Auditory evoked potential index: a quantitative measure of changes in auditory evoked potentials during general anaesthesia

We describe a novel index derived from the auditory evoked potential, the auditory evoked potential index, and we compare it with latencies and amplitudes related to clinical signs of consciousness and unconsciousness. Eleven patients, scheduled for total knee replacement under spinal anaesthesia, completed the study. The initial mean (SD) value of the auditory evoked potential index was 72.5 (11.2). During the first period of unconsciousness it decreased to 39.6 (6.9) and returned to 66.8 (12.5) when patients regained consciousness. Thereafter, similar values were obtained whenever patients lost and regained consciousness. Latencies and amplitudes changed in a similar fashion. From all parameters studied, Na latencies had the greatest overlap between successive awake and asleep states. The auditory evoked potential index and Nb latencies had no overlap. The consistent changes demonstrated suggest that the auditory evoked potential index could be used as a reliable indicator of potential awareness during propofol anaesthesia instead of latencies and amplitudes.     

Pain-related somatosensory evoked potentials following CO2 laser stimulation in peripheral neuropathies

Pain-related somatosensory evoked potentials (pain SEPs) following CO2 laser stimulation were examined in 30 patients with peripheral neuropathies, and the results were compared with clinical sensory findings. Pain SEP findings showed a significant correlation with the clinical impairment of pain sensation, but not with the impairment of deep sensations. In contrast, conventional electrically-stimulated SEPs (electric SEPs) showed a significant correlation with deep sensations, but not with the impairment of pain sensation. Examinations of both pain SEPs and electric SEPs, therefore, are considered to be very useful to evaluate physiological functions of sensory nerves in patients with peripheral neuropathies.     

离子选择电极电位法研究S2O8^2—与I^—反应动力学

用离子选择电极电位法对S_2O_8~(2-)-Ⅰ~-体系反应动力学问题进行了探讨,研究了离子强度对反应速度的影响。结果表明:离子选择电极电位法可用于此体系的动力学研究,并且得到满意的结果;提出了该电极适用的浓度条件;得出生成CuI~+步骤为催化反应决定步骤的新结论;随着离子强度的增加dE/dt值增大,即反应速度加快。     

60例老年椎—基底动脉供血不足的脑干听觉诱发电位分析

对60例临床诊断为椎—基底动脉供血不足的老年人进行脑干听觉诱发电位(BAEP)检查,51例异常者(异常率为85％)均在发作期检查,9例颈性眩晕病人于缓解期检查(BAEP)正常。BAEP异常提示老年人可能由于长期椎—基底动脉供血不足造成脑干内有影响听觉通路的微小梗塞灶。证明BAEP检查叫老年性椎—基底动脉供血不足的诊断很有价值。     

不同检测方法预测白内障术后视力的观察

目的 评价各种检测方法在预测白内障术后视功能恢复的作用。方法 白内障197例(214眼)术前行闪光视网膜电图(F-ERG)、闪光视诱发电位(BVEP)、视网膜计、光定位、色觉及注视性质等综合检测，术后3月复查最佳矫正视力。结果 术前F—ERG的b波、F—VEP的P1波、潜视力、色觉均与术后视力存在显著相关性，其中F-ERG、F—VEP、潜视力预测术后视力的可靠性分别为62．6％、79．0％、60．6％。但排除白内障完全成熟及高龄者(超过80岁)，潜视力预测的可靠性则达82．6％。结论 对于非完全成熟及非高龄者，视网膜计是术前预测白内障术后视力比较理想的方法，而对于完全浑浊及高龄者，视网膜计检查结果的准确性欠佳，应结合F-ERG、F-VEP、色觉及注视性质等多方面因素进行综合讲价。     

湖南省洞庭湖水域洪灾区人群潜在寿命、工作、价值损失年数分析

目的 了解洪灾对人群健康和价值的损害程度。方法 应用标化死亡率和潜在寿命损失年数(WYPLL)、潜在工作损失年数(VYPLL)、潜在价值损失年数(VYPLL)对湖南省洞庭湖水域部分洪灾区人群1995—1999年的死亡情况进行分析。结果 灾区与非灾区两人群死因顺位一致，但损伤、中毒和肿瘤死因的死亡专率，灾区显著高于非灾区。在死因构成中损伤、中毒死亡居第三位，肿瘤居第四位；但在YPLL、WYPLL分析中则跃居第一位和第二位。两人群各年龄段的YPLL、WYPLL、VYPLL分析显示灾区人群40—59岁的各种死亡损失均高于非灾区。结论 降低洪灾区人群损伤、中毒和肿瘤死亡率和重视40—59岁年龄段人群劳动力的保护有重要的社会和经济意义。     

