听觉诱发电位及体感诱发电位在颅脑外伤致昏迷患者的应用

严重颅脑损伤昏迷患者脑功能的监测是判断预后和指导治疗的重要手段。听觉诱发电位(BAEP)及体感诱发电位(SSEP)因其方便、无创并能连续实时监测昏迷患者相关神经传导通路电生理的变化,间接反映脑干上行激活系统、大脑皮层结构与功能的完整性,越来越成为临床对严重颅脑损伤昏迷患者预测预后和指导治疗的重要手段。本文就近年来相关研究进行综述,旨在指导临床实践。     

Influence of stimulation parameters on auditory stimulus processing in schizophrenia and major depression: an auditory evoked potential study

The influence of stimulation frequency and stimulus intensity on the auditory evoked potential components N1 and P2 was investigated in schizophrenic and major depressive patients. The findings in the patients were compared with those in normal controls. At a high stimulation frequency the amplitude of N1 was enhanced in both schizophrenic and major depressive patients; the latency of N1 increased only in the schizophrenic patients. These changes may be related to impairments of auditory input control and processing in these diseases. In the schizophrenic patients, P2 latency was prolonged under treatment with high-potency neuroleptic drugs.     

Delayed recovery of auditory cortical evoked potentials is correlated with cortical neuronal death after transient cerebral ischemia in awake gerbils

Early detection of irreversible neuronal change after transient cerebral ischemia is important so that adequate treatment can be initiated within the therapeutic window. We have examined the correlation between changes in middle-latency auditory evoked potentials (MAEPs) and histological changes in the auditory cortex of awake Mongolian gerbils subjected to 4 min or 12 min of transient cerebral ischemia. Post-ischemic MAEPs were characterized by the appearance of a markedly large negative and positive component at approximately 17–22 ms latency in both groups. Delay in the appearance of the high amplitude (maximal amplitude at 45 min after recirculation in the 12-min ischemia group) precedes the slowly developing death of neurons in the auditory cortex that results from transient cerebral ischemia.     

Depth evoked potential and single unit correlates of vertex midlatency auditory evoked responses

The rostral brainstem and thalamus of awake cats were studied for depth correlates of a surface-recorded midlatency auditory evoked potential, wave "A', with a latency range of 17-25 ms. In response to clicks or pure tones, midlatency potentials were recorded from the level of the cuneiform nucleus (14-15 ms latencies) forward through the medial tegmentum to the level of the intralaminar thalamic nuclei centralis lateralis (CL) and center median (CM) (17-19 ms latencies). While this medial projection system to the thalamus involved primarily CL and CM, slightly longer latency responses were also found in nucleus ventralis anterior (VA) and ventralis lateralis (VL). A ventral diencephalic response was characterized by latencies averaging 0.5-1.2 ms less than those from the dorsal thalamic regions. Both surface and depth midlatency potentials showed comparable sensitivity to rate of stimulation. At click rates above 1/s, peak amplitudes diminished, and for rates greater than 10/s, both surface and depth midlatency responses were abolished. This rate sensitivity differs from that of the auditory brainstem responses (ABRs), which are essentially unchanged at rates of 20/s. Whereas ABRs are unaffected by surgical levels of sodium pentobarbital, the surface and depth midlatency potentials are replaced by a deep negativity within minutes following administration of anesthesia. Extracellular recordings of acoustically responsive single units in CL and CM demonstrated latencies comparable to the CL and CM field potential latencies. Both the units and field potentials were similarly rate sensitive. Each auditory unit showed a best frequency response, but none demonstrated somatosensory convergence. Bilateral aspiration of the inferior colliculus did not abolish the midlatency depth or surface responses. Rather, recordings in CL and CM suggested response enhancement over a two week postoperative period. Taken together these data suggest that the midlatency vertex potential, wave "A', reflects a generator system which projects from cuneiform nucleus, through the medial tegmentum to the medial thalamus, particularly to CL and CM. The functional significance of this medial auditory projection system remains to be determined. It could mediate physiological correlates of "state', modulate sensory input or motor output, or it could provide an integrative mechanism for the focusing of auditory attention.     

