EEG is a recording of brainwaves. Using very sensitive external surface leads (no needles), patterns are recorded from your brain, using your own body's electricity. Changes in these patterns may show indications of seizures, tumors, or even sleep disorders. These tests usually take anywhere from 1 to 2 hours total, including the setup and removal of the head leads.
VEPs are usually completed in about 20-30 minutes total. The patient will be asked to take a sitting position in a chair, where the tech will measure and mark the points used to record specific brainwaves. Once marked (using a grease pencil), the tech will prep these points using a skin cleaner meant to take away any oils between the recording electrode and the scalp. A dab of conductive paste will then be added between the scalp and the electrode. Once the signals are coming through, the patient will be asked to look at a screen placed 1 meter in front of their eyes. The screen is about the size of a 19" tv, with a black and white check pattern displayed. The tech will change the size and pattern of the display during the recording to elicit specific waveforms from the brain. Each pattern will be recorded for a certain amount of time before ending the test. Once the test if finished, the tech will then remove the scalp leads, and clean any left over conductive paste with soap and water. There may be a light residue left on some patients, which will come out with regular shampoo and water. After the recording is completed, the VEP will be sent to the ordering physician.
What you can expect during your AEEG
VEP is a recording of specific brainwaves which are transmitted around the back of the patient's head. Using a certain type of pattern on a screen, we are able to evoke those waveforms, and record them. There is a general set of parameters on what a 'healthy' waveform should look like, and seeing deviations from these parameters helps guide the physician to the root any suspected issues.
BAER or ABR (Auditory Brainstem Response), is a test using sound to trigger specific brainwaves that travel from the eardrum to the sensory cortex in the brain. Using an abbreviated EEG recording setup, these signals will be compared with established standards to help locate suspected abnormalities along this pathway along brainstem.
What you can expect during your NCV
What you can expect during your EEG
What you can expect during your BAER/ABR
What you can expect during your VEP
Nerve Conduction studies are done to test and record the strength and speed of signals produced and transmitted through the nerves of the extremities. A tech will place recording electrodes on the skin, and measure the extremity to find the optimal stimulation sites for each specific nerve. They will then use a stimulator wand (and a dab of conductive gel) to elicit reactions for each of the nerves around the area in question. These reactions are recorded, and compiled into a report for the neurologist. Once the NCV is completed, the recording electrodes are removed, and any residue from the conductive gel will be cleaned.
EEGs and other clinical neurodiagnostics are regularly done for both inpatient and outpatient guests. They are used to help the ordering physician determine if and where any abnormalities could be occurring in the brain, spinal cord, or peripheral nerves.
What you can expect during your EMG
BAER/ABR are completed in about 20-30 minutes total. A tech will measure and mark specific points on the patient's head for optimal placement of recording electrodes. These electrodes will be used to record specific signals in the brain. We are able to elicit these specific signals by using certain sounds (clicks) that are played through over-the-ear headphones. The tech will adjust the frequency and volume of these clicks to help ensure the best signals are being recorded. Once a certain amount of signals are recorded, a report will be compiled and compared with 'normal' waveforms. By comparing the size of the waveforms, along with their latencies, the neurologist will be able to see if and where any abnormalities exist along this specific pathway along the brainstem. Once the test if finished, the tech will then remove the scalp leads, and clean any left over conductive paste with soap and water. There may be a light residue left on some patients, which will come out with regular shampoo and water. The report will be sent to the ordering physician.
EMG studies are done to test the actual muscles of the afflicted extremity. After reading the report from the NCV, the neurologist will have a better idea of where to focus the EMG. The neurologist will use a recording probe to directly record signals and irritations coming from the muscle. During this recording process, the patient may be asked to perform simple exercises to elicit reactions from the muscle. These exercises may include pressing down with the hand or foot. This recording will also be compiled into a report, along with the NCV report, before being sent to the referring physician.
EMG/NCV are separate tests, but mostly done in tandem. They are used to help the neurologists determine if the problem is a muscle issue vs a nerve issue. NCV (Nerve Conduction Velocity) is done by a tech, usually before the EMG. Using a stimulator and adhesive recording electrodes, the tech will elicit and record reactions by the major nerves in the afflicted extremities. The EMG is done by a neurologist, who will test the main muscles in the afflicted extremities. Occasionally, the same muscle group on the opposite side may be tested for comparison.
EMG/NCV (Electromyography/Nerve Conduction Velocity)
AEEGs are generally recorded over 48-72 hours, depending on the referring doctor's order. Patients are hooked up to EEG recording electrodes as described above, and may have an added adhesive applied on top of the leads to help ensure they stay in position throughout the duration of recording. Most leads will be wrapped with a layer of soft coban in an extra attempt to keep them in place over the days ahead. These electrodes are plugged into a recording unit, which is placed in a portable bag (about the size of a fanny pack). The tech will give instructions on what to (or not do) during the recording, as this equipment is very sensitive. A 'diary' will be included in these directions, so that the patient can help keep record of events during the AEEG. After the requested recording time is completed, the patient will come back to have the electrodes removed. The tech will then clean off any left over conductive paste on the scalp using soap and water. There may be a light residue left on some patients, which will come out with regular shampoo and water. After the recording is completed, the AEEG will be sent to the reading neurologist to be interpreted. A report will be made, which is then sent to the ordering physician.
An Ambulatory EEG (AEEG) is an EEG that is recorded over several days. The setup is about the same as routine EEGs, but differ in the point that the patient goes home wearing the recording equipment. The patient will come back after 48-72 hours of recording to have the leads removed.
AEEG (Ambulatory EEG)
VEP (Visual Evoked Potentials)
BAER/ABR (Brainstem Auditory Evoked Response)
EEGs are very common neurodiagnostics tests used to help physicians determine a variety of abnormalities or unexplained events. These tests are always the same in that they have 3 parts that every patient will experience. The hookup is the first part, where the tech will measure and mark the patient's head to make sure the leads are placed in the optimal position for the kind of brainwaves needed that the reading neurologists will use. The tech will then prep each point with a skin cleaner meant to take out any oils between the scalp and the electrode. There is a dab of conductive 'paste' that will go between the patient's skin and the electrode to ensure a reliable waveform to the recording equipment. Next is the actual recording of the waveforms. This will generally take 45 minutes and longer. Most of the recording will consist of the patient laying still in a dim room, with their eyes closed. The leads are very sensitive to anything going on in the room, so visitors or family will usually be asked to leave during the actual recording. If possible, the patient is encouraged to try and take a nap, for at least some of the test. Brainwaves change while sleeping, and the reading neurologists really need to get as many views as they can to see the whole picture. Aside from trying to sleep, there are two exercises that are done to help get that full picture of the brainwaves during the recording. Theses are called the activation procedures, and consist of a breathing exercise and photic stimulation. The breathing exercise goes for 3 minutes with an effort of a brisk walk. The photic stimulation is done with a strobe light placed in front of the patient's face (with eyes closed). The light will flash at different frequencies on and off for about 3-4 minutes. After the test is completed, the final step of the EEG is to take the leads off. This part is pretty quick, as it doesn't involve any more measuring or marking. The tech will then clean off any left over conductive paste on the scalp using soap and water. There may be a light residue left on some patients, which will come out with regular shampoo and water. After the recording is completed, the EEG will be sent to the reading neurologist to be interpreted. A report will be made, which is then sent to the ordering physician.
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