Cortical mechanisms underlying variability in intermittent theta-burst stimulation-induced plasticity: A TMS-EEG study

ObjectiveTo test the hypothesis that intermittent theta burst stimulation (iTBS) variability depends on the ability to engage specific neurons in the primary motor cortex (M1).MethodsIn a sham-controlled interventional study on 31 healthy volunteers, we used concomitant transcranial magnetic stimulation (TMS) and electroencephalography (EEG). We compared baseline motor evoked potentials (MEPs), M1 iTBS-evoked EEG oscillations, and resting-state EEG (rsEEG) between subjects who did and did not show MEP facilitation following iTBS. We also investigated whether baseline MEP and iTBS-evoked EEG oscillations could explain inter and intraindividual variability in iTBS aftereffects.ResultsThe facilitation group had smaller baseline MEPs than the no-facilitation group and showed more iTBS-evoked EEG oscillation synchronization in the alpha and beta frequency bands. Resting-state EEG power was similar between groups and iTBS had a similar non-significant effect on rsEEG in both groups. Baseline MEP amplitude and beta iTBS-evoked EEG oscillation power explained both inter and intraindividual variability in MEP modulation following iTBS.ConclusionsThe results show that variability in iTBS-associated plasticity depends on baseline corticospinal excitability and on the ability of iTBS to engage M1 beta oscillations.SignificanceThese observations can be used to optimize iTBS investigational and therapeutic applications.     

Near-fiber electromyography

ObjectiveDescribe and evaluate the concepts of near fiber electromyography (NFEMG), the features used, including near fiber motor unit potential (NFMUP) duration and dispersion, which relate to motor unit distal axonal branch and muscle fiber conduction time dispersion, and NFMUP segment jitter, a new measure of the temporal variability of neuromuscular junction transmission (NMJ), and axonal branch and muscle fibre conduction for the near fibres (i.e. NF jitter), and the methods for obtaining their values.MethodsTrains of high-pass filtered motor unit potentials (MUPs) (i.e. NFMUP trains) were extracted from needle-detected EMG signals to assess changes in motor unit (MU) morphology and electrophysiology caused by neuromuscular disorders or ageing. Evaluations using simulated needle-detected EMG data were completed and example human data are presented.ResultsNFEMG feature values can be used to detect axonal sprouting, conduction slowing and NMJ transmission delay as well as changes in MU fiber diameter variability, and NF jitter. These changes can be detected prior to alterations of MU size or numbers.ConclusionsThe evaluations clearly demonstrate and the example data support that NFMUP duration and dispersion reflect MU distal axonal branching, conduction slowing and NMJ transmission delay and/or MU fiber diameter variability and that NFMUP jiggle and segment jitter reflect NF jitter.SignificanceNFEMG can detect early changes in MU morphology and/or electrophysiology and has the potential to augment clinical diagnosis and tracking of neuromuscular disorders.     

Predicting addiction potential based on sensation-seeking,psychological hardiness and assertiveness in students in western Iran: an analytical study

ABSTRACT

Background: Addiction has been reported as a major personal, social and political challenge in people of different strata and education levels in all countries. The present study was conducted to predict addiction potential based on sensation-seeking, psychological hardiness and assertiveness in students.

Methods: The present correlational study was conducted in 2018 on a statistical population comprising all the students of the School of Medicine in Kermanshah University of Medical Sciences, Kermanshah, Iran. Convenience sampling was used to select 200 subjects. The data collection tools included the sensation-seeking scale, the psychological hardiness questionnaire, the assertion inventory and the addiction potential scale. The data collected were analyzed in SPSS using the statistical methods of the Pearson correlation coefficient and regression analysis.

Results: Analyzing the findings showed the total scores of addiction potential and active addiction potential are positively associated with the total score of sensation-seeking and negatively and significantly correlated with that of psychological hardiness.

Conclusions: Given the role of sensation-seeking, psychological hardiness and assertiveness in addiction potential, university authorities are recommended to hold workshops and seminars to enhance the awareness of students of the personality traits conducive to addiction.     

