Early auditory evoked potentials (EAEP) in vertebral basilar insufficiency

Summary Stimulation with a short tone pip elicits an acoustic nerve compound action potential (I) and different waves (II–VII) in the initial 10 ms. Seven waves have been studied in 40 control subjects and five waves in 12 patients with vertebral-basilar insufficiency. Abnormalities of the different waves were observed at levels such as cochlea and/or acoustic nerve, medulla, caudal pons, rostral pons, and midbrain. The recording of early auditory evoked potentials (EAEP) is a noninvasive method of confirming impairment of the auditory pathway caused by a reduced vascular supply of vertebral and basilar arteries.     

Brainstem auditory evoked potentials in the diagnosis of multiple sclerosis

Brainstem auditory evoked potentials (BAEPs) have been investigated in 34 patients affected by Multiple Sclerosis. Abnormalities were found in 68% of the patients. Silent lesions of the brainstem were detected in 60% of the clinically definite and in 44% of the probable cases. The diagnostic value of these findings is discussed.

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Sommario I potenziali evocati uditivi sono stati investigati in 34 pazienti affetti da sclerosi multipla. Anormalità sono state evidenziate nel 68% dei pazienti affetti da sclerosi multipla clinicamente definita. Lesioni silenti del brainstem sono state trovate nel 60% delle forme clinicamente definite e nel 44% di quelle probabili. Il valore diagnostico di questi reperti è discusso.

     

Middle latency auditory evoked potentials (MLAEPs) in (MS)

Middle latency auditory evoked potentials (MLAEPs) were studied in 30 definite multiple sclerosis (MS) patients in addition to brain-stem auditory evoked potentials (BAEPs). BAEP abnormalities were detected in 18 (60%) patients. MLAEPs were abnormal in 22 (73%) of them. In 15 patients BAEPs and MLAEPs were both abnormal. MLAEPs were found abnormal in 7 of the 12 patients with normal BAEPs. In 18 patients with abnormal BAEPs only 3 had normal MLAEPs. MLAEPs abnormalities are consistent with a rostral auditory pathway involvement. Therefore, they can be used in combination with BAEPs to examine the whole auditory system to improve the sensitivity.     

Brain-stem involvement in multiple sclerosis: a comparison between brain-stem auditory evoked potentials and the acoustic stapedius reflex

Summary Brain-stem auditory evoked potentials (BAEPs) and the acoustic stapedius reflex (ASR) were recorded in 68 patients with definite, probable and possible multiple sclerosis (using the definitions of McAlpine). The high incidence of abnormal results, 68% and 60%, respectively, pointed to the diagnostic value of these two measures in detecting brain-stem dysfunction. Combination of the methods increased the diagnostic yield to 85%. Since in part the same brain-stem generator sites underlie BAEPs and the ASR, it was considered that a study of their correlation might serve to increase the reliability and validity of these techniques. There was 71% agreement overall between results from the two measures. Furthermore, 72% of the joint BAEP and ASR abnormalities corresponded in detection of the brain-stem lesion site. It was concluded that the combined approach may supply powerful, complementary information on brain-stem dysfunction, which may aid in establishing the diagnosis of multiple sclerosis.This study was supported by the M. Sackler Foundation for Multiple Sclerosis Research     

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.     

Fever and evoked potentials in multiple sclerosis

Summary The somatosensory evoked potentials (SEPs) and visual evoked potentials (VEPs) were studied in 19 patients with multiple sclerosis; 17 controls were studied during fever (38.0°–39.7°C) and 2–3 days following return to normal temperature. The latencies of components N₂₀ and P₁₁₄ were measured and specified as abnormal when their value exceeded the standard deviation of the controls by 2.5 times. The corresponding criterion for the evaluation of the amplitude of components N₂₀ and P₁₁₄ was a reduction in amplitude of more than 50%. In the controls fever did not cause significant changes in evoked potentials. On the other hand, patients with multiple sclerosis showed abnormalities in evoked potentials during fever in a greater number of recordings (26 of SEPs and 33 of VEBs) than after return to normal temperature (19 and 27 respectively). In addition, the average latency of components N₂₀ and P₁₁₄ was clearly greater in the patients during fever (N₂₀=29.5±5.2 ms and P₁₁₄=143±18.1 ms) than after return to normal temperature (N₂₀=6.6±3.5 ms and P₁₁₄=134±16 ms). The amplitude of components N₂₀ and P₁₁₄ in patients during fever was clearly smaller than after return to normal temperature. These differences were statistically significant. Finally, in two patients, a decrease was found, during fever, in the conduction velocity of the peripheral somatosensory pathway from the median nerve to the wrist at Erb's point.

