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1.
目的 探讨全静脉麻醉下经颅电刺激运动诱发电位(TES-MEPs)联合体感诱发电位(SEP)监测颅内前循环动脉瘤手术及预防缺血性卒中的应用价值.方法 47例颅内动脉瘤夹闭手术患者,术中行SEP和TES-MEPs联合监测,以神经功能检查作为评价指标,比较术前和术后神经功能的改变和诱发电位变化之间的关系.结果 43例神经功能未见显著改变,4例神经功能出现不同程度下降,其中3例MEP及SEP同时出现波幅下降>50%或消失,且手术结束时未恢复至基线水平,与术后神经功能障碍发生具有一致性.结论 术中监测指标的改变可较早地获得脑缺血的证据,联合SEP与MEP监测有利于降低术后缺血性脑卒中的发生.  相似文献   

2.
目的 探讨全静脉麻醉下运动诱发电位(MEP)联合体感诱发电位(SEP)术中监测应用于脊髓髓内肿瘤手术的优越性、可靠性及临床应用价值.方法 对72例脊髓髓内肿瘤患者术中行SEP和MEP联合监测,参照McCormick评分标准对术前、术后脊髓功能的改变和诱发电位变化之间的关系进行统计分析.结果 14例脊髓神经功能改善,18例术后脊髓神经功能下降者与诱发电位监测结果具有一致性(P<0.05).结论 对脊髓髓内肿瘤手术进行SEP与MEP监测有利于避免"假阴性/假阳性"结果及术后神经功能障碍的发生.  相似文献   

3.
目的探讨体感诱发电位(SEP)在复杂动脉瘤血管架桥及重建手术中的应用。方法回顾分析2002~2008年24例复杂动脉瘤病人进行动脉瘤血管架桥及重建手术,术中分别采用动脉瘤切除远近端血管吻合,动脉瘤孤立加大隐静脉高流量搭桥或颞浅动脉低流量搭桥等方式处理动脉瘤,实时进行体感诱发电位监测:胫后神经刺激,记录双侧皮层的SEP。将P40波幅下降一半作为脑缺血的预警信号,潜伏期延长3ms作为参考。结果4例行动脉瘤切除远近端血管吻合,16例行大隐静脉高流量血管搭桥术,4例行颞浅动脉低流量血管搭桥。监测结果:Ⅰ型无变化16例;Ⅱ型加重但逐渐恢复:波幅下降一半,但稳定且略有回升4例;Ⅲ型加重无恢复:波幅下降一半,且继续下降,升高血压也无明显改善3例;Ⅳ型波形扁平且无恢复1例;Ⅴ型波形消失0例。结论在复杂动脉瘤手术中,术中体感诱发电位的监测可以提示血流阻断后脑供血情况及功能区脑灌注状态。对颅内动脉瘤手术的安全性提供了一定的保障,减少了手术风险,是一种简便、安全有效的监测技术。  相似文献   

4.
The effects of hypoxic hypoxia on cerebral hemodynamics and somatosensory evoked potential (SEP) were studied in 10 pentobarbital anestheteized dogs. Cerebral blood flow (CBF) was measured using the venous outflow technique and cerebral oxygen consumption (CMRO2) was calculated from the arterio-cerebro-venous oxygen difference times CBF. SEP was evaluated by percutaneous stimulation of an upper extremity nerve and was recorded over the contralateral somatosensory cortex. The latencies of the initial negative wave (N1), second positive wave (P2) and the amplitude of the primary complex (P1N1) were measured. Animals were breathed sequentially with oxygen concentrations of 21, 10, 6, 5, and 4.5% for five minutes each. Animals were returned to room air breathing when the amplitude of the SEP decreased to less than 20% of control and were observed for 30 minutes following reoxygenation. Severe hypoxia (4.5% O2) increased CBF to 200% of control, decreased CMRO2 to 45% of control, decreased amplitude and increased latency of SEP. Following reoxygenation, as CMRO2 increased toward control, latency of SEP decreased and amplitude increased and CBF returned to baseline within 30 min. During hypoxia and reoxygenation, the latencies of N1 and P2 and the amplitude of P1N1 were correlated with CMRO2 in individual animals. We conclude that changes in SEP amplitude and latency reflect changes in CMRO2 despite high CBF during rapidly progressive hypoxic hypoxia and following reoxygenation.  相似文献   

