Test-retest reliability of transcranial magnetic stimulation EEG evoked potentials

Background

Transcranial magnetic stimulation (TMS)-evoked potentials (TEPs), recorded using electroencephalography (TMS-EEG), offer a powerful tool for measuring causal interactions in the human brain. However, the test-retest reliability of TEPs, critical to their use in clinical biomarker and interventional studies, remains poorly understood.

A new electroencephalogram classification with reduced recording time in asphyxiated term infants

Background and objectives: Conventional electroencephalogram (cEEG) is a reliable predictor of outcome in term infants with hypoxic ischemic encephalopathy (HIE). Early therapeutic hypothermia initiated within 6 h after birth is a beneficial treatment in these infants. However, a classification system with reduced cEEG recording time to determine early intervention has not been reported. The aim of this study is to propose a new classification of depression on cEEG with reduced recording time in infants with HIE and to examine the correlation between the classification and short-term outcome. Patients and methods: We retrospectively investigated 20 term infants with HIE in whom cEEG was performed within 12 h after birth, and deaths or outcomes at 18 months of age were assessed. We determined grades 0–3 EEG depression in each 10-min epoch based on the most common EEG patterns of each 20 s epoch defined by our criteria. Results: Eighteen infants could be assessed by depression grade. The Spearman’s rank correlation coefficient Rs between the maximum depression grade in 10-min epochs and three-grade outcomes was 0.68 (P = 0.002), and that between the minimum one and outcomes was 0.66 (P = 0.003). The area under the receiver operating characteristic curve of the maximum and minimum depression grades for predicting abnormal outcome were 0.885 and 0.869, respectively. Conclusions: We demonstrated a new cEEG depression classification with a recording time of at least 10 min in term infants with HIE and a good correlation with short-term outcome.     

老年慢性精神分裂症的脑电地形图和多项诱发电位研究

为了解老年慢性精神分裂症患者与正常老人在脑电图（ＥＥＧ）、脑电地形图（ＢＥＡＭ）、视觉和听觉诱发电位（ＶＥＰ、ＡＥＰ）、脑干听觉反应（ＡＢＲ）和认知电位Ｐ３００（Ｐ３００）检测中的不同表现，对４０例正常老人及３４例老年慢性精神分裂症患者作６项电生理检测。结果发现，患者ＥＥＧ异常率达６６．７％，其ＢＥＡＭ趋向凹字形低密度带，ＶＥＰ（潜伏期Ｐ１、Ｐ２）、Ｐ３００（靶潜伏期Ｎ１—Ｐ２—Ｎ２—Ｐ３）均前移，ＡＥＰ（潜伏期Ｎ２、Ｐ３）延迟，ＡＥＰ、ＶＥＰ和Ｐ３００的Ｐ２、Ｐ３波幅均减低，均有显著性差异（Ｐ＜０．０５或Ｐ＜０．０１）。患者的ＡＢＲ于中央区左右侧不对称，绝对波幅波Ⅰ降低（Ｐ＜０．０１），这与本组对象ＣＴ结果吻合。采用多项诱发电位检测技术能较可靠反映精神分裂症患者脑的功能，可辅助患者的认知功能评定     

EEG and evoked potential findings in mitochondrial myopathies

Electroencephalograms (EEGs) and evoked potentials (EPs) were studied in 43 patients with mitochondrial myopathies. Abnormalities were found most frequently in patients who presented predominantly or exclusively with central nervous system (CNS) dysfunction (abnormal EEGs in 18 of 21 patients, abnormal EPs in 9 of 11 patients). However, of patients presenting with ocular myopathy or proximal muscle weakness who had little or no CNS involvement clinically, 8 of 22 had abnormal EEGs and 5 of 10 had abnormal EPs, suggesting that electrophysiological tests are of value in demonstrating subclinical CNS disease in mitochondrial myopathy, although the abnormalities are not specific.     