Characteristics of brainstem auditory evoked potentials of students studying folk dance★

BACKGROUND： Previous experiments have demonstrated that brainstem auditory evoked potential is affected by exercise, exercise duration, and frequency.
OBJECTIVE： Comparing the brainstem auditory evoked potential of students studying folk dance to students studying other subjects. DESIGN： Observational contrast study.
SETTING： Physical Education College, Shandong Normal University PARTICIPANTS： Fifty-five female students were enrolled at Shandong Normal University between September and December in 2005, including 21 students that studied folk dance and 34 students that studied other subjects. The age of the folk dance students averaged （19 ± 1） years and dance training length was （6.0 ± 1.5） years. The students that studied other subjects had never taken part in dance training or other physical training, and their age averaged （22 ± 1） years, body height averaged （162 ± 5） cm, body mass averaged （51 ± 6） kg. All subjects had no prior ear disease or history of other neurological disorders. All students provided informed consent for the experimental project.
METHODS： The neural electricity tester, NDI-200 （Shanghai Poseidon Medical Electronic Instrument Factory） was used to examine and record Brainstem Auditory Evoked Potential values of the subjects during silence, as well as to transversally analyze the Brainstem Auditory Evoked Potential values. The electrode positions were cleaned and degreased with soapy water, followed by ethanol. The selected bipolar electrodes were situated on the head： recording electrodes were placed at the Baihui acupoint, and the reference electrode was placed at the mastoid of the measured ear, with grounding electrodes in the center of the forehead. Brainstem Auditory Evoked Potential values were elicited by monaural stimulation of a ＂click＂ though an earphone; the other ear was sheltered by the white noise. The click intensity was 102 db, the stimulation frequency was 30 Hz, the bandpass filters were 1 000-3 000 Hz, the sensitivity     

脑干听觉诱发电位改变对Binswanger病的评估价值

目的用脑干听觉诱发电位方法检测Binswanger病的脑功能改变。方法对20例BD病患者、20例非痴呆脑血管病患者、20例老年健康人同时进行脑干听觉诱发电位（BAEP）检查。结果BAEP异常：BD病10例（50％），非痴呆脑血管病2例（10％），经统计学检查BD组BAEP与健康组、非痴呆脑血管病组有显著性差异，非痴呆脑血管病组与健康组无显著性差异。结论BAEP异常反应BD病患者有脑干功能受损和弥漫性脑功能障碍，并可作为BD病患者脑功能损害检查敏感指标，以及与非痴呆脑血管病患者鉴别诊断的一个辅助检查方法。     

接触性热痛诱发电位的临床研究

目的 进一步完善接触性热痛诱发电位(CHEP)的检测方法 和检测痛觉传导通路上段脊髓丘脑束和周围段神经传导时间及周围段神经传导速度. 方法 受检者取卧位,应用CHEP刺激器,于54.5℃应用可调节脉冲,刺激部位为手背、前臂的掌侧面和C7水平皮肤.以Keypoint.net仪器记录,记录点为Cz和Pz,测定CHEP主要波形及外周神经传导速度. 结果 于记录点记录到2个主要成分;Cz/N550、Cz/P750;刺激手背、前臂掌侧面和C7水平皮肤所得CHEP起始波潜伏期男性女性间比较差异无统计学意义(P0.05);介导此诱发电位的外周神经传导速度为(12.9±7.5)m/s,与A8纤维传导速度相对应. 结论 主观疼痛能够进行客观测定,C7点刺激进行CHEP测定有助于判断脊髓丘脑束中枢段和周围段的损害.     

多发性硬化的诱发电位特点

目的分析多发性硬化(multiple sclerosis,MS)模式翻转视觉诱发电位(pattern reversal evoked po-tential,PRVEP)、脑干听觉诱发电位(brainstem auditory evoked potential,BAEP)和体感诱发电位(somatosenso-ry evoked potential,SEP)等三种诱发电位(evoked potential,EP)的临床特点。方法对83例确诊MS患者进行回顾性分析,根据有无相应临床症状、病程及功能残障程度对EP进行分层研究,探讨其变化规律。结果三种EP的异常率在有临床症状组〔PRVEP、BAEP及下肢短潜伏期体感诱发电位(SLSEP)异常率分别为88.00%、66.67%、100%〕与无临床症状组(PRVEP、BAEP及下肢SLSEP异常率分别为60.61%、31.71%、79.63%)间比较均存在统计学差异(均P<0.05)。PRVEP的峰潜伏期(PL)延长及侧间峰潜伏期差值(ILD)增加的异常率之和与病程呈正相关(r=1.0,P<0.05);病程在20年以内时BAEP异常率与病程呈正相关(r=1.0,P<0.05);SLSEP下肢未引出率与病程呈正相关(r=1.0,P<0.05)。PRVEP异常率与EDSS分值呈正相关(r=1.7,P<0.01);SLSEP上肢异常率及下肢未引出率也与EDSS分值呈正相关(分别r=1.8,P<0.01;r=1.6,P<0.01)。结论三种EP的异常率与有无相应临床症状相关,且与病程及功能残障程度在一定范围内呈正相关。     

