Clinical neurophysiology is a medical specialty that studies the central and peripheral nervous systems through the recording of bioelectrical activity, whether spontaneous or stimulated. It encompasses both research regarding the pathophysiology along with clinical methods used to diagnose diseases involving both central and peripheral nervous systems. Examinations in the clinical neurophysiology field are not limited to tests conducted in a laboratory. It is thought of as an extension of a neurologic consultation. Tests that are conducted are concerned with measuring the electrical functions of the brain, spinal cord, and nerves in the limbs and muscles. It can give the precise definition of site, the type and degree of the lesion, along with revealing the abnormalities that are in question. Due to these abilities, clinical neurophysiology is used to mainly help diagnose diseases rather than treat them.[ citation needed ]
In some countries it is a part of neurology or psychiatry, for example the United States [1] and Germany. In other countries it is an autonomous specialty, such as Spain, Portugal, Italy, the United Kingdom, Finland, Sweden and Norway.
Hospitals that have neurologists and neurosurgeons tend to house clinical neurophysiology departments. Usually these tend to be larger hospitals that are able to employ more specialized staff units. In hospitals that possess clinical neurophysiology facilities, the major diagnostic modalities employed include:
The pathway to becoming a clinical neurophysiologist in the U.S. includes completing an undergraduate degree, medical school, and postgraduate medical education, usually in neurology. Following the completion of an accredited residency program, clinicians may choose to enter a fellowship in Clinical Neurophysiology. Programs may expose their fellows to the broad spectrum of electrodiagnostic neurophysiologic studies, or may focus on a single area such as EEG or electrodiagnostic medicine. Clinical neurophysiology fellowships are generally 1–2 years in duration and may lead to board certification in one or more subspecialty areas.[ citation needed ]
There are two healthcare professionals who typically perform neurophysiological investigations in the UK. These are medical staff trained in clinical neurophysiology, and clinical physiologists who undertake four years of practical training whilst undertaking an honours degree. Physiologists perform the majority of EEGs, evoked potentials and a portion of the nerve conduction studies. They are then clinically reported either by the physiology staff or the medical staff. Their professional organisations are the British Society for Clinical Neurophysiology and the Association of Neurophysiological Scientists
Electrodiagnostic medicine is a subset of clinical neurophysiology. Electrodiagnostic medicine focuses only on the peripheral nervous system and not the central nervous system. Whereas a clinical neurophysiologist is trained to perform all the following studies EEG, intraoperative monitoring, nerve conduction studies, EMG and evoked potentials, [3] and electrodiagnostic physician focuses mainly on nerve conduction studies, needle EMG, and evoked potentials. The American Board of Psychiatry and Neurology provides certification examination in clinical neurophysiology. The American Board of Electrodiagnostic Medicine provides certification in EDX medicines. [4] The American Board of Clinical Neurophysiology certifies in electroencephalography (EEG), Evoked Potentials (EP), Polysomnography (PSG), Epilepsy Monitoring, and Neurologic Intraoperative Monitoring (NIOM). [5] In the US physicians typically specialize in EEG or EDX medicine but not both.[ citation needed ]
Hospitals that have neurologists and neurosurgeons tend to house clinical neurophysiology departments. Usually these tend to be larger hospitals that are able to employ more specialized staff units. Clinical neurophysiologists are responsible for analyzing and writing reports on tests that take place within the department. They must also interpret the results that they receive and convey this information to the doctor that referred the patient to the particular neurophysiologist. Many tests involve carrying out an EMG to read the evoked potential recordings. Nerve conduction recordings are extremely common as well.
In neuroscience, an F wave is one of several motor responses which may follow the direct motor response (M) evoked by electrical stimulation of peripheral motor or mixed nerves. F-waves are the second of two late voltage changes observed after stimulation is applied to the skin surface above the distal region of a nerve, in addition to the H-reflex which is a muscle reaction in response to electrical stimulation of innervating sensory fibers. Traversal of F-waves along the entire length of peripheral nerves between the spinal cord and muscle, allows for assessment of motor nerve conduction between distal stimulation sites in the arm and leg, and related motoneurons (MN's) in the cervical and lumbosacral cord. F-waves are able to assess both afferent and efferent loops of the alpha motor neuron in its entirety. As such, various properties of F-wave motor nerve conduction are analyzed in nerve conduction studies (NCS), and often used to assess polyneuropathies, resulting from states of neuronal demyelination and loss of peripheral axonal integrity.