5.
Somatosensory evoked potentials (SEP) have been applied to many men and several animals with cerebral ischemia. But in the Mongolian gerbil, one of the most common models of cerebral infarction, the wave form and the latency of SEP have been studied by few authors. In this report, we studied the effects of hyperthermia on SEP in the gerbil. Six gerbils weighting 40 to 50g were anesthetized and heated with ultra-red ray. Brain and rectal temperatures were continuously monitored. The brain temperature changed from 35 degrees C to 42 degrees C during heating, then returned to 37 degrees C with cooling. Typical SEP peaks have been labelled according to their positive or negative character and their sequential latency determination. The latency of the major positive voltage deflection, P1, was 9.97 +/- 9.94 ms at 37 degrees C. The negative deflection before P1 has been labelled as N0 and the negative waves after P1 and N1 and N2. Peak latency of SEP was significantly reduced gradually during hyperthermia, and increased gradually with recooling. The correlation between the latency of SEP and the brain temperature was very close. Our results emphasize the importance of measurement of SEP during hyperthermia as a monitor of the brain temperature and during experiment for maintenance of the body temperature at 37 degrees C.  相似文献   

6.

Objective

We assessed the relationship between cerebral ischemia-induced changes in evoked potentials and the degree of ischemia tolerance.

Methods

47 patients underwent somatosensory evoked potential (SEP) and motor evoked potential (MEP) monitoring in intracranial aneurysm surgery. Three duration parameters (time) were recorded: Time 1, from the starting of temporary occlusion unavoidable in aneurysm surgery to the time the evoked potentials decrease from basal level to reaching the warning criterion; Time 2, from evoked potentials reaching the warning criterion to the time the blood flow was resumed; Time 3, after resuming the blood flow, the time it took the evoked potentials to recover to baseline. All three times can be reliably calculated in the SEP recording, but not in the MEP recording which consisted of either unchanged amplitudes or abruptly changing amplitudes, making it impossible to obtain Time 1. The ischemic tolerance ratio (ITR) was calculated as ITR = time 2/time 1 × 100%. New decreasing myodynamia and fresh infarction after the surgery were employed for evaluating neurological deficits postoperatively, and their correlations with the ischemia-induced changes of evoked potentials recorded during the surgery were analyzed.

Results

We found a change in SEPs in 12 patients whose cerebral ischemia was induced by temporary occlusion of the aneurysm's parent artery. We also found the development of postoperative neurological deficits in 4 patients whose ischemic tolerance ratio (ITR) reached over 80%, while no deficits were found in the other 8 patients whose ITR was less than 50%. MEP changes were seen in 4 patients whose cerebral ischemia was caused by accidentally clamping the perforating branches, causing the development of postoperative neurological deficits but not necessarily leading to significant SEP changes.

Conclusion

The Ischemia tolerance ratio (ITR) in SEP recordings is valuable to predicting postoperative neurological deficits caused by temporary occlusion of aneurysm's parent artery. Maintaining the ITR under 50% during operation can effectively avoid postoperative neurological deficits, while an ITR above 80% reliably forecasts postoperative neurological deficits. Complementary to SEPs, MEP recordings are particularly valuable in monitoring ischemic effects caused by accidentally clamping perforating branches. Taken together, this system of monitoring makes it possible to promptly adjust surgery procedures and minimize postoperative neurological deficits.  相似文献   

7.
目的 :了解颅内压 (ICP)增高对脑血循环及脑电生理的影响。方法 :对 86例高颅压患者治疗前、后的经颅多普勒超声、体感诱发电位、脑压及血压进行对比研究。结果 :ICP轻度升高脑血流速度增快 ,ICP中重度升高血流速度迅速减慢 ;SEP各波潜伏期延长 ,波幅降低 ,以N2 0 最明显。结论 :ICP与PI、RI、潜伏期、波幅有显著相关性 ,TCD及SEP所测得参数改变可间接推断ICP变化 ,并有助于病情及预后的判断  相似文献   