Contribution of changes in click rate and intensity on diagnosis of multiple sclerosis by brainstem auditory evoked potentials

Brainstem auditory evoked potentials (BAEPs) were recorded in 51 patients with different degrees of certainty with respect to multiple sclerosis (MS): Definite, probable and possible ( McAlpine et al. 1972). Click stimuli were presented at various intensities and rates which were thought to stress the auditory pathways. The main types of abnormal BAEP traces were the absence of some of the brainstem waves (in the presence of a normal audiogram), prolonged brainstem transmission time (BTT) and abnormal amplitude ratio. In the definite MS group, average BTT was prolonged and average amplitude ratio was more than two standard deviations greater than the corresponding parameter in the normal group. The stressful manoeuvres of increasing click repetition rate and lowering click intensity increased the degree of abnormality of BAEP traces. There was no case in which the response to standard click stimuli (75 dB HL, 10 or 20 per sec) showed a normal trace while increasing the stimulus repetition rate and/or decreasing intensity showed a pathological response. The pathophysiology of BAEP traces in MS is discussed.     

The effects of a supratentorial mass lesion on brain-stem auditory evoked potentials and short latency somatosensory evoked potentials

Nineteen patients with unilateral supratentorial mass lesion and without any evident clinical signs of transtentorial herniation were studied with Computed Tomography (CT), brain-stem evoked potentials (BAEPs) and central conduction time (CCT) of short latency somatosensory evoked potentials (SEPs). Sixteen had tumours, two had intracranial haematoma and one had chronic subdural haematoma. CT detected the initial signs of transtentorial herniation in every case. Preoperative I-V interpeak latency (IPL) was significantly (M+2SD) prolonged in 26% of cases on the lesion side and in 21% of cases on the opposite side. The mean I-V IPL was significantly prolonged both on the lesion side and the opposite side (P < 0.01, P < 0.02, respectively). Suppression of Wave V (M-2SD) was seen only in two cases, however, the mean amplitude of Wave V was significantly decreased both on the lesion side and on the opposite side (P < 0.001, P < 0.01, respectively). CCT of SEPs was significantly (M+2SD) prolonged in 33% of cases on the lesion side and in only 13% on the opposite side. The mean CCT was, however, significantly prolonged both on the lesion and on the opposite side (P < 0.001, P < 0.02, respectively). Postoperative I-V IPL was significantly prolonged in only 11% of cases while the mean I-V IPL was still significantly prolonged (P < 0.07) and the mean amplitude of Wave V was still suppressed (P < 0.001) on the lesion side. On the other hand, there was neither abnormality of I-V IPL nor suppression of Wave V on the opposite side. Postoperative CCT was significantly prolonged in 43% of cases and the mean CCT was also significantly (P < 0.01) prolonged on the lesion side. However, there was no prolongation of CCT on the opposite side. Preoperative findings of both BAEPs and SEPs show the abnormality due to the supratentorial lesion and postoperative findings of these potentials indicate both the effects of surgical decompression and the residual abnormalities due to the supratentorial mass lesion.     

Brain stem auditory evoked potentials and myelin changes in triethyltin-induced edema in young adult rats

The effect of white matter edema induced by triethyltin (TET) intoxication on the brain stem auditory evoked potentials was examined in young adult rats. Results show that animals which received TET had lower body weight, increased brain weight, and increased water content in brain tissue. The amount of myelin (normal flotation density) recovered was reduced in TET-treated rats by approximately 45%, however, the recovery of synaptosomes was normal. The decrease in myelin content in the central nervous system of the TET-treated rats was accompanied by a significant increase in the peak latencies of all brain stem auditory evoked potentials (waves I, II, III, IV) as well as the interpeak (IV – I) difference. The potential latencies and the amount of myelin recovered became normal within 2 weeks after discontinuing TET treatment. These results demonstrate the relationship between the amount of myelin in the central nervous system and the latencies of the brain stem auditory evoked potentials and suggest that they may serve as a noninvasive measure of myelin defect.     