Early axonal loss predicts long-term disability in chronic inflammatory demyelinating polyneuropathy

ObjectiveTo investigate early pre-treatment nerve fiber loss as a predictor of long-term clinical outcome in chronic inflammatory demyelinating polyneuropathy (CIDP).MethodsIn 14 patients, motor and sensory conduction studies of the median, fibular, and sural nerves were performed at pre-treatment and follow-up 11–28 years later. Z-scores of amplitudes were combined as biomarkers of axonal loss and Z-scores of conduction properties as demyelination scores. The axonal loss was further examined by electromyography (EMG) and motor unit number estimation. Axonal and demyelination scores were compared to clinical outcomes in the Inflammatory Rasch-built Overall Disability Scale, the Neuropathy Impairment Score, and dynamometry.ResultsAt follow-up 12 patients walked independently, one needed support and one could not walk. The initial and follow-up axonal and demyelination scores were markedly abnormal. The initial axonal loss but not demyelination was strongly associated with both the follow-up axonal loss and the clinical measures. Moreover, delay of treatment initiation negatively influenced the axonal scores and clinical outcomes.ConclusionIn this hypothesis generating limited study, we found that axonal loss at early CIDP was highly predictive for long-term nerve fiber loss and disability.SignificanceThe study indicates that prompt initiation of treatment to prevent nerve fiber loss is necessary for outcome in CIDP.     

Subthalamic dynamic neural states correlate with motor symptoms in Parkinson’s Disease

ObjectiveThis study aims to discriminate the dynamic synchronization states from the subthalamic local field potentials and investigate their correlations with the motor symptoms in Parkinson’s Disease (PD).MethodsThe resting-state local field potentials of 10 patients with PD were recorded from the subthalamic nucleus. The dynamic neural states of multiple oscillations were discriminated and analyzed. The Spearman correlation was used to investigate the correlations between occurrence rate or duration of dynamic neural states and the severity of motor symptoms.ResultsThe proportion of long low-beta and theta synchronized state was significantly correlated with the general motor symptom and tremor, respectively. The duration of combined low/high-beta state was significantly correlated with rigidity, and the duration of combined alpha/high-beta state was significantly correlated with bradykinesia.ConclusionsThis study provides evidence that motor symptoms are associated with the neural states coded with multiple oscillations in PD.SignificanceThis study may advance the understanding of the neurophysiological mechanisms of the motor symptoms and provide potential biomarkers for closed-loop deep brain stimulation in PD.     

Preoperative risk stratification of lymph node metastasis for non-functional pancreatic neuroendocrine neoplasm: An international dual-institutional study

Background/Objectives: Although the presence of lymph node metastasis (LNM) defines malignant potential, preoperative prediction of LNM has not been established for non-functional pancreatic neuroendocrine neoplasm (NF-PNEN). We sought to develop a prediction system using only preoperatively available factors that would stratify the risk of LNM for NF-PNEN.MethodsWe retrospectively reviewed patients who underwent R0/1 resection of NF-PNEN at Kyoto University (2007–2019) and the University of California, San Francisco (2010–2019). Risk stratification of LNM was developed using preoperative factors by the logistic regression analysis. Long-term outcomes were compared across the risk groups.ResultsA total of 131 patients were included in this study. Lymph nodes were pathologically examined in 116 patients, 23 (20%) of whom had LNM. Radiological tumor size [1.5–3.5 cm (odds ratio: 13.5, 95% confidence interval: 1.77–398) and >3.5 cm (72.4, 9.06–2257) against ≤1.5 cm], <50% cystic component (8.46 × 10^6, 1.68 × 10^106-), and dilatation of main pancreatic duct ≥5 mm (31.2, 3.94–702) were independently associated with LNM. When patients were classified as the low-risk (43 patients), intermediate-risk (44 patients), and high-risk groups (29 patients), proportions of LNM differed significantly across the groups (0%, 14%, and 59%, respectively). Recurrence-free survival (RFS) of the low- and intermediate-risk groups were significantly better than that of the high-risk group (5-year RFS rates of 92.2%, 85.4%, and 47.1%, respectively).ConclusionsThe prediction system using preoperative radiological factors stratifies the risk of LNM for NF-PNEN. This stratification helps to predict malignant potential and determine the surgical procedure and necessity of regional lymphadenectomy.     