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Zusammenfassung Wir studierten die somatosensorisch evozierten Potentiale (SSEP) sowie die visuell evozierten Potentiale (VEP) bei 19 Patienten mit Multipler Sklerose und 17 Kontrollpersonen. Die somatosensorisch und visuell evozierten Potentiale wurden in beiden Gruppen unter dem Einfluß von Fieber als auch zwei bis drei Tage nach dem Abklingen des Fiebers untersucht.Die Latenzzeit der Komponenten N₂₀ und P₁₁₄ wurde als pathologisch bewertet, wenn ihre Werte 2,5 Standardabweichungen über dem Mittelwert von Normalpersonen lagen.Der entsprechende Maßstab für die Bewertung der Höhe der Komponenten N₂₀ und P₁₁₄ war eine Höheminderung über 50%.Wir fanden, daß Fieber bei den Kontrollpersonen keinen wesentlichen Einfluß auf SSEP und VEP hatte. Bei den MS-Patienten haben wir wesentlich mehr Abnormitäten der SSEP und VEP während des Fiebers (26 SSEP und 33 VEP) als nach dem Abklingen des Fiebers (19 SSEP und 27 VEP).Darüber hinaus war der Mittelwert der Latenzzeit der Komponenten N₂₀ und P₁₁₄ bei den MS-Patienten während des Fiebers höher (N₂₀=29,5±5,2 ms; P₁₁₄=143±18,1 ms) als nach dessen Abklingen (N₂₀=26,6±3,5 ms; P₁₁₄=134±16,8 ms).Abgesehen davon war die Höhe der Komponenten N₂₀ und P₁₁₄ während des Fiebers wesentlich kleiner als nach dem Abklingen des Fiebers.Diese Unterschiede sind statistisch signifikant.Ferner fanden wir während des Fiebers bei zwei Patienten eine Verminderung der Erregungsleitungsgeschwindigkeit im N. medianus zwischen Handgelenk und Erbschen Punkt.

     

Brainstem auditory evoked potentials in tuberous sclerosis

Brainstem auditory evoked potentials were recorded in 4 subjects and pattern reversal evoked potentials in 1 subject, all with tuberous sclerosis. Alterations were found (absence or delay of components and prolonged interpeak intervals) which may suggest impaired nervous conduction also at brainstem level in patients with tuberous sclerosis.

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Sommario Sono stati registrati i potenziali evocati auditivi troncoencefalici in 4 soggetti con sclerosi tuberosa, in uno di essi sono stati registrati anche i potenziali evocati visivi da pattern reversal. Sono state ritrovate alterazioni delle risposte (assenza o ritardo di alcune componenti ed intervalli interpicco prolungati) che possono suggerire l'esistenza di una conduzione nervosa alterata anche a livello del tronco dell'encefalo nei pazienti con sclerosi tuberosa.

     

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.     

Pudendal nerve somatosensory evoked potentials in probable multiple sclerosis

Bladder dysfunctions are often observed in patients with multiple sclerosis (MS). In order to evaluate their sensitivity in detecting abnormalities in bladder central control pathways, pudendal nerve somatosensory evoked potentials (pSEPs) were recorded in 16 patients with clinically probable MS: six were affected by retention or urge incontinence, and ten were asymptomatic. Conventional visual, auditory and somatosensory evoked potentials were also recorded, and all of the patients underwent a urodynamic examination. Prolonged latency or the absence of pSEP cortical responses was found in eight of the ten asymptomatic patients, and in all of the symptomatic cases (87.5%). The urodynamic evaluation revealed abnormalities in 12 patients (75%). Our findings seem to indicate an early and frequent involvement of bladder control pathways in MS patients, as well as a high rate of subclinical disorders.This work was supported by grants from MURST, Italy     

EDSS correlated analysis of median nerve somatosensory evoked potentials in multiple sclerosis