EEG findings in cooled asphyxiated newborns and correlation with site and severity of brain damage

Objective: EEG and MRI are useful tools to evaluate the severity of brain damage and to provide prognostic indications in asphyxiated neonates. Aim of our study is to analyze the relationship between serial neonatal EEGs and severity and sites of brain lesions on MRI in neonates undergoing hypothermia, following a hypoxic-ischemic injury. Patients and methods: Forty-eight term newborns underwent hypothermia. Serial videoEEG recordings were taken at 6, 24, 48 and 72 h and during 2nd week of life. Brain MRI was performed at the end of 2nd postnatal week and correlated with EEG. Results: EEGs improved during the first days. At the first recording 25 infants showed a severe or very low amplitude EEG pattern while at the 2nd week only 7 showed such patterns. As regards MRI, 21 infants showed a predominant Basal Ganglia and Thalami damage, 4 infants showed a predominant focal Thalami lesion and 23 showed normal imaging or just mild White Matter abnormalities. Severity of EEG pattern was associated with the odds of having MRI lesions at Basal Ganglia, Thalami, White Matter, Internal Capsule, but not at Cortex. Infants who showed only mild EEG abnormalities in the first 2 days had no Basal Ganglia and Thalami MRI lesion. The persistence of a discontinuous EEG at the 2nd week recording is always associated with Basal Ganglia and Thalami damage. Conclusion: The severity of EEG background is associated with severity and site of MRI lesion pattern in neonates treated with hypothermia because of hypoxic-ischemic encephalopathy.     

卡马西平对诱发电位的影响及意义

目的研究长期口服卡马西平治疗癫对诱发电位的影响,并讨论其意义。方法选择尚未治疗的癫病人31例作为试验组;以性别、年龄与癫组相匹配的健康正常人26例作为对照组。两组先分别做脑干听觉诱发电位(BAEP)、事件相关电位P300、视觉诱发电位(VEP)和体感诱发电位(SEP),之后癫组开始卡马西平治疗,服药一年后再作上述各项检查。结果癫组病人治疗前各项电生理学指标与正常对照组相比无显著性差异;癫组卡马西平治疗后各项电生理指标与治疗前相比BAEP各波、P300以及VEP的P100波潜伏期均显著延长;SEP的潜伏期无显著变化。结论神经电生理学检查可以早期发现长期服用卡马西平导致的亚临床毒性。     

卡马西平对诱发电位的影响及意义

目的 研究长期口服卡马西平治疗癫癎对诱发电位的影响,并讨论其意义.方法选择尚未治疗的癫癎病人31例作为试验组;以性别、年龄与癫癎组相匹配的健康正常人26例作为对照组.两组先分别做脑干听觉诱发电位（BAEP）、事件相关电位P300、视觉诱发电位（VEP）和体感诱发电位（SEP）,之后癫癎组开始卡马西平治疗,服药一年后再作上述各项检查.结果 癫癎组病人治疗前各项电生理学指标与正常对照组相比无显著性差异;癫癎组卡马西平治疗后各项电生理指标与治疗前相比BAEP各波、P300以及VEP的P100波潜伏期均显著延长;SEP的潜伏期无显著变化.结论 神经电生理学检查可以早期发现长期服用卡马西平导致的亚临床毒性.     

Somatosensory perception and cortical evoked potentials in established paraplegia

In 66 patients who suffered severe spinal cord injury 7 months to 28 years previously, somatosensory cortical evoked potentials were recorded to electrical stimulation of the leg nerves and compared to clinical assessment of light touch, pain, position sense and two-point discrimination. The patients were separated into 4 categories according to the degree of disintegration of the somatosensory evoked potential waveform. A clear correlation was found between the impairment of somatosensory perception and the deterioration of the somatosensory evoked potential in each group. However, it was not possible to observe any direct correlation between the sensory score or impairment of a single modality and somatosensory evoked potential changes, or among the impairment of single modalities on a case by case basis. This study indicates that the somatosensory evoked potential can be used to provide electrophysiological information independent of the clinical examination on functions of the dorsal columns in the chronic stage of spinal cord injury.     

