Central and Peripheral Motor Conduction Studies by Single-Pulse Magnetic Stimulation.

Single-pulse magnetic stimulation is the simplest type of transcranial magnetic stimulation (TMS). Muscle action potentials induced by applying TMS over the primary motor cortex are recorded with surface electromyography electrodes, and they are called motor-evoked potentials (MEPs). The amplitude and latency of MEPs are used for various analyses in clinical practice and research. The most commonly used parameter is the central motor conduction time (CMCT), which is measured using motor cortical and spinal nerve stimulation. In addition, stimulation at the foramen magnum or the conus medullaris can be combined with conventional CMCT measurements to evaluate various conduction parameters in the corticospinal tract more precisely, including the cortical-brainstem conduction time, brainstem-root conduction time, cortical-conus motor conduction time, and cauda equina conduction time. The cortical silent period is also a useful parameter for evaluating cortical excitability. Single-pulse magnetic stimulation is further used to analyze not only the central nervous system but also the peripheral nervous system, such as for detecting lesions in the proximal parts of peripheral nerves. In this review article we introduce four types of single-pulse magnetic stimulation-of the motor cortex, spinal nerve, foramen magnum, and conus medullaris-that are useful for the diagnosis, elucidation of pathophysiology, and evaluation of clinical conditions and therapeutic effects. Single-pulse magnetic stimulation is a clinically useful technique that all neurologists should learn.

Ischemic Stroke During Daprodustat Therapy for Renal Anemia: A Report of Three Cases.

Hypoxia-inducible factor prolyl hydroxylase (HIF-PH) inhibitors are increasingly used to treat renal anemia. Ischemic stroke is a rare severe adverse event of HIF-PH inhibitor therapy, and its clinical characteristics have not been described to date. We report three cases of ischemic stroke during treatment with daprodustat, a HIF-PH inhibitor, for anemia associated with non-dialysis-dependent chronic kidney disease (CKD). In two patients, the hemoglobin level exceeded the target hemoglobin level of 13 g/dL for renal anemia. Two patients developed ischemic stroke within two months after the daprodustat administration. None of the three patients experienced a recurrence of ischemic stroke after daprodustat discontinuation. Daprodustat therapy is a risk factor for ischemic stroke, particularly during excessive elevation of hemoglobin levels or the early phases of treatment. Daprodustat should be discontinued to mitigate the risk of ischemic stroke recurrence.

Successful Childbirth During Satralizumab Treatment in Neuromyelitis Optica Spectrum Disorder.

A 40-year-old woman with neuromyelitis optica spectrum disorder (NMOSD) and anti-aquaporin 4 antibodies suffered three NMOSD episodes between 35 and 37 years of age. Despite treatment with prednisolone and azathioprine, her condition repeatedly relapsed. We introduced satralizumab, targeting interleukin-6 receptors, which stabilized her condition. At the age of 38, she became pregnant and delivered a healthy baby at 38 weeks. Post delivery, both mother and child stayed healthy with no NMOSD relapses. This case illustrates the efficacy and safety of satralizumab in managing NMOSD, especially for women in their reproductive years who are planning pregnancy.

Guillain-Barré syndrome after percutaneous coronary intervention and transcatheter aortic valve implantation.

Guillain-Barré syndrome (GBS) usually develops after preceding infection, but cardiac surgery can also occasionally cause GBS. Currently, cardiac catheterizations have already become common therapeutic options for heart diseases, but there have been no reports of GBS occurrence after that. Herein, we present a rare case in which GBS occurred following catheterization. An 85-year-old-man with sudden onset chest pain was rushed to our hospital and diagnosed with ST-elevated myocardial infarction. He underwent emergent percutaneous coronary intervention (PCI) to left anterior descending artery, but he still had exertional chest pain. Echocardiography revealed severe aortic stenosis (AS) and our heart team considered AS was the cause of symptom and decided to perform and transcatheter aortic valve implantation (TAVI), 11 days after the PCI. However, 5 days after the TAVI procedure, he presented with symmetrical muscular weakness of extremities. Cranial magnetic resonance imaging showed no significant lesion. Based on several signs including albuminocytologic dissociation in cerebrospinal fluid examination, demyelinating polyneuropathy in nerve conduction study, positive anti-ganglioside antibody, and the lack of preceding infection, he was diagnosed with GBS triggered by cardiac catheterizations. We administered high-dose intravenous immunoglobulin therapy and his motor strength gradually improved, finally discharged with full motor strength after 7 months rehabilitation. Learning objective: •Cardiac surgery has been already reported as a non-infectious risk factor of Guillain-Barré syndrome (GBS) in previous literatures, and cardiac catheterization such as percutaneous coronary intervention and transcatheter aortic valve implantation, which were relatively less invasive procedure, may be a potential risk factor for GBS occurrence as well.•If a patient complains of progressive, symmetrical neurological symptoms after cardiac catheterization, GBS should be considered as the possible cause, and nerve conduction study and cerebrospinal fluid examination may be helpful for the diagnosis.

