Clinical diagnostic utility of transcranial magnetic stimulation in neurological disorders. Updated report of an IFCN committee

The review provides a comprehensive update (previous report: Chen R, Cros D, Curra A, Di Lazzaro V, Lefaucheur JP, Magistris MR, et al. The clinical diagnostic utility of transcranial magnetic stimulation: report of an IFCN committee. Clin Neurophysiol 2008;119(3):504–32) on clinical diagnostic utility of transcranial magnetic stimulation (TMS) in neurological diseases. Most TMS measures rely on stimulation of motor cortex and recording of motor evoked potentials. Paired-pulse TMS techniques, incorporating conventional amplitude-based and threshold tracking, have established clinical utility in neurodegenerative, movement, episodic (epilepsy, migraines), chronic pain and functional diseases. Cortical hyperexcitability has emerged as a diagnostic aid in amyotrophic lateral sclerosis. Single-pulse TMS measures are of utility in stroke, and myelopathy even in the absence of radiological changes. Short-latency afferent inhibition, related to central cholinergic transmission, is reduced in Alzheimer’s disease. The triple stimulation technique (TST) may enhance diagnostic utility of conventional TMS measures to detect upper motor neuron involvement. The recording of motor evoked potentials can be used to perform functional mapping of the motor cortex or in preoperative assessment of eloquent brain regions before surgical resection of brain tumors. TMS exhibits utility in assessing lumbosacral/cervical nerve root function, especially in demyelinating neuropathies, and may be of utility in localizing the site of facial nerve palsies. TMS measures also have high sensitivity in detecting subclinical corticospinal lesions in multiple sclerosis. Abnormalities in central motor conduction time or TST correlate with motor impairment and disability in MS. Cerebellar stimulation may detect lesions in the cerebellum or cerebello-dentatothalamo- motor cortical pathways. Combining TMS with electroencephalography, provides a novel method to measure parameters altered in neurological disorders, including cortical excitability, effective connectivity, and response complexity

Intraoperative Monitoring of patients during Neurosurgical Procedures: A Biochemical and Electrophysiological study

Intraoperative electrophysiological monitoring of the nervous system is used to prevent complications arising during the course of neurosurgical procedures. Various electrophysiological monitoring techniques such as EEG (Electroencephalogram), EP (evoked potentials), EMG (Electromyography) and NCV (Nerve conduction velocity) are used during the course of surgery. The principal goal of intraoperative electrophysiological monitoring is prompt identification of nervous system impairment during surgery and prevent permanent postoperative deficits provide relative reassurance to the surgeon that no identifiable complication has been detected up to that point, allowing the surgeon to proceed further and provide a more thorough or careful surgical intervention than would have been provided in the absence of monitoring modify surgical strategy when any change occurs in the recordings. CONCLUSIONS: Our study shows that intraoperative neurophysiologial monitoring needed specific care and attention during the course of surgery to avoid the permanent postoperative neurological deteriorations. The study also concludes that (1) Usage of multipulse stimulation and multiple sweeps of stimulation (0.7Hz) is very effective in eliciting iMEPs. More studies need to be done to understand this phenomenon. (2) Averaging of these responses can used for more consistent responses. (3) Intravenous anaesthesia (propofol) is more ideal than inhalational anaesthesia (isoflurane) for iMEPs. (4) It is important to monitor more than one muscle to predict postoperative outcome. (5) Pain is the main cause for intraoperative hypertension and it is mediated by increased norepinephrine levels in the circulation. (6) Intraoperative maintenance of stable haemodynamics by pre-emptive therapy with lisinopril (angiotensin converting enzyme inhibitor) would be beneficial and prevent the intraoperative associated postoperative neurological complications. This is particularly important if the patient requires intraoperative neurophysiological monitoring

Neurological Manifestations in Rheumatoid Arthritis.

