An AER analysis of contralateral advantage in the transmission of auditory information.

Average electroencephalic responses (AERs) to clicks were recorded from scalp electrodes over the left and right parietal areas (C₃, C₄) of 12 subjects. Measures of AER latency for monaural click and dichotic click—sentence conditions indicated that during dichotic presentation, the contralateral hemisphere in man responds significantly faster to the click than the ipsilateral hemisphere. These results are consistent with Kimura's (1961a) proposed contralateral-pathway advantage during dichotic listening in man.     

Cyanide intoxication in Macaca mulatta: Physiological and neuropathological aspects

Sodium cyanide was infused intravenously in 11 lightly anaesthetised and spontaneously breathing M. mulatta. In most, the EEG, ECG, respiratory rate, blood pressure, cerebral venous sinus pressure, end-tidal pCO₂ and body temperature were recorded. Blood gases, pH, lactate and pyruvate were estimated in arterial and venous sinus blood samples. There was an initial hyperventilation with tetany in all animals. A rapid rate of cyanide infusion led to apnoea. An isoelectric or near-isoelectric EEG was usually precipitated by bradycardia often with additional hypotension. Neither epileptic seizures nor their EEG concomitants were seen at any stage. Three animals died of early heart failure. Brain damage was seen in 4 animals surviving up to 98 hr. White matter was involved in all. Ischaemic neuronal alterations, restricted to the striatum of one animal, were attributed to major circulatory complications. It was concluded that under these experimental conditions there is no evidence for hypoxic neuronal damage of purely histotoxic type.     

Brainstem auditory evoked potentials evoked by clicks of different polarity in multiple sclerosis patients

Brainstem auditory evoked potentials (BAEP) evoked by condensation, rarefaction clicks and clicks of alternating polarity were examined in 52 controls and in 95 patients with a certain or presumed diagnosis of multiple sclerosis. It was shown that the type of stimulation could influence the shape of the BAEP considerably. In multiple sclerosis patients pathological results were found in 67 ears from 44 patients. Rarefaction as well as condensation clicks independently could elicit BAEPs with increased latencies of one or more peaks, while clicks of alternating polarity failed to detect abnormalities in a great number of cases. These findings make the application of the latter type of stimulation doubtful.     

Detection of brainstem lesions in multiple sclerosis: comparison of brainstem auditory evoked potentials with nuclear magnetic resonance imaging

Topographical information provided by brainstem auditory evoked potentials (BAEPs) was investigated in 43 patients by comparison with cerebral nuclear magnetic resonance imaging (NMR). Lesions in the region of the brainstem auditory pathways were demonstrated by BAEPs in 44.2%, and in 39.5% by NMR. As regards brainstem levels, in 15/21 (71.4%) with abnormal findings at least one lesion was verified by NMR-matched BAEP results. The study confirms the topographical information provided by the BAEPs on the different levels of the brainstem, but not the assumption that generation of the BAEPs is predominantly ipsilateral. BAEPs retain their importance for the detection of disseminated lesions in the diagnosis of multiple sclerosis (MS) in the era of expensive imaging methods.     

The effects of neurotensin and [D-Tyr11]-NT on the hyperactivity induced by intra-accumbens administration of a potent dopamine receptor agonist

The effects of neurotensin on the strong and persistent hyperactivity induced in rats by intra-accumbens administration of ADTN, a potent dopamine agonist, were examined. Neurotensin was administered intraventricularly as well as bilaterally into the accumbens. With both routes of administration neurotensin significantly decreased the hyperactivity produced by ADTN. However, important differences in doses required to produce this effect were noted between the two routes of administration. Whereas intraventricular injection of doses as small as 0.05 micrograms neurotensin was sufficient to reduce hyperactivity, bilateral intra-accumbens administration of at least 1.8 micrograms was required to replicate the effect. ADTN induced hyperactivity was also significantly decreased by intraventricular and intra-accumbens injections of the structural analog [D-Tyr11]-NT. In both routes of administration, the inhibitory action of the analog was more persistent than that observed with neurotensin. As was the case for neurotensin, intraventricular administration of [D-Tyr11]-NT was more potent than intra-accumbens injections. Finally, the results of a preliminary experiment indicate that neurotensin injected intraventricularly can also decrease hyperactivity elicited by intra-accumbens administration of dibutyryl cyclic AMP. Taken together, the results of the present study demonstrate that neurotensin can affect hyperactivity elicited by a strong and persistent activation of mesolimbic dopamine receptors or by stimulation of events beyond these receptors. The observed greater efficacy of intraventricularly administered neurotensin in decreasing ADTN induced hyperactivity suggests an action of the peptide on regions distant from the accumbens, probably on efferent outputs of mesolimbic stimulation.     

