We succeeded in demonstrating the action potentials from the cerebral arterial walls in cats. Discharges of action potentials increased during induced hypotension and decreased during induced hypertension. Since fusaric acid (dopamine beta–hydroxylase inhibitor) suppressed the responses of action potentials to changes in blood pressure, the action potentials from the surface of cerebral arteries may have a close relation to the noradrenergic system.
To clarify the relationship between calcium metabolism and free radical during the reperfusion period following ischemia, we investigated the effect of superoxide dismutase (SOD) on changes in cytosolic free calcium. During reperfusion, the Ca2+ signal ratio remained at a high level in control group, while in the SOD–treated group, the Ca2+ signal ratio decreased. SOD may have ability to attenuate increases in intracellular calcium during the recirculation period following focal cerebral ischemia.
We investigated NO production in eNOS knockout (−/−) mice and nNOS knockout (−/−) mice during cerebral ischemia and reperfusion. NO production was continuously monitored by in vivo microdialysis. Levels of NO3− were significantly lower in eNOS (−/−) mice and nNOS (−/−) mice than in control mice during ischemia and reperfusion. NO3− levels were significantly lower in nNOS (−/−) mice than in eNOS (−/−) mice after the start of reperfusion. These in vivo data suggest that NO production in the striatum after reperfusion is closely related to activities of both nNOS and eNOS, and is mainly related to nNOS following reperfusion.
The autonomic nervous function in patients with migraine was studied during headache–free intervals. Since migraine patients show sympathetic hypofunction together with denervation hypersensitivity of the iris and the arteries, a defective noradrenergic nervous system may play a role in the pathogenesis of migraine.
Migraine patients showed the lower level of plasma CGRP and SP compared to the normal volunteers. Migraine patients may have denervation hypersensitivity to CGRP and SP. Nitric oxide production following L–arginine infusion was enhanced in migraine patients.
Sweating function in patients with migraine was examined during headache–free intervals. After stimulated by intradermal injection of pilocarpine, molds of sweat droplets were obtained using Silastic. The number of droplets in classic migraine was significantly lower than that in the controls. Sweating function was impaired in patients with migraine.
When we investigated the sympathetic function during migraine attack, migraine patients showed the almost normal sympathetic function. These data suggested the sympathetic function of migraine patients will recover when patients have their attack.
The Japanese Society of Neurological Therapeutics (JSNT) was founded in 1983. Neurological therapeutics have developed dramatically. It is important that drugs companies, regulatory government agencies and academic institutes should cooperate to create and develop new therapeutics, especially for rare neurological diseases. The JSNT should contribute to the progress in medical therapeutic research. The JSNT is tackling the education and progress in neurological treatment and care of neurological disorders.
The study of eye movements is an important source of useful information for clinical neurologists. Abnormal eye movements in patients with neurological disorders often provide diagnostic clues for us.
Eyes appear to have first evolved in the bursts of evolution known as the Cambrian explosion (about 540 million years ago) after the discovery of eyes in fossils. Since then eyes show a wide range of adaptation and development to meet the requirements of the species.
The concept of binocularity was noted by Aristotle more than 2000 years ago. He believed that the two eyes operated as a unit rather than independently. This concept was confirmed by Ewald Hering in 1868 and is now referred to as Hering's law of equal innervation. This principle is the basis of the neuro–ophthalmology. In 1903 Raymond Dodge classified the eye movements into 5 categories, saccades, smooth pursuit, optokinetic, vestibulo–ocular eye movements and vergence. Later visual fixation to maintain the visual gaze on a single object was added to the classification of eye movement in the primates which have a fovea on each eye.
The modern Neuro–ophthalmology was founded in the United States by Frank B. Walsh in Johns Hopkins and David G. Cogan in Harvard around 1947∼48. In 1969 FB Walsh and WF Hoyt published the 3rd edition of Handbook of Clinical Neuro–ophthalmology. This legacy continued in the form of subsequent editions edited by NR Miller and NJ Newman. On the basis of these great mentors, neuro–ophthalmology flourishes today. We are now working in a new era when scientific approaches such as genetics, molecular biology will shift the paradigm from phenomenology to hypothesis proving.
Many abnormal eye movements are distinctive and point to a specific pathophysiology and anatomical localization. In this lecture a series of video–clip will be shown for audience to illustrate clinical and basic points of the patients with eye movement disorders, hoping these clinical and scientific information useful for their clinical diagnosis of various neurological diseases.
