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.

---

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.

     

Brainstem auditory evoked potentials in postconcussion syndrome

Brainstem auditory evoked potentials (BAEPs) were recorded from 55 patients with postconcussion syndrome (PCS) to elicit evidence of an organic and subclinical brainstem disorder. Fifteen patients (27.3%) showed abnormal responses unilaterally or bilaterally, especially for one or more interpeak latencies prolonged beyond the upper 99% confidence limits. Other 9 patients had borderline responses. The BAEP alterations were not correlated either with dizziness at the time of recording, or with vestibular troubles in the routine caloric test. Though BAEP abnormalities may be present a long time after injury, we found an improvement of responses in the majority of 14 re-tested patients. These data show that BAEP can give an objective demonstration of a reversible brainstem disorder in patients with PCS.

---

Sommario I potenziali evocati acustici del tronco cerebrale (BAEP) sono stati registrati in 55 pazienti affetti da sindrome soggettiva postcraniotraumatica (PCS), per evidenziare un possibile danno organico subclinico del tronco cerebrale. Quindici pazienti (27.3%) hanno mostrato risposte alterate unilateralmente o bilateralmente, soprattutto a causa della presenza di una o più latenze interpicchi oltre i limiti fiduciali superiori del 99%. Altri 9 pazienti hanno mostrato risposte borderline. Non sono state ritrovate correlazioni tra il reperto di BAEP alterati e la presenza di vertigini all'atto dell'esame, né con il comportamento dell'esame vestibolare. Benché le alterazioni del BAEP si possano osservare anche a distanza di molti mesi dal trauma, la maggioranza dei pazienti con BA EP alterati, ad un secondo esame ha mostrato un miglioramento della risposta. Tali dati dimostrano che i BAEP sono in grado, in alcuni pazienti affetti da PCS, di evidenziare un danno organico del tronco cerebrale, passibile di regressione.

     

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.

---

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.

     

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。     

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.

---

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.

     

Prognostic evaluation of brainstem hematomas: the role of CT scan and brainstem auditory evoked potentials

Abstract– 6 cases of brainstem hematoma were studied utilizing CT scan and brainstem auditory evoked potential (BAEP) recordings. CT scan did not contribute to an early discrimination between primary and secondary hematomas. Size of the hematoma and the presence of blood in the CSF did not represent evident signs in differentiating benign from unfavourable brainstem hematomas or hemorrhages. BAEP recordings showed the presence of electrophysiological anomalies at the level of the lesion, demonstrating that bleeding as well as tumor in the brainstem can provoke a focal damage.     

Changes in auditory P300 event-related potentials and brainstem evoked potentials in diabetes mellitus

To investigate the influence of diabetes mellitus on higher cognitive functions electrophysiologically, we studied auditory P300 event-related potentials (P300) in 40 NIDDM patients, taking into account wave I-V latencies (I-V) in auditory brainstem evoked potentials, clinical parameters and head MRI findings. Compared with 20 controls, diabetics had significantly longer P300 and I-V latencies. P300 latencies in diabetics correlated with neither I-V. HbA₁, blood glucose levels, nor disease duration. Of the 13 diabetics investigated neuroradiologically, four had lacunar infarcts with prolonged electrophysiological values. The remaining nine had normal MRI scans, but their physiological parameters were still significantly longer than those of controls. These findings suggest that NIDDM can independently alter higher cognitive and the central auditory pathway functions. Our data also suggest that these alterations occur regardless of the recent metabolic derangement and disease duration. Cerebrovascular ischemia, if present, also appears to contribute in part to cognitive alterations.     

Contralateral evoked brainstem auditory potentials as an indicator of intraoperative brainstem manipulation in cerebellopontine angle tumors

Abstract

Brainstem auditory evoked potentials (BAEP) were studied during operations to remove acoustic tumors using the retromastoid approach. BAEP were elicited from the side contralateral to the tumor, and changes in the latencies of peaks III and V of the BAEP were compared with changes in cardiovascular parameters throughout the operation. When the changes in the determined cardiovascular parameters were related to surgical manipulations, the related changes in the latencies of peaks III and V of the BAEP were more consistent than the changes in the cardiovascular parameters and they tended to occur earlier than the changes noted in the cardiovascular parameters. [Neurol Res 1996; 18: 528-540]     

The application of evoked potentials in the diagnosis and follow-up of children with intracranial tumors

Somatosensory and brainstem auditory evoked potentials (SSEPs and BAEPs) provide sensitive measures of the central conduction functions of the auditory and somatosensory input systems at different levels of the central nervous system. The contribution of SSEPs and BAEPs in the primary diagnosis and follow-up of 26 children with infra- and supratentorial tumors were reviewed. The SSEPs, especially the specific complex, showed a latency increase in patients with supratentorial and brainstem mass lesions involving directly or distantly the somatosensory tracts. The BAEPs were sensitive for supratentorial pressure effects and for local and distant posterior fossa tumor effects. In the follow-up of children, evoked potentials offer a good method of detecting tumor recurrence, whereas neuroradiological procedures may be obscured by surgical or radiation artifacts.This paper has been presented in part at the Symposium of the European Federation of Child Neurology Societies, June 1983     

Visual and auditory evoked potentials during long-term vigabatrin treatment in children and adolescents with epilepsy.

