Combined monitoring of evoked potentials during microsurgery for lesions adjacent to the brainstem and intracranial aneurysms

Background Neurophysiologic monitoring during surgery is to prevent permanent neurological injury resulting from surgical manipulation. To improve the accuracy and sensitivity of intraoperative neuromonitoring, combined monitoring of transcranial electrical stimulation motor evoked potentials (TES-MEPs), somatosensory evoked potentials (SSEPs) and brainstem auditory evoked potentials (BAEPs) was attempted in microsurgery for lesions adjacent to the brainstem and intracranial aneurysms.Methods Monitoring of combined TES-MEPs with SSEPs was attempted in 68 consecutive patients with lesions adjacent to the brainstem as well as intracranial aneurysms. Among them, 31 patients (31 operations, 28 of posterior cranial fossa tumors, 3 of posterior circulation aneurysms) were also subjected to monitoring of BAEPs. The correlation of monitoring results and clinical outcome was studied prospectively.Results Combined monitoring of evoked potentials (EPs) was done in 64 (94.1％) of the 68 patients. MEPs monitoring was impossible for 4 patients (5.9%). No complication was observed during the combined monitoring in all the patients. In 45 (66.2%) of the 68 patients, EPs were stable, and they were neurologically intact. Motor dysfunction was detected by MEPs in 8 patients, SSEPs in 5, and BAEPs in 4, respectively. Conclusions A close relationship exists between postoperative motor function and the results of TES-MEPs monitoring. TES-MEPs are superior to SSEPs and BAEPs in detecting motor dysfunction, but combined EPs serve as a safe, effective and invasive method for intraoperative monitoring of the function of the motor nervous system. Monitoring of combined EPs during microsurgery for lesions adjacent to the brainstem and intracranial aneurysms may detect potentially hazardous maneuvers and improve the safety of subsequent procedures.     

地方性克汀病人多形式诱发电位及耳蜗电图研究

我们于1987年3月～5月对36例地方性克汀病人进行 BAEPs、SSEPs、VEPs 及ECochG 研究,兹报道如下:研究对象:36例地方性克汀病人选自贵州省镇宁县。年龄13～22岁、平均15.5岁,男女各半。该县属地甲病高发区,     

偏头痛病人脑干诱发电位及个性测定

目的：探讨偏头痛病人发作期和间歇期脑干听沉电位及个性测定。方法：采用诱发电位（ＢＡＥＰ）及艾森个性量表检测３０例偏头痛患者。结果：偏头痛患者ＢＡＥＰ异常率为５３％。Ⅰ,Ⅲ,Ⅴ波潜伏期及Ⅲ－Ⅴ峰间期延长。个性测定性格内向型３人,外向型１２人,中间型１７人。结论：上述结果表明偏头痛患者有脑干传导机能障碍,且与个性有关。     

偏头痛病人脑干诱发电位及个性测定

目的 :探讨偏头痛病人发作期和间歇期脑干听觉诱发电位及个性测定。方法 :采用诱发电位 (BAEP)及艾森克个性量表检测 3 0例偏头痛患者。结果 :偏头痛患者BAEP异常率为 5 3 %。Ⅰ ,Ⅲ ,Ⅴ波潜伏期及Ⅲ～Ⅴ峰间期延长。个性测定性格内向型 3人 (10 % ) ,外向型 12人 (40 % ) ,中间型 17人 (5 6% )。结论 :上述结果表明偏头痛患者有脑干传导机能障碍 ,且与个性有关。     

脑干听觉诱发电位对眩晕的诊断价值

目的探讨脑干听觉诱发电位测定对眩晕的诊断价值。方法对128例眩晕患者进行脑干听觉诱发电位测定分析,并同期选取50例健康体检者为对照组。结果病例组128例中有96例(75%)测定异常;异常病例中内耳型异常20例(20.8%),脑干型异常48例(50%),混合型异常28例(29.2%)。对照组检查无异常。结论 BAEP为无创和客观测定检查,对眩晕患者的损伤部位(脑干或听觉通路)具有定位诊断价值,可作为眩晕患者内耳型、脑干型或混合型病变的客观诊断指标。     