Suspected non–Alzheimer's disease (AD) pathophysiology (SNAP) is a biomarker–based concept that is defined as a condition characterized by normal levels of amyloid–β protein (Aβ) markers (A−), but abnormal neurodegeneration (or neuronal injury) markers (N+). Recent studies indicated that SNAP is found in 17–35% of individuals with mild cognitive impairment (MCI). Similarly, 7–39% of patients with clinically probable AD dementia are negative for Aβ. Progression of cognitive impairment in individuals with SNAP is slower than that in A+N+ subjects with high likelihood of AD pathophysiology. Pathological backgrounds of SNAP are heterogeneous, including non–AD neurodegeneration, cerebrovascular disorders, and mixed pathologies. Non–AD neurodegeneration would include primary age–related tauopathy (PART), which corresponds to senile dementia of the neurofibrillary tangle type (SD–NFT) (tangle–only dementia) at the stage of dementia, and argyrophilic grain disease. Pathogenesis of AD in older people would be more complex than previously recognized, in which widespread Aβ and tau pathologies may be commonly preceded by PART pathology in the medial temporal lobe. Further, current trials of disease–modifying therapies for AD are reviewed. In addition, the author refers to a preventive intervention against dementia/AD with polyphenols under development by his group.
The neurovascular unit (NVU) is a conceptual framework used to better understand the normal physiological interaction between neurons and microvessels as well as the pathophysiology of cerebral ischemia. The major components of the NVU consist of neurons, microvessels, and astrocytes that are interposed between the neuronal synapse and the microvasculature. In addition, other types of glial cells (microglia and oligodendroglia), pericytes, and the extracellular matrix (ECM) play important roles in the neurovascular coupling that enables microvessels to supply adequate glucose and oxygen to neurons when activated. The close proximity of microvessels to astroglial end–feet and the metabolic support of astrocytes for neurons suggest that communication could also be directed from microvessels to the neurons. Regarding alternative energy substrates other than glucose, the highly active astroglial glycolytic pathway provides neurons with lactate as a TCA cycle substrate. In addition, ketone bodies are thought to be generated mainly in astroglia to fuel neurons. The shunt pathway of glycolysis, the pentose–phosphate pathway, plays a pivotal role in the maintenance of NADPH, which that is necessary to protect both neurons and microvessels against reactive oxygen species (ROS). In fact, ROS induces neuronal pyruvate dehydrogenase complex (PDHC) dysfunction and ECM degradation, leading to hemorrhagic transformation after reperfusion. Astrocyte–derived ketone bodies can be utilized by the neuronal TCA cycle even after ischemic insult, since PDHC is not required for their metabolism. The concept of the NVU has expanded our understanding of pathophysiology and aided the development of novel therapeutic strategies against neurodegenerative diseases, neuro–immunological disorders, and stroke.
Human brain MR imaging has made remarkable advances since the 1970s with many improvements in imaging technologies, such as shorter scanning methods and the use of higher magnetic fields.
A quantitative MRI (qMRI) method with QRAPMASTER (quantification method using quantification of relaxation times and proton density by multi–echo acquisition of saturation–recovery using turbo spin–echo readout) pulse sequence, or well known as synthetic MRI (synthetic MR AB, Linköping, Sweden), enables simultaneous quantification of T1 and T2 relaxation rates, and proton density (PD) in a clinically acceptable time. Based on these quantitative values and with dedicated post–processing software, it is possible to obtain any contrast weighted images, such as T1–weighted, T2–weighted and inversion recovery images, automated brain segmentation and myelin measurement. In addition, axon volume fraction and g–ratio can also be estimated by combining this method and neurite orientation dispersion and density imaging (NODDI). Here, we provide an overview of synthetic MRI in brain diseases, such as Sturge–Weber syndrome and multiple sclerosis.
Diffusion MRI has also shown many developments in the last 40 years since its development. One of the advanced diffusion MRI techniques called Oscillating gradient spin–echo (OGSE) was proposed recently. With OGSE it is possible to reduce the diffusion time compare to conventional diffusion MRI technique. Therefore, OGSE has the potential to distinguish between spatial and viscous restriction. In this article, we show the use of OGSE in epidermoid cyst and acute brain infarction cases.
Amyloidosis is a group of disorders characterized by extracellular accumulation of amyloid fibrils derived from various proteins. In systemic amyloidosis, several types, such as hereditary transthyretin (ATTRm) amyloidosis (transthyretin familial amyloid polyneuropathy [ATTR–FAP]), wild–type transthyretin amyloidosis, and amyloid light–chain (AL) amyloidosis, exhibit neurological dysfunction. ATTR–FAP is a common cause of hereditary polyneuropathy worldwide. Thus far, more than 140 mutations in the TTR gene have been identified, and several genotype–phenotype correlations have been reported. For ATTR–FAP, several therapies have been developed in the recent decade. Liver transplantation (LT) reportedly halts the progression of clinical manifestations of ATTR–FAP. In addition to LT, novel disease–modifying drugs for ATTR–FAP, stabilizers of tetrameric TTR, have been developed. Tafamidis can delay disease progression by stabilizing the TTR tetrameric form. Further, gene–silencing therapies, such as small interfering RNA therapy and antisense oligonucleotide therapy, are undergoing clinical trials. Early diagnosis and timely treatment are becoming increasingly important for the management of ATTR–FAP.
