Brain-computer interface (BCI) system is a system that achieves communication and control among humans and computers and other electronic equipment with the electroencephalogram (EEG) signals. This paper describes the working theory of the wireless smart home system based on the BCI technology. We started to get the steady-state visual evoked potential (SSVEP) using the single chip microcomputer and the visual stimulation which composed by LED lamp to stimulate human eyes. Then, through building the power spectral transformation on the LabVIEW platform, we processed timely those EEG signals under different frequency stimulation so as to transfer them to different instructions. Those instructions could be received by the wireless transceiver equipment to control the household appliances and to achieve the intelligent control towards the specified devices. The experimental results showed that the correct rate for the 10 subjects reached 100%, and the control time of average single device was 4 seconds, thus this design could totally achieve the original purpose of smart home system.
Objective To investigate the characteristics of multifocal visual evoked potential (mf-VEP) in healthy individuals, and provide normal reference values for its clinical application. Methods The mf-VEP of 37 healthy individuals (70 eyes) were examined by VERIS ScienceTM4.0. The visual stimulus was adart board with patterns consisted of 60 patches spanning a 25°visual field. The length of m-sequence was 214-1. The results were recorded by bipolar occipital straddle. The signal was amplified 100 K and was put through a band-pass filter between 3 and 100 Hz. The first slice of the second order kernel was analyzed by VERIS software. The summed responses of fields with different stimulus were a nalyzed and compared according to different ages, genders and eyes.Results The latencies and response densities of amplitude had statistically significant differences both in dimidiate and quartered field（Plt;0.05）. The latencies in ≥50 year group were much more delayed in some sectors of the visual field than those in lt; 50 year group（Plt;0.05）. The latencies of women were shorter than those of men（Plt;0.05）. There was no obvious difference of latencies and response densities of amplitude in each field sectors between both eyes（Pgt;0.05）. Conclusions The mf-VEP of healthy individuals can reflect the VEP at different field ocations objectively with its specific physiological characteristics, which may provide normal reference values for its clinical application.(Chin J Ocul Fundus Dis，2003，19：269-332)
This paper is an introduction about the resultsof SEP monitoring in 36 case from 179 cases ofperipheral nerve injuries which have been followedup at least 6 months,since the beging of 1985 tothe end of 1989 in Dapin Hospital. These cases were injured by nerve overstretching 5 cases, complicated with fracture in 14patients, sharp instrument cutting in 17 patients.Of them injured in brachial plexus 3 cases ,axil-lary nerve 1 case, median nerve combined with ul-nar nerve 3 cases, ulnar nerve 12 cases, sciatic nerve, posterior tibial nerve, common peroneal nerve and femoral nerve were 1 case. All the SEP examination results showed closely coordination with clinical entities. Therefore, SEP monitoring peripheral nerve injuries manifested very importent significance in judgement of the injured nerve function.
A new form of static random-dot stereograms free of monocular clues was designed as stimulus to elicit disparity evoked potentials in 40 normal subjects.A characteristic wide positive wave at about 250ms was consistently recorded in disparity stimulation,which may be regard as evdence of the presence of stereopsis.In constrast,recordings for monocular stimulus all demonstrated a relatively smaller and sharper positive wave with a markedly shortened latency. （Chin J Ocul Fundus Dis,1993,9:214-217）
We have utilized the binocular flat and stereoscopic pattern to record visual evoked potentials (VEP) in normal and strabismic subjects. The aim was to find an electrophysiological correlation with the degree of binocular interaction in these subjects.The perception as tridimensional or flat derived from the disparity obtained with polaroid filters placed in front of the eyes. In normal subjects, the results demonstrated a significant increase of VEP amplitude during tridimensional perception of the pattern. In strabismic subjects the electrophysiological response were not correlated with the binocular conditions. The findings in the present study suggest that the binocular disparity in VEP examination is a useful technique and a better objective index for evaluating stereoscopic function than the psychophysical technique. （Chin J Ocul Fundus Dis,1992,8:10-13）
The maximum length sequence (m-sequence) has been successfully used to study the linear/nonlinear components of auditory evoked potential (AEP) with rapid stimulation. However, more study is needed to evaluate the effect of the m-sequence order in terms of the noise attenuation performance. This study aimed to address this issue using response-free electroencephalogram (EEG) and EEGs with nonlinear AEPs. We examined the noise attenuation ratios to evaluate the noise variation for the calculations of superimposed averaging and cross-correlation, respectively, which constitutes the main process in the deconvolution method using the dataset of spontaneous EEGs to simulate the cases of different orders (order 5 to 12) of m-sequences. And an experiment using m-sequences of order 7 and 9 was performed in true cases with substantial linear and nonlinear AEPs. The results demonstrate that the noise attenuation ratio is well agreed with the theoretical value derived from the properties of m-sequences on the random noise condition. The comparison of waveforms for AEP components from two m-sequences showed high similarity suggesting the insensitivity of AEP to the m-sequence order. This study provides a more comprehensive solution to the selection of m-sequences which will facilitate the feasible application on the nonlinear AEP with m-sequence method.
