Multimodality evoked potentials and early prognosis in comatose patients

In 112 comatose patients somatosensory, visual and auditory evoked potentials were registered within 36 hours after the onset of coma or admission. Main causes of coma were head injury, and intracerebral and subarachnoid haemorrhage. The initial bilateral loss of any evoked potential was associated with a mortality of 98%. Normal somatosensory evoked potentials were associated with a survival rate of 74%, while normal visual and normal auditory evoked potentials had a survival rate of 60% and 66%, respectively. It is concluded that SEPs can be valuable for the prognosis of coma after primary brain lesions.     

Clinical approach to comatose patients

Coma is a state of unarousable unconsciousness and can occur as result of many general medical and neurological conditions. In this article we present a structured approach to the investigation and management of a patient who presents with coma and discuss the importance of identifying the underlying cause in attempting to prevent secondary brain damage, as well as for prognostication.     

The brain-stem and 40 Hz middle latency auditory evoked potentials in brain death

Summary Bilateral recordings of brain stem auditory evoked responses were compared with the 40 Hz middle latency auditory evoked responses in 38 patients either brain dead or in coma grade IV. In 4 cases the 40 Hz auditory evoked potential was partly preserved, while the brain stem auditory evoked potential was not reproducible beyond wave II.Recording of the 40 Hz auditory evoked potential is found to be more sensitive in some rare instances.This study was supported in part by the Deutsche Forschungsgemeinschaft, grant Fi 390-1-857/88.     

Neurophysiological evaluation in detrusor instability

Different and complex neuronal systems are involved in the control of continence. Detrusor overactivity has been divided by the International Continence Society into two functional subgroups: a) detrusor instability and b) detrusor hypereflexia. Only in the latter group has neurological damage been shown, but pathophysiological mechanisms are still unknown. In order to complete a full investigation of sensory and motor pathways 12 female patients affected by idiopathic detrusor instability (mean age 60.2 years; range 49–73) and 13 age-matched healthy women were studied. All patients were submitted to a subtracted cistometrogram (CMG), anal sphincter electromyography (EMG) with a bipolar coaxial needle, sacral reflex analysis after stimulation of the dorsal nerve of the clitoris, tibial and pudendal somatosensory evoked potentials, motor evoked potentials after magnetic cortical coil stimulation, and recording from anal sphincter and abductor brevis hallucis muscles. All patients had normal neurophysiological tests, and no significant differences between patients and controls could be seen. Our data confirms the absence of both clinical and subclinical damage of central sensory or motor pathways in detrusor instability; an alteration of suprasegmental mechanisms cannot be excluded.     

Clinical approach to comatose patients

The nature of consciousness itself belongs within a group of ‘underdetermined questions’ to which we might not be able to find an answer. Similarly, we have a limited understanding of disorders of consciousness. In this brief article, we discuss a practical approach to the comatose patient and the importance of promptly identifying the cause to prevent permanent neurologic damage.     

Safe surgery of lesions near the motor cortex using intra-operative mapping techniques: a report on 50 patients

Summary In 50 patients lesions located in or adjacent to the motor strip were microsurgically removed with the help of intra-operative electrophysiological mapping of the sensorimotor cortex. Mapping consisted of cortical stimulation and/or recording of somatosensory evoked potentials. Depending on the patient's pre-operative neurological status, surprisingly good results could be achieved: The surgery resulted in increased permanent sensorimotor deficit in only 4% of cases and in improved neurological status in 30% of cases.It is concluded that surgical removal of centrally located lesions using a microsurgical technique and intra-operative mapping of the motor cortex is safe and permits extensive or radical resection of lesions, even those in the motor cortex itself.     

右美托咪定对特发性脊柱侧弯矫形术中体感诱发电位和运动诱发电位的影响

目的:研究右美托咪定（dexmedetomidine, Dex）对特发性脊柱侧弯矫形术中体感诱发电位（somatosensory evoked potentials, SEPs）和经颅电刺激运动诱发电位（transcranial electric motor evoked potentials, TCeMEPs）的影响...     