INTRODUCTION : Rheumatoid arthritis (RA) is a chronic multisystem disease of autoimmune aetiology. The characteristic feature is the persistent inflammatory synovitis usually involving peripheral joints in a symmetric distribution. Though it is considered a disease predominantly involving the joints it can cause a variety of extraarticular manifeststions.It can affect skin,eye,cardiovascular ,respiratory and nervous systems and may produce hematological complications including an increase in the risk of Hodgkin’s disease,non Hodgkin’s lymphomas, leukemias independent of the immunosuppressive drugs. One of the important extra articular manifestations is the involvement of nervous system. Neurological manifestations may be due to the involvement of central nervous system involvement, peripheral nervous system or autonomic nervous system. They may be either due to the vascular involvement, direct compression or immune mediated mechanism. It is often difficult to diagnose early neuropathies and the study of the peripheral nervous system is made difficult by symptoms resulting from pain in the joints and limitations of movement. It is nevertheless often possible by means of electroneuromyography to show objectively the existence and distribution of even subclinical neuropathies. AIMS AND OBJECTIVES : 1. To study the various neurological manifestations in patients with rheumatoid arthritis. 2. To assess the subclinical neuropathy using the neurophysiological studies. 3. To correlate neurological involvement with Rheumatoid factor positivity and the DAS 28 score. MATERIALS AND METHODS : Sixty eight consecutive patients (15 males, 53 females) with rheumatoid arthritis who attended the department of rheumatology, Madras Medical College were included as the study population. This a prospective study done during September 2004 -April 2007. Thirty four age and sex matched persons were taken as controls for the autonomic function testing. Inclusion criteria: Patients who fulfilled 1988 revised American Rheumatism Association criteria for rheumatoid arthritis. Exclusion criteria: 1. Age above 60 years, 2). Endocrine and metabolic disorders, 3. Hypertension, 4. Treatment with drugs influencing the adrenergic nervous system, 5. Liver, renal, respiratory and cardiac diseases, 6. Pregnancy, 7. Severe anemia. Methods : All the selected patients were subjected for detailed clinical examination. Hematological evaluation included complete hemogram and peripheral smear study. Biochemical parameters including blood glucose, urea, serum creatinine, liver function tests and fasting lipid profile Immunological evaluation included rheumatoid factor and CRP by latex agglutination method, ANA by Indirect immunofluorescence using the mouse liver substrate and Hep 2 cells if negative by mouse liver substrate Cryoglobulin was tested by preparing the centrifuged serum, keeping it at 40C and reading it after 72 hours. Anticardiolipin antibodies Ig G and Ig M by ELISA and Lupus anticoagulant tests activated partial prothrombin time, dilute Russel viper venom test and Kaolin clotting time were done if appropriate. Radiological evaluation included X-Rays of the hands, feet, and cervical spine AP, lateral flexion and neutral, skull AP open mouth views. CT scan and MR Imaging were done if the patients had neurological signs or symptoms. Nerve conduction study was done for all patients. RESULTS : A total of 68 patients were evaluated. The male, female ratio was1: 3.5, the mean age was 39.5 yrs. Mean duration of the disease was 3.6 yrs. Out of 68 patients 27 (male-3, female-24) patients had neurological symptoms in the form of paraesthesia of the hands and feet, numbness, weakness or radicular pain. Seven patients had signs of neurological involvement on clinical examination. Two patients had quadriparesis due to cord compression. One patient had lateral medullary syndrome. Two patients had absent ankle jerk. Two patients had positive Tinel’s sign due to carpal tunnel syndrome. One patient had rheumatoid nodules, 10 patients had deformities in the form of boutonnier’s deformity in 1, swan neck deformity in 1, finger drop in 1, jaccoud’s arthropathy in 1, hallux valgus in 2,hammer toes in 1, instability of the knees in 2, foot drop in 1. Two patients had quadriparesis due to cord compression. CONCLUSION : There was a female predominance in the patients with neurological manifestations due to rheumatoid arthritis. • Autonomic nervous system dysfunction was the commonest manifestation. • Among the peripheral nerve lesions carpal tunnel syndrome was the commonest lesion. • One patient had subclinical neuropathy. • Cervical myelopathy due to atlantoaxial subluxation alone correlated with the duration of the disease. • Rheumatoid factor positivity was not associated significantly with the CNS and PNS lesions. • Active disease was seen in 66% of patients with central nervous system involvement, 75% of patients with peripheral nervous system involvement and 94% of patients with autonomic dysfunction

