Changes during aging in the electroencephalographic cortical
                        synchronization under visual stimulation

This paper analyzes changes during aging in the electroencephalographic (EEG) synchronization between different areas of the cerebral cortex in healthy elderly subjects under visual stimulation. Two groups were selected: one (A) of 10 adults aged 50-65 years and another (B) of 15 subjects aged 66-80 years. EEG recordings of 16 "monopolar" channels were carried out (digitized at 256 Hz), all referenced to the mean and following the standard 10-20 system, and were performed at rest with eyes closed under visual stimulation. From an index (L) of nonlinear generalized synchronization, the average cortical synchronization (ACS) of each channel with the rest and the corresponding average asymmetry in the synchronization (ACM) was estimated. Changes with age (A vs. B) in cortical synchronization and in average interhemispheric asymmetry for all cortical areas were estimated via a repeated measures MANOVA. The results show that under visual stimulation, the SCM decreases with age for most channels (p < 0.01) except for the frontals. The channels that showed asymmetry in the synchronization (p < 0.01) were the frontals F3, F4 y Fp2, the parietal P3 and the temporal T5, in all of them a significant reduction in asymmetry with age (p < 0.01) was observed.

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Changes in the temporal variability of the EEG functional connectivity during aging

European Journal of Investigation in Health, Psychology and Education ◽

10.3390/ejihpe7010001 ◽

2015 ◽

Vol 7 (1) ◽

pp. 5-15

Author(s):

Almudena González ◽

Guzmán Alba ◽

Julián González

Keyword(s):

Functional Connectivity ◽

Cognitive Performance ◽

Temporal Variability ◽

Healthy Subjects ◽

Generalized Synchronization ◽

Performance Deficits ◽

Cortical Areas ◽

Eyes Closed ◽

Eeg Recordings ◽

Eeg Functional Connectivity

This work is aimed at investigating changes in the temporal variability of EEG functional connectivity (FC) during agin. The variability in the FC has been linked to cognitive performance. The study was carried out in two groups of healthy subjects: one of 10 adults between 50-65 years old and another of 15 subjects ranging 66-85 years. EEG recordings were made at rest using 16 monopolar channels: under eyes closed (EC) and under hyperventilation (HV). The cortical FC between all EEG channel pairs was estimated from an index (L) of nonlinear generalized synchronization. For each subject and condition, the global connectivity (GC) of each area/channel with the rest of them was calculated, then the GC average and the GC temporal variability (TVC) of such connectivities was computed from the GC mean and standard deviation of successive EEG recordings respectively. The changes with age and condition of GC and TVC of each cortical area were estimated via a MANOVA. We found that the GC does not change with age during OC or HV, but the TVC of all cortical areas is significantly higher (p<0.01) for subjects under 65 and mainly for the central, temporal and parietal areas (p<0.01). It is concluded that TVC decreasing with aging may be related to cognitive performance deficits.

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Changes in the temporal variability of the EEG functional connectivity during aging

European Journal of Investigation in Health, Psychology and Education ◽

10.1989/ejihpe.v7i1.189 ◽

2015 ◽

Vol 7 (1) ◽

pp. 5-15

Author(s):

Almudena González ◽

Guzmán Alba ◽

Julián González

Keyword(s):

Functional Connectivity ◽

Cognitive Performance ◽

Temporal Variability ◽

Healthy Subjects ◽

Generalized Synchronization ◽

Performance Deficits ◽

Cortical Areas ◽

Eyes Closed ◽

Eeg Recordings ◽

Eeg Functional Connectivity

This work is aimed at investigating changes in the temporal variability of EEG functional connectivity (FC) during agin. The variability in the FC has been linked to cognitive performance. The study was carried out in two groups of healthy subjects: one of 10 adults between 50-65 years old and another of 15 subjects ranging 66-85 years. EEG recordings were made at rest using 16 monopolar channels: under eyes closed (EC) and under hyperventilation (HV). The cortical FC between all EEG channel pairs was estimated from an index (L) of nonlinear generalized synchronization. For each subject and condition, the global connectivity (GC) of each area/channel with the rest of them was calculated, then the GC average and the GC temporal variability (TVC) of such connectivities was computed from the GC mean and standard deviation of successive EEG recordings respectively. The changes with age and condition of GC and TVC of each cortical area were estimated via a MANOVA. We found that the GC does not change with age during OC or HV, but the TVC of all cortical areas is significantly higher (p<0.01) for subjects under 65 and mainly for the central, temporal and parietal areas (p<0.01). It is concluded that TVC decreasing with aging may be related to cognitive performance deficits.

Download Full-text