ObjectiveNumerous foreign researches focused on the changes of EEG during the developmental periods from the newborn to late adulthood. However, the EEG changes of healthy Chinese people is still rare. Therefore, we examined the EEG of 2 357 healthy Chinese people.MethodsIn 1982, guided by Prof. Feng, we analysed the waking EEG of 2 357 healthy people, from 2 to above 60 years old, including open eyes induction test and hyperventilation.ResultsAt age 2 ~ 4, the posterior basic rhythms has reached 8 ~ 9 Hz, but the rhythms were unregular pattern. After age 7, the rhythms were 9 Hz, α index was more than 60%, the amplitude was higher than other ages. At age 12 ~ 14, the main rhythms was 10 Hz, the same as adulthood, α index was 70% ~ 80%. After this age, the amplitude of α rhythm deceased gradually. Above 60 years old, the main rhythm was 9 Hz, α index <60%, the amplitude was lower than adulthood. At age 14 ~ 16, the θ index in frontal and temporal regions was 6%, the same as the adulthood. At age 18 ~ 20, β index was 20%.ConclusionsIn the article, we analyzed the waking EEG of 2 357 healthy Chinese people in Beijing area. Although this multi-center study was accomplished at 1980s, the data is still of great value to the clinical EEG today.
Intracranial electrographic recording, especially stereoencephalography (SEEG), remains the gold standard for preoperative localization in epilepsy patients. However, this method is invasive and has low spatial resolution. In 1982, magnetoencephalography (MEG) began to be used in epilepsy clinics. MEG is not affected by the skull and scalp, can provide signals with high temporal and spatial resolution, and can be used to determine the epiletogensis zone (EZ) and the seizure onset zone (SOZ). Magnetic source imaging (MSI) is a method that superimposes the MEG data on a magnetic resonance image (MRI) and has become a major tool for presurgical localization. The applicability of MEG data has been largely improved by the development of many post-MRI processing methods in the last 20 years. In terms of the sensitivity of localization, MEG is superior to VEEG, MRI, PET and SPECT, despite inferiority to SEEG. MEG can also assist in the intracranial placement of electrodes and improve preoperative planning. Limitations of MEG include high cost, insensitivity to radiation source, and difficulty in locating deep EZ in the medial regions of the brain. These limitations could be overcome by new generations of equipment and improvement of algorithmics.
Currently, about one-third of patients with anti-epilepsy drug or resective surgery continue to have sezure, the mechanism remin unknown. Up to date, the main target for presurgical evaluation is to determene the EZ and SOZ. Since the early nineties of the last century network theory was introduct into neurology, provide new insights into understanding the onset, propagation and termination. Focal seizure can impact the function of whole brain, but the abnormal pattern is differet to generalized seizure. Brain network is a conception of mathematics. According to the epilepsy, network node and hub are related to the treatment. Graphy theory and connectivity are main algorithms. Understanding the mechanism of epilepsy deeply, since study the theory of epilepsy network, can improve the planning of surgery, resection epileptogenesis zone, seizure onset zone and abnormal node of hub simultaneously, increase the effect of resectiv surgery and predict the surgery outcome. Eventually, develop new drugs for correct the abnormal network and increase the effect. Nowadays, there are many algorithms for the brain network. Cooperative study by the clinicans and biophysicists instituted standard and extensively applied algorithms is the precondition of widely used clinically.
Objective To explore the change of EEG waveform recorded by clinical EEG under different filtering parameters. Methods22 abnormal EEG samples of epilepsy patients with abundant abnormal waveforms recorded in Peking University first hospital were selected as the case group (abnormal group), and 30 normal EEG samples of healthy people with matched sex and age were selected as the control group (normal group). Visual examination and power spectrum analysis were then performed to compare the difference of wave forms and spectrum power under different settings of filter parameter between the two groups. ResultsThe results of visual examination show that, lower high-frequency filtering has an effect on the fast wave composition of EEG and may distort and reduce the spike wave. Higher low-frequency filtering has an effect on the overall background and slow wave activity of EEG and may change the amplitude morphology of some slow waves. The results of power spectrum analysis show that, Compare the difference between the EEG normal group and the abnormal group, the main difference under the settings of 0.5~70Hz was on the θ and α3 frequency band, different brain regions were slightly different. In the central region, the difference in the high frequency band (α3, γ1, γ2) decreases or disappears with the decrease of the high frequency filtering. In the rest of the brain, the difference in the δ band appears gradually with the increase of the low frequency filtering. Compare the difference between frontal area and occipital area under different filter set, for the normal group, under the settings of 0.5 ~ 70 Hz, the difference between two regions is mainly on the θ, γ1 and γ2 band. When high frequency filter reduces, the difference between two regions on high frequency band (γ1, γ2) are gradually reduced or disappeared. And when low frequency filter increases, the difference on δ band appears. For the abnormal group, the difference between frontal and occipital region under the settings of 0.5 ~ 70 Hz is mainly on γ1 and γ2 bands. When the high-frequency filter decreases, the difference between two regions on high-frequency bands are gradually decreased or disappeared. All the results can be corrected by FDR. ConclusionThe results show that the filter setting has a significant influence on EEG results. In clinical application, we should strictly set 0.5 ~ 70 Hz bandpass filtering as the standard.