Power spectral analysis is the most common method of quantitative electroencephalogram (qEEG) techniques and enables investigation of the microstructure of insomnia. Previous spectral analysis studies on insomnia have shown inconsistent results due to their heterogeneity and small sample sizes.

We compared the difference of electroencephalogram (EEG) spectral power during sleep among participants without insomnia, insomniacs with no hypnotic use, hypnotic users with no insomnia complaints, and hypnotic users with insomnia complaints.

We used the Sleep Heart Health Study data, which is large sample size and has good quality control. The fast Fourier transformation was used to calculate the EEG power spectrum for total sleep duration within contiguous 30-second epochs of sleep. For 1,985 participants, EEG spectral power was compared among the groups while adjusting for potential confounding factors that could affect sleep EEG.

The power spectra during total sleep differed significantly among the groups in all frequency bands (p corr < 0.001). We found that quantitative EEG spectral power in the beta and sigma bands of total sleep differed (p corr < 0.001) between participants without insomnia and hypnotic users with insomnia complaints after controlling for potential confounders. The higher beta and sigma power were found in the hypnotic users with insomnia complaints than in the non-insomnia participants.

This study suggests differences in the microstructures of polysomnography-derived sleep EEG between the insomnia groups.

No significant relationships.

Attention deficit hyperactivity (ADHD) disorder is a common childhood neurodevelopmental disorder, and Methylphenidate (MPH) is a first-line therapeutic option for treating ADHD.However, how brain connectivity changes with methylphenidate treatment have yet to be studied.

This study investigates how the MPH treatment affects the connectivity in the brain of children with ADHD by coherence-based qEEG analysis during rest.

During eyes-open resting, EEG signals were recorded from 25 boys with ADHD-combined type before MPH administration and at the end of the 1st month of the treatment. Mutual Information (MI),Coherence Function (COH) and Phase Locking Value (PLV) were used to analyse the changes in brain connectivity.

A statistically significant increase in connectivity level was found with MPH treatment between the F3-F4 channels, P3-P4 channels, F7-F8 channels and T5-T6 channels according to PLV, COH and MI analysis (p<0.001).

This is the first study to investigate how MPH treatment affects the connectivity of the brain of children with ADHD. Coherence-based qEEG analysis may be a new method that can be used in diagnostic, clinical and prognostic predictions in ADHD.

No significant relationships.

Previous studies of patients with unipolar depression have shown that early decrease of prefrontal EEG cordance in theta band can predict clinical response to various antidepressants. We have now examined whether decrease of prefrontal quantitative EEG (QEEG) cordance value after 1 week of venlafaxine treatment predicts clinical response to venlafaxine in resistant patients.

We analyzed 25 inpatients who finished 4-week venlafaxine treatment. EEG data were monitored at baseline and after 1 week of treatment. QEEG cordance was computed at three frontal electrodes in theta frequency band. Depressive symptoms and clinical status were assessed using Montgomery–Åsberg Depression Rating Scale (MADRS), Beck Depression Inventory-Short Form (BDI-S) and Clinical Global Impression (CGI).

Eleven of 12 responders (reduction of MADRS ≥50%) and only 5 of 13 non-responders had decreased prefrontal QEEG cordance value after the first week of treatment (p = 0.01). The decrease of prefrontal cordance after week 1 in responders was significant (p = 0.03) and there was no significant change in non-responders. Positive and negative predictive values of cordance reduction for response were 0.7 and 0.9, respectively.

The reduction of prefrontal theta QEEG cordance value after first week of treatment might be helpful in the prediction of response to venlafaxine.

Theta cordance is a novel quantitative electroencephalography (QEEG) measure that correlates with cerebral perfusion. A series of clinical studies has demonstrated that the prefrontal theta cordance value decreases after 1 week of treatment in responders to antidepressants and that this effect precedes clinical improvement. Ketamine, a non-competitive antagonist of N-methyl-d-aspartate (NMDA) receptors, has a unique rapid antidepressant effect but its influence on theta cordance is unknown.

In a double-blind, cross-over, placebo-controlled experiment we studied the acute effect of ketamine (0.54 mg/kg within 30 min) on theta cordance in a group of 20 healthy volunteers.

Ketamine infusion induced a decrease in prefrontal theta cordance and an increase in the central region theta cordance after 10 and 30 min. The change in prefrontal theta cordance correlated with ketamine and norketamine blood levels after 10 min of ketamine infusion.

Our data indicate that ketamine infusion immediately induces changes similar to those that monoamineric-based antidepressants induce gradually. The reduction in theta cordance could be a marker and a predictor of the fast-acting antidepressant effect of ketamine, a hypothesis that could be tested in depressive patients treated with ketamine.