Non-invasive electrical and magnetic stimulation of the brain, spinal cord, roots and peripheral nerves: Basic principles and procedures for routine clinical and research application. An updated report from an I.F.C.N. Committee

These guidelines provide an up-date of previous IFCN report on "Non-invasive electrical and magnetic stimulation of the brain, spinal cord and roots: basic principles and procedures for routine clinical application" (Rossini et al., 1994). A new Committee, composed of international experts, some of whom were in the panel of the 1994 "Report", was selected to produce a current state-of-the-art review of non-invasive stimulation both for clinical application and research in neuroscience. Since 1994, the international scientific community has seen a rapid increase in non-invasive brain stimulation in studying cognition, brain-behavior relationship and pathophysiology of various neurologic and psychiatric disorders. New paradigms of stimulation and new techniques have been developed. Furthermore, a large number of studies and clinical trials have demonstrated potential therapeutic applications of non-invasive brain stimulation, especially for TMS. Recent guidelines can be found in the literature covering specific aspects of non-invasive brain stimulation, such as safety (Rossi et al., 2009), methodology (Groppa et al., 2012) and therapeutic applications (Lefaucheur et al., 2014). This up-dated review covers theoretical, physiological and practical aspects of non-invasive stimulation of brain, spinal cord, nerve roots and peripheral nerves in the light of more updated knowledge, and include some recent extensions and developments

Lumbar spinal stenosis: Assessment of cauda equina involvement by electrophysiological recordings

The objective of this study was to investigate the relationship between electrophysiological recordings and clinical as well as radiological findings in patients suggestive to suffer from a lumbar spinal stenosis (LSS). We hypothesise that the electrophysiological recordings, especially SSEP, indicate a lumbar nerve involvement that is complementary to the neurological examination and can provide confirmatory information in less obvious clinical cases. In a prospective cohort study, 54 patients scheduled for surgery due to LSS were enrolled in an unmasked, uncontrolled trial. All patients were assessed by neurological examination, electrophysiological recordings, and magnetic resonance imaging (MRI) of the lumbar spine. The electrophysiological recordings focused on spinal lumbar nerve involvement. Results: About 88% suffered from a multisegmental LSS and 91% of patients respectively complained of chronic lower back pain and/or leg pain for more than 3 months, combined with a restriction in walking distance. The neurological examination revealed only a few patients with sensory and/or motor deficits while 87% of patients showed pathological electrophysiological recordings (abnormal tibial SSEP in 78% of patients, abnormal H-reflex in 52% of patients). Conclusions: Whereas the clinical examination, even in severe LSS, showed no specific sensory-motor deficit, the electrophysiological recordings indicated that the majority of patients had a neurogenic disorder within the lumbar spine. By the pattern of bilateral pathological tibial SSEP and pathological reflexes associated with normal peripheral nerve conduction, LSS can be separated from a demyelinating polyneuropathy and mono-radiculopathy. The applied electrophysiological recordings, especially SSEP, can confirm a neurogenic claudication due to cauda equina involvement and help to differentiate neurogenic from vascular claudication or musculo-skeletal disorders of the lower limbs. Therefore, electro-physiological recordings provide additional information to the neurological examination when the clinical relevance of a radiologically-suspected LSS needs to be confirme

Paresthesia

Paresthesias are spontaneous or evoked abnormal sensations of tingling, burning, pricking, or numbness of a person's skin with no apparent long-term physical effect. Patients generally describe a lancinating or burning pain, often associated with allodynia and hyperalgesia. The manifestation of paresthesia can be transient or chronic. Transient paresthesia can be a symptom of hyperventilation syndrome or a panic attack, and chronic paresthesia can be a result of poor circulation, nerve irritation, neuropathy, or many other conditions and causes. This book is written by authors that are respected in their countries as well as worldwide. Each chapter is written so that everyone can understand, treat and improve the lives of each patient