Neuromyotonia (NMT) is a form of peripheral nerve hyperexcitability that causes spontaneous muscular activity resulting from repetitive motor unit action potentials of peripheral origin. NMT along with Morvan's syndrome are the most severe types in the Peripheral Nerve Hyperexciteability spectrum. Example of two more common and less severe syndromes in the spectrum are cramp fasciculation syndrome and benign fasciculation syndrome. NMT can have both hereditary and acquired (non-inherited) forms. The prevalence of NMT is unknown.
Neurology is the branch of medicine dealing with the diagnosis and treatment of all categories of conditions and disease involving the nervous system, which comprises the brain, the spinal cord and the peripheral nerves. Neurological practice relies heavily on the field of neuroscience, the scientific study of the nervous system.
An evoked potential or evoked response is an electrical potential in a specific pattern recorded from a specific part of the nervous system, especially the brain, of a human or other animals following presentation of a stimulus such as a light flash or a pure tone. Different types of potentials result from stimuli of different modalities and types. Evoked potential is distinct from spontaneous potentials as detected by electroencephalography (EEG), electromyography (EMG), or other electrophysiologic recording method. Such potentials are useful for electrodiagnosis and monitoring that include detections of disease and drug-related sensory dysfunction and intraoperative monitoring of sensory pathway integrity.
Electromyography (EMG) is a technique for evaluating and recording the electrical activity produced by skeletal muscles. EMG is performed using an instrument called an electromyograph to produce a record called an electromyogram. An electromyograph detects the electric potential generated by muscle cells when these cells are electrically or neurologically activated. The signals can be analyzed to detect abnormalities, activation level, or recruitment order, or to analyze the biomechanics of human or animal movement. Needle EMG is an electrodiagnostic medicine technique commonly used by neurologists. Surface EMG is a non-medical procedure used to assess muscle activation by several professionals, including physiotherapists, kinesiologists and biomedical engineers. In computer science, EMG is also used as middleware in gesture recognition towards allowing the input of physical action to a computer as a form of human-computer interaction.
Polysomnography (PSG) is a multi-parameter type of sleep study and a diagnostic tool in sleep medicine. The test result is called a polysomnogram, also abbreviated PSG. The name is derived from Greek and Latin roots: the Greek πολύς, the Latin somnus ("sleep"), and the Greek γράφειν.
A nerve conduction study (NCS) is a medical diagnostic test commonly used to evaluate the function, especially the ability of electrical conduction, of the motor and sensory nerves of the human body. These tests may be performed by medical specialists such as clinical neurophysiologists, physical therapists, physiatrists, and neurologists who subspecialize in electrodiagnostic medicine. In the United States, neurologists and physiatrists receive training in electrodiagnostic medicine (performing needle electromyography as part of residency training and in some cases acquire additional expertise during a fellowship in clinical neurophysiology, electrodiagnostic medicine, or neuromuscular medicine. Outside the US, clinical neurophysiologists learn needle EMG and NCS testing.
Intraoperative neurophysiological monitoring (IONM) or intraoperative neuromonitoring is the use of electrophysiological methods such as electroencephalography (EEG), electromyography (EMG), and evoked potentials to monitor the functional integrity of certain neural structures during surgery. The purpose of IONM is to reduce the risk to the patient of iatrogenic damage to the nervous system, and/or to provide functional guidance to the surgeon and anesthesiologist.
In neuroscience, nerve conduction velocity (CV) is the speed at which an electrochemical impulse propagates down a neural pathway. Conduction velocities are affected by a wide array of factors, which include age, sex, and various medical conditions. Studies allow for better diagnoses of various neuropathies, especially demyelinating diseases as these conditions result in reduced or non-existent conduction velocities. CV is an important aspect of nerve conduction studies.
Radiculopathy, also commonly referred to as pinched nerve, refers to a set of conditions in which one or more nerves are affected and do not work properly. Radiculopathy can result in pain, weakness, altered sensation (paresthesia) or difficulty controlling specific muscles. Pinched nerves arise when surrounding bone or tissue, such as cartilage, muscles or tendons, put pressure on the nerve and disrupt its function.