Therapeutic approach for acute cerebral ischemia has made great progress in thrombolysis and endovascular approach. In the clinical field, emergent system for acute stroke patients to provide such therapy needs to be rearranged not only in the town but also in the rural area in Japan. However, more than half of patients who suffered acute stroke still need some help in daily life. For future aspect of acute stroke therapy, several promising strategies includes development of novel tissue plasminogen activator, anti–platelet drug, neuroprotective drug, cell therapy and remote limb ischemic conditioning. Collateral circulation is a key factor for determining ischemic severity in the acute stage. Remote ischemic limb condition might show brain protective effect through enhancement of collateral circulation.
Alzheimer's disease (AD), the most common neurodegenerative disorder in the aged, is characterized by the cerebral deposition of fibrils formed by the amyloid β–protein (Aβ), a 40–42 amino acid peptide. The folding of Aβ into neurotoxic oligomeric, protofibrillar, and fibrillar assemblies is hypothesized to be the key pathologic event in AD (Amyloid hypothesis). These facts support the relevance of therapeutic strategies targeting Aβ aggregation. Currently, no disease–modifying therapeutic agents (DMT) are available for AD patients. We summarize here recent efforts to produce DMT targeting Aβ. Conventionally, it has been thought that fibers accumulating as cerebral amyloid exert neurotoxicity, but recently it was reported that dimers extracted from brains of AD patients are the smallest toxic unit of amyloid aggregates, focusing on the study of soluble oligomers (Oligomer hypothesis), AD is called “Oligomeropathy”.
The Japan Stroke Data Bank (http://strokedatabank.ncvc.go.jp) is an ongoing multicenter stroke registry based on a computerized database. It was launched in 1999 supported by the Grant–in–Aid from the Ministry of Health, Labour and Welfare, and thereafter supported by the Japan Stroke Association. In 2015, management of the data bank was transferred to the National Cerebral and Cardiovascular Center as a part of projects for domestic registries of cardiovascular diseases and stroke. In this review, we introduced our systemic review for the literature on stroke registries over the world and outlines of the Japan Stroke Data Bank.
Guillain–Barré Syndrome (GBS) is an acute immune–mediated polyradiculoneuropathy where antibody–mediated complement activation plays an essential role. Randomized Clinical Trials (RCTs) have proved the efficacy of such immunomodulated therapy as plasmapheresis (PP) and intravenous immunoglobulin (IVIg). Outcome of GBS, however, is not as good as might be expected despite application of PP and IVIg. Thirty to forty percent of patients with GBS are intractable to PP or IVIg, 16% of GBS patients are unable to walk independently a year after the onset of GBS, and approximately 40% feel difficulty in walking or running 10 years after the onset of the disease, indicating that part of patients require additional treatments to improve the prognosis. As optional treatments, the second IVIg is considered for patients refractory to the first immunomodulating therapy, and IVIg with combination of intravenous methylprednisolone for patients in whom worse prognosis will be predicted, although the efficacy needs to be proved by RCTs. In addition to modified Erasmus GBS outcome score, delta IgG, and lower levels of serum albumin after IVIg, prognostic models to more precisely predict the clinical course and outcome at the early stage of the disease are required to provide better treatment. In view of the pathophysiology, a new treatment strategy will be developed. A phase 2 trial of eculizumab, a complement C5 inhibitor, was accomplished and it will be applied as an additional treatment in near future.
CIDP (chronic inflammatory demyelinating polyneuritis) is the most common immune–mediated chronic polyneuropathy that comprises typical CIDP (symmetrical demyelinating sensory–motor neuropathy) and several subtypes ; i.e., MADSAM (multifocal acquired demyelinating sensory and motor) neuropathy (Lewis Sumner Syndrome), DADS (distal acquired demyelinating symmetric) neuropathy and multifocal motor neuropathy (MMN). Typical CIDP is usually treated by either intravenous immunoglobulin (IVIg), corticosteroid (CS) or plasma exchange (PLEX). These three therapies are thought as a first line therapy (FLT). Among FLT, IVIg and CS are very often employed because of their simplicity during treatment, however, the efficacy is almost same in three modalities of FLT. If one treatment of FLT failed to lead a good response, other treatment of FLT should be tried. Finally, FLT results in remission in more than 80% of typical CIDP cases. Second line treatment for FLT–resistant cases is still vague although numerous experiences especially about immunosuppressive agents (ISA) have been reported. Among ISA, cyclophosphamide (intravenous pulse) and rituximab seem to be effective although randomized controlled trial is required. IVIg treatment requires maintenance treatment (IVIg every three weeks). Recently efficacy of subcutaneous immunoglobulin treatment (SCIg) in maintenance treatment was proven although it is not approved in Japan. Merit of SCIg is that it can be done by patients in their home. Moreover, SCIg is proven effective as an initial treatment for typical CIDP. This may help patients suffering from CIDP reduce economical, physical or time burden during treatment.
The standard treatment for MADSAM neuropathy is still vague. FLT in typical CIDP should be tried as well. IVIg–responding case needs to adhere maintenance IVIg or SCIg although later is not approved in Japan.
MMN responds to IVIg well, however, delayed diagnosis or treatment results in poor response.
Recently, neuropathy with antibodies against proteins localized in paranode of peripheral nerve is discovered, called as “paranodopathy”.