Management of Degenerative Cervical Myelopathy and Spinal Cord Injury

The present Special Issue is dedicated to presenting current research topics in DCM and SCI in an attempt to bridge gaps in knowledge for both of the two main forms of SCI. The issue consists of fourteen studies, of which the majority were on DCM, the more common pathology, while three studies focused on tSCI. This issue includes two narrative reviews, three systematic reviews and nine original research papers. Areas of research covered include image studies, predictive modeling, prognostic factors, and multiple systemic or narrative reviews on various aspects of these conditions. These articles include the contributions of a diverse group of researchers with various approaches to studying SCI coming from multiple countries, including Canada, Czech Republic, Germany, Poland, Switzerland, United Kingdom, and the United States

Lumbar spinal stenosis: assessment of cauda equina involvement by electrophysiological recordings

The objective of this study was to investigate the relationship between electrophysiological recordings and clinical as well as radiological findings in patients suggestive to suffer from a lumbar spinal stenosis (LSS). We hypothesise that the electrophysiological recordings, especially SSEP, indicate a lumbar nerve involvement that is complementary to the neurological examination and can provide confirmatory information in less obvious clinical cases. In a prospective cohort study, 54 patients scheduled for surgery due to LSS were enrolled in an unmasked, uncontrolled trial. All patients were assessed by neurological examination, electrophysiological recordings, and magnetic resonance imaging (MRI) of the lumbar spine. The electrophysiological recordings focused on spinal lumbar nerve involvement. Results: About 88% suffered from a multisegmental LSS and 91% of patients respectively complained of chronic lower back pain and/or leg pain for more than 3 months, combined with a restriction in walking distance. The neurological examination revealed only a few patients with sensory and/or motor deficits while 87% of patients showed pathological electrophysiological recordings (abnormal tibial SSEP in 78% of patients, abnormal H-reflex in 52% of patients). Conclusions: Whereas the clinical examination, even in severe LSS, showed no specific sensory-motor deficit, the electrophysiological recordings indicated that the majority of patients had a neurogenic disorder within the lumbar spine. By the pattern of bilateral pathological tibial SSEP and pathological reflexes associated with normal peripheral nerve conduction, LSS can be separated from a demyelinating polyneuropathy and mono-radiculopathy. The applied electrophysiological recordings, especially SSEP, can confirm a neurogenic claudication due to cauda equina involvement and help to differentiate neurogenic from vascular claudication or musculo-skeletal disorders of the lower limbs. Therefore, electro-physiological recordings provide additional information to the neurological examination when the clinical relevance of a radiologically-suspected LSS needs to be confirme

The Effects of Filter's Class, Cutoff Frequencies, and Independent Component Analysis on the Amplitude of Somatosensory Evoked Potentials Recorded from Healthy Volunteers

Objective: The aim of this study was to investigate the effects of different preprocessing parameters on the amplitude of median nerve somatosensory evoked potentials (SEPs). Methods: Different combinations of two classes of filters (Finite Impulse Response (FIR) and Infinite Impulse Response (IIR)), three cutoff frequency bands (0.5–1000 Hz, 3–1000 Hz, and 30–1000 Hz), and independent component analysis (ICA) were used to preprocess SEPs recorded from 17 healthy volunteers who participated in two sessions of 1000 stimulations of the right median nerve. N30 amplitude was calculated from frontally placed electrode (F3). Results: The epochs classified as artifacts from SEPs filtered with FIR compared to those filtered with IIR were 1% more using automatic and 140% more using semi-automatic methods (both p < 0.001). There were no differences in N30 amplitudes between FIR and IIR filtered SEPs. The N30 amplitude was significantly lower for SEPs filtered with 30–1000 Hz compared to the bandpass frequencies 0.5–1000 Hz and 3–1000 Hz. The N30 amplitude was significantly reduced when SEPs were cleaned with ICA compared to the SEPs from which non-brain components were not removed using ICA. Conclusion: This study suggests that the preprocessing of SEPs should be done carefully and the neuroscience community should come to a consensus regarding SEP preprocessing guidelines, as the preprocessing parameters can affect the outcomes that may influence the interpretations of results, replicability, and comparison of different studies