磁刺激腰骶部神经根的兴奋点及其在腰骶神经根病中的应用

采用磁刺激腰骶部的神经根运动诱发电位（MEPs）和磁刺激窝F波相结合的方法测定运动神经根传导时间（MRCT）。随机抽查50名正常受试者，在胫前肌（TA）和比目鱼肌（SOL）记录出可靠的运动神经传导时间（MNCT）和MRCT，并根据MRCT推算磁刺激腰骶部神经根的兴奋点位置，结合5例尸解测出的L5和S1神经根的长度，确定该兴奋点在椎间孔的近端。同样方法记录和观察40例手术证实单侧L5或S1神经根受压患者MNCT和MRCT的改变。结果显示：病人组与正常组相比MNCT无显著性差异，而MRCT有显著性差异，异常率为85％。作者认为，无痛无创的磁刺激MEPs对腰骶神经根病有很大的诊断价值。     

TMS—MEP与CSEP诊断脊髓损伤的作用比较

目的比较脊髓损伤后经颅磁刺激运动诱发电位和皮层体感诱发电位检测的诊断价值。方法 １５只家猫脊髓部分切断和６９例ＳＣＩ的ＭＥＰ和ＣＳＥＰ检测。结果 ＭＥＰ对脊髓前柱损伤，前后柱混合损伤和肌力异常极敏感，对后柱损伤不敏感；而ＣＳＥＰ对脊髓后柱损伤，前后柱混合损伤和关节位置觉异常十分敏感，对前柱伤却相反。     

术中无肌松全静脉麻醉用于联合神经电生理监护脊柱手术的可行性

［摘要］ 目的 比较全静脉麻醉下术中使用或不使用肌松药对脊柱手术中联合神经电生理监测结果的影响,探讨安全有效的神经电生理监测麻醉方案。方法 选择拟行联合神经电生理监测的择期脊柱手术病人 40 例,分为A、B两组。两组病人均采用丙泊酚、瑞芬太尼和右美托咪定全凭静脉麻醉,A组病人术中使用小剂量阿曲库铵维持肌松,B组病人术中不使用肌松药。同时监测体感诱发电位（SEP）和运动诱发电位（MEP）评判脊髓功能。记录术中不同时间点两组病人的生命体征和SEP和MEP的波幅和潜伏期,同时记录经颅电刺激时病人是否出现剧烈体动和自主呼吸。比较两组病人术毕后麻醉苏醒时间和质量。结果 两组病人不同时间点的生命体征差异无统计学意义。两组病人的SEP的波幅和潜伏期差异无统计学意义,MEP的潜伏期差异无统计学意义,MEP的波幅差异有显著性统计学意义。两组病人在电刺激时均无自主呼吸和剧烈体动发生。结论 术中不使用肌松药的全静脉麻醉方案可安全有效地用于行神经电生理监测的脊柱手术,并且在电生理监测信号质量和术后苏醒方面具有明显优势。     

慢性脊髓压迫及减压后运动诱发电位及病理学改变

目的探讨脊髓慢性压迫及减压后神经病理学及运动诱发电位(MEP)的变化.方法选用 54只SD大鼠,随机分为对照组,轻、中、重压迫组和减压组.应用磁刺激MEP各组行30 min、6 h和1、2、4周动态观察.用HE染色观察脊髓的组织学变化.结果轻度压迫组MEP潜伏期在损伤后30 min及6 h比术前分别延长0.29倍和0.32倍,至4周恢复,与术前相比,伤后30 min和6 h中度压迫组MEP潜伏期延长0.83倍和0.88倍,重度组延长1.14倍和1.22倍,减压后MEP潜伏期分别缩短了0.21倍和0.23倍.结论轻和中度压迫组的病变是可逆的,而重度压迫导致神经细胞和运动功能的不可逆改变.MEP能反映脊髓受损程度,可作为评价减压效果的客观指标.     

