A History of Electroneurodiagnostics & the Profession - American Society of Electroneurodiagnostic Technologists, Inc.

A History of Electroneurodiagnostics & the Profession
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A Brief History of Electroneurodiagnostics [END]

In 1929, Hans Berger, M.D., a German psychiatrist, published his findings from performing recordings of the electrical activity of the brain through the intact skull. Dr. Berger was hoping to find an organic basis for psychological phenomena. Instead he stumbled onto a very useful, noninvasive neurodiagnostic procedure, the electroencephalogram [EEG]. In 1934, Dr. Adrian and Brian Matthews confirmed Berger’s findings.

Several groups of EEG pioneers researched, discovered, and demonstrated EEG findings in children, epilepsy, coma, brain pathology, sleep and in normal populations. In the 1950s, EEGs were being performed in major medical centers and filtering into private practices.

Digital EEG recordings have replaced analog, paper recordings. With digital capabilities, EEG data analysis, long-term monitoring, and continuous EEG recordings in the ICU are new arenas.

Evoked potentials [EPs] were first introduced by Dawson in 1947. During the 1960s, there was extensive research about EPs. Throughout the 1970s and 1980s, EPs were used to help diagnose multiple sclerosis, to evaluate brain stem functions and to evaluate spinal cord sensory pathways. In recent years, EPs have found their way into the operating room – intraoperative neuromonitoring [IONM] – monitoring of the integrity of sensory and motor pathways during various spinal, chest, abdominal, and head surgeries.

What is Electroneurodiagnostics?

Electroneurodiagnostic [END] technology is the allied health care profession that analyzes and monitors nervous system function to promote the effective treatment of neuropathological conditions. Technologists record electrical activity arising from the brain, spinal cord, peripheral nerves, somatosensory or motor nerve systems using a variety of techniques and instruments.

Where can I get information about neurological disorders?
A good resource for information is available from the American Academy of Neurology [AAN]. They maintain a list of advocacy groups, as well as patient education literature accessible on-line. Visit www.aan.com/professionals/patient/patient_edu.cfm.

What do electroneurodiagnostic technologists do?
END technologists prepare patients for procedures, obtain medical histories, record electrical potentials, calculate results, maintain equipment, and may work with specific treatments. They develop rapport with patients and comfort them during the recording procedure, which can last from 20 minutes [for a single nerve conduction study] to 8 hours for a sleep study, to multiple days admission for long term monitoring. END technologists understand neurophysiology and recognize normal and abnormal electrical activity. They act as eyes and ears for specially trained doctors who later review and interpret the data. Considerable individual initiative, reasoning skill, and sound judgment are all expected of the electroneurodiagnostic professional.

What kinds of procedures do END technologists perform?
The most common electroneurodiagnostic procedures are the electroencephalogram, intraoperative neuromonitoring, long term monitoring, the polysomnogram, evoked potential studies, and nerve conduction studies. The electroencephalogram [EEG] is the most frequently performed procedure.

The Electroencephalogram [EEG] is a recording of the on-going electrical activity of the brain. An EEG can assist in the diagnosis of a variety of neurological problems - from common headaches and dizziness to seizure disorders, strokes and degenerative brain disease. The EEG is also used to determine organic causes of psychiatric symptoms and disabilities in children and can assist physicians in determining irreversible brain death.

Intraoperative Neuromonitoring [IONM] is conducted on patients undergoing surgery. Patients having surgery on arteries in the neck or around the heart often have EEG monitoring performed during the procedure, providing the surgeon with additional information about brain function. Evoked potentials are sometimes used to assess nerve function during surgical procedures involving the spinal cord or brain.

Long Term Monitoring [LTM] is a prolonged EEG, accompanied by continuous video monitoring, which can record both the clinical events and EEG recording to aid in the diagnosis seizures and other neurological disorders.

The Evoked Potential [EP] is a recording of electrical activity from the brain, spinal nerves, or sensory receptors that occurs in direct response to external stimuli. EP waveforms require sophisticated computer equipment to extract data that will allow physicians to determine the functional state of these pathways. This test is commonly performed by the technologist during surgery on the spine to help the surgeon make sure nerves are not damaged during the operation. Evoked Potentials are also performed in a clinical END laboratory, using either earphones to stimulate the hearing pathway, a checkerboard pattern on a T.V. screen to stimulate the visual pathway, or a small electrical current to stimulate a nerve in the arm or leg.

The Polysomnogram [PSG] is a special electroneurodiagnostic procedure that uses EEG and other physiologic monitors to evaluate sleep and sleep disorders. Physicians use Sleep tests to identify dysfunction in sleep/wake cycles, to diagnose breathing disorders during sleep, and to evaluate treatment of these disorders.

Nerve Conduction Studies [NCS] evaluate electrical potentials from peripheral nerves. Technologists stimulate the nerve with an electrical current and then record how long it takes the nerve impulse to reach the muscle.