Brain function in patients with cerebral fat embolism evaluated using somatosensory and brain-stem auditory evoked potentials

Summary In two victims of traffic accidents with broken bones and fat embolism, serial recordings of somatosensory evoked potentials (SEPs) and brain-stem auditory evoked potentials (BAEPs) were examined to assess brain function. Initial SEPs and BAEPs revealed normal subcortical components, while the late cortical components of SEPs were abolished, findings indicative of diffuse dysfunction of grey rather than of white matter. As the neurological functions became normal, the late components appeared. It is concluded that while absent late components of SEPs do reflect cortical dysfunction, they are not necessarily associated with a poor prognosis. Repetitive recordings of SEPs appear to be a useful tool for assessing the neurological condition and the prognosis of patients with cerebral fat embolism.     

Influence of extreme head rotations on brainstem auditory evoked potentials (BAEP)

The influence of extreme head rotations on BAEP was studied in 47 patients who had vertebral artery angiogram. Patients with and without unilateral hypoplasia of the vertebral artery (VA) lumen were identified and all patients were further divided into two groups: with and without hypertension. The subjects underwent a BAEP examination in three head positions: neutral position, extreme right and extreme left rotation. In the subgroup of patients with hypertension and unilateral VA hypoplasia, and following the rotation away from the non-hypoplastic vessel a statistically significant decrease in the PV wave amplitude and prolonged PV wave latency was found. Head maneuvers in subjects with normal blood pressure or in hypertensive patients with symmetrical VA did not cause significant changes in BAEP. These results document the effect of head rotation in subjects with potentially impaired collateral flow. An increase in the PV wave latency and decrease in its amplitude may reflect subtle changes in the brainstem perfusion in hypertensive patients. These changes maybe due to a reduced capacity to compensate for dynamic obstruction of VA following the head rotations.     

体温过高对豚鼠耳蜗电图-脑干听觉诱发电位综合波的影响

目的：探讨体温过高对耳蜗电图-脑干听觉诱发电位综合波(ECochG-BAEP SW)的影响。方法：计算机平均叠加技术记录豚鼠脑干听觉诱发电位(BAEP)、耳蜗电图(ECochG)和：ECochG—BAEP SW，体表物理升温法逐步升高豚鼠体温，观察3组电位波形、波峰潜伏期(PL)、波峰间潜伏期(IPL)和波幅的变化。结果：随体温升高(36℃至42℃)，ECochG-BA：EPSW波形始终兼具BAEP和ECochG的特点，有十分突出的1波，其波幅为BA：EP的I波波幅的数倍，且明显大于ECochG的N1波波幅；与BAEP和ECochG一致，ECochG-BAEPSW的PL和IPL随体温升高而逐渐缩短；与BAEP的Ⅰ，Ⅱ，Ⅲ波和ECochG的N1，N2，N3波波幅相似，ECochG-BAEP SW的1，2波波幅也在体温过高至40℃后开始出现显著降低。结论：体温过高对豚鼠ECochG-BAEPSW的影响与BAEP和ECochG相似，且其波形始终兼具两者特点。     

Visual and auditory evoked potentials in the early diagnosis and follow-up of neurosarcoidosis

Visual and brainstem auditory evoked potentials (VEPs, BAEPs) were recorded in 23 patients with neurosarcoidosis. Eight patients (35%) had abnormal BAEPs, and 10 (43%) had abnormal VEPs. Four of the 8 patients with abnormal BAEPs had facial paresis, one had impaired memory and only 3 had symptoms and signs compatible with brainstem lesion. Seven of the patients with abnormal VEPs had no visual symptoms. These findings suggest that BAEP and VEP can reveal subclinical nervous system involvement in sarcoidosis and can also help in the early diagnosis of neurosarcoidosis. Successive recordings of 5 patients showed that BAEP and VEP were useful in the follow-up of these patients.     

