Vascular studies are a noninvasive (the skin is not pierced) procedure used to assess the blood flow in arteries and veins. A transducer (like a microphone) sends out ultrasonic sound waves at a frequency too high to be heard. When the transducer is placed on the skin at certain locations and angles,
A carotid artery duplex scan is a type of vascular ultrasound study done to assess the blood flow of the arteries that supply blood from the heart through the neck to the brain. There are four carotid arteries – the right and left internal carotid arteries and the right and left external carotid arteries.
Nerve conduction velocity (NCV) test is a measurement of the speed of conduction of an electrical impulse through a nerve. NCV can determine nerve damage and destruction.
During the test, the nerve is stimulated, usually with surface electrode patches attached to the skin. Two electrodes are placed on the skin over the nerve.
(Evoked Brain Potentials, Evoked Responses, Visual Evoked Response [VER], Brainstem Auditory Evoked Response [ABER], Somatosensory Evoked Response [SER])
Evoked potentials studies measure electrical activity in the brain in response to stimulation of sight, sound, or touch. Stimuli delivered to the brain through each of these senses evoke minute electrical signals.
Electromyography, or EMG, is used to diagnose nerve and muscle dysfunction and spinal cord disease. It records the electrical activity from the brain and/or spinal cord to a peripheral nerve root (found in the arms and legs) that controls muscles during contraction and at rest.
During an EMG, very fine wire electrodes are inserted into a muscle to assess changes in electrical voltage that occur during movement and when the muscle is at rest.
Electroencephalography, or EEG, monitors brain activity through the skull. EEG is used to help diagnose certain seizure disorders, brain tumors, brain damage from head injuries, inflammation of the brain and/or spinal cord, alcoholism, certain psychiatric disorders, and metabolic and degenerative disorders that affect the brain. EEGs are also used to evaluate sleep disorders, monitor brain activity when a patient has been fully anesthetized or loses consciousness,