Median nerve somatosensory evoked potentials (SEP) were recorded in 30 patients with multiple sclerosis. The examined patients had an expanded disability status scale (EDSS) between 0 and 6. The primary cortical potential N20, the subcortical potentials P14, N13b, N13a and the peripheral potential P9 were recorded simultaneously. In 5 patients normal SEP were observed (group 1) and in 6 patients there were consecutive disturbances of the somatosensory pathway (group 3). In 19 patients subcortical potentials were abnormal or absent while the following potentials were normal or identified which pattern corresponds to amplification within CNS structures (group 2). The EDSS of groups 1 and 2 were similar and lower than the EDSS of group 3, which indicates that amplification mechanisms could represent a positive prognostic factor in SEP diagnosis of multiple sclerosis. Received: 15 March 2000 / Accepted in revised form: 4 September 2000     

Acoustic tumour detection with early auditory evoked potentials and neuroradiological methods

Summary A total of 43 patients with surgically identified acoustic neuromas were tested. Results of early auditory evoked potentials (EAEP) and of neuroradiological methods were analysed. Abnormal EAEPs were observed in all patients. In 73% of the cases the EAEP indicated the retrocochlear site of the lesion; in 27%, however, the results did not localize the exact site of the lesion owing to a lack of waves I, II and III due to a pronounced hearing loss.Neuroradiological procedures provided an indication of the site and extent of the tumour. The number of true positives was 21 of 29 cases with polytomography of the petrous bone, 23 of 28 with computed tomography and in all cases when pontine angle cisternography and computed tomography combined with gas cisternography were performed.The EAEPs provide a screening-test for acoustic tumour detection at an early stage. Wave abnormalities indicative of a lesion at the acoustic nerve should lead to a neuroradiological investigation and are particularly valuable in cases with small intracanalicular tumours.

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Zusammenfassung 43 Patienten mit einem operativ gesicherten Akustikusneurinom (AN) wurden untersucht, wobei die Aussagekraft der frühen akustisch evozierten Potentiale (FAEP) und verschiedener neuroradiologischer Methoden überprüft wurde. Veränderte FAEPs wurden bei allen Patienten gefunden (100% richtig-positive Befunde). In 73% der Fälle erlaubten die FAEP eine Aussage über den retrocochleären Sitz der Schädigung; in 27% jedoch war eine topische Zuordnung nicht mehr möglich, da die topographisch wichtigen Wellen I-III wegen der Hörstörung nicht zur Darstellung gelangten.Die neuroradiologischen Methoden zeigten Sitz und Ausdehnung des Tumors an. Richtig-positive Befunde zeigten sich in 21 von 29 der Fälle bei der Felsenbeintomographie, in 23 von 28 bei der Computertomographie, in allen 19 Fällen bei der Cisternographie und bei allen 6 Patienten, bei denen eine CT in Verbindung mit einer Luftfüllung durchgeführt wurde.Die FAEP eignen sich als Sreening-Test, wobei sich der Tumor in einem frühen Stadium erfassen läßt. Treten Wellenveränderungen auf, die auf eine Schädigung am N. VIII hinweisen, ist eine weiterführende neuroradiologische Untersuchung indiziert. Die FAEP-Methode hat sich besonders bei kleinen noch intrakanalikulär gelegenen Tumoren bewährt.

     

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 in multiple sclerosis: the relation to VEP,SEP and CSF immunoglobulins

Summary One hundred patients with multiple sclerosis (MS) were analysed retrospectively with respect to investigations of brain-stem auditory evoked potentials (BAEP), pattern reversal visual evoked potentials (VEP), somatosensory evoked potentials (SEP), and cerebrospinal fluid immunoglobulins (CSF-IG). BAEP were abnormal in 42% of those with normal VEP and SEP examinations, and in 38% of patients with normal CSF-IG. The chance of obtaining at least one abnormal EP was lower in patients with normal CSF-IG than in patients with abnormal CSF. When a dispersion ratio was included in the criteria for BAEP abnormality, the sensitivity increased compared with conventional BAEP criteria. We recommend that BAEP should still be included in the EP test battery for patients with suspected MS.     

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.     