8.
闪光视觉诱发电位无创监测颅内压的研究   总被引:6,自引:0,他引:6  
目的 研究闪光视觉诱发电位 (fVEP)各波潜伏期与颅内压的关系 ,评价fVEP在神经内科疾病中颅内压监测临床应用的可行性。方法 测量 2 2名健康人 ,4 4例高颅压患者和 35例腰椎穿刺测量颅内压患者的fVEP ,比较三者各波潜伏期的改变 ,并将无创方法测得颅内压值与实际腰穿测量值比较。结果 当颅内压增高时fVEP的P2 、N2 、P3 、N3 波潜伏期均延迟 (P <0 0 0 1) ;颅内压fVEP测量值和腰穿值的平均相对误差б =15 5 5 % ,其中颅内压增高患者平均相对误差б=8 86 %。fVEP的P2 、N2 、P3 、N3 波潜伏期与颅内压升高均呈正相关 (r=0 5 4 6、0 6 5 1、0 5 38、0 4 33,均P <0 0 0 1) ,以N2 波相关系数最大。结论 fVEP是一个比较准确、无创反映颅内压的方法  相似文献   

9.
The short latency somatosensory evoked potential was studied in 90 normal children of 1 month to 16 years old and 7 adults. Somatosensory stimuli were delivered through a disc electrode placed over the median nerve at the wrist joint. The uniform recording sites used were the central region of the scalp, and the seventh cervical spine or Erb's point. Reference electrodes were placed on the hand contralateral to the median nerve stimulated. Three positive peaks (P1, P2 and P3) and one negative peak (N1) were consistently recorded, a further positive peak (P4) after N1 was not always observed. The latency of each peak per 1 m body length decreased with age until 2 or 5 years of age. The latency of each peak after 2 years of age was positively correlated with the body length and arm length. The value of P1 peak latency per 1 m body length reaches adult values at an earlier rate than the value of P3 peak latency and P2-P3 latency per 1 m body length. This suggests that central lemmiscal pathways mature at a slower rate than peripheral nerve fibers. The wave form pattern of the short latency somatosensory evoked potential changed to the adult pattern at 10 years of age. The peak latency of P4 during deep sleep was slightly prolonged. In recording on infants during sleep, the EEG should be monitored to determine the stage of sleep.  相似文献   

10.
面肌痉挛显微血管减压术中脑干听觉诱发电位监测的应用   总被引:1,自引:1,他引:0  
目的 研究脑干听觉诱发电位(BAEP)监测在显微血管减压术(MVD)治疗面肌痉挛手术中的应用.方法 回顾性分析90例面肌痉挛患者在MVD术中进行BAEP监测的临床资料.结果 MVD手术操作过程均可引起BAEP改变,包括:BAEP的Ⅰ、Ⅲ、Ⅴ波绝对潜伏期明显延长(P<0.01),Ⅰ~Ⅲ、Ⅲ~Ⅴ、Ⅰ~Ⅴ波间期明显延长(P<0.01),Ⅲ波、Ⅴ波波幅明显降低(P<0.01);有16例术中Ⅴ波绝对潜伏期延长超过1ms,Ⅰ波波幅也有明显降低(P<0.01),但术后无听力障碍;手术结束时Ⅲ~Ⅴ波间期及16例的Ⅰ、Ⅴ波波幅恢复较快.2例术后患侧听力丧失的患者中,1例术中Ⅴ波波幅逐渐降低至消失,另1例术中未监测到Ⅴ波波形.结论 MVD手术操作过程均可引起BAEP改变;Ⅴ波绝对潜伏期延迟超过1ms者相对多见,但无听力受损;Ⅴ波波幅下降程度可为术中神经功能受损提供客观指标,以采取相应措施减少听力并发症的发生.  相似文献   