Brain stem auditory and visual evoked potentials in multiple sclerosis

The diagnostic value of the checkerboard pattern-reversal visual evoked potential (VEP) and the random, low rate stimulated brain stem auditory evoked potential (BAEP) was compared in 99 patients with established or suspected multiple sclerosis (MS). In normal subjects examined by both techniques no abnormal recordings were found. In 49 patients with definite MS an incidence of abnormality was found in 100% of VEP and in 84% of BAEP recordings. In 50 patients with probable or possible MS an abnormal VEP was found in 70% and an abnormal BAEP in 50%. When the two examinations were combined, the diagnostic yield increased to 100 and 80%, respectively. 22 patients had only spinal symptoms; in these the VEP gave 73%, the BAEP 55% and the combination 82% abnormalities. The combination of the two techniques was found useful for demonstrating demyelinating lesions in the central nervous system, the diagnostic value being greatest when these lesions were clinically silent.     

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.     

Aspects of cellular immunity in multiple sclerosis. Antigen-reactivity of lymphocytes and lymphokine activity.

Some new results of cell-mediated immunity in multiple slcerosis (MS) are presented, based on the determination of charge-changing lymphokines as products of antigen sensitive lymphocytes (C PAL), obtained by several forms of the electrophoretic mobility (EM) method. Lymphocytes from MS react to myelin basic protein (BP), the reactivity in other neurological diseases depending on the degree of destruction of nervous parenchyma. Applying a membrane-associated antigen from normal brain (NTA), positive reactivity of MS lymphocytes was obtained. Besides the usual determination of lymphokines in vitro the sensitive EM test allows the demonstration of lymphokine activities in vivo; i.e. in body fluids such as cerebrospinal fluid (CSF) and serum. In CSF of MS a high lymphokine activity was found. The differentiation of lymphokines and comparison between in vitro and in vivo activity were carried out. Moreover, a characteristic lymphokine pattern for MS with high activities in all regions of molecular weight, especially in the CSF, could be detected. On the basis of these findings, important also from the pathogenetic point of view, a diagnostic scheme for MS is suggested, consisting of a program of determination of the immuno-reactive CSF syndrome and some special procedures, including examination of lymphocyte reactivity.     

Variations of brain stem auditory evoked potentials correlated to duration and severity of multiple sclerosis

A total of 158 recordings of brain stem auditory evoked potentials (BAEPs) were obtained in 121 patients with multiple sclerosis. A statistically significant increased incidence of abnormality and diffusely abnormal recordings was found with increasing duration and severity of symptoms. Alterations in follow-up recordings might reflect changes in the clinical state, but also occurred in clinically stable patients. These findings suggested that transition from normality of BAEPs might occur either by successive disappearance of the later waves or by uniformly decreasing amplitudes of all the waves to diffusely abnormal recordings. It was concluded that the main value of BAEP recording in patients with multiple sclerosis was to indicate clinically silent lesions, and its value in monitoring the clinical condition of the individual patient was dubious.     

Quantitative studies of ciliary and sphenopalatine ganglia in familial dysautonomia

In 3 patients with familial dysautonomia (FD) sphenopalatine ganglia were less than one fifth normal in volume and their total neuronal content was reduced to a mean of 1,510 (control mean 56,500). Parasympathetic denervation accounts for absence of overflow tears in FD. Ciliary ganglia were not reduced in volume and in 4 patients the mean neuron total was only slightly diminished to 2,900 (control 3,670, P ? 0.05). This does not appear sufficient to account for pupillary supersensitivity to methacholine in FD on the basis of denervation. Temporal differences in the embryogenesis of sphenopalatine and ciliary ganglia may underlie the observed differences in neuronal populations and suggest that the developmental anomaly in FD does not occur early in gestation.     

Cellular hypersensitivity to gangliosides and myelin basic protein in multiple sclerosis

Peripheral blood lymphocytes from patients with multiple sclerosis (MS), other neurological diseases and healthy controls were investigated for the presence of cell-mediated hypersensitivity to brain gangliosides and myelin basic protein using an active E-rosette assay. Sensitivity to myelin basic protein and gangliosides was found in MS patients in acute relapse and with progressive disease, whereas no sensitivity was found in MS patients in remission. Patients with other neurological diseases showed no response to gangliosides, but sensitization to myelin basic protein was found in a patient with leucoencephalopathy and in 4 of 6 stroke patients. Healthy controls did not respond to either antigen. In MS patients a positive correlation was seen between lymphocyte responses to myelin basic protein and to gangliosides. The data suggest that in comparison to gangliosides, myelin basic protein is a weaker stimulator of active rosette-forming cells. Moreover, cellular hypersensitivity to myelin basic protein is not MS-specific and may be present as a consequence of brain damage. However, cellular hypersensitivity to gangliosides appears to be more specific to MS and may be important in the pathogenesis of the disease.     

Vector analysis of brain-stem auditory evoked potentials in patients with multiple sclerosis and subtentorial tumors.

