Search Results

1 - 5 of 5 items

  • Author: Jordan Pop-Jordanov x
Clear All Modify Search


EEG can determine changes in brain activity that might be useful in diagnosing different brain disorders as well as some mental states. Many advantages of this record have been the reason for resurrect the EEG in current clinical practice and research. More sophisticated form, the Q-EEG comprises a procedure that processes the recorded EEG activity from a multi-electrode recording using a computer, where data is processed with various algorithms, such as the Fourier or Wavelet analysis. Q-EEG data are important as a marker for many psychophysiological disorders.

Neurofeedback (NF) is a form of behavioural training aimed at developing skills for self-regulation of brain activity. It is a treatment method for altering brain functioning by the use of signals provided to a patient that reflect the moment-to-moment changes in the patient’s electroencephalogram.

This article summarizes some of our large experience with neurofeedback training in different groups of disorders in children and adolescents. Positive outcome is promising for more expansive use of this non-pharmacological, cost-benefit methodology in paediatric and general population.


Stress, as a kind of emotion, is inevitable in everyday life. In psychosomatic medicine stress represents a powerful link in the pathophysiological chain of disorder. Having evidence about the power of stress on the body, the interest in medicine was how to measure it in appropriate, fast way and with minimal cost. Electrodermal activity seems to be available for this purpose.

The galvanic skin response (GSR) is an objective, transient indication of autonomic nervous system arousal in response to a stimulus. It refers to changes in sweat gland activity that are reflective of the intensity of our emotional arousal.

In this article we discuss physiological specifics of skin conductance/resistance and how it is measured in practice. The most used application of GSR is in biofeedback methodology. Biofeedback assessment and training exactly uses skin reaction to different stimuli and aims to gain voluntary control over this autonomic response. The aim of this article is to show effectiveness of this method in paediatric practice.


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.


In the last decade, many studies have tried to define the neural correlates of attention deficit hyperactivity disorder (ADHD). The main aim of this study is the comparison of the ERPs independent components in the four QEEG subtypes in a group of ADHD adults as a basis for defining the corresponding endophenotypes among ADHD population.

Sixty-seven adults diagnosed as ADHD according to the DSM-IV criteria and 50 age-matched control subjects participated in the study. The brain activity of the subjects was recorded by 19 channel quantitative electroencephalography (QEEG) system in two neuropsychological tasks (visual and emotional continuous performance tests). The ICA method was applied for separation of the independent ERPs components. The components were associated with distinct psychological operations, such as engagement operations (P3bP component), comparison (vcomTL and vcom TR), motor inhibition (P3supF) and monitoring (P4monCC) operations.

The ERPs results point out that there is disturbance in executive functioning in investigated ADHD group obtained by the significantly lower amplitude and longer latency for the engagement (P3bP), motor inhibition (P3supF) and monitoring (P4monCC) components. Particularly, the QEEG subtype IV was with the most significant ERPs differences comparing to the other subtypes.

In particular, the most prominent difference in the ERPs independent components for the QEEG subtype IV in comparison to other three subtypes, rise many questions and becomes the subject for future research.

This study aims to advance and facilitate the use of neurophysiological procedures (QEEG and ERPs) in clinical practice as objective measures of ADHD for better assessment, subtyping and treatment of ADHD.


Introduction: Covering a handful of decades but spanning across two centuries, mobile phones announced the dawn of the technological revolution, standing at the forefront as its′ most prominent symbol. Over the course of their sovereign dominance, human generations born with the birth of the mobile phone reached the age of maturity, while scientific community started reaching for experience-based perceptivity.

Aim: The following review serves as a short-cut across a half-decade old research gap, and a clear-cut analysis on the cutting-edge knowledge of the EMF induced EEG changes.

Material and Methods: The selection covers 28 articles about mobile phone effects on resting wakeful EEG in humans conducted over the last two decades, across three continents and 12 countries, of which 75% had positive findings.

Conclusions: At present, the general protocol of a typical study includes investigations on adults (20-60 yrs) grouped in smaller samples and exposed to shorter intervals of GSM-like pulse-modulated signal (10-30 subjects/minutes). The assessment usually involves linear methods for quantitative analysis, while the results mostly revolve around posterior increase in alpha and beta frequency range. The qualitative variations, however, remain open to interpretation. Future research may benefit from multiplication of sub-specific studies leading to replication of more consistent results. The long-term and large-size epidemiologic studies, stratified by age and gender, may also improve the expected outcomes. Regarding the interpretation, non-linear methods could be employed for assessment of individual variations. The emphasis should be placed on theories/measures for better understanding of the subtle interplay between the spectral individualities and mobile phone radiation specifics.