Aberrant Whole-Brain Resting-State Functional Connectivity Architecture in Obsessive-Compulsive Disorder: An EEG Study

Abstract

Obsessive-compulsive disorder (OCD) is a common neuropsychiatric disorder characterized by intrusive thoughts (obsessions) and repetitive behaviors (compulsions), and few studies have assessed the whole-brain functional connectivity architecture of OCD with electroencephalogram (EEG) during different resting states. Graph theory and network-based statistics (NBS) were employed to examine the neural synchronization and the whole-brain functional connectivity (FC) based on the phase-locking value (PLV) of OCD patients and healthy controls (HCs) during eyes-closed (EC) and eyes-open (EO) states. Compared with HCs, OCD patients exhibited not only decreased global synchronization in terms of phase synchrony but also aberrant global topological properties (decreased average shortest path lengths and normalized shortest path lengths together with increased global efficiencies and normalized clustering coefficients) together with inhibited intra-hemispheric and interhemispheric FCs during rest, which suggested an imbalance between functional integration and segregation of brain networks for OCD patients. Meanwhile, OCD patients had increased global efficiencies and normalized clustering coefficients, but decreased average clustering coefficients and normalized shortest path lengths together with significantly decreased FCs in the alpha band from EC to EO states, which suggested a dynamic switch between highly integrated (EC state) and highly specialized (EO state) modes of information processing. Moreover, the decreased FCs of OCD patients showed obvious hemispheric asymmetry within or between groups during EC and EO states, which might serve as a potential biomarker to classify OCD patients from HCs.

The Dynamics of Resting-State EEG and Salivary Trace Elements in Patients with Obsessive-Compulsive Disorder

“…Previous findings demonstrated EEG changes were typical for most of the mental disorders with prominent cognitive deficits and included decreased global functional connectivity, , and elevated low-frequency activity with decreases across higher frequencies . At the same time, the promising results regarding specific EEG changes in patients with OCD were found in the case of emotional stimulation. , According to the previous findings, patients with OCD exhibit the most prominent symptoms and manifestation of the disease when subjected to mental and emotional stress, a common occurrence in many individuals with mental and neurological disorders .…”

“…The resulting spectral power (μV 2 ) values were integrated over intervals of unit width in the range of interest for the following bands (2−3 Hz, 3−4 Hz, ..., 19−20 Hz). Additionally, the PSD data were united in broader frequency bands as follows: slow-wave (2−6 Hz), alpha 1 (8−10 Hz), alpha-2 (10−12 Hz), and beta (12)(13)(14)(15)(16)(17)(18)(19)(20). The logarithmic values of the PSD of the bands were used for statistical analysis.…”

“…various elements in the blood of OCD patients, which may indicate a violation of elemental homeostasis. 12 Previous findings demonstrated EEG changes were typical for most of the mental disorders with prominent cognitive deficits and included decreased global functional connectivity, 13,14 and elevated low-frequency activity with decreases across higher frequencies. 15 At the same time, the promising results regarding specific EEG changes in patients with OCD were found in the case of emotional stimulation.…”

Connectivity Analysis in EEG Data: A Tutorial Review of the State of the Art and Emerging Trends

“… Functional integration, based on the concept of path [ 248 , 254 ] and estimating the ease of communication between brain areas. These measures have been found useful in studies related to obsessive-compulsive disorders, since their alterations seem to be correlated with the severity of the illness [ 255 , 256 ]. Networks which are simultaneously highly segregated and integrated are referred to as small-world networks; a measure of small-worldness was proposed to describe this property [ 248 , 257 ].…”

Effect of the Emotional Antisaccade Tasks on Salivary Trace Elements and Resting State EEG in Patients with Obsessive-Compulsive Disorder

“…Regarding the EEG speci c changes in patients with OCD, previous ndings demonstrated studies the non-speci c EEG changes were typical for most of the mental disorders with prominent cognitive de cits and included decreased global functional connectivity [15] [16], and elevated low-frequency activity with decreases across higher frequencies [17]. At the same time, the promising results regarding speci c EEG changes in patients with OCD contributed to the dynamics changes of the EEG in the case of emotional stimulation [18] [19].…”