Valley Health Neurodiagnostic Center offers a comprehensive array of testing
services and technology including:
- Neuro Autonomic Tilt Testing
- Long Term Monitoring Evoked Potentials (SSEP, Visual, BAER)
- Specialized Neurodiagnostic Testing (WADA, Intra-operative Monitoring,
Ambulatory EEG, Electrocorticography)
Common Neurodiagnostic Procedures:
Sometimes referred to as the "brain wave test," an EEG records
the electrical activity of the brain. EEGs are performed on patients who
have experienced seizures, epilepsy, passing out, headaches or brain attacks
(strokes). An EEG can also be performed to determine the level of consciousness
of a patient, mental status changes and for determination of brain death.
To perform an EEG, small metal disks are attached with a conductive cream
to the scalp of the patient. The patient is asked to lie quietly for 20-30
minutes while data is being recorded. During the recording, the technologist
will ask the patient to open and close his or her eyes, perform hyperventilation
(breathing faster and deeper than usual), look at a strobe light, and
go to sleep. These procedures enable the technologist to obtain detailed
information for interpretation by the physician. The entire procedure,
including patient set-up, takes approximately two hours. An EEG is also
the basis for long-term monitoring for epilepsy.
This EEG differs from a routine EEG (above) in that the patient wears electrodes
home for up to 48 hours so that more information can be gathered. The
electrodes feed data into a small recorder that gathers information over
the 24-hour period. During an ambulatory EEG, the patient wears electrodes
attached to the scalp to monitor brain waves, and the chest to record
the heart rate. The patient comes back to the hospital for removal of
the electrodes. The data in the recorder is then processed and interpreted
by the physician.
Long-Term Monitoring for Epilepsy (LTME)
Epilepsy patients are observed through the use of an EEG with simultaneous
video monitoring. This is done to document seizure activity over an extended
period of time. The patient is admitted to the hospital to monitor his
or her safety and to observe his or her events. Patients will remain in
Epilepsy Monitoring Unit pending individual needs on a case by case basis.
Evoked Potentials (EP)
The EP provides a measurement of how long it takes an impulse to travel
from a point of stimulation to the brain. There are three modalities,
or types, of EPs: Brainstem Auditory Evoked Response (BAER), Visual Evoked
Response (VER), and Somatosensory Evoked Potentials (SSEP) of the arms
or legs. Evoked potentials are performed to detect and determine the severity
of multiple sclerosis, spinal cord injury or disease, and brainstem injury
or disease. Evoked potentials may also be used to determine brain death.
To perform an EP, small metal disks are attached to the scalp and to various
places along the path of the nerve being tested. The time needed to perform
an EP varies, depending on the modality being done. It can take approximately
two hours, including patient set-up, to perform one type of evoked potential.
When performing multiple modalities, four to six hours may be needed.
Electrocorticography is performed to take recordings directly from the
surface of the brain through special electrodes. This is done to localize
the exact area of abnormal seizure activity arising from the brain.
Intraoperative Monitoring (IOM)
Because surgery involving the nervous system is delicate, neurodiagnostic
modalities can be used to ensure patient safety during surgery. The electrical
activity of the central nervous system is monitored while the patient
is undergoing surgery. The electrical activity from the brain, brainstem,
spinal cord and/or peripheral nerves is recorded, especially when there
may be a risk to vital neurological structures (such as the brain or spinal
cord) during surgery. EEGs, EPs, ECOG and electromyograms (to detect muscle
innervation) are commonly performed during surgical procedures.
For more information on EEGs or other neurodiagnostic tests, call the Valley
Health Neurodiagnostic Center at 540-536-8287. To schedule a test, call
centralized scheduling at 540-536-8988.