多发性硬化脑干诱发电位Ⅰ波异常21例分析

目的研究多发性硬化(MS)患者听神经脱髓鞘损害.方法对21例MS患者23例次脑干诱发电位(BAEP)Ⅰ波异常进行分析,以及结合MRI表现探讨听神经脱髓鞘损害部位.结果 BAEPⅠ波异常单侧17例,双侧4例,包括Ⅰ波两耳潜伏期差(ILD)异常11例,Ⅰ波消失单、双侧各2 例,分化不清,潜伏期不肯定3例,潜伏期延长3例.其中单侧主观听力障碍2例.同时,BAE P显示脑干内损害10例.MRI显示脑干内病灶5例.结论部分MS患者存在听神经远端脱髓鞘损害.主要表现为I波ILD异常,部分为BAEP Ⅰ波潜伏期延长,Ⅰ波消失,较少部分听神经脱髓鞘严重可出现突聋.     

腺病毒转染CTLA4-Ig对实验性自身免疫性脑脊髓炎大鼠治疗作用的研究

目的探索CTLA4-Ig转基因对实验性自身免疫性脑脊髓炎（EAE）大鼠的疗效，为临床治疗多发性硬化（MS）提供新思路。方法将表达CTLA4-Ig的重组腺病毒（AdCTLA4-Ig）注射至Wistar大鼠EAE模型侧脑室内，与地塞米松治疗组对比观察实验动物发病情况和神经电生理改变。结果AdCTLA4-Ig注射后的大鼠EAE发病情况得以改善，脑干听觉诱发电位（brainstem auditory evoked potential，BAEP）和体感诱发电位（somatosensory evoked potential，SEP）异常改变有所减轻。结论AdCTLA4-Ig对EAE大鼠有治疗作用，其疗效略优于地塞米松。     

59例听神经瘤患者脑干听觉诱发电位分析

目的 分析听神经瘤(acoustic neuroma,AN)患者的脑干听觉诱发电位的变化特征及健侧耳峰间期改变.方法 对59例听神经瘤(AN)患者进行脑干听觉诱发电位(BAEP)检测,测定Ⅰ、Ⅲ、Ⅴ波潜伏期(PL)、峰间期(IPL),双耳PL、IPL之间差值(ILD)等数值.结合MRI、CT影象学资料进行分析,并与36例健康者对照.结果 AN组与正常对照组BAEP各波PL、IPL测值比较差异有极显著性(P＜0.01).AN患侧BAEP异常率98.3%(58/59);主要表现:①Ⅰ、Ⅲ、Ⅴ波缺失;②Ⅲ、Ⅴ波PL延长;③Ⅰ～Ⅲ、Ⅲ～Ⅴ、Ⅰ～Ⅴ波IPL延长.AN患者健侧BAEP的异常率69.5%(41/59),主要表现:①Ⅴ波PL延长;②Ⅲ～Ⅴ及Ⅰ～Ⅴ波IPL延长;③Ⅲ～Ⅴ/Ⅰ～Ⅲ波IPL比值＞1.肿瘤直径＞2cm,BAEP的异常率有显著提高.不同大小肿瘤组间健侧BAEP测值比较:健侧Ⅴ波PL差异有显著性(P＜0.05),Ⅲ～Ⅴ及Ⅰ～ⅤIPL差异有极显著性(P＜0.01).结论 BAEP对AN诊断具有重要意义,它为病变提供了定位诊断依据,尤其健侧Ⅲ～Ⅴ/Ⅰ～Ⅲ波IPL比值异常,是脑干受压的敏感指标.     

帕金森病脑干听觉诱发电位变化30例报告

目的 探讨脑干听觉诱发电位(BAEP)对帕金森病的诊断价值.方法 对30例帕金森病人进行脑干听觉诱发电位(BAEP)检查.结果 30例帕金森病人双耳听阈增高,Ⅰ～Ⅲ波潜期延长者13例,Ⅲ～Ⅴ波潜期延长者17例,Ⅰ～Ⅴ波潜期延长者9例,Ⅰ～Ⅴ波潜期不清楚5例.提示不同程度的听觉通路及脑干的损害.结论 脑干听觉诱发电位对帕金森病的诊治有临床应用价值,值得推广.     

