Facilitation of motor evoked potentials after tetanic peripheral nerve stimulation.

OBJECTIVE: Tetanic stimulation of a peripheral nerve prior to transcranial electrical stimulation (TES) may enhance motor evoked potential (MEP) amplitudes. The purpose of this study was to investigate the post-tetanic MEP (p-MEP) technique in improving MEP amplitudes. METHODS: Conventional TES MEPs (c-MEP) and p-MEPs with left upper limb stimulation (p-MEPUL) or left lower limb stimulation (p-MEPLL) were performed in 26 patients. Bilateral hand and foot MEP amplitudes obtained with each protocol were compared. Subgroup comparisons were performed for myelopathy and peripheral neuropathy patients. Within-subject amplitude differences between c-MEP and each p-MEP technique were compared using a Wilcoxon test. RESULTS: The mean age of the patients was 52.7 years (range, 12-79 years). Overall, p-MEPUL resulted in MEP improvement in 25 of 26 (96%) patients, and p-MEPLL improved MEPs in 19 of 26 (73%) patients. The increase in MEP amplitudes were statistically significant in all muscle groups except left foot. Similar improvements were seen in the myelopathy group; in the neuropathy group, p-MEPUL produced similar results, but p-MEPLL did not. CONCLUSIONS: The p-MEP technique can improve MEP amplitudes, including in patients with myelopathy. In patients with peripheral neuropathy, the results were mixed. SIGNIFICANCE: Tetanic stimulation can enhance intraoperative MEP amplitudes.

Diagnostic Yield of Electroencephalography When Seizure Is Suspected in Acute Ischemic Stroke.

INTRODUCTION: Seizures are a common complication after an ischemic stroke. Electroencephalography can assist with the diagnosis of seizures however, the diagnostic yield of its use when seizure is suspected in the setting of acute ischemic stroke is unknown. We aim to evaluate the yield and cost of EEG in the acute ischemic stroke setting. METHODS: We conducted a retrospective chart review of patients admitted to a single academic tertiary care center in the United States between September 1, 2015 to November 30, 2019 with a primary diagnosis of acute ischemic stroke and who were monitored on electroencephalography (EEG) for suspected seizures (total number of 70 patients). The primary outcome was how often EEG monitoring changed clinical management defined as starting, stopping, or changing the dose of an anti-epileptic drug. Secondary analysis was estimating the cost of EEG monitoring per change in management. RESULTS: We identified 126 patients admitted with acute ischemic stroke who underwent EEG of which 70 met all inclusion and exclusion criteria. EEG monitoring resulted in a change in management in 22 patients (31%). Predictors associated with EEG monitoring resulting in a change in management were admission to the ICU, pre-existing atrial fibrillation, and symptomatic hemorrhagic transformation. Estimated cost of EEG per change in management was $1374.96 USD. CONCLUSION: EEG monitoring resulted in a changed management in nearly one-third of patients admitted with acute ischemic stroke suspected of having seizures.

Temporal lobe epilepsy with a contralateral parietal seizure-onset zone.

Achieving sustained seizure freedom following epilepsy surgery remains a challenge in some patients. Lesional temporal lobe epilepsy (TLE), for example, in patients with mesial temporal sclerosis or other MRI abnormalities, carries a good prognosis for seizure freedom compared to significantly lower chances of seizure freedom in patients with non-lesional epilepsy. However, even in some lesional TLE cases, persistent post-operative seizures suggest seizure onset from a brain region that is clinically and electrographically silent but manifests only after propagation to the temporal lobe. A notable example of such a brain region is the parietal lobe, which has extensive connectivity to various brain regions. While certain seizure semiologies, for example, sensory seizures, suggest parietal lobe onset, some medial parietal seizures may be semiologically indistinguishable from temporal lobe seizures. Here, we report a patient with focal impaired awareness seizures that manifested semiologically and electrographically as left TLE but proved to originate from the contralateral medial parietal lobe. We discuss putative seizure propagation pathways.

Monoclonal Antibody-Based Therapies for Myasthenia Gravis.

