Motor potentials evoked by magnetic stimulation of the motor cortex in normal subjects and patients with motor disorders.

Motor evoked potentials (MEPs) elicited by magnetic coil stimulation of motor cortex were studied at rest and during maximum voluntary muscle contraction in 20 normal subjects and 42 patients with motor disorders. MEP parameters employed in this study included: onset latency, amplitude, MEP/M wave amplitude ratio and background EMG/MEP area ratio. Maximum voluntary contraction increased the amplitude of MEPs compared to the size of M waves elicited by peripheral nerve stimulation. A reduced MEP/M wave amplitude ratio had a higher correlation with pyramidal tract involvement than did a prolonged MEP onset latency. Analysis of MEP parameters may help in the differential diagnosis of cerebral infarction, ALS and cervical spondylotic radiculomyelopathy. The inhibitory period which follows MEPs during voluntary contraction was observed in all subjects; the mean duration in normal subjects was 126.6 +/- 29.5 msec. The mean duration of the inhibitory period in patients with cerebral infarction, ALS and cervical spondylotic radiculomyelopathy was 73.9 +/- 41.7 msec, 79.5 +/- 54.5 msec and 85.1 +/- 36.5 msec, respectively. These values were significantly shorter than in normal subjects.     

难治性癫(癎)的循证外科治疗

目的 为难治性癫(IE)患者的外科治疗制定循证方案.方法 针对1例IE患者诊治中的临床问题,检索临床指南、系统评价、meta分析及随机对照试验,并评价其质量,判断其真实性、适用性,获取最佳证据并应用于临床.结果 共检索到3篇指南、5篇系统评价和1篇结局研究,分析结果表明IE从定义到诊治都还存在着许多争议.结合患者情况,应用循证证据治疗,随访半年的疗效较好.结论 循证治疗可以提高患者疗效,但仍然缺乏充分的证据.     

Paraspinal motor evoked potentials by magnetic stimulation of the motor cortex

The authors studied five patients with MS and four patients with HTLV-1 associated myelopathy (HAM) to investigate the usefulness of paraspinal motor evoked potentials (MEP) after magnetic stimulation of the motor cortex. In patients with MS, MEP disappeared or onset latencies were delayed below the lesion. In patients with HAM, the onset latencies were prolonged bilaterally. Thus, paraspinal MEP are very useful in detecting spinal cord lesions.     

Cloxazolam treatment for patients with intractable epilepsy

We examined the antiepileptic effect of cloxazolam on seizures in 23 patients with intractable epilepsy. Most of the patients had central nervous system complications, as well as frequent seizures, and were being treated with polypharmacy. Cloxazolam was administered 1 to 5 mg/day (0.05 to 0.14 mg/kg) at initiation, in two divided doses daily, and gradually increased (1 to 4 mg/day; 0.05 to 0.15 mg/kg) every month at the outpatient clinic. Plasma levels of the main active metabolite, chloro-N-desmethyldiazepam, were measured in 13 patients. Four of 23 patients (17%) became seizure-free, and nine patients (39%) manifested a good response. Both patients with generalized and partial epilepsy manifested a good response. The spectrum of cloxazolam as an antiepileptic was wide. Effective doses were 0.07 to 0.56 mg/kg, and plasma effective levels of chloro-N-desmethyldiazepam were 12.3-115.1 ng/mL. Cloxazolam may be an effective and safe antiepileptic for intractable epilepsy, and should be used as an adjunct to other antiepileptic drugs or administered after other agents.     

