Studies have shown that the clinical manifestation of patients with neuropsychiatric disorders might be related to the abnormal connectivity of brain functions. Psychogenic non-epileptic seizures (PNES) are different from the conventional epileptic seizures due to the lack of the expected electroencephalographically epileptic changes in central nervous system, but are related to the presence of significant psychological factors. Diagnosis of PNES remains challenging. We found in the present work that the connectivity between the frontal and parieto-occipital in PNES was weaker than that of the controls by using network analysis based on electroencephalogram (EEG) signals. In addition, PNES were recognized by using the network properties as linear discriminant nalysis (LDA) input and classification accuracy was 85%. This study may provide a feasible tool for clinical diagnosis of PNES.
Brain ; physiopathology ; Electroencephalography ; Epilepsy ; Humans ; Seizures ; diagnosis

Electroencephalogram (EEG) is the primary tool in investigation of the brain science. It is necessary to carry out a deepgoing study into the characteristics and information hidden in EEGs to meet the needs of the clinical research. In this paper, we present a wavelet-nonlinear dynamic methodology for analysis of nonlinear characteristic of EEGs and delta, theta, alpha, and beta sub-bands. We therefore studied the effectiveness of correlation dimension (CD), largest Lyapunov exponen, and approximate entropy (ApEn) in differentiation between the interictal EEG and ictal EEG based on statistical significance of the differences. The results showed that the nonlinear dynamic char acteristic of EEG and EEG subbands could be used as effective identification statistics in detecting seizures.
Brain ; physiopathology ; Electroencephalography ; Entropy ; Epilepsy ; physiopathology ; Humans ; Nonlinear Dynamics ; Seizures

Epileptic spike is an indicator of hyper-excitability and hyper-synchrony in the neural networks. The inhibitory effects of spikes on theta rhythms (4-8 Hz) might be helpful to understand the mechanism of epileptic damage on the cognitive functions. To quantitatively evaluate the inhibitory effects of spikes on theta rhythms, intracerebral electroencephalogram (EEG) recordings with both sporadic spikes (SSs) and spike-free transient period between adjacent spikes were selected in 4 patients in the status of rapid eyes movement (REM) sleep with temporal lobe epilepsy (TLE) under the pre-surgical monitoring. The electrodes of hippocampal CA3 and entorhinal cortex (EC) were employed, since CA3 and EC built up one of key loops to investigate cognition and epilepsy. These SSs occurred only in CA3, only in EC, or in both CA3 and EC synchronously. Theta power was respectively estimated around SSs and during the spike-free transient period by Gabor wavelet transform and Hilbert transform. The intermittent extent was then estimated to represent for the loss of theta rhythms during the spike-free transient period. The following findings were obtained: (1) The prominent rhythms were in theta frequency band; (2) The spikes could transiently reduce theta power, and the inhibitory effect was severer around SSs in both CA3 and EC synchronously than that around either SSs only in EC or SSs only in CA3; (3) During the spike-free transient period, theta rhythms were interrupted with the intermittent theta rhythms left and theta power level continued dropping, implying the inhibitory effect was sustained. Additionally, the intermittent extent of theta rhythms was converged to the inhibitory extent around SSs; (4) The average theta power level during the spike-free transient period might not be in line with the inhibitory extent of theta rhythms around SSs. It was concluded that the SSs had negative effects on theta rhythms transiently and directly, the inhibitory effects aroused by SSs sustained during the spike-free transient period and were directly related to the intermittent extent. It was indicated that the loss of theta rhythms might qualify exactly the sustained inhibitory effects on theta rhythms aroused by spikes in EEG. The work provided an argumentation about the relationship between the transient negative impact of interictal spike and the loss of theta rhythms during spike-free activity for the first time, offered an intuitive methodology to estimate the inhibitory effect of spikes by EEG, and might be helpful to the analysis of EEG rhythms based on local field potentials (LFPs) in deep brain.
CA3 Region, Hippocampal ; physiopathology ; Electroencephalography ; Entorhinal Cortex ; physiopathology ; Epilepsy, Temporal Lobe ; physiopathology ; Humans ; Male ; Theta Rhythm