Quadripulse transcranial magnetic stimulation inducing long-term depression in healthy subjects may increase seizure risk in some patients with intractable epilepsy.

Objective: This study aimed to assess the efficacy and safety of quadripulse transcranial magnetic stimulation-50 (QPS-50) in patients with intractable epilepsy. Methods: Four patients were included in the study. QPS-50, which induces long-term depression in healthy subjects, was administered for 30 min on a weekly basis for 12 weeks. Patients' clinical symptoms and physiological parameters were evaluated before, during, and after the repeated QPS-50 period. We performed two control experiments: the effect in MEP (Motor evoked potential) size after a single QPS-50 session with a round coil in nine healthy volunteers, and a follow-up study of physiological parameters by repeated QPS-50 sessions in four other healthy participants. Results: Motor threshold (MT) decreased during the repeated QPS-50 sessions in all patients. Epileptic symptoms worsened in two patients, whereas no clinical worsening was observed in the other two patients. In contrast, MT remained unaffected for 12 weeks in all healthy volunteers. Conclusions: QPS-50 may not be effective as a treatment for intractable epilepsy. Significance: In intractable epilepsy patients, administering repeated QPS-50 may paradoxically render the motor cortex more excitable, probably because of abnormal inhibitory control within the epileptic cortex. The possibility of clinical aggravation should be seriously considered when treating intractable epilepsy patients with non-invasive stimulation methods.

Anti-nuclear matrix protein 2 antibody-positive dermatomyositis with gastrointestinal ulcers: A case report.

Gastrointestinal manifestations are a very rare complication of dermatomyositis (DM) and are much less frequent in adult cases than in juvenile cases. Only a few previous papers have reported adult patients who had DM with anti-nuclear matrix protein 2 (anti-NXP2) antibodies and who developed gastrointestinal ulcers. Herein, we report a similar case of a 50-year-old man who had DM with anti-NXP2 antibodies followed by relapsing multiple gastrointestinal ulcers. Even after the administration of prednisolone, his muscle weakness and myalgia deteriorated and gastrointestinal ulcers relapsed. In contrast, intravenous immunoglobulin and azathioprine improved his muscle weakness and gastrointestinal ulcers. Based on the parallel disease activity of the muscular and gastrointestinal symptoms, we considered that his gastrointestinal ulcers were a complication of DM with anti-NXP2 antibodies. We also propose that early intensive immunosuppressive therapy would be required for the muscular and gastrointestinal symptoms in DM with anti-NXP2 antibodies.

A novel micro-ECoG recording method for recording multisensory neural activity from the parietal to temporal cortices in mice.

