Advanced Neurophysiology Tests

Northwest Neurological offers patients advanced testing for neurological disorders. We practice the latest techniques and use the most current diagnostic tools to accurately determine causes and develop treatment plans.

For certain patients, specialized assessments are conducted as an extension of the neurological examination. These tests are also available without a corresponding neurological consultation.


Electroencephalography (EEG) is a test used to diagnosed conditions affecting the nervous system. Your doctor may order this test to determine whether there is a neurological cause for symptoms of confusion, lapses of consciousness, convulsive movements, or seizures.

To perform this test a technologist will place electrodes on the scalp. Wires connect the electrodes to a powerful computer that is able to detect very small changes in electrical activity. The activity measured by the EEG is brain activity that occurs beneath the scalp and skull. Through EEG technology, doctors are able to most accurately diagnose the cause of neurological symptoms and determine the best plan of care.

Ambulatory EEG

Ambulatory EEG is very similar to the standard EEG test. For this test an EEG technologist will attach small electrodes to the scalp with glue and then cover the head with a protective bandage to ensure the EEG electrodes stay in place. The EEG is connected to a small carrying case worn close to the body and left in place for three days. The patient is then sent home with the EEG case.

The ambulatory EEG enables doctors to measure a longer amount of brain activity. Where the shorter, routine standard EEG may cover 30 minutes of activity, the ambulatory EEG covers up to three days of activity. By tracing activity over the course of a day in your normal living situation, the test is better able to detect abnormal brain activity so that a doctor can make the most accurate diagnosis.

Another reason your doctor may order an ambulatory EEG is to “capture” abnormal symptoms that may not be present all the time. By pushing a button on the EEG device the symptom is captured along with brain activity at the time of the symptom or episode suspicious for a seizure. On some occasions a patient may be sent home with a small video camera in addition to the EEG machine. This video camera is connected wirelessly to the EEG equipment and may enable your doctor to see the episode that is of  concern and connect this with brain activity.

EMG and Nerve Conduction Study

The Electromyography (EMG) and nerve conduction test is used to diagnosis nerve and muscle disorders. Carpal tunnel syndrome, pinched nerves in the neck, nerve injury, and muscle disease may be causes for weakness and changes in sensation. This test has two parts.

The first part is the nerve conduction study. For this part of the test the nerve is stimulated with a low level of electricity to send a signal down the length of the nerve. This will enable the doctor to measure how fast the signal travels and the strength of the signal. A blockage of the nerve signal may suggest the site for nerve disease.

The EMG is the second part of the test. For this part a small needle the size of an acupuncture needle is inserted just below the surface of the skin. This allows the doctor to look and listen for muscle activity.

By combining the measurement of the nerve signal and muscle activity the doctor can best diagnosis the cause of symptoms and find the right treatment plan.


Video Infra-Red Electronystagmography (VENG) is a very useful test to determine the cause for balance problems and falling. Falls with head injury, aging, and other neurological conditions may result in dizziness. By using a VENG test the doctor is able to look for the cause of your problem. The VENG test involves examination of eye movements and inner ear.

The test may allow the doctor to find the cause of dizziness, balance problems, and falling. Inner ear disorders may respond well to special types of physical therapy. The test may also suggest medication or neurological conditions as causes of walking and balance problems.


Sudoscan is a very sensitive test that allows the doctor to diagnose a type of nerve disease called small fiber neuropathy and problems with the autonomic nervous system. This test uses a very small electrical current to measure the strength of electricity from the sweat in your hands and feet. This test takes about three minutes to administer.

Patients with small fiber neuropathy may experience unexplained pain, numbness, tingling, and extreme sensitivity. Problems with the autonomic nervous system may result in difficulty with lightheadedness, unusual pattern or sensitivity to sweat, problems with erection and bladder control, and constipation. By use of Sudoscan, your doctor may be able to better determine if nerve disease is the cause of these symptoms.


Posturography testing is a good way for your doctor to look for the cause of balance problems. You will be asked to stand on different types of surfaces. The machine will examine your ability to balance with your eyes closed compared to your eyes being open. The measurements will be compared to others without balance problems to determine if you have an abnormal level of balance difficulty. The posturography is a good first step to determine the cause for balance problems.