The Queen’s Medical Center
Queen Emma Tower (QET)
5th Floor – Ewa
1301 Punchbowl Street
Honolulu, Hawaii 96813
Monday – Friday, 8am – 4:30pm
The Queen’s Medical Center – West Oahu
Clinical Service Center, 3rd Floor
91-2135 Fort Weaver Road
Ewa Beach, Hawaii 96706
Monday – Friday, 8am – 5pm
An electroencephalogram, or EEG, records the electrical activity of the brain through highly sensitive electrodes placed at measured intervals on a patient’s scalp.
What to Expect with EEG Testing
The EEG test usually takes about 90 minutes and is not painful. The principal role of the patient is simply to remain still, relaxed and comfortable.
The head is measured and electrodes are placed on the scalp with a paste-like substance. During the test, the patient may be asked to take repeated deep breaths and will be shown a strobe light that flashes at different speeds. Both activities can help reveal brain patterns that are useful for diagnosis.
At times, physicians may order a sleep-deprived EEG to increase the chances of observing certain brain patterns that occur during sleep. For this test, the patient may be asked to stay awake most of the night before the EEG appointment.
At the Queen’s Punchbowl campus, our dedicated epilepsy monitoring unit allows for specialized video EEG monitoring along with cardiac telemetry monitoring in the hospital setting over a multi-day period. This test is useful in diagnosing seizures, epilepsy, or other conditions, particularly in patients with only intermittent or infrequent symptoms that do not occur every day.
An ambulatory EEG allows for overnight EEG recording in the comfort of your own home, and can provide a prolonged recording to give your epileptologist/neurologist more information about the electrical activity of your brain.
An Evoked Potential study, or EP, is a recording of electrical activity from the brain, spinal nerves or sensory receptors to specific external stimulation.
EPs are helpful in evaluating a wide range of neurological problems, including:
What to Expect with an Evoked Potential Study
Electrodes are applied to the scalp and other areas of the body, commonly the legs and arms. A series of stimuli is introduced, and a computer records the neurological responses. Hundreds of responses are received, amplified and averaged by a computer. The final response is plotted and graphed by computer and interpreted by physicians who analyze the waveforms and their speed of transmission.
There are different types of EP which evaluate different parts of the brain or spinal cord. Common examples include brainstem auditory evoked potential (BAER), visual evoked potential (VEP) and somatosensory evoked potential (SSEP).
Transcranial Doppler ultrasound assesses the blood flow velocity, or the speed at which blood flows, in the major arteries of the brain. The assessment of blood flow velocity helps to decide whether there is a narrowing or blockage in some of the arteries in the brain.
TCD technology is an important noninvasive diagnostic tool used in the Neuroscience Intensive Care Unit for the evaluation of subarachnoid hemorrhage-induced cerebral vasospasm.
What to Expect with Transcranial Doppler Ultrasound
The TCD ultrasound is a painless, noninvasive procedure and takes approximately one hour to complete.
The test is done by using a small probe over the temples. The skull is thin in this area and provides a “window” for the ultrasound beam. The probe is also placed over the eyelids, at the back of the neck and the sides of the neck.
To learn more about Neurodiagnostics or to schedule an appointment, please call The Queen’s Neuroscience Institute Neurodiagnostic Lab at 808-691-4218.