脑血管病患者经颅磁刺激运动诱发电位的研究

采用经颅磁刺激运动诱发电位（ＭＥＰ）对７２例脑血管病（ＣＶＤ）患者和５０例正常人进行检测。结果：ＣＶＤ患者瘫痪侧上肢磁刺激无反应或皮层潜伏期和中枢传导时间（ＣＭＣＴ）较正常对照组和健侧显著延长（Ｐ＜０．００１）；瘫痪侧下肢磁刺激无反应或ＣＭＣＴ较正常对照组和健侧显著延长（Ｐ＜０．０５）。脑出血与脑梗塞患者ＭＥＰ异常率无显著差异（Ｐ＞０．０５），而与临床病情轻重和病变部位密切相关。提示ＭＥＰ能客观反映ＣＶＤ患者中枢运动传导通路功能受损的情况。     

磁刺激运动诱发电位对大脑半球切除术前运动功能的评估价值

目的探讨应用经颅磁刺激运动诱发电位（TMS—MEP）评估双侧肢体运动功能的半球支配情况。方法对10例顽固性癫痫、准备行改良大脑半球切除术的病人进行TMS—MEP检查。检查时蝶形线圈置于双侧大鱼际肌的皮质运动功能区，单侧刺激，同时记录双侧大鱼际肌的皮质TMS—MEP。将结果分为功能完全代偿、部分代偿和不能代偿。结果功能完全代偿2例，部分代偿6例．不能代偿2例。完全代偿的病人术后无运动功能损害加重．部分代偿的病人术后短期运动功能损害加重，3个月内运动功能恢复到术前水平。不能代偿的病人行改良大脑半球切除术。结论TMS—MEP能够客观评估顽固性癫痫病人双侧肢体运动功能的半球支配情况．是一种有效、可靠且无创的评估手段。     

Pathology of intractable epilepsy with regard to surgical treatment]

There have recently been a number of new pathological findings of specimens from epileptic foci that have increasingly been highlighted as opportunities for surgical treatment. These findings include a wide range from hippocampal sclerosis-related lesions of temporal lobe epilepsy to newly established malformative lesions. As to the former, special interest has been paid to additional knowledge regarding the pathology inside and outside the medial temporal regions, such as the significance of 1) accumulation of corpora amylacea in hippocampal sclerotic lesions, 2) dispersion of the granular layer of the dentate gyrus, 3) various pathologic features in the lateral temporal lobe, and 4) dual pathology in extratemporal areas. As increasing opportunities for surgical treatment of intractable epilepsy, new categories of malformative lesions are being established, including focal cortical dysplasia and microdysgenesis, the latter of which can be diagnosed only by pathological examination after surgery. In the field of surgical pathology of epilepsy patients, further clues to clarify the pathomechanism of epilepsy remain to be discovered.     

Pattern-reversal visual evoked potentials in patients with newly diagnosed epilepsy

PURPOSE: The possible occurrence of evoked potential (EP) abnormalities in patients with newly diagnosed epilepsy has been little investigated. The main purpose of the present study was to investigate possible changes in pattern-reversal visual evoked potential (P-VEP) responses in newly diagnosed epilepsy patients. METHODS: By using P-VEPs, latency values of the N75 and P100 together with amplitude values of P100 were recorded in newly diagnosed idiopathic epilepsy patients. The patients comprised two groups; nonphotosensitive (non-PS), and photosensitive (PS) patients. RESULTS: Shortened N75 and normal P100 latencies of the P-VEP with higher than normal P100 amplitudes were detected in PS patients. In non-PS patients, N75 latencies of the P-VEPs were unaffected; however, P100 latencies were prolonged, and P100 amplitudes were unchanged. CONCLUSIONS: P-VEPs are different from those of controls in previously untreated idiopathic epilepsy patients. Results also indicate different P-VEP features in patients with and without photoparoxysmal responses. The changes might be the result of a disorder of one or more neurotransmitters or subtle morphologic damage such as microdysgenesis.     

Effect of exercise on motor evoked potentials elicited by transcranial magnetic stimulation in psychiatric patients.