Most of these cases have IgG4 antibodies against Neurofascin 155, 140, 186, contactin–1, or contactin–associated protein 1 (Caspr). They present unique signs compared to typical CIDP, i.e., relatively rapid progression, remarkable ataxia or tremor. Most of these cases present poor response for IVIg. Rituximab seems to be a hopeful therapeutical candidate in the future although strong evidence is not available at this moment.
Levodopa has been the most efficacious drug for the treatment of motor symptoms in Parkinson's disease. However, its pulsatile stimulation on dopamine receptors causes motor complications such as wearing off phenomenon and dyskinesia. Therefore, in the post–levodopa era therapeutic developments for Parkinson's disease are focused on the concept of “continuous dopaminergic stimulation”. To date, various remedies have been launched. In the present lecture, I explained clinical evidences of recently developed dopaminergic and non–dopaminergic drugs and devices, and introduced desirable strategies against advanced Parkinson's disease recommended in the latest Japanese guideline.
Although dizziness is very common symptom, there are few specific treatments for dizziness. In dizziness of peripheral origin, benign paroxysmal positional vertigo can be treated with otolith repositioning maneuver. Ménière's disease can also be treated specifically although effectiveness is not enough. On the other hand, there have been no specific treatments for the dizziness of central origin. Recently, we indicated that chronic post–lateral medullary infarction dizziness was caused by a cerebellar control disorder of the vestibulo–ocular reflex (VOR). Based on this, we enrolled patients with chronic post–lateral medullary infarction dizziness, applied cerebellar repetitive transcranial magnetic stimulation (rTMS) to improve cerebellar control of VOR, and followed these patients up for up to 25 months for clinical symptoms, signs, and neurophysiological examinations. This study indicated that cerebellar rTMS appeared to be effectual for treatment of chronic post–lateral medullary infarction dizziness. We also successfully treated ocular flutter/opsolconus, which were caused by cerebellar control disorder of the fastigial nucleus, with cerebellar rTMS. Improving cerebellar control of vestibular or deep cerebellar nuclei by cerebellar rTMS may become a forthcoming treatment of dizziness of central origin.
Parkinson disease (PD) is a progressive neurodegenerative disorder. Neuropathological hallmarks of PD are prominent loss of dopaminergic (DA) neurons in the substantia nigra and formation of intraneuronal protein inclusions termed Lewy bodies, composed mainly of α–synuclein (αSyn). PD has serious issues for both patients and clinicians, because this disorder is typically difficult to treat with traditional pharmacological approaches once develop due to the complexicity of the nervous system and physical barriers that limit distribution of medications into the central nervous system after peripheral administration. Patients of this disorder suffer from both symptoms and sequelae in their remaining lifetime. New strategies are progressively developed to overcome the unmet medical needs in conventional therapy. The recent discovery that αSyn can transmit from cell to cell in a prion–like fashion suggests that the therapy to regulate the expression of αSyn such as antibody, vaccine and antisense oligonucleotide might be viable options for PD treatment. On the other hand, mitochondrial dysregulation, such as reduced complex I activity, bioenergetic failure, and perturbation of mitochondrial dynamics and mitophagy, has long been implicated in the pathogenesis of PD. Recently, we found that necdin promoted mitochondrial biogenesis through stabilization of endogenous PGC–1α to exert neuroprotection against mitochondrial insults. Necdin will also be one of candidates of new treatment to delay the progression of PD. I will introduce these new topics for disease–modifying therapies in PD in this review.
Myelin “wraps” around neural axons not only to electrically insulate, but also to metabolically support them. More than 20,000 Japanese patients are suffering from demyelinating diseases of the central nervous system (CNS), including multiple sclerosis (MS) and neuromyelitis optica–spectrum disorders (NMOSD). The etiology of MS remains unknown, and therefore no curative therapy is available at present. Relapses and remissions characterize MS and a number of disease–modifying drugs (DMDs) reducing relapse rate have been developed, six of which are also available in Japan. An appropriate selection of DMD most suitable for individual MS patients is mandatory for the better prognosis. On the other hand, NMOSD cases are mostly caused by pathogenic autoantibodies including anti–aquaporin4 (AQP4) antibodies. Similarly to other autoimmune diseases, the use of systemic steroids or immunosuppressive medicines mainstay as a therapeutic strategy to halt the production of such autoantibodies. In both MS and NMOSD, anti–inflammatory therapies such as intravenous methylprednisolone therapy (IVMP) and plasmapheresis are considered during the acute inflammatory phase. In this article, therapies for MS and NMOSD will be reviewed.
