Other Diagnostic Services
Electroencephalography (EEG)
This is a test of the function of the brain itself. It is to the brain what the EKG is to the heart. During the course of this test, electrical signals are recorded from the brain by means of electrodes placed on the scalp. The patient simply relaxes on a bed. It is a painless test that takes about an hour to complete. Another type of EEG, 24-hour video/EEG monitoring, requires that a patient stay in the hospital while their EEG is recorded over a longer period of time. For those people with questionable epilepsy, this provides a doctor with information regarding the type of epilepsy and hence, the medications used to treat it. It also helps the neurosurgeon in the treatment of epilepsy in those patients who do not respond to medication and who may be a good candidate for surgical treatment. Click here for more information on EEG.
Evoked Response Testing (ERT)
This test determines the function of nerves in the body that are involved with our sensations. The principle behind this test is that if you stimulate a nerve somewhere in the body, the brain should respond to that stimulus. By means of electrodes placed on the scalp, we are able to record the response and see how the nerve is functioning.
Somatosensory Evoked Response (SER)
This test is used to detect diseases that affect the nerves in the arms, legs, spinal cord and brain that are responsible for touch. Electrodes are placed on the arms, legs, back and scalp. While the patient is lying down, the wrists and ankles are stimulated by a small electrical shock.
Brainstem Auditory Evoked Response (BAER)
This test is used to detect diseases that affect the parts of the nervous system that are responsible for hearing. Electrodes are placed on the scalp and the patient responds to clicking noises through headphones while lying down. The ears are tested one at a time.
Visual Evoked Response (VER)
This test is used to detect diseases that affect the parts of the nervous system that are responsible for vision. Electrodes are placed on the scalp and the patient's eyes are stimulated by a red flash. Or the test may be
administered
to the patient while viewing a checker-board of black and white squares.
Electroetinogram (ERG)
This test measures the mass retinal response to a light flash using a Burian Allen Contact Lens (corneal electrode) and a ground electrode placed on the ear. Topical anesthesia drops are used and then the contact lens is placed in the eye in contact with the cornea. The contact lens records the retinal response to a light flash. The procedure is very useful in distinguishing between a variety of retinal disorders such as cone dystrophy, retinitis pigmentosa and other retinal diseases.
Electrooculogram (EOG)
This test measures eye movement and the resting potential of the retina. A pair of electrodes is placed to the left and right side of the eye. When the eye moves, a positive and negative waveform is recorded.
Nerve Conduction Study (NCS)
Nerve conduction studies are used to detect damage to nerves and muscles. Nerve damage may be confined to just one point on a nerve (carpal tunnel syndrome) or may damage nerves throughout the body (peripheral neuropathy). Recording electrodes are placed on the skin over the muscles. Nerves going to muscles are responsible for controlling our strength. Electrodes are also placed over nerves in the skin that allow us to feel. The nerves going to the recording electrodes are stimulated with a small electrical shock. The time it takes for this electrical charge to travel down the nerve to the electrodes is calculated. When the nerve is damaged, the time it takes is longer than normal. Nerve conduction studies can be performed on nerves in the head, arms, legs and trunk. The intensity of shock used for testing may be a little uncomfortable. Pain occurs only at the time of the test and there are no side effects from testing.
Nerve conduction studies are often combined with an electromyographic test. The combined results are used to detect diseases of nerves and muscles that cause pain, weakness and numbness.
Electromyogram (EMG)
An electromyogram (EMG) is a diagnostic test that is used to detect damage to nerves and muscles (muscular dystrophy or Lou Gehrig’s Disease (ALS)). When a muscle is contracted it generates an electrical charge. A small needle is inserted into various muscles of the head, neck, back, arms and legs. This needle acts as a sensor to record changes that are detected by recording electrical charges that are different than normal. The recording needle is not hollow so nothing is injected and no blood is drawn with the needle. There is some pain associated with the insertion of the needle but only temporarily. There should be no pain after the examination.
Transcranial Doppler (TCD)
The transcranial doppler ultrasonography clinical test is used to detect diseases that affect the blood flow in the brain. It is a noninvasive test that uses sound waves to measure the velocity of the blood moving through the arteries in the brain. Ultrasound gel is placed on the head and a transducer (probe) is used to measure the blood velocity. The velocity is recorded through the probe over three places on the head. These are over the temporal areas, the eyelid and the upper neck. The patient lies quietly on their back and only feels the probe being gently moved by the examiner over the head. The signals are recorded, amplified, displayed and interpreted to detect clogged or narrowed arteries in the brain. The test is used to help prevent brain damage.
The transcranial doppler ultrasonography monitoring test is performed the same way as the clinical test. While the patient lies on their back ultrasound gel is placed on each temporal area and a probe is placed over both sides of the head. The probe is held in place by a head band. The velocity of blood in both sides of the brain is recorded for 30 minutes. Two 30 minute recording sessions are required. The patient returns on another day for the second 30 minute recording.
The transcranial doppler ultrasonography monitoring test is used to detect the presence of small particles (microemboli) that are moving in the arteries of the brain. If not detected, these particles may clog or narrow a blood vessel causing brain damage.
|