术中皮质体感诱发电位与电刺激术定位脑功能区

目的探讨脑功能区手术中利用脑皮质体感诱发电位(SEP)及直接皮质电刺激定位脑功能区的方法及意义。方法对10例脑功能区病变病人在唤醒麻醉下进行手术，利用皮质SEP及皮质直接电刺激定位感觉区、运动区及语占区，住保护脑功能区的前提下，手术切除病变。结果7例病人利用SEP及皮质电刺激确定出运动感觉区，其中4例利用SEP位相倒置确定出中央沟，3例病变位于左侧额颞叶的病人通过皮质直接电刺激确定出语言区?术后功能均较术前明显好转。结论术中SEP及直接皮质电刺激可准确、实时确定脑功能区，最大程度地保护功能，切除病变。     

单纯脑白质疏松症与皮质下动脉硬化性脑病的临床对比研究

目的探讨单纯脑白质疏松症(LA)和皮质下动脉硬化性脑病(BD)的临床表现、影像学及脑诱发电位的改变特征。方法(1)调查114例单纯脑白质疏松症患(LA组)和41例皮质下动脉硬化性脑病患(BD组)的发病危险因素和临床表现。(2)两组患均行CT检查，并按照脑白质异常程度分为3型。(3)LA组74例患，BD组35例患行MRI检查，根据T2WI显示的脑室周围高信号分为5型。(4)两组分别选择部分伴有高血压的患进行躯体感觉诱发电位(SEP)、脑干听觉诱发电位(BAEP)和视觉诱发电位(VEP)检查。结果(1)LA组患的危险因素呈多样化，无神经局灶体征，临床表现仅为轻度记忆力减退、步态不稳。CT显示脑白质异常以1型为主，占70．2％(80／114)；MRI脑白质异常也同样以1型为主，占71．6％(53／74)，均无脑室扩大。电生理学检查显示，SEP异常率为83．7％(36／43)，其中轻度60．5％，中度23．2％；BAEP异常率为62．8％(27／43)，潜伏期和峰间期延长；VEP异常率为53．5％(23／43)，各波潜伏期延长，均无波形消失。(2)BD组患危险因素以高血压为主(95．1％)，临床表现以神经局灶体征、明显认知功能障碍和卒中样发作为主。CT分型以3型多见，为73．2％(30／41)；MRI检查显示3型为54．3％(19／35)，4型45．7％(16／35)，41例患均有双侧脑室对称性扩大。电生理学检查显示，SEP异常率为96．7％(29／30)，其中轻度6．7％，中度46．7％，重度43．3％；BAEP异常率86．7％(26／30)，潜伏期和峰间期进一步延长，部分伴有Ⅲ、Ⅴ波缺失；VEP异常率为83．3％(25／30)，各波潜伏期进一步延长，部分P2单侧波形消失。结论单纯脑白质疏松症无特征性临床表现，诊断主要以影像学1型脑白质异常为依据；诱发电位表现为各波潜伏期延长，无波形完全缺失。皮质下动脉硬化性脑病的危险因素为高血压，临床有较明显的认知功能障碍，常见卒中样发作等特征，影像学检查CT显示3型脑白质异常，MRI显示3型或4型为诊断依据；诱发电位呈现各波潜伏期进一步延长并伴有部分波形完全缺失。     

Applied potential tomography

Applied potential tomography (APT) is a new noninvasive, nonradioactive method of measuring gastric emptying, which generates profiles of emptying of liquids that are similar to those obtained simultaneously by scintigraphy and dye dilution. This study validates the ability of APT to measure emptying of a solid beefburger test meal from the stomach by comparing the results obtained with those obtained simultaneously by scintigraphy. When acid secretion was inhibited, there was a significant correlation between the two methods for the time taken for half the meal to empty from the stomach and the amount of meal emptied at different time intervals. Furthermore, the profiles of gastric emptying obtained by APT resembled those obtained by scintigraphy in most studies. If acid secretion was not inhibited, there was no correlation between values obtained by the two methods.