阿尔茨海默病患者脑电图和多项脑诱发电位的变化研究

目的探讨阿尔茨海默病患者自发和诱发脑电特征。方法应用脑电图和多项脑诱发电位检测方法对26例阿尔茨海默病患者及15名正常对照者进行脑电图(EEG)、脑干听觉诱发电位(BAEP)、视觉诱发电位(VEP)和P300等检测。结果(1)轻度阿尔茨海默病患者的EEG异常率及异常者的EEG表现与对照组基本一致;但随着阿尔茨海默病程度的加重,EEG异常率及异常者的EEG表现与对照组间相比,差异具有显著性意义(P<0.01);(2)与对照组相比,中、重度阿尔茨海默病患者的BAEPⅢ波和Ⅴ波绝对波潜伏期延长及绝对波幅降低,VEP的P200波潜伏期明显延长,差异具有显著性意义(P<0.05或P<0.01);(3)与对照组相比,阿尔茨海默病患者的P300潜伏期明显延长(P<0.05或P<0.01),且轻、中、重度患者间差异亦有显著性意义(P<0.05)。结论脑电图和多项脑诱发电位相结合的检测方法能较为客观地反映阿尔茨海默病患者的脑功能状态,有可能作为阿尔茨海默病辅助的脑电生理诊断方法,也是近年来提出病因假说的间接佐证。     

Wilson's disease: evoked potentials and computed tomography

Summary Multi-modality evoked potentials and computed cranial tomography (CT) were performed in ten patients with Wilson's disease to determine if any of these studies would correlate reliably with neurologic status. While all four patients with CT abnormality had neurologic signs, two additional patients with neurologic findings had normal scans. Evoked responses were normal in nine patients. The remaining patient displayed abnormal visual, brainstem, and somatosensory evoked potentials, and follow-up studies after clinical deterioration revealed worsening of the brainstem and visual evoked potentials. This patient died unexpectedly from a subdural hematoma, and postmortem examination confirmed the radiographic findings of cortical atrophy of the cerebrum and cerebellum and bilateral cystic degeneration of the basal ganglia. However, localized demyelination in the visual, auditory, and sensory pathways was not present. We conclude that the clinical neurologic status of patients with Wilson's disease cannot be reliably predicted by either CT or multi-modality evoked potentials.     

Effects of carnosine on olfactory bulb EEG, evoked potentials and DC potentials

Carnosine is a dipeptide found in great quantities in the primary olfactory nerve and has been suggested to be the neurotransmitter of the olfactory receptor axons. The aim of the present study was to describe some of its electrophysiological actions in the olfactory bulb (OB) of rabbits under anesthesia. Carnosine as a 10% solution in amounts of 2-5 microliter was injected to the OB at the level of the glomerular layer by means of a pipette attached to a Hamilton syringe. Average evoked potentials (AEPs) on the stimulation of the lateral olfactory tract (LOT-AEP), electroencephalographic (EEG) activity and slow potential (DC) recordings were obtained. The LOT-AEPs were analyzed by fitting damped sine waves to them. The parameters of amplitude, frequency, decay rate, phase and rise rate were measured and statistically compared to the values obtained prior to the carnosine injection. An increase in frequency and decreases in the phase and the decay rate of the AEP were found. Carnosine also produced a sustained oscillation in the EEG and a surface negative, deep positive shift in the DC recording. The changes were maximal within the first minute after injection and lasted 2-7 min. Tyrodes' solution, which was used as the carnosine vehicle, did not produce any changes, nor did beta-alanine, which is one of the constituents of carnosine, at equivalent osmotic concentrations. It is concluded that carnosine has an excitatory action on the mitral/tufted cells, and that this effect is obscured by a secondary increase in granule cell (inhibitory) activity.     