Alzheimer's disease (AD) is a neurodegenerative process that progresses from normal to mild cognitive impairment and from mild cognitive impairment to dementia referred to as AD continuum. Cholinesterase inhibitors and NMDA receptor antagonist can only be used in dementia stage but not in mild cognitive impairment stage. Research communities have presented a hypothesis that amyloid and tau are two major players that contribute to cause neuron death and dementia alone or in combination. In Tohoku University, we have a long experience of developing new biomarkers that help making clinical trials successful. However, it is a great disappointment that all of the clinical trials of disease–modifying drugs (DMDs) were unsuccessful or halted due to lack of clinical benefits or due to incident adverse effects in treated group compared to placebo group. In the most recent clinical trials of amyloid–directed DMDs, only participants with amyloid positivity demonstrated by baseline amyloid PET or decreased cerebrospinal fluid amyloid–β42 were recruited in order to exclude non–AD participants. Such clinical trials with DMDs are currently in progress predominantly in prodromal and preclinical AD, but not in AD dementia. Research communities hope that we are able to stop AD by effective preemptive therapies before symptoms begin. We hope that AD can be preventable disease by 2025.
Autonomic dysfunction presents several symptoms and signs, such as constipation, urinary problems and sweat abnormalities. Fainting (syncope) or swooning (presyncope) is one of the more common autonomic symptoms, and medical staff require to obtain knowledge and skill to manage syncope. Vasovagal syncope and orthostatic hypotension are representative of diseases which can cause syncope. This review will outline the current understanding of diagnosis, pathophysiology and management of vasovagal syncope and orthostatic hypotension for medical staff.
Management of acute ischemic stroke had dramatically changed since 2015 when HERMES collaboration succeed to establish the evidence of acute mechanical thrombectomy (MT). It is required for comprehensive stroke centers to provide MT to patients with emergent large vessel occlusion (ELVO) in addition to rt–PA thrombolysis ＜4.5 hour. The number needed to treat (NNT) for 1 rank improvement on modified Rankin Scale (mRS) score of MT is 2.6, though that of rt–PA is 6.7. Among the candidate of HERMES collaboration, 48% achieved mRS 0–2 at 3 months. This number is reproducible and also is a target for our daily routine practice. We need to blush up pre–hospital transfer and in–hospital triage systems, and create “drip, ship and retrieve” style inter–hospital collaboration with telestroke support.
Acute anti–platelet therapy is chosen for non–cardioembolic ischemic stroke. As shown by CHANCE trial, dual anti–platelet therapy (DAPT) i.e. combination of clopidogrel plus aspirin, is commonly used. However, clopidogrel loading (300mg) is not certified in Japan. Therefore, argatroban hydrate or ozagrel sodium is used in the acute phase.
For cardioemblic stroke, anti–coagulation (A/C) is necessary. When and how to start A/C remains unsolved clinical question. The A/C activity of direct oral anti–coagulants (DOAC) rises rapidly. Thus, it is ideal to start DOAC in the acute stage. Both Italian RAF study (4–14 days) and Japanese RELAXED study (＜14 days) support the validity of acute DOAC therapy.
After the discovery of new class of autoantibodies against neuronal cell surface antigens and synaptic proteins (NSA–antibodies), the concept of encephalitis has dramatically changed. Encephalitis can be divided into infectious and autoimmune (non–infectious) groups. Autoimmune encephalitis (AE) may have autoantibodies against intracellular onconeuronal antigens (e.g. Hu, Yo, Ri, CV2/CRMP5, Ma2, amphiphysin) or NSA (e.g. NMDAR, AMAPAR, GABAaR, GABAbR, DPPX). Most of the former antibodies are not pathogenic but are used as a biomarker of classical paraneoplastic neurological syndromes, whereas IgG NSA–antibodies are more likely pathogenic, and the presence of the antibodies implies that patients may respond to immunotherapy. With infectious etiologies in mind previous diagnostic criteria for encephalitis has been made based on fever, mental status changes, inflammatory CSF, and brain MRI and EEG abnormalities ; however, these abnormalities may not be present in patients with NSA antibody–positive AE. Although early initiation of immunotherapy is often emphasized in AE, antibody testing is not readily accessible in most situation, thus initiation of immunotherapy may be delayed. Therefore, in 2016, a practical diagnostic approach to AE was proposed to achieve prompt immunotherapy at 3 levels of evidence for AE (possible, probable, and definite) with several new diagnostic criteria. A recent study showed that diffuse brain atrophy in anti–NMDAR encephalitis can be reversible and does not imply a poor clinical outcome. In contrast, cerebellar atrophy was irreversible and associated with a poor outcome. First–line immunotherapy can be started depending on the severity of patients with possible AE at early stage while excluding alternative diagnosis, but the second–line immunotherapy should be carefully used after confirming the NMDAR–antibodies in CSF with appropriate testing.
In this lecture, I focus on anti–NMDAR encephalitis and talk about a potential pitfall in clinical diagnosis of the disease.
