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Neurodiagnostics analyzes and monitors nervous system function to promote the effective treatment of neurological diseases and conditions.
Neurodiagnostic technologists record electrical activity arising from the brain, spinal cord, and peripheral nerves using a variety of techniques and instruments. This involves preparing patients for procedures, obtaining medical histories, recording electrical potentials, calculating results, and maintaining equipment.
Neurodiagnostic technologists are trained to 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.
Some screening tools available at Kadlec include:
Electroencephalogram (EEG) measures and records the electrical activity of the brain and translates that activity into a series of wavy lines. Conditions such as seizures often will demonstrate changes in this electrical activity. The EEG test will likely be ordered to see whether there are any continuing irregularities in the brain’s electrical activity that may be producing seizures.
Normal electrical activity in the brain makes a recognizable pattern. Seizures produce very specific, abnormal patterns. Even without having a seizure, doctors can recognize abnormal patterns that are markers for the risk of seizures.
Having an EEG is a painless, safe procedure.
EEG tests may be given at KNC. Sometimes the person having the test will be told to stay up late the night before and to avoid caffeine drinks on the morning of the test.
Before the test, the EEG technologist applies the small metal disks (called electrodes) to several places on the scalp. A special glue or paste is used to attach the electrode disks. It washes out afterwards. Sometimes a cap with the wires already attached is used instead.
Some EEG tests are made with the patient sitting in a chair; others are performed with the patient lying down on a couch.
During the test, the technologist may ask the patient to breathe deeply through the mouth for a short time, which may produce a slightly dizzy feeling or numbness in the hands or feet, which goes away once breathing returns to normal. The technologist may shine a flashing light into the eyes, or to open and close them rapidly a few times. The patient may be asked to sleep or to make other simple responses, depending on the aims of the test.
The average EEG test may last 35 to 40 minutes; one involving a period of sleep will take longer.
Electromyography (EMG) are tests used to measure muscle and nerve function. They are diagnostic tests used to identify the cause of pain, numbness, tingling, weakness, or atrophy. Examples of conditions that can be diagnosed include neuropathy, carpal tunnel syndrome, and sciatica.
They are in-office procedures and do not require hospitalization. On average, an EMG takes anywhere between 30 minutes and two hours, depending on how extensive a test the doctor orders. It can be done at any time during the day and, with few exceptions, does not require any special preparation.
Few preparations are needed for an EMG. There is no need to fast or eat any particular kinds of food before the test. The patient can drive to and from the test. As for clothing, since in a great majority of cases the low back and buttocks area may need to be studied or in cases of neck problems, the back of the neck and shoulder areas studied, it is best not to wear clothes which will interfere with access to these areas.
With few exceptions, patients may continue taking prescribed medication. However, if the patient is taking a blood thinner, the Lab where your EMG is being done should be notified. Also if patients are on any medication for Myasthenia Gravis such as Mestinon or other, the medication may interfere with the test, so you should also notify the Lab.
During this test, the patient will be lying on an examination table, next to an EMG machine (which looks like a desktop or laptop computer). The test consists of two parts, though at times one may be done without the other. The first part is called Nerve Conduction Studies (see below). When this happens, the patient will feel a tingling sensation that may or may not be painful. Between the brief pulses you will not feel pain.
As there are several nerves in each extremity which need to be tested, the procedure is repeated three or four times or more per extremity studied. The amount of current delivered is always kept at a safe level. Patients wearing pacemakers or other electrical devices need not worry since this current will rarely interfere with such devices.
The second part of the test is called Needle Examination. The needles used are thin, fine and about one and a quarter inches long. This tests the muscle to see if there has been any damage to it as a result of the nerve problem or if the disease involves the muscle itself rather than the nerve. Usually five or six muscles are sampled in one extremity, but occasionally, if you have problems in more than one area, additional muscles may need to be studied.
The needle is usually inserted in the relaxed muscle and moved inside gently in order to record the muscle activity. The painful part of this section is when the needle is first inserted through the skin since all of the pain receptors are located in this area. Once inside the muscle, the sensation is usually perceived as discomfort or pressure rather than pain.
During the needle exam, no electrical pulses are delivered. Also, since the needle probe is used here only as a recording device, no injections are given through the needle into the muscle. On the average, a muscle can be sampled in two to five minutes though this may vary with the type of problem being investigated.
It is common that no sedation is given in any form since in most instances, patients wish to return to work or other regular activity after the test is completed. Another reason for not giving sedation is that patients should always have someone drive him or her home after receiving sedation and this is not always easy to arrange.
Nerve Conduction Studies (NCS) are used to evaluate the electrical conduction of nerves in the body. Examples of conditions that can be diagnosed with NCS include neuropathy, carpal tunnel syndrome, and radiculopathy.
An NCS is done by providing a small electrical pulse to the nerve with a probe on the skin at one site and recording the signal at a different place along the nerve by placing electrodes on the skin. The patient usually experiences a small tingling similar to the feeling when one hits the "funny bone" at the elbow.
Evoked Potentials [EP] are recordings of electrical activity from the brain, spinal nerves, or sensory receptors in response to specific external stimulation. Evoked potentials are helpful in evaluating a number of different neurological problems, including spinal cord injuries, hearing loss, blurred vision and blind spots, acoustic neuroma, and optic neuritis. Evoked potentials are performed using either earphones to stimulate the hearing pathway, a checkerboard pattern on a television screen to stimulate the visual pathway, or a small electrical current to stimulate a nerve in the arm or leg.
We offer testing on all ages of patients both in the hospital and on an outpatient basis. Pediatric EEG interpretations are done in cooperation with Seattle Children's Hospital and Swedish Medical Center. Older children and adult interpretations are done by Kadlec Neuroscience Neurologists.