Brain-computer interface (BCI) has high application value in the field of healthcare. However, in practical clinical applications, convenience and system performance should be considered in the use of BCI. Wearable BCIs are generally with high convenience, but their performance in real-life scenario needs to be evaluated. This study proposed a wearable steady-state visual evoked potential (SSVEP)-based BCI system equipped with a small-sized electroencephalogram (EEG) collector and a high-performance training-free decoding algorithm. Ten healthy subjects participated in the test of BCI system under simplified experimental preparation. The results showed that the average classification accuracy of this BCI was 94.10% for 40 targets, and there was no significant difference compared to the dataset collected under the laboratory condition. The system achieved a maximum information transfer rate (ITR) of 115.25 bit/min with 8-channel signal and 98.49 bit/min with 4-channel signal, indicating that the 4-channel solution can be used as an option for the few-channel BCI. Overall, this wearable SSVEP-BCI can achieve good performance in real-life scenario, which helps to promote BCI technology in clinical practice.
目的 探讨躯体感觉诱发电位（SEP）在颈脊髓损伤术前、术中监测的意义。 方法 纳入2010年1月－2012年4月治疗的241例颈脊髓损伤患者，术前按美国脊柱脊髓损伤协会（ASIA）评分并分级，确定损伤平面。术前与术中SEP监测，分析不同损伤分级以及不同损伤平面术前的波幅及潜伏期的差异，术中SEP监测以波幅下降＞50%和或潜伏期延长＞10%为预警标准。 结果 各损伤分级组术前SEP监测：A级组SEP波消失，呈一直线，而B、C、D、E级组均测出SEP波形，根据是否可测出SEP波形，可将A级与B、C、D、E及组区别。B、C、D级组之间波幅和潜伏期均无统计学意义（P＞0.05）。E级组较B、C、D级组波幅增高、潜伏期缩短，差异有统计学意义（P＜0.05）；不完全性颈脊髓损伤组内不同损伤平面组之间波幅和潜伏期差异均无统计学意义（P＞0.05）。术中SEP对脊髓功能损伤监测的灵敏度83.3%、特异度98.7%。其中术中：SEP阳性8例，真阳性5例，4例术者处理后波幅及潜伏期回复至正常范围，术后无新的神经功能损伤，另1例术者采取各种处理后波幅及潜伏期无恢复，术后神经功能损伤较术前加重；假阳性3例，1例麻醉师给予升高血压后波形恢复至正常，另2例经麻醉师调整麻醉深度后波形恢复正常，此3例术后无新的神经功能损伤。SEP阴性233例，真阴性232例，术后无新的神经功能损伤；假阴性1例，患者术中、术后波形未见异常，术后运动功能损伤程度较术前加重。 结论 ① SEP能准确评估完全性和不完性颈脊髓损伤，但对不完全性颈脊髓损伤的损伤程度不能作出准确评估、也不能区分颈脊髓损伤的损伤平面；② 术中SEP监测能较好地反映颈脊髓功能完整性，对减少颈脊髓损伤术中发生医源性颈脊髓损伤风险具有重要意义。
This study investigates a brain-computer interface (BCI) system based on an augmented reality (AR) environment and steady-state visual evoked potentials (SSVEP). The system is designed to facilitate the selection of real-world objects through visual gaze in real-life scenarios. By integrating object detection technology and AR technology, the system augmented real objects with visual enhancements, providing users with visual stimuli that induced corresponding brain signals. SSVEP technology was then utilized to interpret these brain signals and identify the objects that users focused on. Additionally, an adaptive dynamic time-window-based filter bank canonical correlation analysis was employed to rapidly parse the subjects’ brain signals. Experimental results indicated that the system could effectively recognize SSVEP signals, achieving an average accuracy rate of 90.6% in visual target identification. This system extends the application of SSVEP signals to real-life scenarios, demonstrating feasibility and efficacy in assisting individuals with mobility impairments and physical disabilities in object selection tasks.