Characterization of inter-regional interactions in brain is essential for understanding the mechanism relevant to normal brain function and neurological disease. The recently developed flexible micro (µ)-electrocorticography (µECoG) device is one prominent method used to examine large-scale cortical activity across multiple regions. The sheet-shaped µECoG electrodes arrays can be placed on a relatively wide area of cortical surface beneath the skull by inserting the device into the space between skull and brain. Although rats and mice are useful tools for neuroscience, current µECoG recording methods in these animals are limited to the parietal region of cerebral cortex. Recording cortical activity from the temporal region of cortex in mice has proven difficult because of surgical barriers created by the skull and surrounding temporalis muscle anatomy. Here, we developed a sheet-shaped 64-channel µECoG device that allows access to the mouse temporal cortex, and we determined the factor determining the appropriate bending stiffness for the µECoG electrode array. We also established a surgical technique to implant the electrode arrays into the epidural space over a wide area of cerebral cortex covering from the barrel field to olfactory (piriform) cortex, which is the deepest region of the cerebral cortex. Using histology and computed tomography (CT) images, we confirmed that the tip of the µECoG device reached to the most ventral part of cerebral cortex without causing noticeable damage to the brain surface. Moreover, the device simultaneously recorded somatosensory and odor stimulus-evoked neural activity from dorsal and ventral parts of cerebral cortex in awake and anesthetized mice. These data indicate that our µECoG device and surgical techniques enable the recording of large-scale cortical activity from the parietal to temporal cortex in mice, including somatosensory and olfactory cortices. This system will provide more opportunities for the investigation of physiological functions from wider areas of the mouse cerebral cortex than those currently available with existing ECoG techniques.

Facile formation of barium titanium oxyhydride on a titanium hydride surface as an ammonia synthesis catalyst.

Oxyhydrides are promising compounds as supports for ammonia synthesis catalysts because they suppress hydrogen poisoning on the catalyst surface and enhance the ammonia synthesis activity. Herein, we developed a facile method for preparing BaTiO2.5H0.5, a perovskite oxyhydride, on a TiH2 surface via the conventional wet impregnation method using TiH2 and Ba hydroxide. Scanning electron microscopy and high-angle annular dark-field scanning transmission electron microscopy observations revealed that BaTiO2.5H0.5 crystallized as nanoparticles of ca. 100-200 nm on the TiH2 surface. The Ru-loaded catalyst Ru/BaTiO2.5H0.5-TiH2 exhibited 2.46 times higher ammonia synthesis activity (3.05 mmol-NH3 g-1 h-1 at 400 °C) than the benchmark Ru catalyst Ru-Cs/MgO (1.24 mmol-NH3 g-1 h-1 at 400 °C) because of the suppression of hydrogen poisoning. The analysis of reaction orders showed that the effect of suppressing hydrogen poisoning on Ru/BaTiO2.5H0.5-TiH2 was equivalent to that of the reported Ru/BaTiO2.5H0.5 catalyst, thus supporting the formation of BaTiO2.5H0.5 perovskite oxyhydride. This study demonstrated that the selection of appropriate raw materials facilitates the formation of BaTiO2.5H0.5 oxyhydride nanoparticles on the TiH2 surface using the conventional synthesis method.

Early detection of cognitive decline in Alzheimer's disease using eye tracking.

Background: Patients with Alzheimer's disease (AD) are known to exhibit visuospatial processing impairment, as reflected in eye movements from the early stages of the disease. We investigated whether the pattern of gaze exploration during visual tasks could be useful for detecting cognitive decline at the earliest stage. Methods: Sixteen AD patients (age: 79.1 ± 7.9 years, Mini Mental State Examination [MMSE] score: 17.7 ± 5.3, mean ± standard deviation) and 16 control subjects (age: 79.4 ± 4.6, MMSE score: 26.9 ± 2.4) participated. In the visual memory task, subjects memorized presented line drawings for later recall. In the visual search tasks, they searched for a target Landolt ring of specific orientation (serial search task) or color (pop-out task) embedded among arrays of distractors. Using video-oculography, saccade parameters, patterns of gaze exploration, and pupil size change during task performance were recorded and compared between AD and control subjects. Results: In the visual memory task, the number of informative regions of interest (ROIs) fixated was significantly reduced in AD patients compared to control subjects. In the visual search task, AD patients took a significantly longer time and more saccades to detect the target in the serial but not in pop-out search. In both tasks, there was no significant difference in the saccade frequency and amplitude between groups. On-task pupil modulation during the serial search task was decreased in AD. The number of ROIs fixated in the visual memory task and search time and saccade numbers in the serial search task differentiated both groups of subjects with high sensitivity, whereas saccade parameters of pupil size modulation were effective in confirming normal cognition from cognitive decline with high specificity. Discussion: Reduced fixation on informative ROIs reflected impaired attentional allocation. Increased search time and saccade numbers in the visual search task indicated inefficient visual processing. Decreased on-task pupil size during visual search suggested decreased pupil modulation with cognitive load in AD patients, reflecting impaired function of the locus coeruleus. When patients perform the combination of these tasks to visualize multiple aspects of visuospatial processing, cognitive decline can be detected at an early stage with high sensitivity and specificity and its progression be evaluated.