OBJECTIVE: To investigate the clinical significance of high-frequency oscillations (HFOs) on scalp electroencephalography (EEG) in patients with epileptic encephalopathy with continuous spike-and-wave during sleep (CSWS). METHODS: Twenty-one CSWS patients treated for epilepsy from January 2006 to December 2016 in Pediatric Department of Peking University First Hospital were enrolled into the study. Selected clinical variables including gender, age parameters, seizure frequencies and antiepileptic drugs were compared between (a). HFO-positive group and HFO-negative group before methylprednisolone treatment and (b). excellent seizure outcome group and not-excellent seizure outcome group after methylprednisolone treatment. Interictal HFOs and spikes in pre- and post-methylprednisolone scalp EEG were measured and analyzed. RESULTS: Before methylprednisolone treatment, there were 12 of 21 (57%) CSWS patients had HFOs, with a mean value 43.17 per 60 s per patient. The 12 patients with HFOs tended to have more frequent epileptic negative myoclonus/atonic/myoclonus/atypical absences than those without HFOs in a month before methylprednisolone treatment. A total of 518 HFOs and 22 592 spikes were found in the pre-methylprednisolone EEG data of 21 patients, and 441 HFOs (86%) were associated with spikes. The highest amplitudes of HFOs were significantly positively correlated with that of spikes (r=0.279, P<0.001). Rates reduced by methylprednisolone treatment were statistically significant for both HFOs (P=0.002) and spikes (P=0.006). The percentage of reduction was 91% (473/518) and 39% (8 905/22 592) for spikes and HFOs, respectively. The percentage of spike and HFOs changes was respectively 100% decrease and 47% decrease in the excellent seizure outcome group, and they were 79% decrease and 18% increase in the not-excellent seizure outcome group. CONCLUSION Prevalence of HFOs might reflect some aspect of epileptic activity. HFOs were more sensitive to methylprednisolone treatment than spikes and had a good correlation with the prognosis of seizures, and HFOs could be applied to assess epilepsy severity and antiepileptic therapy.
Anticonvulsants/therapeutic use* ; Child ; Electroencephalography/methods* ; Epilepsy/physiopathology* ; Epilepsy, Absence ; Humans ; Methylprednisolone ; Scalp ; Seizures ; Sleep

Post traumatic epilepsy （PTE） refers to the epileptic seizures after traumatic brain injury. Organic damage can be found by imaging examination, and abnormal electroencephalogram can be detected via electroencephalogram examination which has the similar location of the brain injury. PTE has the characteristics of low incidence, absence of case reports, and easy to exaggerate the state of illness, which add difficulties to the forensic identification. This paper reviews the status of epidemiology, pathogenesis, clinical treatment and forensic identification for PTE.
Brain Injuries, Traumatic/physiopathology* ; Electroencephalography ; Epilepsy ; Epilepsy, Post-Traumatic/pathology* ; Forensic Pathology ; Humans ; Incidence

Child ; Electroencephalography ; Epilepsy ; drug therapy ; physiopathology ; Female ; Humans ; Sleep ; physiology

The time phase of epileptic seizures has attracted more and more attention. Epileptic seizures have their own circadian rhythm. The same type of epilepsy has different seizure frequencies in different time periods and states (such as sleeping/awakening state and natural day/night cycle). The circadian rhythm of epileptic seizures has complex molecular and endocrine mechanisms, and currently there are several hypotheses. Clarification of the circadian rhythm of epileptic seizures and prevention and administration according to such circadian rhythm can effectively control seizures and reduce the adverse effects of drugs. The research on the circadian rhythm of epileptic seizures provides a new idea for the treatment of epilepsy.
Circadian Rhythm ; physiology ; Epilepsy ; drug therapy ; physiopathology ; Humans

Neural mass models are able to produce epileptic electroencephalogram (EEG) signals in different stages of seizures. The models play important roles in studying the mechanism analysis and control of epileptic seizures. In this study, the closed-loop feedback control was used to suppress the epileptic-form spikes in the neural mass models. It was expected to provide certain theory basis for the choice of stimulus position and parameter in the clinical treatment. With the influence of measurement noise taken into account, an unscented Kalman filter (UKF) was added to the feedback loop to estimate the system state and an UKF controller was constructed via the estimated state. The control action was imposed on the hyper-excitable population and all populations respectively in simulations. It was shown that both UKF control schemes suppressed the epileptic-form spikes in the model. However, the control energy needed in the latter scheme was less than that needed in the former one.
Computer Simulation ; Electroencephalography ; Epilepsy ; physiopathology ; Feedback ; Humans ; Models, Neurological

Adult ; Child ; Child, Preschool ; Electroencephalography ; Epilepsy, Absence ; physiopathology ; Humans

Epilepsy ; chemically induced ; Humans ; Poisoning ; physiopathology ; Xylenes ; poisoning