SUMMARY: Under normal conditions, motor evoked potentials (MEPs) elicited by transcranial magnetic stimulation increase in amplitude if the subject exercises the examined muscle immediately before recording. The authors examined the effect of nonfatiguing exercise on the amplitude of MEPs on 42 psychiatric, medicated inpatients (14 with depression, 14 with schizophrenia, and 14 with mania) compared with 14 healthy control subjects. For each subject, a total of 50 baseline and 50 postexercise MEPs were recorded. The mean (+/- standard deviation) postexercise MEP facilitation, expressed as a percentage of mean baseline values, was significantly lower (p 相似文献   

Outcome of surgical treatment in non-lesional intractable childhood epilepsy

PurposeThe aim of this study is to investigate seizure outcomes following epilepsy surgery in non-lesional neocortical pediatric epilepsy.MethodsWe performed a retrospective study on 27 patients with intractable childhood epilepsy who received epilepsy surgery between 1999 and 2006 at Sang-gye Paik Hospital and Severance Children's Hospital. None of the patients had any detectable lesions on MRI. Surgical outcome was assessed at least 2 years postoperatively; clinical characteristics, surgical outcome, pathologic findings, types of surgery, localizing features on SPECT, FDG-PET, and long-term video-EEG were reviewed.ResultsEighteen patients (67%) demonstrated an Engel class I outcome postoperatively. The mean follow-up duration was 4.3 years (range, 2.2–9 years). Eighteen out of 27 cases (67%) showed focal localizing features on ictal SPECT, and 21 of 27 cases (78%) showed abnormal findings on PET. Single lobectomy was the most common procedure, and was performed in 20 patients (74%). Multilobar resection was performed in seven patients (26%). Cortical dysplasia was the most common finding during pathological examination, and was observed in 15 (56%) cases. In addition, gliosis was found in two patients (7%) and non-specific pathological findings were described in 10 patients (37%).ConclusionsIn children with intractable epilepsy and a MRI demonstrating no abnormal lesions, epileptic surgery should be strongly considered when cortical pathology can be identified from other studies.     

Transventricular hemispherotomy for surgical treatment of intractable epilepsy

Surgical procedures for cerebral hemispherotomy may be broadly divided into those using a lateral and those using a vertical approach. However, careful study of surgical procedures using the lateral approach described in the literature shows differences in the approach to the ventricles. We discuss the application of transventricular hemispherotomy as a technique which provides relatively easy ventricular access for cerebral hemispherotomy. Transventricular hemispherotomy was successfully performed in a 36-year-old woman who was diagnosed with intractable epilepsy due to Sturge-Weber disease, and in a 25-year-old man who had developed intractable post-traumatic seizures after suffering cerebral contusion in a traffic accident as a child. These patients had no seizures or complications after surgery, and both patients have been weaned from antiepileptic drugs. The transventricular approach, as compared with other lateral approaches described in the literature, provides easy access to the ventricular cavity. Transventricular hemispherotomy proved to be a useful approach that allowed the following four common steps in cerebral hemispherotomy to be performed safely: (i) interruption of the internal capsule and corona radiata; (ii) resection of the medial temporal structures; (iii) transventricular corpus callosotomy; and (iv) disruption of the frontal horizontal fibers.     

Inhibitory period following motor potentials evoked by magnetic cortical stimulation.

Following motor potentials evoked (MEPs) by magnetic cortical stimulation, there is a transient suppression of muscle action potentials (inhibitory period). We recorded MEPs, the inhibitory period, V1 waves and F waves from the abductor pollicis brevis muscle in 20 normal subjects and in 17 patients with spastic hyperreflexia due to cerebral infarction. The duration of the inhibitory period increased in correspondence with increasing stimulus intensity and did not necessarily depend on the amplitude of the MEPs. The duration of the inhibitory period elicited by a twin coil, which can stimulate the motor cortex locally, was shorter than by a single coil. The mean duration of the inhibitory period was significantly shorter in patients with spastic hyperreflexia than in normal subjects, and it correlated with the amplitude of F waves. The effects of the inhibitory period on V1 waves were different from its effects on F waves in one patient with large V1 and F waves. The amplitudes of V1 waves recorded during the inhibitory period were approximately 30-50% of the maximal amplitude of V1 waves, but F waves were not smaller. The inhibitory period is probably caused primarily by central inhibitory mechanisms.     