Tropical support vector machines: Evaluations and extension to function spaces.

Support Vector Machines (SVMs) are one of the most popular supervised learning models to classify using a hyperplane in an Euclidean space. Similar to SVMs, tropical SVMs classify data points using a tropical hyperplane under the tropical metric with the max-plus algebra. In this paper, first we show generalization error bounds of tropical SVMs over the tropical projective torus. While the generalization error bounds attained via Vapnik-Chervonenkis (VC) dimensions in a distribution-free manner still depend on the dimension, we also show numerically and theoretically by extreme value statistics that the tropical SVMs for classifying data points from two Gaussian distributions as well as empirical data sets of different neuron types are fairly robust against the curse of dimensionality. Extreme value statistics also underlie the anomalous scaling behaviors of the tropical distance between random vectors with additional noise dimensions. Finally, we define tropical SVMs over a function space with the tropical metric.

Methotrexate-induced Subacute Encephalopathy That Showed No Abnormalities on Magnetic Resonance Imaging Soon after Symptom Appearance.

A 21-year-old woman was diagnosed with acute lymphoblastic leukemia. After the administration of intrathecal methotrexate (MTX), the patient experienced dysarthria and paralysis for one hour. Magnetic resonance imaging (MRI) performed one hour from the onset and just before symptoms disappeared revealed no abnormalities. The next day, the symptoms appeared again, and diffusion-weighed MRI revealed a high-intensity area in the left frontal lobe. The patient was diagnosed with MTX-induced encephalopathy. This case suggested that MRI performed as soon as symptoms appear might show normal findings in MTX-induced encephalopathy.

Orbital Intravascular Natural Killer/T-cell Lymphoma: An Unusual Cause of Ocular Symptoms.

Orbital intravascular lymphoma is rare and typically of B-cell lineage. In this study, we report a patient who developed orbital lesions of intravascular natural killer/T-cell lymphoma (IVNKL), an extremely rare lymphoma. An 88-year-old man presented with rapidly progressive right vision loss and double vision. A neurological examination revealed that he had decreased visual acuity and severe oculomotor impairment in the right eye. Magnetic resonance imaging showed right-dominant, nonmass lesions in both orbits. No lesions were found in the lymph nodes, skin, or brain. The patient received immunosuppressive and antifungal therapy, but his clinical condition rapidly deteriorated, and he died of multiple organ failure. Autopsy revealed natural killer/T-cell lymphoma proliferation within the lumina of small blood vessels in multiple organs, including the ocular adnexa of the right orbit. These findings show that he was ultimately diagnosed with IVNKL. IVNKL could initially cause ocular symptoms due to the involvement of the ocular adnexa. Ocular involvements have not been described previously. Even if patients initially present with only ocular symptoms, IVNKL should be considered.

Enhanced ammonia synthesis activity of Ru-supported cerium-lanthanum oxide induced by Ti substitution forming mesopores.

Ru/Ce0.5La0.5-xTixO1.75+0.5x solid solutions with cubic fluorite structure were successfully synthesized via the polymerized complex method. While the Ti substitution enhanced Ce4+ reducibility by compensating for oxygen vacancies, the reducibility showed no correlation with ammonia synthesis activity. However, Ru/Ce0.5La0.4Ti0.1O1.8 showed the highest activity originating from the facilitated formation of mesopores.

Intravenous Immunoglobulin in the Treatment of Adalimumab-associated Optic Neuritis.