11.
BACKGROUND: Several studies have demonstrated that visual evoked potentials can be influenced by sport events. To the best of our knowledge, there are no specific parameters for the most appropriate stimulation for evaluating the functional state of athletes. OBJECTIVE: To investigate the best stimulation in visual evoked potential to apply to functional evaluation of athletes. DESIGN, TIME AND SETTING: Ninety-five, healthy students from the Shandong Normal University took part in an observational, contrast study. PARTICIPANTS: All active participants were male. Sixty-five students majored in physical education, and had participated in exercise for the duration of (4.26 ± 3.08) years. An additional 30 students majored in other subjects. METHODS: The neural electricity tester, NDI-200, was adapted to examine and record visual evoked potential with varying probes using bipolar electrodes attached to the head of all the participants in a dark room. The visual evoked potential values were analyzed transversally. A chessboard pattern reversal method was applied with the following parameters: 2 Hz stimulation frequency, brightness of 90 cdp, 80% contrast, 1–100 Hz bandpass filters, and 10 μV sensitivity; 100 responses were averaged. MAIN OUTCOME MEASURES: latency, peak latencies, and inter-peak latencies were measured in N75, P100, N145 with varying probe stimulations. RESULTS: (1) Comparisons between the little check, middle check, and big check stimulation, demonstrated that the common tendencies in visual evoked potential indexes of the two groups of N75 latency were successively shorter and N145 were longer. P100-N145 peak latency was decreased and each inter-peak latency was longer. (2) Changes of N75, P100, and N145 with different check stimulations in the physical education student group: after compared with the middle check stimulation, N75 latency was significantly longer (P < 0.01), and N75-P100 inter-peak latency (P < 0.05) and N75-N145 inter-peak latency were both shorter (P < 0.05). N75-P100 inter-peak latency was shorter (P < 0.01) in the little check stimulation. When compared with the big check stimulation, N75 latency was significantly longer (P < 0.01) and N145 was shorter (P < 0.01). Compared with the big check stimulation, N145 latency was significantly shorter (P < 0.05). (3) Changes of N75, P100, and N145 with different check stimulations in the normal students: when compared with the big check stimulation, N75 latency was significantly longer (P < 0.05) and N145 latency was shorter (P < 0.05). Each inter-peak latency was shorter (P < 0.05) in the little check stimulation. When comparing the middle check stimulation, N75-N145 inter-peak latency was shorter (P < 0.05). CONCLUSION: Large visual evoked potential differences were observed between students majoring in physical education and other subjects when medium probe stimulation was applied. These results suggest that the use of medium probe stimulation (25 mm×25 mm) should be adopted when evaluating the functional state of athletes. Key Words: visual evoked potential; functional evaluation; probe stimulation  相似文献   

12.
Summary The cortical somatosensory evoked potential (SEP) of the rat, evoked by contralateral forepaw stimulation, consisted of early (P 1 and N 1) and late components (P 2 and N 2). Microelectrode recording yielded evoked unitary responses of short latencies in the range of the early components and responses of longer latencies in the range of P 2. During the development of focal epilepsy after topical application of penicillin, the late components of SEP were enhanced and the enhanced late negativity corresponded to a surface negative cortical spike. The prominent enlargement of later components was associated with prolonged, often recurrent discharges of longer latency unitary responses and with enlarged local field potentials. Early components of SEP remained relatively unaffected and so did unitary responses with short latencies.Epileptic spike-conditioned SEPs in the cuneate nucleus, thalamic sensory relay nucleus and sensory cortex were depressed from 100 ms (cuneate nucleus) to about 300 ms (thalamus and cortex) subsequent to spike discharge. Transmission in the cuneate nucleus was least affected. Thalamic and cortical early components of SEP had similar time courses of recovery, which differed markedly from that of cortical late components. Our findings suggest that two different neuronal activities generate different components of SEP and are differentially involved in the epileptic activities, which results in the different amplitude recovery following spontaneous epileptic spike discharges.This work was supported by the Deutsche Forschungsgemeinschaft (German Research Council)  相似文献   

13.
Several authors have demonstrated a correlation between short latency somatosensory evoked potentials (short latency SEPs) and cerebral blood flow (CBF). It is also known that ischemia may modify the amplitude of the cortical SEP while its latency is less sensitive to CBF fluctuations. Phychotropic drugs — Oxiracetam, SAMe, Naloxone, L-acetylcarnitine and GM1 — affect some parameters of the early components of cortical SEPs, chiefly the amplitude, which makes SEP recording a useful method for monitoring pharmacological activity in acute stroke.
Sommario Molti studi hanno dimostrato l'esistenza di una relazione fra potenziali evocati a breve latenza (Short-latency SEP) e flusso ematico cerebrale (CBF). è anche noto che condizioni d'ischemia possono modificare l'ampiezza del SEP corticale, mentre la latenza si dimostra meno sensibile a fluttuazioni del flusso ematico cerebrale. La somministrazione di farmaci nootropi — Oxiracetam, SAMe, Naloxone, M-Acetilcarnitina, GM1 —altera alcuni parametri delle componenti precoci del SEP corticale, principalmente l'ampiezza, facendo di tale metodica un utile mezzo per monitorare l'attività farmacologica, nella fase acuta dello stroke.
  相似文献   

