Objective To observe the functional state of the optic nerve and discover the injury of visual pathway function in time under general ane sthesia. The flash visual evoked potential (F-VEP) was used to monitor visual function during orbital surgery. Methods A total of 252 out of 282 patients undergoing orbital surgery under general anesthesia were successfully monitored by F-VEP during the surgery. All patients were monitored by this method under the following conditions:consious state before operation, under general anaesthesia, during and after dissection of orbital tumor and at the end of operation. Results ①There was no significant difference of wave amplitude and latency under general anesthesia and consciousness condition. ②The amplitude and latency of F-VEP were normal in the orbital surgery withou toptic nerve injury. ③Pulling and oppression of optic nerve could cause temporary wave loss, but the wave recovered after removal of the pull and oppression. ④ The wave loss of F-VEP would occur immedicately when optic nerve was severe injured and its blood supply was deficient. Since the application of the visual function monitoring, 24 cases were treated in time during disturbance of visual function and no patient has unexpected visual loss during orbital surgery. Conclusion The intraoperative monitoring of F-VEP during orbital surgery can decrease the proportion of permanent visual loss caused by orbit al surgery, and help the surgical procedures go to function-anatomy stage from experience-anatomy stage. (Chin J Ocul Fundus Dis, 2001,17:260-263)
The capacity of embryonic spinal cord tissue in the repair of injured structure of spinal cord has been noted for years. In order to investigate the embryonic spinal cord graft in the repair of motor function of injured spinal cord, the embryonic spinal cord tissue was transplanted to the hemisection cavity in spinal cord in adult rat. One hundred adult Wistar Rats were used to simulate the hemisectional injury of spinal cord by drilling 2-3 mm cavity in lumbar enlargement. Sixty rats were treated with rat embryonic spinal cord tissue grafting while the other forty were chosen as control. The outcome was evaluated according the combined behavioural score (CBS) and motor evoked potential (MEP) in the 1, 2, 4 and 12 weeks. The grafting group was superior to the control as assessed by CBS (P lt; 0.05), especially within 4 weeks. (P lt; 0.01). The restoration of the latent peak of early wave(P1, N1) was better in the grafting group, too. This suggested that embryonic spinal cord graft could improve the recovery of motor function of injured spinal cord in adult rat. The effect of the embryonic spinal cord tissue graft might be concerned with its secretion of several kinds of neurotrophic factors, nerve growth factor, nerve transmitted factor, or adjustment of hormone.
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)
Motor imaging therapy is of great significance to the rehabilitation of patients with stroke or motor dysfunction, but there are few studies on lower limb motor imagination. When electrical stimulation is applied to the posterior tibial nerve of the ankle, the steady-state somatosensory evoked potentials (SSSEP) can be induced at the electrical stimulation frequency. In order to better realize the classification of lower extremity motor imagination, improve the classification effect, and enrich the instruction set of lower extremity motor imagination, this paper designs two experimental paradigms: Motor imaging (MI) paradigm and Hybrid paradigm. The Hybrid paradigm contains electrical stimulation assistance. Ten healthy college students were recruited to complete the unilateral movement imagination task of left and right foot in two paradigms. Through time-frequency analysis and classification accuracy analysis, it is found that compared with MI paradigm, Hybrid paradigm could get obvious SSSEP and ERD features. The average classification accuracy of subjects in the Hybrid paradigm was 78.61%, which was obviously higher than the MI paradigm. It proves that electrical stimulation has a positive role in promoting the classification training of lower limb motor imagination.
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.
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.