Vector analysis of BAEPs was done in 10 patients with posterior fossa tumors and 14 patients with MS. Latency abnormalities were found in both groups without significant differences. However, deviations of wave V vectors from its normal orientation were observed in tumor cases, correlated with tumor size and latency increase. It is concluded that vector deviations may indicate distortion of auditory pathways in the brain-stem.     

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。     

电刺激诱发瞬目反射和脑干听觉诱发电位在多发性硬化诊断中的作用

目的　探讨瞬目反射 (BR)在多发性硬化 (MS)诊断中的价值。方法　对 32例确诊MS患者分别进行BR和脑干听觉诱发电位 (BAEP)检测。结果　MS组BR检测在有脑干症状组和无脑干症状组的脑干损害检出率分别为 85 7%和 5 0 0 % ;BR检测对MS组患者Ⅴ、Ⅶ脑神经损害的异常检出率均为 2 1 9% ;BAEP检测在有脑干症状组和无脑干症状组的脑干损害检出率分别为 71 4 %和4 4 4 % ;BR、BAEP及二者联合检测检出MS患者脑干损害的阳性率分别为 6 5 6 %、5 6 3%和75 0 %。结论　BR能检出MS患者脑干、三叉神经及面神经的亚临床病灶 ;BR与BAEP联合检测更易于发现脑干亚临床病灶 ,有助于MS的早期诊断     

Brain stem auditory evoked potentials are related to interaural time discrimination in patients with multiple sclerosis

In a combined psychophysical-electrophysiological study on 29 patients with multiple sclerosis (MS), a compromised ability to make interaural time discriminations was nearly always found to be associated with ‘abnormal’ brain stem potentials evoked by clicks to at least one ear. However, no obvious relationships were found between evoked brain stem potentials and several other auditory behavioral measures such as interaural intensity discrimination, pure-tone thresholds and speech discrimination.     

Racial modification of clinical picture of multiple sclerosis: Comparison between British and Japanese patients

Two hundred and four consecutive British cases and 60 consecutive Japanese cases of probable (clinically definite) multiple sclerosis, seen at The National Hospital for Nervous Diseases, Maida Vale, London and at Kyushu University Hospital, Fukuoka, Japan, respectively, over a defined period of time, were reviewed retrospectively by the same neurologist, using the same diagnostic criteria and the same method of analysis. The clinical pictures in the present 2 series were in many respects similar to each other and to that of other reported series. Some significant differences were found, however: there was (1) a greater incidence of visual loss at the onset of illness, (2) more frequent and severe involvement of spinal cord and brainstem during the course of illness, as judged clinically, and (3) more severe visual disability, in the Japanese series as compared with the British series.     

Diagnostic value of electroencephalography and brainstem auditory evoked potentials in dizziness

Electroencephalogram (EEG) and brainstem auditory evoked potentials (BAEP) were recorded from 142 dizzy patients. The results were compared with those obtained by other neurological examinations of the same patients. Thirty-three percent (N = 44) of the patients had an abnormal EEG: 21% (28) showed focal abnormality, 12% (16) irritative features, and 10% (13) generalized disturbance. There were no differences in the distribution of abnormal EEGs in different diagnostic categories of dizziness, but irritative findings were not found in the cases of peripheral vestibular or psychogenic disturbances. EEG findings in 3 patients suggested temporal epilepsy, correlating with the clinical picture. BAEPs were abnormal in 18% (N = 21) of the recordings. There were 3 cases of MS and 5 ischaemic lesions in the vertebro-basilar region. Twelve of the 13 other patients with abnormal BAEP showed evidence of CNS pathology with other methods. EEG abnormalities were mostly non-specific; however, the irritative findings suggested cerebral pathology, such as epilepsy. An abnormal BAEP offers reliable evidence for brainstem lesion and is thus a useful examination in dizziness.     

The location by early auditory evoked potentials (EAEP) of acoustic nerve and brainstem demyelination in multiple sclerosis (MS)

Summary Tone pips of suprathreshold intensities elicit an acoustic nerve response (I) and six low amplitude brainstem potentials (II–VII) during the initial 10 ms. Seven waves were studied in 40 control subjects and 5 waves (I–V) in 47 patients with MS. The results suggest involvement of the auditory pathway of 24 of 27 patients in the clinically definite, of 5 of 9 cases in the probable and in none of 5 patients in the possible MS groups. EAEPs were normal in 6 cases with a spinal form with one exception where changes of potential were indicative of a midbrain lesion. Dysfunction within the acoustic pathway was observed at the level of the acoustic nerve and in the medulla oblongata, pons and midbrain. The significance of the bilateral EAEP abnormalities found in some patients at different levels is discussed with regard to a polytopic location of the underlying lesion.This work includes part of a thesis of E. Schäfer (University of Mainz)