2型糖尿病患者脑干听觉诱发电位的改变及相关因素分析

目的分析2型糖尿病(2DM)患者脑干听觉诱发电位(BAEP)的改变,从而探讨BAEP对糖尿病患者脑干功能损害的检测价值。方法对50例2型糖尿病患者进行脑干听觉诱发电位(BAEP)检测,比较听觉通路左右耳损害及周围段与中枢段损害差别,并分析病程、空腹血糖对BAEP的影响。结果 (1)2DM患者BAEP左右耳比较潜伏期(PL)及潜伏期差(IPL)差异无统计学意义。(2)2DM患者BAEP中枢段与周围段比较,中枢段损害重于周围段,差异有统计学意义。(3)2DM患者BAEP异常与病程有相关性,与空腹血糖无相关性。结论 BAEP检测对2DM患者在无脑部受损临床症状时可以早期发现听神经是否受累及受累部位。     

飞机噪声职业暴露人群脑干听觉诱发电位测定研究

目的 研究脑干听觉诱发电位作为飞机噪声听力影响测试指标的可行性。方法 (1)用意大利产VAGA—10型电生理仪对60名飞机维修保养人员及120名对照人群进行脑干听觉诱发电位(Brainstem Auditory Evoked Potentials,BAEP)测试。(2)根据统计分析研究脑干听觉诱发电位作为飞机噪声引起的听力损害的早期检测指标的可行性及相关职业因素对脑干听觉诱发电位的影响。结果(1)飞机噪声职业接触人群脑干听觉诱发电位Ⅰ、Ⅲ、Ⅴ波的潜伏期值及Ⅰ～Ⅴ波的峰间潜伏期值与对照组有显著性差异,P<0.05;左耳Ⅰ-Ⅲ波、右耳Ⅲ—Ⅴ波的峰间潜伏期值两组比较也有显著性差别,P<0.05。(2)脑干听觉诱发电位数据多因素方差分析表明BAEP各波的潜伏期值与工龄、职业接触飞机噪声、接触噪声强度、日接触时间等因素均有关。年龄、工龄等因素对职业接触高强度飞机噪声产生的听力影响有增效作用。结论 BAEP潜伏期值可预测飞机噪声对听力的早期影响,BAEP测试方法可作为飞机噪声职业危害的早期敏感性检测指标。     

重症肌无力患者IgG脑室内注射对大鼠EEG及BAEP的影响

目的 观察重症肌无力(myasthenia gravis，MG)患者IgG(AChRAb)经大鼠脑室内注入对其脑电图(electroencephalography，EEG)及脑干听觉诱发电位(brain stem auditory evoked potential，BAEP)的影响，并探讨AChRAb影响大鼠中枢神经系统(CNS)的机制。方法将从确诊的、AChRAb阳性的MG患者血清中提纯的IgG(AChRAb)，注射到实验组大鼠侧脑室，对照组大鼠则注射健康人IgG，观察大鼠行为学、BAEP、EEG改变。结果实验组大鼠术后出现类似于实验性自身免疫性MG的行为学改变，部分大鼠出现癫痫发作BAEP峰间潜伏期(IPLs)延长EEG异常，即δ、θ增多与痫性波发放增加。结论 MGAChRAb可致大鼠CNS损害，AChRAb与大鼠CNS神经元型乙酰胆碱受体结合，可能是其病理生理机制。     

多发性硬化脑干诱发电位I波异常21例分析

目的 研究多发性硬化（MS）患者听神经脱髓鞘损害。方法 对21例MS患者23例次脑干诱发电位（BAEP）I波异常进行分析,以及结合MRI表现探针听神经脱髓鞘损害部位。结果 AEP I波异常单侧17例,双侧4例,包括I波两耳潜伏期差（ILD）异常11例,I波消失单、双侧各2例,分化不清,潜伏期不稳定3例,潜伏期延长3例。其中单侧主观听力障碍2例。同时,BAEP显著脑干内损害10例。MRI显示脑干内病灶5例。结论 部分MS患者存在听神经远端脱髓鞘损害。主要表现为I波ILD异常,部分为BAEP I波替伏期延长,I波消失,较少部分听神经脱髓鞘严重可出现突聋。     