Optic neuritis (ON) is a rare complication of tumor necrosis factor (TNF)-α inhibitors. The autoantibody serostatus, treatment, and outcome of TNF-α inhibitor-associated ON remain unclear. We herein report a 50-year-old woman with ON following adalimumab therapy. The patient presented with decreasing visual acuity of the right eye, quickly diminishing to light perception. Anti-aquaporin-4 (anti-AQP4) and anti-myelin oligodendrocyte glycoprotein antibodies were negative. Adalimumab was discontinued, and intravenous methylprednisolone and intravenous immunoglobulin (IVIg) were administered. However, her visual acuity improved only up to counting fingers. IVIg may be ineffective depending on the pretreatment severity.

Assessment of safety of self-controlled repetitive trans-vertebral magnetic stimulation.

OBJECTIVE: The aim of this study was to assess safety issues of self-controlled repetitive trans-vertebral magnetic stimulation (rTVMS) in humans. METHODS: We investigated effects of self-controlled rTVMS (≤20 Hz, ≤90% intensity) on vital signs and subjective sensations in 1690 trials of 30 healthy volunteers and 12 patients with spinal cord disorders. RESULTS: Healthy volunteers and the patients received 4595 ± 2345, and 4450 ± 2304 pulses in one day, respectively. No serious adverse events were observed in any participants, and only minor events were seen as follows. While blood pressure was unaffected in the patients, the diastolic blood pressure increased slightly after rTVMS in healthy volunteers. The peripheral capillary oxygen saturation increased after rTVMS in healthy volunteers. "Pain" or "Discomfort" was reported in approximately 10% of trials in both participants groups. Degree of the evoked sensation positively correlated with stimulus intensity and was affected by the site of stimulation. CONCLUSION: Self-controlled rTVMS (≤20 Hz and ≤90% intensity) did not induce any serious adverse effects in healthy volunteers and patients with spinal cord disorders. SIGNIFICANCE: Our results indicate that rTVMS can be used safely in physiological investigations in healthy volunteers and also as treatment for neurological disorders.

Diagnostic contribution and therapeutic perspectives of transcranial magnetic stimulation in dementia.

Transcranial magnetic stimulation (TMS) is a powerful tool to probe in vivo brain circuits, as it allows to assess several cortical properties such asexcitability, plasticity and connectivity in humans. In the last 20 years, TMS has been applied to patients with dementia, enabling the identification of potential markers of thepathophysiology and predictors of cognitive decline; moreover, applied repetitively, TMS holds promise as a potential therapeutic intervention. The objective of this paper is to present a comprehensive review of studies that have employed TMS in dementia and to discuss potential clinical applications, from the diagnosis to the treatment. To provide a technical and theoretical framework, we first present an overview of the basic physiological mechanisms of the application of TMS to assess cortical excitability, excitation and inhibition balance, mechanisms of plasticity and cortico-cortical connectivity in the human brain. We then review the insights gained by TMS techniques into the pathophysiology and predictors of progression and response to treatment in dementias, including Alzheimer's disease (AD)-related dementias and secondary dementias. We show that while a single TMS measure offers low specificity, the use of a panel of measures and/or neurophysiological index can support the clinical diagnosis and predict progression. In the last part of the article, we discuss the therapeutic uses of TMS. So far, only repetitive TMS (rTMS) over the left dorsolateral prefrontal cortex and multisite rTMS associated with cognitive training have been shown to be, respectively, possibly (Level C of evidence) and probably (Level B of evidence) effective to improve cognition, apathy, memory, and language in AD patients, especially at a mild/early stage of the disease. The clinical use of this type of treatment warrants the combination of brain imaging techniques and/or electrophysiological tools to elucidate neurobiological effects of neurostimulation and to optimally tailor rTMS treatment protocols in individual patients or specific patient subgroups with dementia or mild cognitive impairment.

Symmetrical Interhemispheric Subdural Hematoma.

Interhemispheric subdural hematoma (ISDH) is a rare subtype of subdural hematoma. We report the case of an 81-year-old woman on hemodialysis with sudden nausea and vomiting. A computed tomography (CT) scan of the brain showed a bilaterally symmetrical increase in the thickness and density of the falx cerebri. At first, the findings were overlooked, but were later identified as an acute ISDH. The patient was treated conservatively and the symptoms completely resolved. The possibility of ISDH should be considered even if CT images of the brain are symmetrical.