Brainstem auditory evoked potentials in patients with delayed encephalopathy after acute carbon monoxide poisoning

Objective:To evaluate the changes of brainstem auditory evoked potential (BAEP) in patients with delayed encephalopathy after acute carbon monoxide poisoning. Methods: BAEPs were performed in 32 controls and 40 patients. Wave Ⅰ , Ⅱ , Ⅲ ,Ⅳ, Ⅴ latencies and Ⅰ-Ⅲ , Ⅲ-Ⅴ , Ⅰ-Ⅴ interpeak latencies were measured, respectively. Results: Abnormalities of BAEPs in 13 patients (13/40, 32 ％). Among the13 abnormal BAEPs, 3 displayed prolongation of latency to waves in one side, no potential in another side; 5 displayed a similar abnormality which was bilateral prolongation of latency to waves ;and another 5 displayed unilateral latency delay. Compared wave Ⅰ , Ⅱ , Ⅲ , Ⅳ, Ⅴ latencies and Ⅰ-Ⅲ , Ⅲ-Ⅴ , Ⅰ-Ⅴ interpeak latencies in the patients and the controls, there were no significant differences (P＞0.05). Conclusion: BAEPs can be used for evaluating the diagnostic and prognostic values in the cases of delayed encephalopathy after acute carbon monoxide poisoning.     

双耳刺激,双侧记录的脑干听觉诱发电位在围脑干肿瘤手术中的监护

目的 :研究脑干听觉诱发电位 (BAEP)在围脑干肿瘤手术中进行监护的临床应用价值。方法 :用双耳刺激、双侧记录的脑干听觉诱发电位对 13例围脑干肿瘤 (桥小脑角除外 )进行术中监护。结果 :所有病人在手术操作时 ,均出现 BAEP改变 ,按其改变程度大致可分为轻度改变、中度改变和重度改变三种。结论 :BAEP改变程度能反映脑干功能受影响程度 ,重度改变是脑干功能受到不可逆损害的具体指标 ;术中 BAEP监护有助于提高手术效果 ,且能预测预后     

Multimodality evoked potentials in patients with delayed encephalopathy after acute carbon monoxide poisoning

Objective： To evaluate the diagnostic and prognostic values in patients with delayed encephalopathy after acute carbon monoxide poisoning. Methods： The tibial nerve somatosensory evoked potentials （SEPs）, vision evoked potentials （VEPs）, and brain stem audition evoked potentials（BAEPs） were performed in 32 healthy adults and 43 patients with delayed encephalopathy after acute carbon monoxide poisoning. Results： This paper indicated abnormalities of tibial nerve SEPs in 31 patients （31/43, 72.1%）, VEPs in 17 patients （17/28, 60.7%）, and BAEPs in 14, patients （14/43, 32.6%）. These results showed that the greatest diagnostic value was SEPs, followed by VEPs and, BAEPs with the lowest sensitivity. Conclusion： Multimodality evoked potentials （EPs） can be used for evaluating the diagnostic and prognostic values in cases of delayed encephalopathy after acute carbon monoxide poisoning.     

The effect of lead on brainstem auditory evoked potentials in children

Objective To determine whether lead affects brainstem auditory evoked potentials (BAEPs) in low-to-moderate lead exposed children. Methods BAEPs were recorded from 114 asymptomatic children aged 1-6 years. Average values were calculated for peak latency (PL) and amplitude (Amp). Whole blood lead (PbB) levels were assessed by graphite furnace atomic absorption spectroscopy. Based on their PbB levels, subjects were divided into low lead (PbB<100 μg/L) and high lead subgroups (PbB ≥100 μg/L). Results The PbB levels of the 114 subjects ranged from 32.0 to 380.0 μg/L in a positively skewed distribution. The median of PbB levels was 90.0 μg/L while the arithmetic average was 88.0 μg/L. Of the subjects, 43.0% (49/114) had levels equal to or greater than 100 μg/L. Bilateral PLs Ⅰ, Ⅴ, and Ⅲ of the left ear in the high lead subgroup were significantly longer than those in the low lead subgroup (P<0.05). A positive correlation was found between PbB levels and bilateral PLs Ⅰ, Ⅴ and Ⅲ of the left ear (P<0.05), after controlling for age and gender as confounding factors. A significant and positive correlation between PbB levels and PL Ⅰ of the left ear, even when PbB levels were lower than 100 μg/L, in the low subgroup (r=0.295, P=0.019) was also found.Conclusions Lead poisoning in children younger than 6 years old is a very serious problem to which close attention should be paid. The indications that lead prolongs partial PLs may imply that lead, even at PbB levels lower than 100 μg/L, impairs both the peripheral and the central portions of the auditory system. BAEPs may be a sensitive detector of subclinical lead exposure effects on the nervous system in children.     

