BACKGROUND: One of the key issues in electroencephalogram (EEG) monitoring is accurate signal acquisition with less cumbersome electrodes. In this study, the L2 phase electro-deposited nanoporous platinum (L2-ePt) electrode is introduced, which is a new type of electrode that utilizes a stable nanoporous platinum surface to reduce the skin-electrode impedance. METHODS: L2-ePt electrodes were fabricated using electro-deposition technique. Then, the effect of the nanoporous surface on the surface roughness and the electrode impedance were observed from the L2-ePt electrodes and the flat platinum (FlatPt) electrode. The skin-electrode impedances of the L2-ePt electrodes, a gold cup electrode, and the FlatPt electrode were evaluated when placed on the hairy occipital area of the head in ten subjects. For the validation of using the L2-ePt electrode, a correlational analysis of the alpha rhythms was performed in the same subjects for simultaneous EEG recordings using the L2-ePt and clinically-used EEG electrodes. RESULTS: The results indicated that the L2-ePt electrode with a roughness factor of 200 had the lowest mean impedance performance. Moreover, the proposed L2-ePt electrode showed a significantly lower mean skin-electrode impedance than the FlatPt electrode. Finally, the EEG signal quality recorded by the L2-ePt electrode (r = 0.94) was comparable to that of the clinically-used gold cup electrode. CONCLUSION: Based on these results, the proposed L2-ePt electrode is suitable for use in various high-quality EEG applications.
Alpha Rhythm ; Electric Impedance ; Electrodes* ; Electroencephalography* ; Head ; Platinum*

BACKGROUND: Anesthesia induces the spectral changes in EEG. Attempts to relate these spectral changes to adequacy of anesthesia have been hindered due to the complex waveforms of EEG. The objective of this investigation is to monitor the awareness of patients during cesarean section by means of EEG spectral analysis. METHODS: 20 patients for cesarean section aged from 24 to 39 and ASA class I or II, were maintained with O2(50%)-N2O(50%)-enflurane(0.8%). And they were administered with midazolam(0.07 mg/kg) in group I(n=6), fentanyl(1 microgram/kg) in group II(n=7), and fentanyl(2 microgram/kg) in group III(n=7) after birth. The density of each spectral band in EEG (delta 1-3.25 Hz, theta 3.5-7.75 Hz, alpha 8-12.15 Hz and beta 13-31.75Hz) was analyzed to derive total density, delta ratio and median power frequency. RESULTS: The spectral data demonstrated that the alpha rhythm was dominant in pre-induction period and beta rhythm was abundant both in the immediate post-induction period and after birth for all three groups. Delta ratio and median power frequency decreased after injection of midazolam and fentanyl in all three groups. None of patients could recall the memory about experience during cesarean section. CONCLUSIONS: These findings indicate that EEG spectral analysis is potentially useful to determine the changes of cerebroelectrical activity but difficult to monitor the awareness of patients during cesarean section.
Alpha Rhythm ; Anesthesia ; Anesthetics ; Anesthetics, Intravenous* ; Beta Rhythm ; Cesarean Section* ; Electroencephalography* ; Enflurane ; Female ; Fentanyl ; Humans ; Isoflurane ; Memory ; Midazolam ; Parturition ; Pregnancy

We report two patients with frequent isolated sleep paralysis (SP). They have neither cataplexy nor daytime sleepiness, and there was no HLA DR2 or DQ1 association. We elicited one episode of sleep paralysis from a patient by a sleep interruption schedule. The polysomnographic recording during SP showed abundant alpha rhythm with persistent atonia, which indicate a concurrence of REM-atonia and wakefulness. The frequency of SP was markedly reduced by a use of clomipramine
Alpha Rhythm ; Appointments and Schedules ; Cataplexy ; Clomipramine ; Humans ; Polysomnography ; Sleep Paralysis* ; Sleep, REM ; Wakefulness

Complex Morlet wavelets, as a wavelet function, is most commonly used in the time-frequency analysis of EEG signal and in the extraction of the instantaneous power and phase. This article explains how to use the Morlet wavelet transform for obtaining EEG's alpha wave energy distribution over time, and how to use the EEG data of mental arithmetic experiment for obtaining the changes of the alpha wave duration.
Algorithms ; Alpha Rhythm ; Electroencephalography ; methods ; Humans ; Signal Processing, Computer-Assisted ; Wavelet Analysis

