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Electroneurodiagnostic Technologists


The brain constantly discharges small electrical impulses. These signals can be picked up from the surface of the head, amplified, and then recorded on paper or electronic devices. Richard Caton, who used electrodes on the exposed brains of rabbits and monkeys, first detected these currents in England in 1875. The picture of this electrical brain activity, usually called a tracing, became known as an electroencephalogram (EEG).

Other researchers independently studied this phenomenon of brain activity in the late 1800s and early 1900s. In 1929, the first electroencephalograph to be used on human beings was developed by Hans Berger in Germany.

In the mid-1930s, electroencephalograms were developed to diagnose epilepsy. Shortly afterward, they were used to locate brain tumors. By the end of the 1930s, a new field had opened up through which doctors and technicians could better diagnose and treat neurological disorders.

Evoked potentials (EPs), the study of electrical activity in the brain, spinal nerves, or sensory receptors in response to specific types of stimuli, was introduced in 1947. Research regarding this field continued through the 1950s and 1960s. During the 1970s and 1980s, according to the ASET-The Neurodiagnostic Society, evoked potentials were used to "help diagnose multiple sclerosis, to evaluate brain functions, and to evaluate spinal cord sensory pathways." Today, EPs are used in the operating room to monitor patients’ sensory and motor pathways during surgery.

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