Inter- and Intra-Hemispheric EEG Coherence Study in Adults with Neuropsychiatric Disorders

Abstract

Functional connectivity between different regions of the brain in the resting state has been a recent topic of interest in neurophysiological research. EEG coherence happened to be an useful tool for measuring changes in neuro-psycho-physiological functioning which are not detectable by simply measuring amplitude or power spectra. The aim of our study was to investigate the changes in the EEG coherence in groups of different mental disorders such as: depression, general anxiety disorder, ADHD, Asperger syndrome and headaches, compared to control group. All measures were made in two conditions: eye opened (EO) and eyes closed (EC). The obtained results show that in EO condition there is a significantly lower coherence for delta waves between analyzed groups. For theta coherence only for Asperger syndrome we found lower coherence compared to control group, ADHD and headaches in parietal region (P3-P4). Obtained results for intrahemispheric coherence have shown that there was significantly lower coherence in both conditions for delta and theta bands in almost all sites for Asperger’s syndrome, and opposite increased intrahemispheric coherence for patients with headaches (for delta band in the anterior regions and for theta band in the posterior regions). ADHD patients expressed lower delta inter-hemispheric coherence in frontal regions, and increased coherence of theta in central regions but increased delta coherence in posterior regions only in EO condition. For depressive and anxiety patients we found decreased intrahemispheric coherence for EO condition for delta brain waves all over the cortex. Concerning the coherence in anxiety patients in our current study we have obtained hypo coherence in centro-parieto-occipital region only for delta in inter-hemispheric coherence and also lower delta coherence through the cortex for intrahemispheric coherence. Our findings for interhemispheric hyper coherence in subjects with depression specifically for alpha and beta bands were confirmed in other studies. We suggest that EEG coherence analysis could be a sensitive parameter in the detection of electrophysiological abnormalities in patients with anxiety, depression, ADHD, Asperger syndrome and headaches. These results can confirm the development of QEEG state and trait biomarkers for psychiatric disorders.

Frontal EEG Asymmetry of Emotion for the Same Auditory Stimulus

“…This characteristic was particularly noticeable in the positive valence group. Delta coherence increases with cognitive load [79] and reflects the emotion regulation process [34]; this characteristic of delta connectivity may be relevant to changes in emotion. In addition, in line with our results, there is a positive correlation between valence and frontal inter-hemispheric flow [80].…”

“…Usually, these sounds are expected to elicit positive emotions [33], but we expected that they would elicit different emotions. Delta and alpha bands play an important role in the emotion regulation process [15], [34]. In this regard, we hypothesized that the brain signals may differ with subjective emotions, especially in delta and alpha bands, even if participants listened to the same auditory stimulus.…”

Abnormalities in cortical pattern of coherence in interictal migraine detected using ultra high-density EEG

“…To rectify this, we examined auditory and visual evoked signals across the five EEG frequency bands. The key results from the spatial coherence analysis, a measure of synchronization of the electro-cortical activities (Markovska-Simoska, et al, 2018), revealed that migraineurs showed significantly lower spatial coherence of alpha-band neural activities during the auditory and visual stimuli in comparison with the controls. This profile was especially evident in lower to mid-range distances (not too large, not too short) between the frontal clusters of scalp electrodes and other clusters especially during the visual stimulation.…”

“…Although EEG amplitude measurements or calculation of power spectra are simple to compute, we elected to study coherence, which is considered to be a reliable measure of synchronization of the electro-cortical activities (Markovska-Simoska, et al, 2018) and has been used to investigate connectivity in migraine previously (refs where applicable). Because spatial coherence drops as a function of distance between electrodes, we analyzed the estimated coherence as a function of inter-electrode distance (link length).…”

Analysis of EEG Characteristics and Coherence in Patients Diagnosed as Borderline Personality

“…In our previous research we evaluated inter and intrahemispheric EEG coherence in different psychiatric disorders such as: ADHD, anxiety, depression, and Asperger's syndrome (ASP) compared with healthy controls [14].…”