The alpha rhythm in electroencephalograph has been associated with the mental state of the brain. The aim of the present study was to analyze the complexity of the alpha activity in depression patients by Renyi entropy (RE) under two conditions, i.e., resting with eyes closed followed by a simple mental arithmetic. The EEGs were recorded in 20 depression patients and 20 age-matched control subjects. Results showed that the alpha activity of depression patients is more complex during resting and is more regular during the mental arithmetic than that of the controls. RE analysis can well characterize the alpha activity in depression patients and could be a valuable tool to study cognitive process and also a potential effective approach for the diagnosis of depression.
Adult ; Alpha Rhythm ; Depression ; physiopathology ; Electroencephalography ; Entropy ; Female ; Humans ; Male ; Signal Processing, Computer-Assisted

Although neuroimaging techniques and other diagnostic procedures has been developed, electroencephalography(EEG) is still very important for the evaluation of various brain diseases and functional studies of human brain. EEG is formed mainly by spatial and temporal summations of postsynaptic potentials generated from a large population of pyramidal cells that can be considered as a collection of oscillating dipoles. EEG shows continuous rhythmic oscillation depending on sleep-waking state. Alpha rhythms are generated in cortical areas acting as epicenters with local spread, although the precise cellular mechanism is still unknown. It's been known that neurons in the nucleus reticular thalami are the pacemakers of sleep spindle. Alterations in the circuit of the reticular nuclei-thalamocortical relay neuron-cortical neuron are responsible for generalized spike and wave complexes. At the intracellular level, large paroxysmal depolarizing shifts produce focal epileptic spikes. Slow waves of EEG appear to be related to thalamocortical and/or corticothalamic deafferentation. The interpretation of routine EEG requires a well training from a qualified EEG teacher and reading adequate amount of EEG under supervision. Frequent misinterpretations of routine EEG have been observed in both local clinics and general hospitals. The most common findings of normal routine EEG misinterpreted as abnormal are normal variants and artifacts of various sources. There are considerable variations of normal EEG rhythms and pseudoepileptiform discharges. Eyeball movements produce prominent or subtle EEG changes over the frontal regions that are sometimes hard to be differentiated from abnormal slow waves over that region. Systematic approach was described for a good interpretation of routine EEG.
Alpha Rhythm ; Artifacts ; Brain ; Brain Diseases ; Electroencephalography* ; Electrophysiology* ; Hospitals, General ; Humans ; Neuroimaging ; Neurons ; Organization and Administration ; Pyramidal Cells ; Synaptic Potentials

In regard to the controls and schizophrenia EEGs, we have got alpha rhythm from three points of view and verified the nonlinearity of the three kinds of rhythms. The results show that neither normal EEG alpha nor patients EEG alpha have the typical nonlinear characteristics. Therefore, we could not blindly use the theories of nonlinear dynamics to analyze the rhythm of brain wave.
Alpha Rhythm ; statistics & numerical data ; Brain ; physiology ; physiopathology ; Electroencephalography ; statistics & numerical data ; Humans ; Nonlinear Dynamics ; Schizophrenia ; physiopathology