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??Abstracts?? Objective To investigate the changes of ventricular late potentials ??VLP?? in children with vasovagal syncope of vasodepressor response ??VVS-V??. Methods Totally 184 children ??aged from 4 to 14 years old??the average age being ??10.54±2.15?? years old?? had been diagnosed with VVS-V by head-up tilt table test ??HUTT?? ??study group?? from July 2006 to January 2013 in the Second Xiangya Hospital of Central South University?? male 85 cases?? the average age of ??10.85±2.01?? years old?? female 99 cases?? mean age ??10.27±2.24?? years old. Totally 105 healthy children were matched as controls. All subjects underwent VLP examination. Investigate the difference in HR?? TQRS?? LAS40 and RMS40 between the study group and the control group. Results Compared with the control group?? in the study group heart rate ??HR?? decreased ???83.96±12.27?? beats/min vs??87.28±13.75?? beats/min?? t = -2.113?? P??0.05???the total QRS time??TQRS?? ???84.89±12.05?? ms vs ??81.21±8.23?? ms?? t = 3.070?? P??0.05?? and high frequency and low amplitude limit??LAS40?? ???62.43±19.17?? ms vs ??56.79±1.83?? ms?? t = 2.442?? P??0.05?? were prolonged??and the root mean square plant??RMS40?? increased ???28.73±7.23?? μV vs ??26.89±7.36?? μV?? t = 2.059?? P??0.05??. Conclusions Compared to healthy controls??in VVS-V children HR reduces??TQRS and LAS40 prolong??and RMS40 increases. It suggests that VVS-V childrenare more likely to have cardiovascular incidents.     

The use of somtaosensory evoked potential (SSEP) and motor evoked potential (MEP) monitoring in a patient with Brugada syndrome

IntroductionWe report on the use of Somastosensory Evoked Potential (SSEP) and Motor Evoked Potential (MEP) monitoring in a patient with Brugada syndrome.ObjectivesThe concern in this case was that the amount of current/voltage generated by SSEP/MEP might trigger arrhythmias in a patient with underlying Brugada syndrome.MethodsA 42 year-old male patient with Brugada syndrome underwent excision of an intramedullary tumour with the use of SSEP and MEP monitoring. Preoperatively, he was not on antiarrhythmic medication, nor had an Implantable Cardioverter Device (ICD) in-situ.ResultsThe patient remained stable & in sinus rhythm throughout the operation and was successfully extubated postoperatively.ConclusionThis case report indicates that SSEP/MEP monitoring may be used in patients with Brugada syndrome.     

生长棒撑开术中经颅刺激运动诱发电位和体感诱发电位监测的应用价值

目的:分析生长棒撑开术中经颅刺激运动诱发电位(MEP)和体感诱发电位(SEP)神经功能监测的应用价值。方法:回顾性分析2010年10月~2015年1月我院进行的65例141次生长棒撑开手术,在生长棒撑开术中,运用MEP和SEP进行神经功能监测。MEP监测采用经颅刺激C3、C4,记录外周肌源性MEP,SEP监测采用刺激双侧胫后神经,记录电极采用Cz-CPz。阳性诊断标准:与基线相比,MEP波幅下降75%,SEP波幅下降50%或潜伏期延长10%。结果:141例次撑开手术中成功获得具有监护价值且重复性较好MEP 139例次,检出率98.6%,全程失败2例次(占1.4%);SEP成功监测140例次,检出率99.3%,失败1例(占0.7%)。所有患者均能成功记录到一种以上的诱发电位。本组141例次手术中未出现MEP及SEP监测阳性。所有患儿术后神经系统检查均无异常发现,神经功能监测结果均为真阴性。结论:生长棒撑开术是简单安全的手术操作,但是,运用MEP和SEP进行术中神经功能监测可以为生长棒撑开术提供客观的安全评估指标。