Chen-Sen Ouyang

EARLY PREDICTION OF MEDICATION REFRACTORINESS IN CHILDREN WITH IDIOPATHIC EPILEPSY BASED ON SCALP EEG ANALYSIS

Refractory epilepsy often has deleterious effects on an individuals health and quality of life. Early identification of patients whose seizures are refractory to antiepileptic drugs is important in considering the use of alternative treatments. Although idiopathic epilepsy is regarded as having a significantly lower risk factor of developing refractory epilepsy, still a subset of patients with idiopathic epilepsy might be refractory to medical treatment. In this study, we developed an effective method to predict the refractoriness of idiopathic epilepsy. Sixteen EEG segments from 12 well-controlled patients and 14 EEG segments from 11 refractory patients were analyzed at the time of first EEG recordings before antiepileptic drug treatment. Ten crucial EEG feature descriptors were selected for classification. Three of 10 were related to decorrelation time, and four of 10 were related to relative power of delta/gamma. There were significantly higher values in these seven feature descriptors in the well-controlled group as compared to the refractory group. On the contrary, the remaining three feature descriptors related to spectral edge frequency, kurtosis, and energy of wavelet coefficients demonstrated significantly lower values in the well-controlled group as compared to the refractory group. The analyses yielded a weighted precision rate of 94.2%, and a 93.3% recall rate. Therefore, the developed method is a useful tool in identifying the possibility of developing refractory epilepsy in patients with idiopathic epilepsy.

Detection of induction motor operation condition by acoustic signal

This paper offers a new method to measure the operational condition of the induction motor. The acoustic signal is measured for analysis. It can not only still be detected normally when other signals cant, but it also has the function of motor fault monitoring when it combines with a monitoring system completely. It makes signal sampling more convenient and easier, and also expands the functions and items of monitoring. The way of this method includes the following steps: firstly, the acoustic signal must be transformed into a spectrum by fast Fourier transform; secondly, the first band of the spectrum must be analyzed, and the peak frequency of this band calculated; thirdly, peak frequency-speed relation must be established; fourthly, the unknown speed with Lagrange polynomial must be calculated. From these steps, the method has a high degree of accuracy, and could detect induction motor speed and power.

Cumulative effect of transcranial direct current stimulation in patients with partial refractory epilepsy and its association with phase lag index-A preliminary study

There is an urgent need for alternative treatments for refractory epilepsy. We investigated the effect of two courses of cathodal transcranial direct current stimulation (tDCS) in nine patients with partial refractory epilepsy. A two-course treatment (1u202fmonth per course, with six sessions of stimulation per course within the first 2u202fweeks by 2-mA cathodal tDCS for 20u202fmin) was administered to each patient. After the first course of tDCS, the average seizure frequency had decreased by 37.8u202f±u202f21.9% compared with baseline (pu202f=u202f0.001). After the second course, the average seizure frequency had decreased by 48.9u202f±u202f31.2% compared with baseline (pu202f=u202f0.002). Only seven of the nine patients maintained the same state of wakefulness in three electroencephalogram (EEG) recordings. We analyzed the EEG recordings of these seven patients on day 0 immediately posttreatment and on days 4 and 9 in the first course of tDCS. When compared with baseline, no significant change in the number of epileptiform discharges was observed. The day 9 phase lag index (PLI) decreased in five patients with seizure reduction after tDCS but increased in two patients without seizure reduction after tDCS. A significant negative correlation was observed between the day 9 PLI of alpha band and first-course seizure reduction (R2u202f=u202f0.6515) (pu202f=u202f0.028). The results revealed that tDCS may be considered as an alternative treatment option for patients with refractory epilepsy, and its effect might be cumulative after repeated stimulations and associated with a decrease in PLI.