Peripheral neuropathy is caused by a variety of diseases. Early diagnosis and initiation of treatment is important because irreversible damage may occur. Although careful assessment of the mode of progression, symptoms and signs, blood and cerebrospinal fluid examinations, and electrophysiological studies may lead to diagnosis, nerve biopsy is also useful to determine the underlying diseases in some of the patients with neuropathy. Representative neuropathies are Guillain–Barré syndrome (GBS) and chronic inflammatory demyelinating polyneuropathy (CIDP). The degradation of the myelin sheath by macrophages has been reported in demyelinating form of GBS (i.e., acute inflammatory demyelinating polyneuropathy) and CIDP, and been considered to play an important role in the pathogenesis of these diseases. By contrast, recent studies suggested the association of autoantibodies directed against paranodal junctional proteins, such as anti–neurofascin 155 and anti–contactin 1 antibodies, to subpopulations of CIDP patients. Classical macrophage–induced demyelination is not observed in patients with these antibodies, whereas paranodal axo–glial dissection resulted from attachment of IgG4 antibodies to paranodal junctions plays a pivotal role in the mechanisms of neuropathy. Therefore, there are, at least, two distinct mechanisms that lead to nerve conduction abnormalities from pathological viewpoint. Physicians should take the variability of clinical and pathological findings of neuropathy.
The purposes of the needle EMG examination are as follows ; 1. To identify the origin of the clinically observed weakness : Neurogenic, myopathic or central. 2. To clarify whether the abnormal condition is in the chronic or active phase. 3. To clarify the distribution of the pathologic lesion : regional or systemic. 4. To detect the abnormal condition that cannot be shown without EMG study, such as myotonic discharges in hyper–kalemic periodic paralysis.
The spontaneous activities are divided into two groups ; one originates from muscle fiber potentials, another from motor unit potentials. The muscle fiber origin spontaneous activities include fibrillation potential, positive sharp wave, myotonic discharge and complex repetitive discharge, etc. The motor unit potential origin spontaneous activities are represented as fasciculation potential, myokymic potential, and etc. These potentials or discharges have specific firing patterns and waveforms.
The most important role in the EMG diagnosis is to evaluate firing pattern of the motor unit potentials in the voluntary contraction. The motor unit potentials fire in a “semi-rhythmic” pattern and the onset–firing rate in smallest contraction is 4 to 5Hz. The recruitment–firing rate of 2nd motor unit is usually less than 11Hz. Firing of the single motor unit exceeds 15Hz strongly supports the motor unit loss ; reduced recruitment. The poor activation of motor unit potentials suggests the central weakness. The full interference in apparent weakness suggests the myopathic condition.
Needle EMG can detect the abnormalities objectively, based on the specific firing patterns of spontaneous potentials and MUPs.
I provide comprehensive yet concise commentaries on recent topics regarding risk factors of ischemic stroke, embolic stroke of undetermined source (ESUS), and diagnosis and treatment for aortogenic cerebral embolism.
Parkinson's disease is a neurodegenerative disease showing movement disorders and variable systemic non–motor symptoms. Motor symptoms are manifested by magnification of Lewy pathology into the substantia nigra pars compacta, which induces dopaminergic neuronal loss and dopamine deficiency in the nigro–striatal dopaminergic projection. The activity of daily life and/or social activity can be directly obstructed by the motor deficits. Levodopa replacement therapy is the gold standard in pharmacotherapy in Parkinson's disease. Now a days, dopaminergic agonists, dopamine economizers as well as non–dopaminergic agents are clinically available in Japan. Drug delivery systems are also developed as transdermal and intrajejunal administration in Japan, subcutaneous continuous injection and sublingual film in foreign countries. Most of them are based on the therapeutical strategy of the concept of continuous dopaminergic stimulation. Non–motor symptoms are alternative practical problems in Parkinson's disease, which include sensory problems, autonomic dysfunctions, mood disorders, cognitive dysfunction, and so on. Because non–motor symptoms are variable and uneasy to cure, a medical treatment corresponding to each non–motor problem are required in clinical practice. These can deteriorate patients' quality of life as unmet needs. Practical pharmacotherapy is important against these refractory problems, which should be established on the well–organized communication between physicians and both patients and care givers as well as an advanced adherence.
A new guideline for the diagnosis and treatment of Parkinson's disease (PD) will be launched in 2018. In this symposium, I focused on the clinical diagnosis of PD. Firstly, the new clinical criteria for PD launched by Movement Disorder Society in 2015 was introduced. Then important non–motor symptoms to make a diagnosis of PD, such as REM sleep behavior disorders, olfactory dysfunction, and constipation were explained. Finally, neuroimaging tools including brain MRI, MIBG cardiac scintigraphy, dopamine transporter scintigraphy, brain perfusion scintigraphy, and transcranial sonography were present in detailed. These non–motor symptoms and neuroimaging findings extremely contribute to the clinical diagnosis of PD.
Parkinson disease (PD) is a slowly progressing neurodegenerative disease with typical features such as bradykinesia, resting tremor, and cogwheel rigidity. The pathological hallmarks of PD are marked loss of dopaminergic neurons in the substantia nigra pars compacta (SNc) ; therefore, dopamine replacement therapy improves the motor dysfunction of PD. Although L–dopa is the most effective drug for PD, long term L–dopa treatment is usually associated with motor complications, such as L–dopa–induced dyskinesia and wearing off.