多发性硬化患者前庭诱发肌源性电位的临床意义

目的研究多发性硬化(multiple sclerosis,MS)患者前庭诱发肌源性电位(vestibularevoked myogenic potentials,VEMPs)各参量的变化及临床意义,比较VEMPs与核磁共振、脑干听觉诱发电位对MS病变的检测能力。方法采用双耳短声刺激记录37例MS患者(有脑干症状21例、无脑干症状16例)和20名健康对照的VEMPs的潜伏期和振幅值,计算双侧在13ms左右出现的正波(p13)波幅潜伏期差值(Δp13)和振幅比(SR)。37例MS患者均做核磁共振成像,其中33例记录脑干听觉诱发电位。结果有脑干症状组和对照组相比,p13潜伏期显著延长[左侧为(13.84±2.57)ms和(12.20±1.10)ms,P<0.05;右侧为(14.69±2.96)ms和(12.10±2.60)ms,P<0.01],Δp13显著增大(1.63±1.82和1.00±1.44,P<0.01),而无脑干症状组差异无统计学意义。两组MS患者的p13-n23(在23ms左右出现的负波)振幅值与对照组相比均降低[左侧分别为(149.98±52.2)、(175.51±49.22)、(272.80±165.81)μV;右侧分别为(156.88±97.04)、(167.74±57.32)、(257.50±138.49)μV,P均<0.05],扩展的残疾功能量表评分与振幅有相关性(左侧r=0.45,右侧r=0.46,P均<0.05)。VEMPs与核磁共振相比,对病灶的检出率低(分别为33%与100%,P<0.05),与脑干听觉诱发电位相比差异无统计学意义。结论p13潜伏期及Δp13可作为判定MS前庭脊髓通路脱髓鞘的参考指标。VEMPs作为辅助诊断MS的一项新的诱发电位,对脑干病灶的诊断有一定临床参考意义。     

Early predictors of short term neurodevelopmental outcome in asphyxiated cooled infants. A combined brain amplitude integrated electroencephalography and near infrared spectroscopy study

Background: Brain Cooling (BC) represents the elective treatment in asphyxiated newborns. Amplitude Integrated Electroencephalography (aEEG) and Near Infrared Spectroscopy (NIRS) monitoring may help to evaluate changes in cerebral electrical activity and cerebral hemodynamics during hypothermia. Objectives: To evaluate the prognostic value of aEEG time course and NIRS data in asphyxiated cooled infants. Methods: Twelve term neonates admitted to our NICU with moderate-severe Hypoxic-Ischemic Encephalopathy (HIE) underwent selective BC. aEEG and NIRS monitoring were started as soon as possible and maintained during the whole hypothermic treatment. Follow-up was scheduled at regular intervals; adverse outcome was defined as death, cerebral palsy (CP) or global quotient <88.7 at Griffiths’ Scale. Results: 2/12 Infants died, 2 developed CP, 1 was normal at 6 months of age and then lost at follow-up and 7 showed a normal outcome at least at 1 year of age. The aEEG background pattern at 24 h of life was abnormal in 10 newborns; only 4 of them developed an adverse outcome, whereas the 2 infants with a normal aEEG developed normally. In infants with adverse outcome NIRS showed a higher Tissue Oxygenation Index (TOI) than those with normal outcome (80.0 ± 10.5% vs 66.9 ± 7.0%, p = 0.057; 79.7 ± 9.4% vs 67.1 ± 7.9%, p = 0.034; 80.2 ± 8.8% vs 71.6 ± 5.9%, p = 0.069 at 6, 12 and 24 h of life, respectively). Conclusions: The aEEG background pattern at 24 h of life loses its positive predictive value after BC implementation; TOI could be useful to predict early on infants that may benefit from other innovative therapies.     