OBJECTIVE: To study the effects of moxibustion at different time points on serum level of tumor necrosis factor-α (TNF-α) in rats with rheumatoid arthritis (RA), and to explore its regulation mechanism on circadian rhythm. METHODS: A total of 96 Sprague-Dawley (SD) adult rats were randomly assigned into a blank group, a model group, a moxibustion at 5-7 AM group and a moxibustion at 5-7 PM group, 24 rats in each group, half male and half female. Each group was further divided into a 0 AM group, a 6 AM group, a 12 N group and a 6 PM group, 6 rats in each group. All rats were treated with the 12 h/12 h light-dark cycle in the whole process of experiment. Except for the blank group, all rats were treated with intracutaneous injection of freund's complete adjuvant (FCA) at right foot pad to establish the RA model. The rats at the two moxibustion groups were treated with grain-sized moxibustion at "Shenshu" (BL 23) and "Zusanli" (ST 36) at 5-7 AM and 5-7 PM, respectively, one side per treatment, once a day; six treatments were taken as one course and 3 courses were given with an interval of one day between courses. The rats in the remaining groups were treated with identical fixation but without moxibustion intervention. The right foot volume was measured before model establishment, after model establishment and after treatment. The blood samples were collected after treatment and the serum level of TNF-α was measured by ELISA. The SPSS 21.0 software and Halberg Cosinor were adopted to analyze the experiment data. RESULTS: After treatment, compared with the blank group, the foot swelling severity was significantly increased in the model group, moxibustion at 5-7 AM group and moxibustion at 5-7 PM group (all <0.01); compared with the model group, the foot swelling severity was significantly reduced in the moxibustion at 5-7 AM group and moxibustion at 5-7 PM group (both <0.01). Compared with the blank group, the serum level of TNF-α was increased significantly in the model group and moxibustion at 5-7 AM group (both <0.05); compared with the model group, the serum level of TNF-α was reduced significantly in the moxibustion at 5-7 AM group and moxibustion at 5-7 PM group (both <0.05). The serum level of TNF-α showed circadian rhythm in all the groups (all <0.05), and the peak appeared at night phase; compared with the blank group, the median value of TNF-α was increased significantly in the model group (<0.05), the peak phase was delayed and the amplitude was increased (<0.05); compared with the model group, the median value of TNF-α was significantly reduced in the moxibustion at 5-7 AM group and moxibustion at 5-7 PM group (<0.01), the peak phase was advanced and the amplitude was reduced (<0.05). CONCLUSION Moxibustion could effectively reduce the serum level of TNF-α to relieve the foot swelling severity in RA rats. Moxibustion could regulate the circadian rhythm of TNF-α to play its effects on the inhibition of the synthesis of TNF-α. No efficacy is observed between the treatment at 5-7 AM and 5-7 PM.
Acupuncture Points ; Animals ; Arthritis, Rheumatoid ; Circadian Rhythm ; Female ; Male ; Moxibustion ; Rats ; Rats, Sprague-Dawley ; Tumor Necrosis Factor-alpha

OBJECTIVES: Obsessive-compulsive disorder (OCD) and schizophrenia have many common clinical and neurocognitive features. However, not all of them share the same underlying mechanism. The aim of this study was to discover evidences that indicate a pathophysiological mechanism specific to OCD by comparing correlations of quantitative electroencephalography (QEEG) patterns and neurocognitive function in patients with OCD and schizophrenia. METHODS: Resting-state QEEG data of total 265 patients were acquired retrospectively and parameters such as absolute power, relative power and peak frequency were analyzed from the data. Stroop test and Trail Making Test results as well as demographic features were reviewed for this study. The correlation of neurocognitive functions and brain electrical activities in each group were assessed and compared by correlation analysis. RESULTS: Compared with the OCD group, the schizophrenia group performed poorly in neurocognitive tests. Mean values of QEEG parameters in patients with OCD and schizophrenia did not show significant differences. Both absolute and relative power of alpha rhythm in central and frontal regions showed significant positive correlation with Stroop test results in OCD patients. CONCLUSIONS: Findings in this study shows distinctive correlations between frontal executive dysfunction and frontal alpha rhythm in the OCD patients, both of which might be a candidate for endophenotype underlying obsessive rumination.
Alpha Rhythm ; Brain ; Electroencephalography* ; Endophenotypes ; Humans ; Obsessive-Compulsive Disorder* ; Retrospective Studies ; Schizophrenia* ; Stroop Test ; Trail Making Test

A single measurement of serum 17alpha-hydroxyprogesterone (17OHP) level can be unreliable because of its marked diurnal variation. We investigated the relationship of serum level of 17OHP with that of androstenedione (AD), which shows a smaller diurnal variation. And we tested whether the responses of these two hormones to low-dose ACTH stimulation are correlated in patients with 21-hydroxylase deficiency. Baseline serum 17OHP and AD levels were measured in 87 patients and a low-dose ACTH stimulation test was performed in 41 patients. The basal 17OHP level correlated positively with the basal AD level independently of sex, type of 21-hydroxylase deficiency, and the time of day of blood sampling (n = 87, R2 = 0.75, P < 0.001). The area under the curve of 17OHP and AD correlated positively with their respective basal levels. The fold-change increase in 17OHP after ACTH injection correlated negatively with the basal 17OHP level, but that of AD did not correlate with the basal AD level. The random serum 17OHP level, used in the clinic, is a reliable guide and a low-dose ACTH stimulation test provides no extra benefit for assessing the treatment adequacy in patients with 21-hydroxylase deficiency.
17-alpha-Hydroxyprogesterone/*blood ; Adolescent ; Adrenal Hyperplasia, Congenital/*diagnosis/drug therapy ; Adrenocorticotropic Hormone/*diagnostic use ; Androstenedione/*blood ; Circadian Rhythm ; Female ; Humans ; Male ; Steroid 21-Hydroxylase/metabolism ; Young Adult