Quantitative EEG findings and response to treatment with antiepileptic medications in children with epilepsy

BACKGROUNDnEpilepsy is a common chronic disorder in pediatric neurology. Nowadays, a variety of antiepileptic drugs (AEDs) are available. A scientific method designed to evaluate the effectiveness of AEDs in the early stage of treatment has not been reported.nnnPURPOSEnIn this study, we try to use quantitative EEG (QEEG) analysis as a biomarker to evaluate therapeutic effectiveness.nnnMETHODSn20 epileptic children were enrolled in this study. Participants were classified as effective if they achieved a reduction in seizure frequency over 50%. Ineffective was defined as a reduction in seizure frequency less than 50%. Eleven participants were placed in the effective group, the remaining 9 participants were placed in the ineffective group. EEG segments before and after 1-3months of antiepileptic drugs start/change were analyzed and compared by QEEG analysis. The follow-up EEG segments after the 2nd examinations were used to test the accuracy of the analytic results.nnnRESULTSnSix crucial EEG feature descriptors were selected for classifying the effective and ineffective groups. Significantly increased RelPowAlpha_avg_AVG, RelPowAlpha_snr_AVG, HjorthM_avg_AVG, and DecorrTime_snr_AVG values were found in the effective group as compared to the ineffective group. On the contrary, there were significantly decreases in DecorrTime_std_AVG, and Wavelet_db4_EnergyBand_5_avg_AVG values in the effective group as compared to the ineffective group. The analyses yielded a precision rate of 100%. When the follow-up EEG segments were used to test the analytic results, the accuracy was 83.3%.nnnCONCLUSIONnThe developed method is a useful tool in analyzing the effectiveness of antiepileptic drugs. This method may assist pediatric neurologists in evaluating the efficacy of AEDs and making antiepileptic drug adjustments when managing epileptic patients in the early stage.

Listening to Mozart K.448 decreases electroencephalography oscillatory power associated with an increase in sympathetic tone in adults: a post-intervention study

Summary Objective Listening to Mozart K.448 has been demonstrated to improve spatial task scores, leading to what is known as the Mozart Effect. However, most of these reports only describe the phenomena but lack the scientific evidence needed to properly investigate the mechanism of Mozart Effect. In this study, we used electroencephalography (EEG) and heart rate variability (HRV) to evaluate the effects of Mozart K.448 on healthy volunteers to explore Mozart Effect. Design An EEG-based post-intervention analysis. Setting Kaohsiung Medical University Hospital, Kaohsiung, Taiwan. Participants Twenty-nine college students were enrolled. They received EEG and electrocardiogram examinations simultaneously before, during and after listening to the first movement of Mozart K.448. Main outcome measure EEG alpha, theta and beta power and HRV were compared in each stage. Results The results showed a significant decrease in alpha, theta and beta power when they listened to Mozart K.448. In addition, the average root mean square successive difference, the proportion derived by dividing NN50 by the total number of NN intervals, standard deviations of NN intervals and standard deviations of differences between adjacent NN intervals showed a significant decrease, while the high frequency revealed a significant decrease with a significantly elevated low-frequency/high-frequency ratio. Conclusion Listening to Mozart K.448 significantly decreased EEG alpha, theta and beta power and HRV. This study indicates that there is brain cortical function and sympathetic tone activation in healthy adults when listening to Mozart K.448, which may play an important role in the mechanism of Mozart Effect.

Complete parameter estimation of induction machines by time-varied parameters

This paper proposes a method to find the equivalent circuit parameters, moment of inertia, and friction coefficient of an induction machine. The reference data include time-varied signals of voltage, current and rotor speed. By the time-varied voltage and current, a time-varied impedance can be found. The parameters of equivalent circuit can be found from the variation of impedance to the rotor speed. And then, the torque can be found via dynamic system model and rotor speed. From the torque and rotor speed with time, moment of inertia and friction coefficient of the motor can be obtained, too. The least mean square method is used to solve the above parameters in this paper. The initial values of least mean square are also described. The comparison of the simulated performance in starting states of an induction machine with the real one is discussed in this paper, accordingly, practicability and accuracy of this method has been proven.

Performance of Multiuser TAS/MRC Systems with a High Selection Gain in Severe Fading Channels

This paper investigates the performance of multiuser Transmit Antenna Selection / Maximal Ratio Combining (TAS/MRC) systems with a high selection gain in severe Nakagami-m fading channels. First, the amount of fading (AF) is derived as closed-form expressions for integer m. For arbitrary m, the AF is expressible as a single infinite series of Gamma function. The analytical results lead to the following observations. Regardless of high selection gain, the AF decreases in weak fading as expected. However, the outage performance can exhibit that the severe Nakagami-m fading results in positive effect on the performance of multiuser TAS/MRC systems with a high selection gain.