听神经瘤术中神经电生理监护的应用分析

目的研究听神经瘤术中脑干及相应颅神经功能较敏感的电生理监测手段,以达到减少伤残率及提高颅神经的解剖及功能保留率。方法对28例听神经瘤病人,用同一监护仪于手术前、术中及术后分别进行脑干听觉诱发电位(BAEP)及肌电图连续实时监护,观察手术操作对它们的影响。结果听神经瘤手术操作均可以引起BAEP改变,BAEP的Ⅰ、Ⅲ、Ⅴ波潜伏期,Ⅰ-Ⅴ、Ⅲ-Ⅴ峰间潜伏期的明显延长(P<0.05),Ⅴ波波幅明显降低(P<0.05),其中BAEP的Ⅴ波潜伏期及波幅改变最为显著。当接近、触及、牵拉、刺激面神经时,肌电图出现突发的、双相或多相的高幅电位改变,而通过直接电刺激可定位面神经解剖,面神经的解剖及功能保留得以明显提高。结论BAEP的Ⅴ波潜伏期延长和波幅下降以及突发的双相或多相的高幅肌电图改变是听神经瘤术中敏感的电生理指标,对其进行监护,可为术中避免神经功能损伤及术后其功能预测提供客观指标,降低手术伤残率。     

Wistar大鼠实验性变态反应性脑脊髓炎的模型建立

目的:建立Wistar大鼠多病程实验性变态反应性脑脊髓炎(EAE)的动物模型,并进行病理学研究,为多发性硬化(MS)的研究提供实验依据。方法:以豚鼠全脊髓匀浆(GPSCH)为抗原免疫Wistar大鼠建立EAE的动物模型,并在光镜下观察不同发病类型EAE的病理改变。结果:根据病理和临床表现可将Wistar大鼠EAE模型分为5种发病形式:急性型、缓解-复发型、持续进展型、良性型和隐匿型。光镜下可见不同发病时期的EAE的病理改变有所不同,但都以血管"袖套"状改变、脑室周围及白质脱髓鞘改变为主,伴有神经元肿胀变性。结论:首次建立了Wistar大鼠多病程EAE,是研究多发性硬化的理想动物模型。     

Acoustic nerve conduction abnormalities in Guillain-Barré syndrome

We recorded brainstem auditory evoked potentials (BAEPs) in two patients with Guillain-Barré syndrome (GBS). One patient was acutely deaf with total absence of BAEP waveforms indicative of acoustic nerve conduction block. Hearing improved during early convalescence, and there were prolonged wave I latencies. Normal BAEPs were recorded on recovery. A second patient had bilaterally prolonged wave I latencies. These BAEP findings suggest that acoustic nerve conduction abnormalities from demyelination may occur in GBS.     

Intraoperative electrophysiological monitoring for hearing preservation in acoustic neurinoma surgery

Five acoustic neurinomas have been operated with hearing preservation as a goal. We monitored intraoperative brainstem auditory evoked potentials (BAEP) in all five cases, electrocochleogram (ECoG) using needle electrode in external auditory meatus in four, and compound action potentials directly recorded from the cochlear nerve (CAP VIII) in three. In all five cases the tumor was totally resected and cochlear nerve was anatomically preserved. However, in only one case useful hearing was preserved with preservation of all wave forms of the BAEP. Another patient with preservation of all wave forms of BAEP and the ECoG showed postoperative severe hearing loss. Other three patients showed postoperative severe hearing loss: only Wave I of BAEP and ECoG were preserved without preservation of the CAP VIII in one whose cochlear nerve was thought to be damaged in cerebellopontine angle cistern; Wave I of BAEP, ECoG and CAP VIII were preserved in one in whom it was suggested cochlear nerve near brainstem or cochlear nucleus was damaged; none of the BAEP, ECoG and CAP VIII was preserved in one in whom it was suggested distal cochlear nerve, or internal auditory artery was damaged. These different patterns of changes suggested that different causes for the hearing loss and difficulties in hearing preservation during acoustic neurinoma surgery. Having identified the putative mechanism of the hearing loss by monitoring those potentials, suggestions are made about how such hearing loss might be avoided. For preservation of the hearing in acoustic neurinoma surgery, all of those potentials including all wave forms of BAEP, ECoG and CAP VIII should be preserved during surgery.(ABSTRACT TRUNCATED AT 250 WORDS)     

The pathophysiology of myelin basic protein-induced acute experimental allergic encephalomyelitis in the Lewis rat