脑梗塞的体感诱发电位与临床的研究

对 10 0例脑梗塞患者进行双下肢短潜伏期体感诱发电位 (SLSEP)检测 ,同时记录患者的肢体功能障碍情况、头颅CT所示的梗塞灶部位和大小范围 ,对其中的重度异常的 2 0例经治疗后进行复查 ,分析和比较它们之间的关系。结果显示 :72 %的患者SLSEP异常 ,2 8%正常。其中重度异常 (表现为引不出可辨认之波形 ) 2 0例 ,轻～中度异常 (表现为病侧半球SLSEPP4 0 ～N75波幅较对侧降低 5 0 %以上 ,或P4 0 潜伏期较健侧延长 2 .90ms以上 ,或SLSEP各波峰潜伏期延长超过正常对照值 ) 5 2例。临床查出有感觉障碍者 (40例 )SLSEP异常 3 6例 (异常率 90 % ) ,无感觉障碍者 (60例 )SLSEP异常 3 6例 (异常率 60 % )。 2 0例复查时SLSEP有改善者 12例 ,肢体功能恢复得较好 ;8例无变化 ,恢复较差。认为SLSEP异常可作为评价脑梗塞患者肢体功能障碍的客观电生理证据 ,特别是体感通路受损的客观证据。但部分病人肢体功能障碍与SLSEP无明显关联。动态观察SLSEP有助于对肢体功能障碍恢复的判断。     

脑干听觉诱发电位分级对脑创伤长期意识障碍患者预后评估的价值

目的通过对脑干听觉诱发电位（BAEP）的检测,探讨BAEP分级对长期昏迷脑损伤患者预后评估的临床价值。方法根据93例脑损伤后意识障碍超过2周的患者清醒前BAEP检测结果,将BAEP分为I级、Ⅱ级和Ⅲ级。采用格拉斯哥预后评分（GOS）作为判断标准对患者的预后进行评估,并进一步分析BAEP分级与预后评估之间的关系。结果I级的预后不良率为36．48％,Ⅱ级和Ⅲ级的总预后不良率为94．55％。分级与预后差异有统计学意义（P〈O．05）,分级越高,患者预后越差。结论BAEP能客观敏感地反映中枢神经系统功能,因而BAEP分级科学地反映了不同程度的脑功能损伤,进而准确预测预后情况,具有较好的临床应用价值。     

Recording of spared motor evoked potentials and its augmentation by 4-aminopyridine in chronic spinal cord-injured rats

