Derya Durusu Emek-Savaş1, Bahar Güntekin2, Görsev G Yener3, Erol Başar4. 1. Department of Psychology, Dokuz Eylül University, Izmir 35160, Turkey; Department of Neurosciences, Dokuz Eylül University, Izmir 35340, Turkey; Brain Dynamics, Cognition and Complex Systems Research Center, Istanbul Kültür University, Istanbul 34156, Turkey. 2. Brain Dynamics, Cognition and Complex Systems Research Center, Istanbul Kültür University, Istanbul 34156, Turkey. 3. Department of Neurosciences, Dokuz Eylül University, Izmir 35340, Turkey; Brain Dynamics, Cognition and Complex Systems Research Center, Istanbul Kültür University, Istanbul 34156, Turkey; Department of Neurology, Dokuz Eylül University Medical School, Izmir 35340, Turkey; Brain Dynamics Multidisciplinary Research Center, Dokuz Eylül University, Izmir 35340, Turkey. 4. Brain Dynamics, Cognition and Complex Systems Research Center, Istanbul Kültür University, Istanbul 34156, Turkey. Electronic address: e.basar@iku.edu.tr.
Abstract
BACKGROUND: The purpose of this study was to investigate changes in delta event-related oscillations (EROs) in younger and older healthy elderly subjects. We hypothesized that delta EROs were affected by age-related changes, which could be reflected in a visual oddball paradigm. METHOD: The study included two groups of subjects, 17 younger healthy elderly (mean age: 63.1±2.8years) and 17 gender- and education-matched older healthy elderly (mean age: 79.6±5.2years), who performed a visual oddball paradigm. EEG was recorded from F3, Fz, F4, C3, Cz, C4, P3, Pz, P4, O1, Oz and O2 locations. Peak-to-peak amplitudes of delta (0.5-3Hz) target ERO responses during the post-stimulus 0-800ms time window were measured. Repeated measures of ANOVA was used to analyze four locations (frontal, central, parietal, occipital), at three sagittal (left, midline, right) sites. Independent t-tests were applied for post-hoc analyses. RESULTS: The older healthy elderly group had 16-25% lower values for the maximum peak-to-peak amplitudes of delta ERO compared with the younger healthy elderly group over frontal (p<0.003), central (p<0.0001) and parietal (p<0.007) locations [F3.96=4.396, p=0.015]. Furthermore, there was a moderate negative correlation between age and Cz peak-to-peak amplitude of target delta responses [r=-0.401, p<0.02], indicating the notion that peak-to-peak amplitude of Cz decreases as age increases. CONCLUSION: In the present study younger healthy elderly showed significantly higher event-related delta responses than older healthy elderly at frontal, central and parietal locations. Moreover, delta ERO responses decreased in accordance with age.
BACKGROUND: The purpose of this study was to investigate changes in delta event-related oscillations (EROs) in younger and older healthy elderly subjects. We hypothesized that delta EROs were affected by age-related changes, which could be reflected in a visual oddball paradigm. METHOD: The study included two groups of subjects, 17 younger healthy elderly (mean age: 63.1±2.8years) and 17 gender- and education-matched older healthy elderly (mean age: 79.6±5.2years), who performed a visual oddball paradigm. EEG was recorded from F3, Fz, F4, C3, Cz, C4, P3, Pz, P4, O1, Oz and O2 locations. Peak-to-peak amplitudes of delta (0.5-3Hz) target ERO responses during the post-stimulus 0-800ms time window were measured. Repeated measures of ANOVA was used to analyze four locations (frontal, central, parietal, occipital), at three sagittal (left, midline, right) sites. Independent t-tests were applied for post-hoc analyses. RESULTS: The older healthy elderly group had 16-25% lower values for the maximum peak-to-peak amplitudes of delta ERO compared with the younger healthy elderly group over frontal (p<0.003), central (p<0.0001) and parietal (p<0.007) locations [F3.96=4.396, p=0.015]. Furthermore, there was a moderate negative correlation between age and Cz peak-to-peak amplitude of target delta responses [r=-0.401, p<0.02], indicating the notion that peak-to-peak amplitude of Cz decreases as age increases. CONCLUSION: In the present study younger healthy elderly showed significantly higher event-related delta responses than older healthy elderly at frontal, central and parietal locations. Moreover, delta ERO responses decreased in accordance with age.