Histological and electrophysiological studies were performed on Lewis rats with acute experimental allergic encephalomyelitis (EAE) induced by inoculation with guinea-pig myelin basic protein (MBP) and Freund's adjuvant. The histological studies showed demyelination in the lumbar, sacral and coccygeal dorsal and ventral spinal roots and to a lesser extent in the spinal cord, including the dorsal root entry and ventral root exit zones. The electrophysiological studies demonstrated reduced conduction velocities between the lumbar ventral roots and sciatic nerve. Conduction block was demonstrated at the ventral root exit zone of the lumbar spinal cord but was less severe than in rats with whole spinal cord-induced acute EAE. Recordings of the M wave and H reflex elicited in a hindfoot muscle by sciatic nerve stimulation showed a normal M wave, indicating normal peripheral nerve motor conduction, but a markedly reduced H reflex. The reduction in the H reflex is accounted for by demyelination-induced nerve conduction block in the dorsal and ventral spinal roots, intramedullary ventral roots and at the dorsal root entry and ventral root exit zones of the spinal cord. Demyelination and nerve conduction abnormalities were well established in the relevant lumbar segments on the day of onset of hindlimb weakness. It is concluded that demyelination in the lumbar ventral roots and to a lesser extent in the lumbar spinal cord, including the ventral root exit zone, is an important cause of hindlimb weakness in myelin basic protein-induced acute EAE in the Lewis rat.     

Mechanisms of intraoperative brainstem auditory evoked potential changes.

Brainstem auditory evoked potential (BAEP) changes during intraoperative monitoring may reflect damage to or potentially reversible dysfunction of the ear, the eighth nerve, or the brainstem auditory pathways up to the level of the mesencephalon. They may also be caused by other physiologic mechanisms such as anesthesia, hypothermia, and acoustic masking from drilling noise, or they may result from technical factors that prevent proper stimulus delivery or recording of an evoked potential that is actually present. Cochlear ischemia or infarction resulting from compromise of the internal auditory artery and inner ear damage during temporal bone drilling will affect all BAEP components, including wave I. Direct mechanical or thermal trauma to the eighth nerve will delay, attenuate, and possibly eliminate waves III and V, but wave I, which is generated at the cochlear end of the eighth nerve, may be preserved. During scraping of tumor off the eighth nerve, force applied in an ear-toward-brainstem direction can avulse the fragile fibers of the distal eighth nerve at the area cribrosa. Prolonging the I-to-III interpeak interval during retraction of the cerebellum and brainstem reflects stretching of the eighth nerve, and is often reversible. Vasospasm within the eighth nerve can cause similar, potentially reversible BAEP changes. Damage to the brainstem auditory pathways at or below the level of the mesencephalon will delay and attenuate or eliminate wave V. Wave III is affected similarly if the damage is at or caudal to the region of the superior olivary complex. These BAEP changes may reflect direct mechanical or thermal damage to the brainstem, brainstem compression, or ischemia or infarction resulting from vascular compromise. During BAEP monitoring, examination of the pattern of BAEP changes, analysis of their correlation with surgical maneuvers, and investigation for possible contributory technical factors can help to determine the cause of the BAEP changes and provide the appropriate information to the rest of the surgical team.     

实验性自身免疫性脑脊髓炎的视神经病理改变

目的 研究实验性自身免疫性脑脊髓炎(EAE)的视神经病理改变.方法 足垫皮下注射豚鼠脊髓匀浆和完全弗氏佐剂(CFA)混合物制作Wismr大鼠EAE模型,于发病后第6d将大鼠处死,取视神经、脑和脊髓,行HE和LFB染色,光镜和电镜下观察其病理改变.结果 病理检查发现EAE模型组大鼠脑、脊髓有不同程度的炎症反应和脱髓鞘改变;均有视神经病变,光镜主要表现为炎症反应和脱髓鞘,视神经髓鞘脱失重于炎症反应;电镜主要表现为髓鞘稀疏,少突胶质细胞数量减少、胞核固缩,其周围包裹的髓鞘板层松解,轴突髓鞘分离.结论 EAE大鼠存在明显的视神经病变,主要为视神经炎症反应和脱髓鞘改变.     

Peripheral nerve demyelination in rabbits after inoculation with Freund's complete adjuvant alone or in combination with lipid haptens

The pathology of demyelination in rabbits with experimental allergic neuritis (EAN) or galactocerebroside-induced neuritis was compared to that in rabbits inoculated with either an emulsion of lipid haptens (gangliosides, lecithin and cholesterol) and Freund's complete adjuvant or Freund's complete adjuvant (FCA) alone. In rabbits inoculated with bovine peripheral myelin in FCA, perivenular demyelination associated with infiltrates of lymphocytes and macrophages occurred after 30 days, while those animals inoculated with galactocerebroside (GC) in Freund's adjuvant did not develop lesions until 60-90 days. GC rabbits had demyelination and severe nerve edema without cellular infiltrates. In rabbits inoculated with FCA alone, demyelination was restricted to ganglia and proximal nerve roots. Myelin basic protein (MBP) and GC antibodies from EAN, GC and lipid hapten-inoculated rabbits were detected by ELISA in sera at all post-inoculation time points. Appreciable P0 and P2 antibody titers were detected only in EAN animals. The results indicate that Freund's complete adjuvant alone or in combination with lipid haptens is capable of producing neuropathic effects in the rabbit independent of those produced by EAN or galactocerebroside neuritis.     