Effects of a competitive stressor on motor cortex excitability: a pilot study

Several intervening variables may influence motor evoked potentials (MEP) from transcranial magnetic stimulation (TMS). Among the most common are motor (e.g. executed or intended muscle contraction) and sensory factors. However, little is known about the effects of a well defined stressor on MEPs and thus on central motor control. We studied 11 healthy right‐handed volunteers (five men and six women), aged 21–32 years (mean 25.2 years, SD=3.5). All subjects underwent a 20 min rest and a 20 min stress period (sequence‐controlled, cross‐over design). The stressor employed a competitive videogame. MEPs from the left abductor digiti minimi muscle were obtained immediately after rest and stress. We found that six (54.5 per cent) subjects presented a significant increase (p<0.05) of MEP amplitudes from rest to stress, three (27.3 per cent; p<0.05) decreased, and two (18.2 per cent) did not change. F‐ and M‐waves did not change significantly. Psychological testing (state and trait anxiety inventory, STAI) revealed that individuals who presented an increase in MEP latency scored lower in state and trait anxiety than others, probably indicating a lower vulnerability to stress. We believe that the observed increase in MEP amplitudes, combined with a decrease in MEP latency, can be regarded as neurophysiological evidence of stress‐induced facilitation related to higher excitability of the corticospinal system and/or presynaptic neurons. Copyright © 2000 John Wiley & Sons, Ltd.     

Effects of dexmedetomidine on intraoperative motor and somatosensory evoked potential monitoring during spinal surgery in adolescents

Background: Dexmedetomidine may be a useful agent as an adjunct to an opioid–propofol total intravenous anesthesia (TIVA) technique during posterior spinal fusion (PSF) surgery. There are limited data regarding its effects on somatosensory (SSEPs) and motor evoked potentials (MEPs). Methods: The data presented represent a retrospective review of prospectively collected quality assurance data. When the decision was made to incorporate dexmedetomidine into the anesthetic regimen for intraoperative care of patients undergoing PSF, a prospective evaluation of its effects on SSEPs and MEPs was undertaken. SSEPs and MEPs were measured before and after the administration of dexmedetomidine in a cohort of pediatric patients undergoing PSF. Dexmedetomidine (1 μg·kg^?1 over 20 min followed by an infusion of 0.5 μg·kg^?1·h^?1) was administered at the completion of the surgical procedure, but prior to wound closure as an adjunct to TIVA which included propofol and remifentanil, adjusted to maintain a constant depth of anesthesia as measured by a BIS of 45–60. Results: The cohort for the study included nine patients, ranging in age from 12 to 17 years, anesthetized with remifentanil and propofol. In the first patient, dexmedetomidine was administered in conjunction with propofol at 110 μg·kg^?1·min^?1 which resulted in a decrease in the bispectral index from 58 to 31. Although no significant effect was noted on the SSEPs (amplitude or latency) or the MEP duration, there was a decrease in the MEP amplitude. The protocol was modified so that the propofol infusion was incrementally decreased during the dexmedetomidine infusion to achieve the same depth of anesthesia. In the remaining eight patients, the bispectral index was 52 ± 6 at the start of the dexmedetomidine loading dose and 49 ± 4 at its completion (P = NS). There was no statistically significant difference in the MEPs and SSEPs obtained before and at completion of the dexmedetomidine loading dose. Conclusion: Using the above‐mentioned protocol, dexmedetomidine can be used as a component of TIVA during PSF without affecting neurophysiological monitoring.     

磁刺激运动诱发电位在腰椎间盘突出所致的腰骶神经根病变中的应用研究

在35例有L5和／或S1神经根损害表现的腰椎间盘突出患者腰椎区进行磁刺激运动诱发电位（MEP）检查，测定、记录胫前肌、展肌和小趾展肌MEP的起始潜伏期（OL）。结果显示，35例中至少有一条总侧肌肉MEP异常33例（94．3％）。在L4－5椎间盘突出中，以胫前肌的MEP异常为主；在L5－S1椎间盘突出中，以小趾展肌的MEP异常为主。表明腰椎区MEP检查对腰椎间盘突出所致的腰骶神经根病变较为敏感，可为临床诊断提供可靠依据并有助于定位诊断。     

术中神经监测技术在脊柱手术中的临床应用

术中神经监测(Intraoperative Neuromonitoring,IOM)伴随着科技和麻醉技术的发展,逐渐被推广并广泛使用,尤其在脊柱手术对脊髓和神经功能的有效监测,降低了手术风险。但在手术的施行过程中,引起监测信号变化的影响因素非常多。本文将对时下常用的几种监测方式进行回顾,并进一步讨论和分析在脊柱手术的过程中,监测信号变化的原因。     

