ObjectiveTo evaluate the role of several examinations in the presurgical localization of insular/peri-insular cortex epilepsy (IPICE). MethodsThe data of patients with IPICE who were identified by resective surgery from 2011.1 to 2015.4 were retrospectively analyzed. The role of semiology, scalp EEG, MRI and magnetoencephalography (MEG)in the localization of epileptogenic zones for patients with IPICE were evaluated. Results18 patients were selected according to the criteria. The localization of IPICE was supported by semiology in 16 patients, supported by MRI in 6 patients, supported by MEG in 17 patients. In 12 patients with negative MRI, the dipoles were showed in insular/peri-insular area in 11 patients. The localization role of MEG for patients with IPICE is more obvious than that of MRI (P < 0.05). The MEG result played conclusive role in 9 patients. According to result of MEG, the plans of intracranial recording were canceled in 3 patients, and the plans of intracranial electrodes implanting were modified in 5 patients. The resective surgery involving the insular/peri-insular cortex was performed in all the 18 patients. During the follow-up of 12~48 months, seizure-free was reported in 11 patients, although 2 patients were missed. ConclusionThe combination of the results of semiology, scalp EEG, MRI and MEG was helpful in the localization of epileptogenic zones for patients with IPICE, and MEG played a valuable role in this localization.
Objective To investigate the application of Magnetoencephalograph (MEG), Wada test combined with neuronavigation in the surgical treatment of frontal and temporal epilepsy caused by focal cortical dysplasia (FCD ). Methods The epileptogenic focus and IQ, memory and language examination were performed in 34 patients with frontal and temporal epilepsy caused by FCD. MEG and Wada test were conducted to determine the language and memory advantage hemisphere, and to clarify the scope and memory function of language function areas. Operation was guided by the Medtronic stealhealth 7 surgical navigation system (USA) to remove the FCD and protect nerve function. IQ, memory and language examination were measured 1 year after operation, and the difference was observed before and after operation. The postoperative follow-up was 23 ~ 46 months, curative effect of epilepsy was determined according to the international anti-epilepsy union Engel’s standard. Results Thirty-four patients with epilepsy (21 temporal lobe epilepsy and 13 frontal lobe epilepsy) were included in this study. The examination process of MEG and Wada test was smooth. MEG can accurately locate the position of language function area. Twenty-eight patients’ dominant hemisphere of language was on the left and 6 was on the right side. Wada test can evaluate the patient’s memory function. Twenty-three patients’ dominant hemisphere of memory was located on the left, 8 on the right and 3 on the bilateral hemisphere. Compared with the dominant hemisphere and nondominant hemisphere, the memory score was significantly different (P<0.05). Statistics showed that the verbal IQ and total IQ increased (P<0.05)1 year after operation, but there was no significant change in memory IQ and Performance IQ (P>0.05). FCD patients recovered well without language, memory and limb impairment. The curative effect of epilepsy: 15 cases of Engel’sⅠgrade, 14 cases of Engel’sⅡgrade and 5 cases of Engel’s Ⅲ grade. Conclusion MEG, Wada test combined with neuronavigation was of important value in locating and guiding the surgical resection of FCD in patients with refractory frontal and temporal epilepsy, protecting cortical function, avoiding severe postoperative complications, and improving the therapeutic effect of epilepsy.
Brain-computer interaction (BCI) is a transformative human-computer interaction, which aims to bypass the peripheral nerve and muscle system and directly convert the perception, imagery or thinking activities of cranial nerves into actions for further improving the quality of human life. Magnetoencephalogram (MEG) measures the magnetic field generated by the electrical activity of neurons. It has the unique advantages of non-contact measurement, high temporal and spatial resolution, and convenient preparation. It is a new BCI driving signal. MEG-BCI research has important brain science significance and potential application value. So far, few documents have elaborated the key technical issues involved in MEG-BCI. Therefore, this paper focuses on the key technologies of MEG-BCI, and details the signal acquisition technology involved in the practical MEG-BCI system, the design of the MEG-BCI experimental paradigm, the MEG signal analysis and decoding key technology, MEG-BCI neurofeedback technology and its intelligent method. Finally, this paper also discusses the existing problems and future development trends of MEG-BCI. It is hoped that this paper will provide more useful ideas for MEG-BCI innovation research.
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.