On the other hand, dopamine agonists and MAO–B inhibitors, which are second line drugs for PD, might be associated with little motor fluctuations. However, they have a lesser anti–parkinsonian effect than L–dopa and have many adverse effects, such as sleep disturbance, impulse control disorder, orthostatic hypotension, psychosis, and so on.
In patients with advanced PD, L–dopa–induced motor complications, including dyskinesia and wearing off, are usually associated with impairment of quality of life and activity of daily living. In this article, we reviewed the management of motor dysfunction in PD.
Although Parkinson disease (PD) is generally considered a movement disorder, a majority of PD patients also suffer from non–motor symptoms (NMS) adding to the overall burden of parkinsonian motor symptoms. NMS in PD are numerous and include sleep disturbance (insomnia, excessive daytime sleepiness, sudden onset of sleep, REM sleep behaviour disorders, restless legs syndrome), mood disorders (depression, anxiety, apathy) and fatigue, neuro–psychiatric disturbance (hallucination, delirium, delusion, impulse control disorders, dopamine dysregulation syndrome, cognitive dysfunction, dementia), autonomic dysfunction (orthostatic hypotension, constipation, urinary dysfunction, sexual dysfunction, hyperhydrosis) and sensory disturbance (pain). Despite the high prevalence and associated disability of NMS in PD, many of the NMS may not have effective treatment options. One possible strategy for assisting clinicians in decision–making is the use of evidence–based medicine (EBM) treatment guideline, whose principles allow clinically meaningful conclusions to be drawn from clinical trials, and therefore the comparison of results from these different trials is simplified. The new Japanese “PD clinical guideline 2018” updates the previous PD treatment guideline 2011 and incorporates new data on efficacy, safety, and implications for clinical practice of treatments for NMS of PD published from January 2009 to February 2016. By using the current evidence in the medical literature, EBM helps to provide the best possible care to patients. There is a paucity of research concerning the diagnosis and treatment of NMS in PD. The NMS of PD are frequently missed or undeclared during routine consultations and well–performed large–scale RCTs for the treatment of the different NMS in PD are lacking. A large number of studies indicates that this is a continually changing field and that there is a need for constant updates.
Transthyretin (TTR) is a representative amyloidogenic protein in humans. TTR protein destabilised by TTR gene mutation is prone to dissociate from its native tetramer to monomer, then misfold and aggregate into amyloid fibrils, which results in autosomal dominant hereditary ATTR amyloidosis. Patients with hereditary ATTR amyloidosis show progressive sensorimotor neuropathy, autonomic dysfunction, cardiomyopathy, cerebral amyloid angiopathy, and ocular amyloidosis. In the natural course, patients die 10 to 15 years after the onset due to malnutrition, infection, or cardiac failure. Liver transplantation used to be the only disease modifying therapy for hereditary ATTR amyloidosis, which allows suppression of the main source of variant TTR. However, large numbers of patients are not suitable transplant candidates because of their age and/or advanced disease status. Recently, clinical effects of TTR tetramer stabilisers, tafamidis and diflunisal, were demonstrated in randomized controlled trials, and tafamidis has been approved for the treatment of hereditary ATTR amyloidosis in more the 30 countries. In addition, gene therapies with small interfering RNAs (siRNAs) and antisense oligonucleotides are promising strategies to ameliorate hereditary ATTR amyloidosis. Patisiran is an investigational RNA interference (RNAi) therapeutic agent that binds to a conserved sequence in the TTR messenger RNA in the liver. The results of phase III clinical trial of patisiran was disclosed at the end of 2017, which showed its excellent efficacy and tolerability in hereditary ATTR amyloidosis patients.
Diabetic neuropathy is a common peripheral neuropathy. Glycemic control is most essential to prevent the development of diabetic neuropathy. The presence of hypertension, obesity, smoking and hyperlipidemia may exacerbate diabetic neuropathy. Thus in order to suppress the progression of diabetic neuropathy, it is necessary to strictly control these factors.
Epalerstat, an aldose reductase inhibitor, is only one commercially available drug for the treatment of diabetic neuropathy. However, epalerstat is ineffective cases of severe neuropathy and patients with poor glycemic control. Future availability of new drugs is expected, but development has not been successful thus far.
In the development of new drugs, it is important to detect early abnormalities in diabetic neuropathy. The loss of small fiber in the epidermis is an early pathological change in diabetic neuropathy and this change, as well as skin denervation can be detected by skin biopsy. However, special skills are required for specimen analysis, and only a few laboratories in Japan can analyze skin biopsy specimen. Therefore, the establishment of an easy and efficient method to evaluate abnormalities in the early phases of diabetic neuropathy is very important.
Fabry Disease is an inherited disease with lack of enzyme activity of α–galactosidase and resulted in accumulation of glycolipids including globotriaosylceramide (Gb3) or globotriaosylsphingosine (Lyso–Gb3) in various cell types of organs.
Currently Enzyme Replacement Therapy (ERT) in which α–galactosidase is infused intravenously has been available and there are many reports showing good outcomes including improvement of prognosis or lower the life–threatening event rates.