Induction of recurrent experimental allergic encephalomyelitis with myelin basic protein

Recurrent experimental allergic encephalomyelitis (EAE) was induced in Lewis rats by inoculation of human myelin basic protein (MBP) and complete Freund's adjuvant (CFA). The animals developed clinical disease characterized by unsteadiness, ataxic gait, and abnormal posturing of the limbs. Spontaneous remissions and relapses were noted for periods up to 120 days. Histologically there were perivascular infiltrates of mononuclear cells, especially prominent in the cerebellar white matter. There was little evidence of demyelination. This study demonstrates that relapsing EAE may be induced with MBP in the rat. Sensitization with other myelin antigens is not required, although immunity to such antigens may be necessary to induce demyelination. It is postulated that relapsing EAE may be associated with a defect in suppressor cell function.     

Role of nonspecific myelin destruction by delayed type hypersensitivity in primary demyelination

To clarify the role of nonspecific myelin destruction mediated by delayed type hypersensitivity (DTH) in primary demyelination, DTH to tuberculin was induced within the endoneurium by intraneural injection of purified protein derivative (PPD) or sonicated Mycobacterium tuberculosis into the sciatic nerves of Lewis rats and guinea pigs which had previously been sensitized to tuberculin. The morphological features of the nerves proximal to the site of needle insertion were assessed 5 days after injection. By changing the PPD concentration of solution for intraneural injection, various degrees of DTH reaction could be produced in the nerve. Infiltration of mononuclear cells including macrophages was observed around the vessels and in the vicinity of the myelin sheaths. Although nonspecific damage of axons, myelin sheaths and Schwann cells was observed in areas heavily infiltrated with inflammatory cells, primary demyelination was hardly recognized. Another group of Lewis rats previously immunized with galactocerebroside (GC), the major glycolipid hapten of myelin, in Freund's complete adjuvant received intraneural injection of PPD or GC liposomes. Neither cellular nor humoral immunity to GC was detected in these rats. The nerves injected with GC liposomes showed no inflammatory cell infiltration except for a few macrophages containing liposomes and those injected with PPD showed infiltration of mononuclear cells without primary demyelination. Our findings reveal that nonspecific myelin destruction induced by DTH does not play an important role in immune-mediated demyelination.     

F response and somatosensory and brainstem auditory evoked potential studies in HMSN type I and II.

To evaluate conduction along the proximal and distal segments of motor and sensory long limb nerves, as well as along the very short acoustic nerve, F response and somatosensory and brainstem auditory evoked potential were studied in a series of patients with hereditary motor and sensory neuropathy (HMSN) types I and II. A diffuse and comparable slowing of conduction in proximal and distal nerve segments, as well as along the acoustic nerve, seems to favour a primary myelin defect in HMSN I. F response and motor conduction velocity showed a similar derangement in both proximal and distal motor segments. Latencies of somatosensory evoked potentials were symmetrically prolonged and correlated with motor nerve impairment. Central conduction times were normal. Studies of brainstem auditory evoked potentials showed a high incidence of acoustic nerve involvement, the most evident abnormality being a statistically significant increase in the latency of the I wave. Our data seem to support the presence of primary myelinopathic damage in HMSN I.     

Chronic experimental allergic neuritis. An electrophysiological and histological study in the rabbit

Ten adult outbred New Zealand white rabbits were inoculated with a single multiportal dose of purified bovine peripheral nerve myelin and Freund's adjuvant containing 500 mg of nerve antigen. Seven animals developed chronic relapsing or progressive disease which was followed by clinical examination for 14 months. Electrophysiological studies showed marked slowing of motor conduction velocity, dispersion of the evoked muscle action potential (MAP) and reduction in amplitude of the MAP derived from distal stimulation. Histological examination of the peripheral nervous system showed at 12 months a marked hypertrophic neuropathy in the nerve roots with well developed onion bulbs, active demyelination and a moderate nerve fibre loss. It is suggested that these animals provide a reliable and predictable model for human chronic inflammatory demyelinating polyneuropathy (CIDP) which should prove valuable for therapeutic trials and studies of pathogenetic mechanisms.