14.
目的探讨经颅多普勒超声(TCD)联合体感诱发电位(SEP)监测在颈动脉内膜剥脱(CEA)术中的应用价值。方法对29例颈动脉狭窄患者在CEA术中采用TCD和SEP联合监测,用TCD监测术侧大脑中动脉(MCA)平均血流速度(Vm)的变化,并记录同时段SEP波幅的变化。根据术中TCD和SEP的变化综合判断是否实施转流术,并判断开放颈动脉后有无出现脑血流高灌注。结果本组患者经术中应用TCD和SEP联合监测均顺利完成手术;3例TCD监测MCA Vm及SEP波幅下降均达到转流标准的患者,术中行转流术。SEP(10.3%,3/29)和TCD(44.8%,13/29)监测达到转流标准比率的差异有统计学意义(χ2=4.118,P=0.002)。5例患者TCD监测示术中出现脑血流过度灌注,但此时SEP并无阳性表现,通过适当降血压及压迫颈动脉处理,其中仅1例患者术后出现脑过度灌注综合征。本组患者术后1周内复查CTA或DSA显示颈动脉狭窄均消失。术后随访3~18个月,仅1例患者在术后第10 d出现术侧手功能区小片状脑梗死,其他患者均无出现并发症。结论TCD与SEP联合监测在CEA术中具有较高的临床应用价值;SEP在判断术中是否使用转流方面更有优势,TCD在判断CEA术中高灌注方面有优势。  相似文献   

15.
《Clinical neurophysiology》2021,132(2):372-381
ObjectiveChanges in the N20/P25 amplitude of somatosensory evoked potentials (SEP) of the median nerve have been found to correlate with those in cortical regional cerebral blood flow (rCBF). Our study presents the use of median nerve SEP amplitude in predicting the clinical outcome of urgent surgical internal carotid artery (ICA) recanalization.MethodsA total of 27 patients suffering an acute ischemic stroke (AIS) with extracranial ICA occlusion within 24 h were prospectively recruited. The primary preoperative endpoints included the SEP amplitude absolute value (SEP-amp) and the SEP amplitude side-to-side ratio (SEP-ratio).Clinical outcome at 3 months postoperatively was assessed using the modified Rankin scale (mRS-3M).ResultsThe positive predictive values (PPVs) for SEP-amp and SEP-ratio were 95.5% and 100%, respectively, with the negative predictive values (NPVs) being 60.0% and 100%, respectively. The SEP-ratio correlated fully with mRS-3M.ConclusionThe median SEP side-to-side N20/P25 amplitude ratio seems to be a very strong positive and negative predictor of the clinical outcome of urgent recanalization of an extracranial ICA occlusion.SignificanceThe results suggest that cortical evoked activity may help in selection patient for surgical recanalization and predict clinical recovery after an acute ischemic stroke.  相似文献   

16.
A 2-yr-3-mo-old girl with metachromatic leukodystrophy (MLD) was examined using serial multiple electrophysiological procedures. Sensory nerve conduction velocity was delayed earlier and more severely than motor nerve conduction velocity. Visual evoked potentials (VEPs) showed prolonged latency of wave IV. Auditory brainstem responses (ABRs) showed prolonged latency of waves I and V, and the I-V interval. As to the interpeak latency of somatosensory evoked potentials (SEPs), the P9-P14 and the P14-N20 intervals were prolonged on admission. Two months later, both intervals were more prolonged, but the prolongation of the P9-P14 interval was the most prominent. The demyelination in our case may have started in the cerebral white matter, progressed to the peripheral nerves, and at last via the spinal root reached the brainstem. An electrophysiological follow-up study may be valuable in the understanding of the progressive pathological changes and in the evaluation of therapeutic measures.  相似文献   