Right/left differences of median nerve evoked scalp potentials in multiple sclerosis

Summary Scalp potentials evoked by electrical stimulation of the median nerve at the wrist were examined in multiple sclerosis patients and healthy controls. The latencies of the first negative peak (about 18 ms latency) of the response to right and to left-sided stimulation were compared. Forty-eight of 60 measured latency differences in 15 suspected or certain MS patients were more than 3 standard deviations beyond the average difference in controls (arbitrary norm limit), whereas none of the 56 results of the 14 controls was in that range. Fifteen of 24 latency differences in 6 patients without anamnestic or clinical sensory disturbances in the arms were above the limit. On the other hand, conduction velocity between wrist, neck and scalp did not differentiate controls from patients.We suggest using latency differences of the early components of right and left median nerve-evoked scalp potentials as a mean for the early detection of functional disturbances in multiple sclerosis.Supported in part by Schweiz. Multiple-Sklerose-Gesellschaft (Jubiläumsstiftung der Schweiz. Lebens- und Rentenversicherung), Swiss National Science Foundation, and Stiftung Wiss. Forschung, Zürich     

Comparative study of visual evoked potentials in spinocerebellar ataxias and multiple sclerosis

Visual evoked potentials (VEPs) were delayed in 11 out of 18 patients with Friedreich's ataxia, in 1 out of 8 patients with Strumpell's hereditary spastic ataxia, in 2 out of 5 cases with cerebellar atrophy and in 42 out of 50 patients with multiple sclerosis (MS). Responses were normal in 5 cases with Pierre Marie's disease. Amplitude and temporal dispersion were statistically analyzed in the above-mentioned groups of patients with respect to controls. An abnormal temporal dispersion, also considered as interpeak N1P2, was frequently found in MS but only occasionally in spinocerebellar ataxias. Amplitude was statistically reduced in Friedreich's ataxia group, where an inverse relationship between latency and amplitude was found. No relation was found between VEP delay and duration of the disease, in any group considered.     

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.     

Evaluation of various brain structures in multiple sclerosis with multimodality evoked potentials,blink reflex and nystagmography

Summary Pattern reversal visual evoked potentials (VEP), blink reflexes, auditory brainstem evoked potentials (ABEP), spinal and scalp recorded somatosensory evoked potentials (SSEP), and nystagmographic records were investigated in 55 patients with multiple sclerosis (MS), who were separated in different categories of probability according to the clinical history, symptoms, and signs. The combined use of different electrophysiological methods forms a sensitive battery for investigating clinically uncertain cases of MS. It was stressed that care should be taken in the interpretation of the electrophysiological findings, since a single lesion in the central nervous system, particularly in the brainstem, may affect different functional systems simultaneously and therefore mimic a disseminated disease.

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Zusammenfassung Visuelle musterevozierte Potentiale, der elektrisch ausgelöste Blinkreflex, auditorisch evozierte Hirnstammpotentiale, somatosensorisch evozierte Potentiale mit Ableitung über dem unteren Cervicalmark und dem jeweiligen kontralateralen Handfeld sowie nystagmographische Ableitungen wurden bei 55 Patienten mit einer Multiplen Sklerose untersucht. Die Patienten wurden entsprechend der anamnestischen Daten und der klinischen Symptomatologie in vier Gruppen unterschiedlicher diagnostischer Wahrscheinlichkeit getrennt. Die Resultate zeigten, daß die Kombination verschiedener evozierter Potentiale einen hohen Aussagewert in solchen Fällen haben kann, in denen die Diagnose einer MS klinisch nicht eindeutig ist. Es wird jedoch hervorgehoben, daß die Interpretation der elektrophysiologischen Befunde mit großer Sorgfalt vorgenommen werden soll, da eine einzige Läsion im Zentralnervensystem, besonders im Bereich des Hirnstammes, gleichzeitig verschiedene funktionelle Systeme befallen und dadurch eine disseminierte Erkrankung vortäuschen kann.

     

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。     

Effects of carbamazepine and valproate on brainstem auditory evoked potentials in epileptic children

Brainstem auditory evoked potentials (BAEPs) were recorded in 18 epileptic children receiving carbamazepine and 10 epileptic children receiving valproate. BAEPs were recorded before the administration of antiepileptic drugs (AEDs) and 13 months later during which the children received AEDs. Statistical analysis of peak latencies and interpeak intervals of waves I–III–V were made. Carbamazepine treatment resulted in prolongation of peak latencies of waves I–III–V and interpeak intervals I–III and I–V. Valproate monotherapy, on the other hand, caused no consistent changes on BAEP. On the basis of these results we suggest that chronic carbamazepine therapy exerts a suppressive influence on the auditory pathways, both peripherally at the level of the cochlea and/or auditory nerve, and centrally at the brainstem.