Somatosensory evoked potential is the electrical activity of the brain that results from the stimulation of touch. SEP tests measure that activity and are a useful, noninvasive means of assessing somatosensory system functioning. By combining SEP recordings at different levels of the somatosensory pathways, it is possible to assess the transmission of the afferent volley from the periphery up to the cortex. SEP components include a series of positive and negative deflections that can be elicited by virtually any sensory stimuli. For example, SEPs can be obtained in response to a brief mechanical impact on the fingertip or to air puffs. However, SEPs are most commonly elicited by bipolar transcutaneous electrical stimulation applied on the skin over the trajectory of peripheral nerves of the upper limb or lower limb, and then recorded from the scalp. In general, somatosensory stimuli evoke early cortical components, generated in the contralateral primary somatosensory cortex (S1), related to the processing of the physical stimulus attributes. About 100 ms after stimulus application, additional cortical regions are activated, such as the secondary somatosensory cortex (S2), and the posterior parietal and frontal cortices, marked by a parietal P100 and bilateral frontal N140. SEPs are routinely used in neurology today to confirm and localize sensory abnormalities, to identify silent lesions and to monitor changes during surgical procedures.
Joseph A. Sgro is an American mathematician, neurologist / neurophysiologist, and an engineering technologist / entrepreneur in the field of frame grabbers, high-speed cameras, smart cameras, image processors, computer vision, and machine vision and learning technologies.
The Mischer Neuroscience Institute is a combined research and education effort between the Vivian L. Smith Department of Neurosurgery and the Department of Neurology at McGovern Medical School at UTHealth Houston and Memorial Hermann Hospital. Located in Houston, the Institute draws patients from around the world for specialized treatment of diseases of the brain and spine. It was the first center in Texas and one of only a few institutions in the country to fully integrate neurology, neurosurgery, neuroradiology, neuro-oncology, spine surgery, pain medicine and neurorehabilitation.
Clinical Electrophysiological Testing is based on techniques derived from electrophysiology used for the clinical diagnosis of patients. There are many processes that occur in the body which produce electrical signals that can be detected. Depending on the location and the source of these signals, distinct methods and techniques have been developed to properly target them.
Charles Francis Bolton, is a Canadian professor of neurology at Queen's University in Ontario, Canada. He was first to describe critical illness polyneuropathy in a series of patients.
Electrodiagnosis (EDX) is a method of medical diagnosis that obtains information about diseases by passively recording the electrical activity of body parts or by measuring their response to external electrical stimuli. The most widely used methods of recording spontaneous electrical activity are various forms of electrodiagnostic testing (electrography) such as electrocardiography (ECG), electroencephalography (EEG), and electromyography (EMG). Electrodiagnostic medicine is a medical subspecialty of neurology, clinical neurophysiology, cardiology, and physical medicine and rehabilitation. Electrodiagnostic physicians apply electrophysiologic techniques, including needle electromyography and nerve conduction studies to diagnose, evaluate, and treat people with impairments of the neurologic, neuromuscular, and/or muscular systems. The provision of a quality electrodiagnostic medical evaluation requires extensive scientific knowledge that includes anatomy and physiology of the peripheral nerves and muscles, the physics and biology of the electrical signals generated by muscle and nerve, the instrumentation used to process these signals, and techniques for clinical evaluation of diseases of the peripheral nerves and sensory pathways.
The American Association of Neuromuscular & Electrodiagnostic Medicine (AANEM) is a medical society for the medical subspecialty of neuromuscular and electrodiagnostic medicine based in the United States. Members are primarily neurologists and physiatrists—as well as allied health professionals and PhD researchers.
Michael Jeffrey Aminoff is a clinical neurologist and neurophysiologist whose later clinical work focused on treating Parkinson's disease and related movement disorders. He retired in 2022 and lives in San Francisco, California.
Shin Joong Oh is a South Korean and American physician who is Distinguished Professor of Neurology Emeritus at The University of Alabama at Birmingham in the United States. Oh is a clinician, researcher, and educator known for his contributions to the fields of neurology and electrodiagnostic medicine, particularly electromyography. He retired in 2014.
Zachary London is an American scientist. He is the James W. Albers Collegiate Professor of Neurology at the University of Michigan and program director of the neurology residency at the University of Michigan. He specializes in neuromuscular disease and electromyography. He has been celebrated for his innovative approach to interactive educational tools, and received the American Academy of Neurology A. B. Baker Award for Lifetime Achievement in Neurology Education in 2023.
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