阴茎勃起障碍病人神经诱发电位146例临床分析

本文对１４６例阴茎勃起障碍病人的阴部神经诱发电位（ＰｕｄｅｎｄａｌＥＰｓ）进行了检测分析，其中骨盆骨折３１例，腰椎骨折１１例，盆腔手术９例，高血压１６例，糖尿病１７例，严重手淫６２例。分析结果：阴部皮层体感神经诱发电位（ＣＰＥＰ）、骶髓反射时（ＳＲＬ）和生殖皮层运动诱发电位（ＣＭＥＰ）总体异常率在骨盆骨折、腰椎损伤、盆腔手术、高血压、糖尿病及严重手淫组分别为５１．６１％、５４．５５％、７７．７７％、３１．２５％、４７．０５和３２．２６％，超强度电流刺激在骨盆骨折、腰椎损伤、盆腔手术、高血压、糖尿病及严重手淫组依次为５５．５５％、４５．５４％、４１．１７％、３８．７０％、３０．６０％和６．２５％。研究结果表明：在骨盆骨折、腰椎损伤、盆腔手术及糖尿病人，其ＰｕｄｅｎｄａｌＥＰｓ异常率及超强度刺激率都相当高。提示在这些病人中阴部神经受损的机率较高，而ＰｕｄｅｎｄａｌＥＰｓ检测将有助于阴茎勃起障碍的病因学诊断     

脊髓型颈椎病磁刺激运动诱发电位的临床研究

目的：为脊髓型颈椎病（ＣＳＭ）早期诊断寻找一种客观、敏感的检查方法。方法：采用磁刺激运动诱发电位（ＭＥＰ）和电刺激Ｆ波相结合的方法，测定１９例脊髓型颈椎病人外展拇短肌（ＡＰＢ）和胫前肌（ＡＴ）的中枢运动传导时间（ＣＭＣＴ），并与２０例正常受试者作对照。结果：１８例（９４．７％）ＣＳＭ病人上、下肢ＭＥＰ异常，ＡＰＢ肌及ＡＴ肌ＣＭＣＴ明显延迟，并与临床功能障碍（ＪＯＡ评分）显著相关，与ＭＲＩ所示脊髓受压程度无相关性。结论：磁刺激ＭＥＰ作为检测ＣＳＭ患者运动功能状态的客观指标具有重要的诊断价值。     

麻醉对术中诱发电位监测的影响

诱发电位（EPS）能监测术中运动传导束和感觉传导束的功能．在减少术后神经系统并发症方面显示出很好的前景。已有报道EPS监测用于颅内手术和脊柱手术的术中监测以减少术后感觉和运动功能缺陷．也有报道其用子胸主动脉手术．监测术中有无脊髓缺血。很多常用的麻醉药物对EPS监测有抑制作用．而且某些麻醉药物对其抑制呈剂盛依赖性。因此．较好的了解麻醉药物对EPS的影响．才能更好的发挥EPS监测的作用。本文就麻醉对术中EPS监测的影响做一综述。     

运动诱发电位对足筋膜间隔综合征诊断价值的探讨

目的探讨电刺激运动诱发电位对足筋膜间隔综合征的诊断价值。方法对202例足部损伤患者在双侧腘窝上缘用电刺激坐骨神经。刺激强度为20 mA,时程0.2 m s。同心圆针电极插入足部各筋膜间隔内相应的肌肉中,记录各自运动诱发电位的潜伏期及波幅变化。各电极阻抗均<5 kΩ,滤波带通20~200 Hz,分析时程50 m s。同时采用W h iteside法测压装置监测足部各筋膜间隔内压的变化。结果21例主诉伤足无法忍受的剧痛进行性加重,伴有明显伤足肿胀患者,相应肌肉MEP潜伏期明显延长。当潜伏期为健侧的1.9±0.16倍时,筋膜间隔内压均>4 kPa(30 mmHg),确诊为足筋膜间隔综合征。结论电刺激MEP作为诊断足筋膜间隔综合征的客观指标具有重要的价值。