Evoked potentials in full-term and premature infants: a comparative study

In this study the maturation of the central nervous system of full-term and premature infants were investigated electrophysiologically. The subjects were 16 full-term and 15 premature infants. Neurologic examination, psychometric tests, and measurement of evoked potentials were carried out periodically in babies who had no birth trauma, metabolic disorder, or intrauterine infection. Neurophysiologic comparison of the results was evaluated. As the babies grew older, I-V interpeak latency became shorter according to the results of brainstem auditory evoked potentials; N₁-P₁ amplitude became higher and P₁ latency shorter according to the results of visual evoked potentials. Central nervous system maturation of full-term babies and prematures appear to be alike at 6 months of age.     

多发性硬化患者头颅磁共振、诱发电位和IgG指数的对比研究

报道43例多发性硬化(MS)患者头颅磁共振成像(MRI)、诱发电位(EP)和IgG指数(IgGIndex)的对比研究结果。发现MRI的检测异常率为81.4％,而VEP仅53.7％、BAEP47.5％、IgGIndex57.5％。MRI在显示空间脱髓鞘方面是最敏感的方法,但VEP、BAEP只要有一项异常即判断为EP异常则其异常率高达79.5％,接近MRI。作者认为三者同时检查可以提高诊断的准确性。     

遗传性小脑共济失调的多形式诱发电位研究

研究遗传性小脑共济失调的诱发电位变化。方法采用多种形式诱发电位，对３６例此类疾病的患者进行检测，并与３０～４０名健康者作对比。结果全部患者至少存在１种以上的诱发电位异常。磁刺激运动诱发电位（ＭＥＰ）、脑干听觉诱发电位（ＢＡＥＰ）及胫后神经与正中神经体感诱发电位（ｔＳＥＰ、ｍＳＥＰ）的异常率分别为８３．３％、８８．９％、８０．０％和６２．５％。不同类型小脑共济失调的诱发电位异常率不同，各型ＢＡＥＰ的异常率普遍较高，橄榄－桥脑－小脑萎缩患者的ＭＥＰ与遗传性痉挛性共济失调的ｔＳＥＰ异常率也很高。ＭＥＰ测试时，刺激皮质在患者中所记录到的双峰波、多相波以及波宽增加，表明皮质运动神经元的异常放电。结论多形式诱发电位改变应列为慢性小脑变性分类学上的诊断依据     

Influence of magnetic resonance imaging on somatosensory and brain-stem auditory evoked potentials in man

Summary There is still a need to prove that even static magnetic fields up to 1.5 T used in magnetic resonance imaging (MRI) are biologically safe and harmless for humans. Recordings of median and ulnar nerves and brain-stem auditory evoked potentials in 20 patients were completed prior to and after MRI investigation of the central nervous system. Neither the somatosensory nor the auditory evoked potentials exhibited any significant change of latencies, interpeak latencies or amplitudes. Since these electrophysiological parameters are highly dependent on the quality of nerve conduction and integrity of information processing in various nuclei, it may be assumed that MRI causes no lasting changes in either respect.     

多发性硬化患者的MRI及多种诱发电位研究

目的探讨磁共振成像(MRI)和诱发电位(EPs)在诊断多发性硬化中的价值。方法对68例多发性硬化患者的头颅MRI、脑干听觉诱发电位、视觉诱发电位以及体感诱发电位等指标进行回顾性分析和比较。结果多发性硬化患者的头颅MRI、脑干听觉诱发电位、视觉诱发电位以及体感诱发电位的异常率分别为91.2%(62/68)、80.9%(55/68)、82.4%(56/68)和77.9%(53/68),且均发现多发性硬化的亚临床病灶;两项或多项联合检查的异常率较单项检查的异常率增高,差异有统计学意义(P<0.01)。结论头颅MRI和诱发电位检查有助于临床早期确诊多发性硬化,联合应用可使其敏感性提高。     

Visual evoked potentials in ataxia telangiectasia

Summary Pattern reversal visual evoked potentials (VEPs) elicited in four patients with ataxia telangiectasia revealed normal results in two and absent responses in two. The pathogenesis of the VEP abnormalities is discussed. It is surmised that the VEP changes reflect progressive degeneration of the nerve fibres in the anterior visual pathway, as in Friedreich's ataxia.