帕金森病早期多种诱发电位检测的临床诊断价值

目的 观察帕金森病早期体感诱发电位(SL-SEP)、脑干听觉诱发电位(BAEP)和视觉诱发电位(PR-VEP)的异常特征．寻找敏感可靠的诊断指标。方法 对一组52例Yahr分期为Ⅰ期的帕金森病人和一组40例年龄匹配的健康对照组进行三种诱发电位观测。结果帕金森病早期SLSEP异常率为69．2％；BAEP的异常率为32．7％：PR-VEP的异常率为30、7％，病例组SL-SEP各主波峰潜伏期、峰间潜伏期、P25和N30波幅与对照组比较差异有湿著性意义；病例组BAEPⅠ—ⅢIPL、Ⅲ—ⅤIPL、Ⅰ一Ⅲ／Ⅲ一Ⅴ比值和PR-VEP的P100PL与对照组比较差异无显著性意义．结论 在帕金森病的早期，皮层感觉处理过程已受到干扰：体感诱发电位中央前成份以及顶成份P25是一个敏感的诊断指标。     

大鼠诱发电位检测法及正常值探讨

目的 :探讨大鼠诱发电位检测方法及皮层诱发电位正常值。方法 :对 4 0只 Wistar大鼠进行 BAEP及CEP检测。结果 :BAEP的 I至 V波潜伏期 ( X± S)分别为 1 .5 9± 0 .2 ,2 .4 0± 0 .2 6 ,3.1 7± 0 .36 ,4 .2 5± 0 .37及 5 .2 5± 0 .36 ms波峰间期分别为 I- 1 .5 8± 0 .2 8ms、 -V 2 .0 9± 0 .3ms及 I-V3.6 7± 0 .31 ms、CEP主反应呈先正后负的 PN型 ,部分出现后发放 ,主反应潜伏期为 6 .6 3± 1 .33ms。结论 :用这种方法检则大鼠诱发电位 ,方法可靠 ,图形清晰 ,重复性好 ,数据相对较稳定 ,为今后大鼠脑诱发电位异常判断奠定了良好的基础。     

Direction‐specific adaptation of motion‐onset auditory evoked potentials

Auditory evoked potentials (AEPs) to motion onset in humans are dominated by a fronto‐central complex, with a change‐negative deflection 1 (cN1) and a change‐positive deflection 2 (cP2) component. Here the contribution of veridical motion detectors to motion‐onset AEPs was investigated with the hypothesis that direction‐specific adaptation effects would indicate the contribution of such motion detectors. AEPs were recorded from 33 electroencephalographic channels to the test stimulus, i.e. motion onset of horizontal virtual auditory motion (60° per s) from straight ahead to the left. AEPs were compared in two experiments for three conditions, which differed in their history prior to the motion‐onset test stimulus: (i) without motion history (Baseline), (ii) with motion history in the same direction as the test stimulus (Adaptation Same), and (iii) a reference condition with auditory history. For Experiment 1, condition (iii) comprised motion in the opposite direction (Adaptation Opposite). For Experiment 2, a noise in the absence of coherent motion (Matched Noise) was used as the reference condition. In Experiment 1, the amplitude difference cP2 ? cN1 obtained for Adaptation Same was significantly smaller than for Baseline and Adaptation Opposite. In Experiment 2, it was significantly smaller than for Matched Noise. Adaptation effects were absent for cN1 and cP2 latencies. These findings demonstrate direction‐specific adaptation of the motion‐onset AEP. This suggests that veridical auditory motion detectors contribute to the motion‐onset AEP.     

Least-squares deconvolution of evoked potentials and sequence optimization for multiple stimuli under low-jitter conditions

ObjectiveRapid presentation of stimuli in an evoked response paradigm can lead to overlap of multiple responses and consequently difficulties interpreting waveform morphology. This paper presents a deconvolution method allowing overlapping multiple responses to be disentangled.MethodsThe deconvolution technique uses a least-squared error approach. A methodology is proposed to optimize the stimulus sequence associated with the deconvolution technique under low-jitter conditions. It controls the condition number of the matrices involved in recovering the responses. Simulations were performed using the proposed deconvolution technique.ResultsMultiple overlapping responses can be recovered perfectly in noiseless conditions. In the presence of noise, the amount of error introduced by the technique can be controlled a priori by the condition number of the matrix associated with the used stimulus sequence. The simulation results indicate the need for a minimum amount of jitter, as well as a sufficient number of overlap combinations to obtain optimum results. An aperiodic model is recommended to improve reconstruction.ConclusionsWe propose a deconvolution technique allowing multiple overlapping responses to be extracted and a method of choosing the stimulus sequence optimal for response recovery.SignificanceThis technique may allow audiologists, psychologists, and electrophysiologists to optimize their experimental designs involving rapidly presented stimuli, and to recover evoked overlapping responses.