Objective To research the direct electrophysiological evidence of discomplete spinal cord injury (SCI) and the effect of 4-aminopyridine on it.Methods Motor evoked potentials (MEPs), both spinal cord recorded MEPs (scMEPs) and extr acellularly recorded MEPs (exMEPs) were recorded and characterized on a T(13) epidural electrode (scMEPs) and an extracellular microelectrode (exMEPs) for 10 normal rats and 40 rats with lesions of various severity (sham, 35 g·cm for ce (gcf), 70 gcf, 100 gcf impact injury) at the T(8)-T(9) cord using the Allen ’s drop model. The incline plane and Tarlov techniques were used to assess clin ical neurological function. Results MEPs in the normal rats were elicited by applying transcortical suprathreshold s timulation consisting of 3-4 early negative peaks (N(1), N(2), N(3) and N(4)) f ollowed by several late waves. The N(1) and N(2) peaks were largest in the ante rior and ventrolateral funiculus, respectively, which was indicative of extrapyr amidal pathways. The 100 gcf impact injuries and the cord transection abolishe d the MEP distal to the lesion, whereas the 35 gcf injuries resulted in a laten cy shift and amplitude decrement of the MEP peaks. Eighteen of the 20 rats wit h 70 gcf injuries showed clinical paraplegia. Among them, 7 rats had neurophys iological evidence of residual conduction pathways through the lesioned cord seg ment, such as the presence of N(1) and N(2) peaks in the scMEPs or exMEPs. Afte r 4-aminopyridine (4-AP) administrations (1 mg/kg), the amplitude of the spar ed exMEP increased significantly and spread more widely. Conclusions MEPs evoked by transcortical stimulation travel mostly in the extrapyramidal tra ct. MEP monitoring could provide an excellent method of detecting the functiona l integrity of the motor tracts after SCI, and could even detect spared motor fi bers after discomplete SCI. Furthermore, the use of 4-AP or other K(+) channel blocking agents may be a potential treatment for patients with chronic moderate to severe SCI.     

地方性克汀病患者短潜时体感诱发电位研究

本文记录了30例地方性克汀病人的短潜时体感诱发电位,同时行神经系统检查及CT 扫描。结果表明:有瘫痪或 CT 扫描有阳性发现者,分别采用 Chipappa 氏法、CCT 计算法和 NT+W 计算法其阳性率分别为128.75%、50%、92.86%;而无瘫痪和 CT 正常组阳性率分别为12.5%、12.5%、6.25%。14例 NT+W 值异常者之 W 值均明显异常。     

椎旁体感诱发电位在神经根病变中的定位探讨

目的了解椎旁体感诱发电位（SSEP）在腰椎后路手术前后皮层电位潜伏期和波幅的改变，探讨椎旁SSEP在神经根病变中的定位价值。方法5例L4、5椎管狭窄症患者做术前、术后L4节段双侧椎旁SSEP，记录其P30潜伏期和波幅。10例L4、5单侧椎间盘突出伴有同侧临床腰腿痛症状的腰椎间盘突出症患者，做术前L4节段双侧椎旁SSEP及双侧胫神经SSEP，记录椎旁SSEP的P30潜伏期和胫神经SSEP的P40潜伏期。结果椎管狭窄症患者的椎旁SSEP手术前后P30潜伏期差异明显，术后较术前缩短，而P30波幅无明显差异。L4、5单侧椎间盘突出症患者双侧椎旁SSEP的P30潜伏期差异明显，双侧胫神经SSEP的P40潜伏期无明显差异。结论神经根病变可能引起椎旁SSEP的P30潜伏期延长，椎旁SSEP在神经根病变的定位上有参考价值。     

Phrenic nerve conduction and diaphragmatic motor evoked potentials: evaluation of respiratory dysfunction

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贵州省地方性克汀病脑CT和电生理改变

本文克汀病病人组颅脑CT表现特征:1.部分患者大脑皮质和髓质发育不良,表现为额叶、枕叶和顶叶的脑沟增宽(35％),脑外侧裂增宽(28％)。大脑皮质除额叶外各叶CT值均减低,侧脑室有前角扩大和体部相对性扩大。2.丘脑受到侵犯,表现为CT值减低和第三脑室扩大。3.脑干发育不良。4.部分(32％)患者小脑发育不良。本组患者BAEPs全部异常,其它检查的异常率SSEPs为27.2％,VEPs为25.5％,CET为81.8％,EEG为75.8％。     

脑缺血病人的短潜时体感诱发电位及其在治疗选择中的作用研究

对32例单侧病变之缺血性脑血管病人进行短潜时体感诱发电位测定并以50例正常人作对照。以N_9～N_20传导时间为重要判断标准。32例中异常诱发电位发生率为59.4％,18例有不同瘫痪之病人中异常率为78％,在诱发电位监测下一次大剂量注射烟酸可帮助选择手术病例及指导内科用药治疗,体感诱发电位还可作为颅外-颅内动脉吻合后效果的客观判断指标。     