17.
脊髓手术中体感诱发电位监测的临床研究   总被引:3,自引:0,他引:3  
报告30例脊髓手术中体感诱发电位(SEP)连续监测的临床研究结果。SEP记录包括脊髓SEP(SSEP)和皮层SEP(SCEP)。麻醉药物对SEP有一定程度影响,SCEP相对较大。认为,至少术中SEP潜伏期延长不超过8%和波幅降低不超过50%,不会引起术后并发症,超过该范围由于病例较少,尚不能肯定与预后的关系,需进一步探讨。  相似文献   

18.
Human cortical somatosensory evoked potentials (SEP) can be modified by concomitant motor tasks ('gating'), through peripheral occlusion and/or central mechanisms. The present study aimed (1) at refining earlier results concerning motor-gating of the primary cortical EPSP-related N20 response after electric median nerve stimulation, and (2) at providing first data on motor-gating of the 600 Hz SEP wavelet burst which occurs superimposed onto N20 and primarily reflects repetitive cerebral population spikes. In 12 healthy subjects median nerve SEP were elicited, using electrical stimuli with intensities below, at and above motor threshold, under either rest or an isometric fist clenching task. Amplitude and latency modifications were analysed for the peripheral compound action potential (CAP), low-frequency SEP components (N20, P25, N35 and P70) and the high-frequency burst. While the peripheral CAP remained unchanged, isometric motor innervation significantly attenuated N20, P25 and P70 amplitudes and shortened peak latencies progressively for all components after N20. In contrast, the high-frequency 600 Hz burst was modulated neither in amplitude nor in latency. Regular amplitude recruitment occurred for all components independent from the motor task, excluding channel saturation as an explanation for gating. We suggest that SEP gating under isometric motor innervation is a central process which selectively operates on specific SEP components and could partly reflect an "efference copy" mechanism.  相似文献   

19.
The purpose of this study was to standardize the method of spinal cord monitoring with evoked potentials in the rat. Seventeen male Wistar rats were anesthetized with α-chloralose and urethane. Somatosensory evoked potential (SEP) and cerebellar evoked potential (CEP) following sciatic nerve stimulation were mapped at different time points after induction of anesthesia. SEP peaks at latencies of 13–18 ms (P13, N18) were localized to an extremely small area over the sensory cortex. In contrasts, a negative peak of the SEP at 11 ms (N11) and the CEP were widely distributed over the cerebral or cerebellar surface. Anesthesia significantly influenced the cortical components of the SEP. In 10 rats, MEP or posterior fossa evoked potential (PFEP) following stimulation of the sensorimotor or cerebellar cortices respectively, were recorded at T9. Stimulation of different points produced little change on the waveforms of the MEP or PFEP. Successive recordings of MEP and SEP revealed that the P13-N18 complex of the SEP was markedly suppressed after MEP recordings were made. In conclusion, this study identified several factors which alter SEP waveforms in the rat including location of recording, anesthesia and sequence with respect to MEP recording. MEP by stimulation of the same sensory cortex as SEP recordings should not be used for concurrent monitoring, since cortical stimulation will change the waveforms of the SEP.  相似文献   

20.
目的观察研究神经干细胞(NSCs)移植入视神经部分损伤SD大鼠后闪光视觉诱发电位(F-VEP)的变化。方法24只健康成年SD大鼠随机分为NSCs移植组(N组)和对照组(C组),每组12只大鼠,两组均使用精确校准方法在大鼠右眼造成部分视神经损伤,左眼为正常对照。从胚胎SD大鼠海马分离NSCs,利用细胞培养和体内移植技术,将培养后的NSCs注入视神经损伤后N组大鼠玻璃体内,C组大鼠视神经损伤眼玻璃体内注入同等体积的PBS。以上两组分6个时间段,即损伤前、损伤时、损伤后1周、2周、3周、4周分别检测损伤视神经眼的F-VEP,记录P1波幅及峰潜时,并进行统计分析。结果N组及C组P1波幅随时间延长均不同程度降低,但前者趋势较后者缓和。自第2周开始N组波幅均高于C组,且差异有显著性;N组及C组P1峰潜时均随时间变化,在第3周时达到最长,第4周时P1峰潜时有缩短;自第1周开始N组峰潜时均较C组缩短,且差异均有显著性意义。结论NSCs移植入视神经部分损伤大鼠可部分改善视神经传导功能。  相似文献   

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