effects on delta [F-(2.57): 8.353; p=0.001}, theta [F-(2.57): 5.038; p=0.010}, alpha 1 [F-(2.57): 3.837; p=0.027}, and alpha 2 [F-(2.57): 4.209; p=0.020} power between groups. Moreover, interaction effects for anterior-posterior electrode location x group on delta [F-(6.171): 2.621; p=0.038}, and theta [F-(6.171): 3.537; p=0.020} power were also detected. AD group demonstrated decreased delta power in frontal, central and parietal locations (for all; p<0.040) compared to HC and aMCI groups. In addition, the AD group also had decreased alpha and alpha1 power in comparison with HC (for all; p<0.026). Furthermore, we recorded a sensitivity of 80.0% and a specificity of 80.0% of delta power when using the cut-off score of >1.71 to identify AD from aMCI at central electrodes, and >1.73 to identify AD from HC at parietal electrodes. Moderate correlations were also detected among cognitive scores and rsEEG rhythms. Conclusion: This study revealed the importance of delta and theta activity in rsEEG both as an electrophysiological indicator of cognitive status in AD and as a discriminatory tool for detecting aMCI.