In the traditional P300 brain-computer interface (BCI) system, the electroencephalogram (EEG) signals can only provide limited information with a low signal-to-noise ratio. A BCI paradigm under visual stimulus was proposed in our study aiming to effectively activate the related brain areas and response signal while dealing with specific cognitive task (mental arithmetic task), so as to enhance the EEG signals. The result was compared with the traditional P300 counting task paradigm. Then the collected EEG data were preprocessed including extracting signal features with coherent averaging method, and analyzing the influences of different experimental paradigms on main components of event related potential (ERP). In the improved paradigm experiments the average increasing rate of P300 amplitude was 6. 83MV (73. 94%). The brain activity from 400ms was more active and lasted longer. Besides, unlike traditional counting task, mental arithmetic task appeared to have apparent activation at 650ms. The results showed that the improved paradigm could activate the related brain areas better and enhance the characteristics of signal. This provides a new system paradigm for BCI.
Brain-Computer Interfaces ; Electroencephalography ; Event-Related Potentials, P300 ; physiology ; Humans ; Mathematical Concepts ; Mental Processes ; physiology ; Task Performance and Analysis

Objective:To analyze the characteristics of electroencephalogram (EEG) and clinical manifestations of children with moyamoya disease (MMD), and to explore the value of EEG in the clinical diagnosis of childhood MMD.Methods:Twelve children indicated as cerebrovascular diseases by EEG and later diagnosed with MMD by head magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA) in Wuhan Children′s Hospital, Tongji Medical College, Huazhong University of Science and Technology from January 2012 to June 2019 were enrolled in this study.Their EEG and clinical data were retrospectively analyzed.Results:Nine cases were male and 3 cases were female, with the onset age of 3.0-8.7 years old.Ten cases were taken to the hospital because of paroxysmal limb weakness on one side or both sides, 1 case was because of paroxysmal fall, and 1 case was because of paroxysmal posture abnormalities.EEG background activities of 12 cases were normal.Interictal EEG was normal in 8 cases, borderline in 1 case, and abnormal in 3 cases (1 case had many slow waves in bilateral anterior head, and its number significantly increased during the awakening period; 1 case had a great many irregular delta slow waves on bilateral prefrontal cortex, showing significant aggravation during the awakening period; 1 case had many multifocal delta slow waves especially in the right frontopolar region). The hyperventilation (HV) induction test was abnormal, and rebuild-up of slow waves was noted in 4 cases.The focal delta slow waves (especially in the anterior head) developed to diffuse slow waves after stopping HV for 0.5 to 1.0 minutes, and lasted for 5 to 9 minutes after relief of symptoms.The delayed disappearance of asymmetric focal slow waves was noted in 8 cases.Focal slow waves (especially in anterior head) developed to diffuse slow waves at 1.5 to 2.0 minutes after HV initiation, and lasted for 5 to 10 minutes in total.Among them, 1 case pre-sented no obvious accompanying symptoms during HV, while 11 cases showed transient ischemic symptoms that were basically consistent with the chief complaint.The duration of symptoms was much shorter than the appearance of slow waves in EEG.Besides, brain MRI of 3 cases suggested local malacia lesions or abnormal signals, especially in parietal and basal ganglia areas.The high signal shadow was observed in the sulcus of bilateral cerebral hemispheres on the fluid attenuating inversion recovery sequence of one case.All of 12 cases were proved to MMD by head MRA.Conclusions:Clinical symptoms of children with MMD are paroxysmal limb weakness.Rebuild-up of slow waves or the delayed disappea-rance of focal slow waves is highly suggestive of MMD.These 2 kinds of abnormal EEG patterns sustain over long periods of time.Focal slow waves (especially in anterior head) develop to diffuse slow waves, and lastly decrease to focal slow waves in anterior head.

Objective To investigate the characteristics of ictal and interictal electroencephalogram (EEG) and clinical manifestation in children with startle epilepsy. Methods The age of onset, inducing factors, the types of attacks, EEG features, cognitive function, treatment and prognosis were retrospectively analyzed in 8 cases of children with startle epilepsy from June 6, 2012 to March 2016. Results In 8 cases, 3 cases were male and 5 were female. The onset age was from 2.3 to 8.1 years old. The forms of onset were varied from generalized (tonic, myoclonic, atonic) to partial seizures (the asymmetry of posture rigidity, spasm). The most common ictal EEG finding was a diffuse electrodecremental pattern (5 cases), and the interictal EEG showed a large number of multifocal, generalized spines, slow waves and multiple spinous waves. There was one case with no history of brain injury while the other 7 cases had a history of brain injury. There were 7 cases with imaging abnormality, and the lesions of the frontal, parietal and temporal regions were indicated with a partial cerebral softening and brain atrophy. In 7 cases, all children had abnormal mental and motor development, and 1 case had normal cognitive function. The 7 cases with shock epilepsy showed no obvious response to the treatment of multiple antiepileptic drugs, and 1 case had no clinical onset after 2 months of treatment with VPA. Conclusions Startle epilepsy is mostly symptomatic, and few are non-symptomatic. The former had history of brain structure abnormalities, certain degree of motor retardation and mental disability, and no clinical response to antiepileptic drug therapy. The latter had basically normal cognitive function, and antiepileptic drug VPA treatment is effective. The degree of interictal epileptic was not an indicator of cognitive impairment and prognosis in children with startle epilepsy.

Objective To investigate the factors in diagnosis delay in Guillain-Barré syndrome (GBS) and its impact on prognosis.Methods In this study 118 GBS children including Miller-Fisher syndrome (MFS) and pharyngeal-cervical-brachial Guillain-Barré syndrome (PCB) were studied.All children included were divided into 2 groups as GBS-initially-diagnosed group (GBSid,n=76) and not-GBS-initially diagnosed group (nGBSid,n=42) based on the initial diagnosis.Analysis was performed with age at disease onset,preceding infection,Hughes functional grading (HG),the department where the instial diaghosis is done,main complain,the days from disease onset to seeing doctor,time start to treatment,the discharge time,evaluation by a neurologist.Results Among 118 GBS,90 children were of classical GBS,13 of MFS,and 6 of PCB.Atypical muscle weakness,neuropathic pain and impaired respiration function were more frequently seen in nGBSid group (P＜0.05).At the initial diagnosis,lacking of neurological evaluation was found more frequently in nGBSid group (P＜0.05).The duration from onset to the commencement of treatment was longer in nGBSid group than that in GBSid group (P＜0.05),and short term prognosis was poor in GBSid group (P＜0.05).Conclusions Atypical main complaints including neuropathic pain,the impaired respiration function and atypical muscle weakness,and lack of neurological evaluation were all associated with a delay in considering the diagnosis of GBS.The delay in diagnosis had a significant impact on short term prognosis.