OBJECTIVES: The aim of the study was to estimate the effects of Vigabatrin (VGB) as add-on therapy on visual (VEP) and brain-stem (BAEP) evoked potentials. METHOD: The investigation covered 100 epileptic patients from 8 to 18 years of age. The treatment included therapy with carbamazepine (CBZ) or valproate acid (VPA) using slow release formulations of these AEDs. Combination therapy was administered using add-on VGB in the recommended dose 57.4+/-26.5 mg/kg body mass/day. VEP and BAEP evoked potentials were recorded by means of Multiliner (Toennies, Germany). The obtained values were compared with age matched control group. RESULTS: Compared to control groups, significant differences in epileptic groups emerged in latencies of the peak III, V along with the interpeak intervals I-III of BAEP. Also VEP studies showed the reduction of N75/P100 and P100/N145 amplitudes. CONCLUSIONS: Adding VGB did not significantly increase the percentage of pathological abnormalities observed from EPs. Our electrophysiological studies demonstrate abnormalities in EPs parameters due to subclinical toxicity induced by AEDs. Major alterations produced bitherapy of VPA-SR + VGB and minor SR formulations of CBZ or VPA.     

脑干听觉诱发电位及体感诱发电位在重型颅脑损伤患者预后评估中的作用

目的 分析探讨脑干听觉诱发电位(BAEP)及体感诱发电位(SEP)与重型颅脑损伤病人预后的关系.方法 对33 例重型颅脑损伤患者早期行BAEP 及SEP 测定并进行动态监测,同时行头颅CT 检查并记录GCS 评分.结果 BAEP 及SEP 预测预后的敏感性、特异性、准确性均较高.BAEP、SEP 异常程度低,则预后较好;异常程度高,则预后不良.结论 BAEP、SEP 可以比较准确地评估重型颅脑损伤患者的预后.     

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.     

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。     

Multimodal evoked potentials in neuro-Behçet: a longitudinal study of two cases

Two neuro-Behçet patients have been studied, over a period of several months, by means of peroneal and median somatosensory- (SEP), brainstem auditory- (BAEP), and visual- (VEP) evoked potentials. In both patients, peroneal SEP showed evidence of a pathological reduction in the central conduction velocity without a related deep sensation impairment, while VEP changes were consistent with the visual disorders. Conversely, BAEP and median SEP findings did not show disease-related abnormalities. The observed anomalies were detectable irrespective of the clinical phase of the disease. Thus, evoked potential assessment is useful in providing objective evidence for evaluating and monitoring CNS damage in neuro-Behçet's syndrome.     

Selective attention differentially affects brainstem auditory evoked potentials of electrodermal responders and nonresponders

Brainstem auditory evoked potentials (BAEPs) were recorded in adult male chronic schizophrenics on maintenance neuroleptic therapy, drug-free alcoholics, and normal subjects. Subjects were subdivided into electrodermal responders (Rs) and nonresponders (NRs). Attention was directed toward auditory or visual stimuli. Independent of diagnosis, latencies of BAEP wave V were longer in NRs when visual rather than auditory stimuli were attended to, while there was no task effect for Rs. This finding is interpreted as a sign of excessive selective filtering of auditory stimuli in NRs. In the alcoholic NRs, wave I-V conduction times were longer than those in any other subgroup, possibly indicating retarded neural transmission.     

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.     

Visual evoked potentials in diabetes mellitus

25 diabetic patients have been studied in order to investigate the possible effects of the disease on the central nervous system by means of pattern shift visual evoked potentials. Patients with diabetic retinopathy, glaucoma and cataract were excluded from the study. Results obtained from a control group of 30 normal subjects were compared to those of the patient group in which sural nerve conduction velocities have also been determined to see whether there is a correlation between peripheral and central involvement of the nervous system. In diabetic patients latency prolongation in the P100 and N140 components were observed. The N90-N140 interpeak latency was also prolonged. In addition, in patients with longstanding diabetes mellitus the incidence of VEP abnormalities was found to be high. Pathologic changes in VEP latencies did not show any correlation with sural nerve conduction abnormalities.     

Age, sex and mental retardation related changes of brainstem auditory evoked potentials in Down's syndrome

Brainstem auditory evoked potentials (BAEPs) were recorded in 51 Down's syndrome (DS) subjects and compared with those of 38 normal controls; the correlations between the BAEP measures and age, sex, and degree of mental retardation were then evaluated. The DS patients showed a significant reduction in wave V latency and amplitude and in I–III, III–V, and I–V interpeak intervals. An age-related shortening of the I–V interpeak interval found in DS patients was interpreted as being a result of changes in central inhibitory/excitatory mechanisms. In both groups, female subjects presented an I–V interval shorter than that of males but this difference was greater in the DS subjects than in the normal population. The DS patients with severe mental retardation showed significantly longer I–V interpeak intervals than those with moderate retardation; this could be due to the presence of additional central nervous system abnormalities.

---

Sommario I potenziali evocati auditivi tronco-encefalici (BAEP), registrati in 51 pazienti con sindrome di Down (SD), sono stati messi a confronto con quelli ottenuti in 38 soggetti normali di controllo. In seguito è stata valutata la correlazione tra i parametri dei BAEP con l'età, il sesso e il grado di ritardo mentale. I pazienti con SD mostravano una riduzione significativa della latenza e dell'ampiezza dell'onda V e della lunghezza dell'intervallo I–V, rispetto ai controlli. Una ulteriore riduzione età correlata dell'intervallo I–V è stata osservata nei pazienti con SD; questa è stata interpretata come il risultato di modificazioni dei meccanismi inibitori/eccitatori centrali. Le femmine con SD presentavano un intervallo I–V più breve di quello dei maschi in maniera più evidente che nella popolazione normale. Inoltre, i pazienti con ritardo mentale più grave mostravano un intervallo I–V significativamente più prolungato di quelli con ritardo mentale medio; questo potrebbe essere dovuto alla presenza di anomalie strutturali aggiuntive nei soggetti più compromessi.