Amyotrophic lateral sclerosis (ALS) is a rapidly progressive neurodegenerative disorder of the motor neurons in the motor cortex, brainstem, and spinal cord. The clinical phenotype of ALS is underscored by a combination of upper and lower motor neuron dysfunction. Although this phenotype was observed over 100 years ago, the site of ALS onset and the pathophysiological mechanisms underlying the development of motor neuron degeneration remain to be elucidated. Transcranial magnetic stimulation (TMS) enables noninvasive assessment of the functional integrity of the motor cortex and its corticomotoneuronal projections. To date, TMS studies have established cortical dysfunction in ALS, with cortical hyperexcitability being an early feature in sporadic forms of ALS and preceding the clinical onset of familial ALS. Taken together, a central origin of ALS is supported by TMS studies, with an anterograde dying-forward mechanism implicated in ALS pathogenesis. Of further relevance, TMS techniques reliably distinguish ALS from mimic disorders, despite a compatible peripheral disease burden, thereby suggesting a potential diagnostic utility of TMS in ALS. This chapter reviews the mechanisms underlying the generation of TMS parameters utilized in assessment of cortical excitability, the contribution of TMS in enhancing the understanding of ALS pathophysiology, and the potential diagnostic utility of TMS techniques in ALS.
The chief role of the axon is that of impulse conduction, which depends on the electrical cable structure and voltage-dependent ion channels of the axonal membrane. Over recent decades, the development of specialized techniques such as patch clamping and site-directed mutagenesis have established the contribution of neuronal ion channel function to the processes of impulse conduction in myelinated nerves. Recently, these insights from in vitro studies have been translated into the clinical realm. In keeping with this progress, clinical axonal excitability techniques have been developed to provide information related to the activity of a variety of ion channels, energy-dependent pumps, and ion exchange processes activated during impulse conduction in peripheral axons. These noninvasive techniques have been extensively applied to the study of the biophysical properties of human peripheral nerves in vivo and have provided important insights into axonal ion channel function in health and neurological disease, particularly in relation to the pathophysiological mechanisms that underlie neuropathy.
2014 BMA Medical Book Awards Highly Commended in Radiology category! Image-Guided Interventions, a title in the Expert Radiology Series, brings you in-depth and advanced guidance on all of today?s imaging and procedural techniques. Whether you are a seasoned interventionalist or trainee, this single-volume medical reference book offers the up-to-the-minute therapeutic methods necessary to help you formulate the best treatment strategies for your patients. The combined knowledge of radiology experts from around the globe provides a broad range of treatment options and perspectives, equipping you to avoid complications and put today's best approaches to work in your practice. "... the authors and editors have succeeded in providing a book that is both useful, instructive and practical" Reviewed by RAD Magazine, March 2015 Formulate the best treatment plans for your patients with step-by-step instructions on important therapeutic radiology techniques, as well as discussions on equipment, contrast agents, pharmacologic agents, antiplatelet agents, and protocols. Make effective clinical decisions with the help of detailed protocols, classic signs, algorithms, and SIR guidelines. Make optimal use of the latest interventional radiology techniques with new chapters covering ablation involving microwave and irreversible electroporation; aortic endografts with fenestrated grafts and branch fenestrations; thoracic endografting (TEVAR); catheter-based cancer therapies involving drug-eluting beads; sacroiliac joint injections; bipedal lymphangiography; pediatric gastrostomy and gastrojejunostomy; and peripartum hemorrhage. Know what to look for and how to proceed with the aid of over 2,650 state-of-the-art images demonstrating interventional procedures, in addition to full-color illustrations emphasizing key anatomical structures and landmarks. Quickly reference the information you need through a functional organization highlighting indications and contraindications for interventional procedures, as well as tables listing the materials and instruments required for each. Access the fully searchable contents, online-only material, and all of the images online at Expert Consult.
Thank you for visiting our website. Would you like to provide feedback on how we could improve your experience?
This site does not use any third party cookies with one exception — it uses cookies from Google to deliver its services and to analyze traffic.Learn More.