However, in the cases who already have had advanced cardiac or renal symptoms before starting ERT, those symptoms were deteriorated despite of ERT. It indicates importance of as early intervention as organ damages are not revealed yet and that early diagnosis and early intervention is critical.
Migraine is a most common neurological disease that affects nearly 10% of the general population. However, the pathophysiology of migraine is obscure. Previously, it was believed that the pathophysiology of migraine could be explained entirely by the vascular theory, which is that all symptoms including aura of migraine and headache are caused by abnormal vascular responses. However, many subsequent researches have revealed that it is not possible to explain the symptoms of migraine only by abnormal vascular responses. Instead, functional abnormalities of the neuronal activities observed in the cortical spreading depression are thought to be also involved in the pathophysiology of migraine. Furthermore, it is reported the changes of functional connectivity in cerebral pain matrix system and functional abnormality of descending pain inhibitory system in migraine patients. In addition, it is also believed that the sensitization of the trigeminovascular neurons play an important roles in migraine pathophysiology. The present review discusses the recent findings of migraine pathophysiology.
In migraine patients, trigger factors include sleep loss, oversleeping, stress and climate changes. During the phase of migraine attacks, patients experience various premonitory symptoms, such as neck stiffness, fatigue, decreased concentration, nausea, appetite changes, photophobia and phonophobia, and auras, such as visual, sensory and language symptoms. Involvement of the dopaminergic system and activation of the hypothalamus are likely involved in the premonitory phase. In the aura phase, cortical spreading depression, changes in cortical metabolism, cerebral blood flow and neurovascular coupling have been implicated. In this review, we would like to discuss the role of trigger factors, premonitory symptoms and aura symptoms in the course of migraine attacks and the correlation between these factors and clinical signs of migraine.
Migraine is a chronic, disabling, and recurrent neurological disorder. The guideline published by Japanese Headache Society, based on evidence–based medicine data, is a useful source of guidance, especially for acute and preventive therapies of migraine (Japanese Clinical Practice Guideline for Chronic Headache 2013). At present, migraine therapy can be classed as acute therapy and preventive therapy. In acute therapy, we give migraineurs NSAIDs or triptans for abortive medicines. We have five triptans (sumatriptan, zolmitriptan, eletriptan, rizatriptan, and naratriptan) in Japan. Notably, sumatripotan has three dosage forms (oral tablet, inhalant, and injection). They are used appropriately by the type of migraine attacks. In general, we firstly give an oral tablet. However, when patients have nausea and vomiting, they cannot take oral medicines. At that time, we use inhalant or injection, especially using injection for a severe attack. It's best timing to take a triptan just after the attack to get the most effective treatment. On the other hand, we usually use calcium blockers, anti–epileptic drugs, anti–depressants, and β–blockers for preventive therapy. Among them, lomerizine, verapamil, valproic acid, amitriptyrine, and propranolol have insurance adaptation in Japan. In preventive therapy, you should not change another preventive drug at least two months. Moreover, you should choose appropriate preventive drug with individual patients. As for the trick of acute treatment, we sometimes give a migraineur both triptan and NSAIDs when a migarineur has a severe attack.
Neuromodulation is focused as a new therapy for primary headache disorders.
Non–invasive neuromodulation devices are free from surgical risks and those costs are practical ranges in primary care settings. It is also important most of these devices are self–applicable after the appropriate introductions.
Transcutaneous supraorbital trigeminal neurostimulation (Cefaly) is widely used in Europe and United States, and clinical evidence for migraine management have been accumulated. I demonstrated our preliminary favorable results of Cefaly devices for Japanese migraine sufferers. Non–invasive vagus nerve stimulation (nVNS) has been approved in United States. Single–pulse transcranial magnetic stimulation (sTMS) is also expected to be a new device for chronic pain including migraine headache.
These non–invasive neuromodulation devices will open new avenues on the management of primary headaches including migraine.
Migraine is a common and debilitating neurological disorder. With the advent of triptans, migraine therapy has much improved. Nevertheless, alternative therapy is required to treat those who are intractable to triptans or who have a cardiovascular complication(s). Calcitonin gene–related peptide (CGRP) is abundantly expressed in trigeminal ganglion neurons. Blood CGRP concentrations are increased in some migraine patients, and intravenous administration with CGRP has been shown to induce delayed migraine–like headache attacks almost exclusively in migraineurs. Hence, attempts have been made to develop CGRP–targeted migraine therapy. Initially, an injectable small–molecule CGRP receptor antagonist termed BIBN 4096 BS (Olcegepant) was found to abort migraine attacks. Subsequently, oral CGRP receptor antagonists demonstrated significant efficacy for migraine attacks. However, some of them have been abandoned because of hepatotoxicity. Recently, monoclonal antibodies against CGRP or its receptor have been shown to be effective in migraine prophylaxis with minimal side effects. Moreover, it has been made clear that such antibody therapy is able to ameliorate chronic migraine, which is extremely disabling and generally drug–resistant. In this article, recent advance in CGRP–based migraine therapy and its perspective are discussed.