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The Queen’s Medical Center
Neuroscience Institute
Neurodiagnostic Lab
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
Neuroscience Institute

Neuroscience Clinic
Clinical Service Center, 3rd Floor

91-2135 Fort Weaver Road
Ewa Beach, Hawaii 96706


Monday – Friday, 8am – 5pm

» Conditions & Treatments » Neuroscience » Neurodiagnostics

Neurodiagnostic studies assist with evaluation of the electrical activity in the brain and nervous system. Tests are performed by Queen’s Neuroscience Institute technologists. The results are then interpreted by a specially-trained physician.

Electroencephalogram (EEG)

An electroencephalogram, or EEG, records the electrical activity of the brain through highly sensitive electrodes placed at measured intervals on a patient’s scalp. An EEG may be appropriate to evaluate a variety of neurological symptoms, particularly those associated with seizures or epilepsy.

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.

Epilepsy Monitoring Unit (EMU)

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.

24-Hour Ambulatory EEG

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.

Evoked Potential (EP)

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).

  • Auditory: The BAER helps in evaluating the auditory nerve pathways from the ears through the lower portion of the brain. Electrodes are attached to the scalp and earlobes, and earphones are placed over the ears. The earphones deliver a series of clicks or tones to each ear separately.
  • Visual: VEPs evaluate the visual pathways of the nervous system from the eyes to the occipital (visual) cortex of the brain. Electrodes are applied to the scalp, and the patient is asked to focus on a pattern on a video screen while remaining fully alert. Each eye is tested separately.
  • Somatosensory: SSEPs assess pathways from nerves in the arms or legs, through the spinal cord, to the brainstem or cerebral cortex. Electrodes are placed on the scalp, along the spinal cord and along the arms or legs. A small electrical current is then applied to the skin overlying nerves on the arms or legs. The current creates a tingling sensation but is usually not painful. Each arm or leg is tested separately.

Transcranial Doppler (TCD) Ultrasound

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.

For More Information About Neurodiagnostics

To learn more about Neurodiagnostics or to schedule an appointment, please call The Queen’s Neuroscience Institute Neurodiagnostic Lab at 808-691-4218.