Myasthenia gravis (MG) is an autoimmune, neuromuscular disorder that produces disabling weakness through a compromise of neuromuscular transmission. The disease fulfills strict criteria of an antibody-mediated disease. Close to 90% of patients have antibodies directed towards the nicotinic acetylcholine receptor (AChR) on the post-synaptic surface of skeletal muscle and another 5% to the muscle-specific kinase, which is involved in concentrating the AChR to the muscle surface of the neuromuscular junction. Conventional treatments of intravenous immunoglobulin and plasma exchange reduce autoantibody levels to produce their therapeutic effect, while prednisone and immunosuppressives do so by moderating autoantibody production. None of these treatments were specifically developed for MG and have a range of adverse effects. The extensive advances in monoclonal antibody technology allowing specific modulation of biological pathways has led to a tremendous increase in the potential treatment options. For MG, monoclonal antibody therapeutics target the effector mechanism of complement inhibition and the reduction of antibody levels by FcRn inhibition. Antibodies directed against CD20 and signaling pathways, which support lymphocyte activity, have been used to reduce autoantibody production. Thus far, only eculizumab, an antibody against C5, has reached the clinic. We review the present status of monoclonal antibody-based treatments for MG that have entered human testing and offer the promise to transform treatment of MG.

COVID-19: Neurology residents' perspective.

Throughout this pandemic, neurology resident education and service has, and will continue to be, affected during this unprecedented time. Balancing the safety of our residents as well as the anticipated inpatient service demands, we have, and continue to, make changes to meet the needs of our community. Education certainly has been affected but we have made great effort to maintain normalcy. We are leveraging web-based technologies to continue formal didactics. The American Academy of Neurology has provided program directors with various tools to share to provide high-yield academic education. AAN Synapse, distance learning modules, and podcasts are a few examples. Each residency training program will likely face different challenges depending on location and community structure. We have an obligation to help all of our colleagues in the hospital in providing quality and compassionate care during this time of need. Our training and education will only benefit from this experience teaching us lessons on adaptability, the importance of teamwork, and self-sacrifice.

Yield and cost-effectiveness of tilt table tests combined with video-EEG.

To study the outcomes of a series of consecutive tilt table tests combined with video-EEG (TTVE) at a single center, and assess their cost-effectiveness compared with other neurophysiological tests. We retrospectively reviewed medical records of patients who underwent TTVE studies between March 1st, 2013 to April 1st, 2018. Detailed clinical history, including patient demographics, reasons for referral, anti-seizure medications, and neurophysiological studies obtained prior to the TTVE studies were extracted from chart reviews. The fee for each neurophysiological test was identified from the Centers for Medicare & Medicaid Services. Fifty-two patients underwent TTVE studies. Thirteen patients (25%) were diagnosed with vasovagal syncope, two (3.8%) were diagnosed with postural orthostatic tachycardia syndrome, and three (5.8%) had psychogenic non-epileptic events during the test. Four out of 12 patients stopped anti-seizure medication(s) after the TTVE. Prior to referral for TTVE, an average of $3,748 per person was spent on neurophysiological tests, which were inconclusive. The average fee for one TTVE test was $535.32, and the fee per test affecting diagnosis or management (defined as the cost divided by the yield of the test) was $1,547. The TTVE test is cost-effective in evaluating refractory episodes of loss of consciousness, atypical of epileptic seizures. In addition to diagnosing syncope, TTVE can be valuable in identifying psychogenic events.

Early Outcomes after Carotid Endarterectomy and Carotid Artery Stenting for Carotid Stenosis in the ACS-NSQIP Database.

BACKGROUND: Carotid endarterectomy (CEA) and carotid artery stenting (CAS) are both viable treatment options for carotid artery stenosis. We sought to compare perioperative outcomes after CEA and CAS for the management of carotid stenosis using a "real-world" sample. METHODS: We conducted a retrospective observational study using the National Surgical Quality Improvement Program database to compare 30-day (periprocedural) outcomes in patients with carotid stenosis undergoing CEA versus CAS from 2005 to 2012. Baseline characteristics and periprocedural outcomes including stroke, myocardial infarction, mortality and combined outcome (composite of any stroke, myocardial infarction, or death) were compared. RESULTS: A total of 54,640 patients were identified who underwent CEA and 488 who underwent CAS. Patients undergoing CEA were more likely to be older and have symptomatic stenosis, and less likely to be white, have congestive heart failure, and have chronic obstructive pulmonary disease. There were no significant differences between CEA and CAS in periprocedural mortality (0.9% vs. 1.2%, p = 0.33), stroke (1.6% vs. 1.6 p = 0.93), myocardial infarction (0.9% vs. 1.6%, p = 0.08), or combined outcome (3.0% vs. 4.9%, p = 0.09). The interaction between symptomatic status and procedure type was not significant, indicating the association of symptomatic status with 30-day mortality (p = 0.29) or the combined periprocedural outcome (p = 0.57) were similar in cases receiving CEA and CAS. CONCLUSION: Early outcomes after CEA and CAS for carotid artery stenosis appear to be similar in a "real-world" sample and comparable to clinical trials. Patients undergoing CAS were more likely to be younger and surgically have higher risk based on baseline characteristics likely reflecting clinical practice case selection.