Topographic differences in task-dependent facilitation of magnetic motor evoked potentials

OBJECTIVE: To look for differences in task-dependent facilitation of magnetic motor evoked potentials (MEPs) in proximal and distal upper extremity muscles. BACKGROUND: Postexercise facilitation of MEPs has been demonstrated repeatedly in forearm muscles. Proximal muscles are prominently involved in limb stabilization, a largely isometric activity. In contrast, distal hand muscles specialize in precision movements. Based on these functional differences between proximal and distal muscles, we postulated that there might be topographic differences in task-dependent facilitation of MEPs. METHODS: We studied the effects of isometric exercise and a precision grip task on MEPs in proximal and distal upper extremity muscles. RESULTS: Isometric exercise of the target muscle was associated with significant facilitation of MEPs in biceps and extensor carpi radialis muscles, but not in first dorsal interosseous or abductor digiti minimi muscles. In contrast, a precision grip task was associated with significant post-task facilitation of MEPs in first dorsal interosseous, but not in extensor carpi radialis. CONCLUSIONS: These differences in the facilitation of MEPs depending on the motor task and whether the muscle is proximal or distal may reflect the relative importance of proximal muscles in maintaining posture.     

Proton magnetic resonance spectroscopy of brain biopsies from patients with intractable epilepsy.

In the present study metabolite concentrations were determined by proton magnetic resonance spectroscopy (MRS) in biopsies obtained from patients suffering intractable epilepsy from several different causes. Seven patients had gliosis, four had mild cortical dysplasia, three had tuberous sclerosis, two had astrocytomas, and one had a cavernous angioma. No significant differences were found in gliotic tissue in comparison with controls except for an increase in lactate. However, in the subgroup with tuberous sclerosis an increase was found in GABA and a dramatic decrease in N-acetyl aspartate (NAA). The most marked changes were found in the group with mild cortical dysplasia. There was a considerable decrease in NAA as well as large increases in GABA, alanine, tyrosine, acetate, inositol, glucose and lactate. The GABA content did not appear to correlate with antiepileptic therapy. Moreover, since all these patients required surgery, an elevated GABA level does not necessarily provide protection from seizures. The results indicate that use of proton MRS could become a useful presurgical predictor of underlying pathology.     

High-dose ketamine hydrochloride maintains somatosensory and magnetic motor evoked potentials in primates.

Monitoring the descending neural motor volleys (MEPs), in comparison to muscle action potentials, allows sensitive motor assessment under anesthesia irrespective of the use of muscular blockade and status of skeletal musculature. Ketamine hydrochloride (KH) had preserved muscle MEPs on a pre-established primate model. The present work examines the effect of incremental hypnotic KH dosages thoracic neural on somatosensory (SEP) and MEPs recorded epidurally in response to transcranial magnetic stimulation (TMS). Through a small thoracic T11-T12 laminotomy, an insulated double bipolar electrode was inserted epidurally and cephalad in seven cynomolgus monkeys. Thoracic spinal TMS-MEPs, and SEPs, were tested against graded increase of KH doses (0.01, 0.018, 0.032, 0.056, 0.1, and 0.18 mg kg(-1) min(-1) i.v. infusion). The direct (D-) and indirect (I-) epidural MEP peaks were well-defined under sole KH infusion. The waveforms were consistent at various dosages. At the highest cumulative dose (0.18 mg kg(-1) min(-1), total 6.5 mg kg(-1) over 150 min), I5 was host and I3 and I4 latencies were delayed. The scalp and spinal SEP showed no significant change. Recording of both neural D- and I- MEPs and SEPs is feasible under high sole i.v. KH. It is the first agent to maintain up to four later I1 peaks. The reproducibility of both modalities is unquestionable under KH-based deep anesthesia. This reflects the maintenance of state of neural excitability under KH.