兔急性颅内高压模型中体感诱发电位与听觉诱发电位的变化

目的 :探索颅内压 (ICP)升高过程中体感诱发电位 (SEPs)与脑干听觉诱发电位 (BAEPs)的变化规律。方法 :采用幕上不同部位放置球囊引起急性ICP增高的动物模型。将新西兰兔 30只分为 3组 :A组动物球囊置入右顶部硬膜下 ;B组动物球囊置入右颞底 ,C组以上部位动物各半 ,球囊内不注水。结果 :(1)A组SEPsP1波幅在ICP升至(1.48± 0 .35 )kPa即发生显著变化 ,而B组中ICP达 (8.10± 1.2 5 )kPa才出现波幅显著压缩。A组BAEPs在ICP升至(9.40± 1.6 0 )kPa时才出现IV ,V ,VII波的PL延长 ,而B组在ICP为 (3.11± 0 .80 )kPa时即见III波PL显著延长。 (2 )随ICP增高 ,P1波幅先随之升高 ,继而转为下降。结论 :SEPs与BAEPs的变化不仅受ICP高低的影响 ,还与病变的部位有关 ;SEPsP1波幅在ICP增高过程中呈先升后降的趋势     

兔急性脊髓损伤后磁刺激运动诱发电位与病理变化的相关性

目的观察兔急性脊髓损伤后经颅磁刺激运动诱发电位（transcranial magnetic stimulation motor evoked pontentials，TMS-MEP）的变化规律，并与脊髓病理变化相比较，探讨其相关性。方法将日本大耳兔32只随机分为4组，每组8只。A组为对照组，B、C、D组为实验组（脊髓损伤组）。然后对每组动物分别于麻醉后、暴露脊髓后、伤后5min、30min、1h、6h、1d、3d、7d检测TMS-MEP，对所得波形数据进行统计学分析。于伤后1d、3d、7d采用后肢的Tarlov分级行运动功能评分。以损伤部位为中心切取脊髓标本，行HE染色光镜、电镜观察。结果随着脊髓损伤的加重，MEP的潜伏期逐渐延长，波幅在逐渐减小，病理显示白质纤维脱髓鞘越重，神经细胞损伤数目越多，MEP的潜伏期延长和波幅降低越明显。结论经颅磁刺激运动诱发电位与脊髓病理变化有明显的相关性，TMS-MEP对脊髓损伤十分敏感，能客观地检测脊髓运动功能，反映脊髓损伤程度。     

兔急性颅内高压模型中体感诱发电位与听觉诱发电位的变化

OBJECTIVE: To study the changes in somatosensory evoked potentials (SEPs) and brainstem auditory evoked potentials (BAEPs) during intracranial hypertension. METHOD: A rabbit model of acute intracranial hypertension was developed. Thirty New Zealand rabbits were divided into 3 group. Both Group A and B were groups with intracranial hypertension; Group C was the control group. In Group A, balloons were placed to the right parietal lobe beneath the dura mater; in Group B, to temporal at the middle fossa near the brainstem. RESULT: (1) In Group A, when ICP rose to (1.48 +/- 0.35) kPa, P1 amplitude of SEPs was significantly changed, whereas latencies of Wave IV, V, and VII of BAEPs were prolonged when ICP rose to (9.40 +/- 1.60) kPa. In group B, P1 amplitude of SEPs was changed when ICP reached (8.10 +/- 1.25) kPa, and latency of Wave III of BAEPs was prolonged when ICP rose to (3.11 +/- 0.80) kPa. (2) P1 amplitude increased with ICP value when the balloon volume increased from V = 0.0 ml, ICP = (0.43 +/- 0.10) kPa to V = 0.4 ml, ICP = (2.44 +/- 0.65) kPa and then decreased afterward. CONCLUSIONS: (1) Changes in SEPs and BAEPs relate to not only ICP value but also the location of the balloon. (2) With the increasing of ICP, P1 amplitude increases firstly and then decreases.