Neuroscience: Neurology: 

Diagnostic Tests

Evaluating and diagnosing damage to the nervous system is complicated because:

• Similar symptoms can occur in various combinations among neurological disorders, and
• Many of these disorders lack definitive causes, markers or tests.

However, there are several reliable diagnostic tests for nervous system disorders. Following a complete medical history and a thorough physical exam, these may include:

• Neuropsychological evaluation refers to tests of specific brain functions-such as memory, attention span and problem-solving ability.
• Magnetic Resonance Imaging (MRI) is a diagnostic procedure that uses a combination of large magnets, radiofrequencies, and a computer to produce detailed images of the body's organs and structures.
• Computed Tomography Scan (CT or CAT scanning) is a diagnostic imaging procedure comprising a combination of x-rays and computer technology to produce cross-sectional, horizontal and vertical images of the body. CT scans are more detailed than x-rays, but their image resolution is less than MRI images. They show detailed images of any part of the body-including the bones, muscles, fat and organs.
• Electroencephalogram (EEG) is a procedure that records the brain's continuous, electrical activity via electrodes attached to the scalp.
• Positron Emission Tomography (PET) is a nuclear medicine procedure that measures cellular metabolic activity.
• Electromyography (EMG) and Nerve Conduction Velocity (NCV) are electrodiagnostic tests that evaluate and diagnose disorders of the muscles and motor neurons. Electrodes are inserted into the muscle, or placed on the skin overlying a muscle or muscle group, and electrical activity and muscle response are recorded.
• Lumbar Puncture (spinal tap) occurs when a special needle is placed into the lower back, into the spinal canal. This is the area around the spinal cord. The pressure in the spinal canal and brain can then be measured. A small amount of cerebral spinal fluid (CSF) can be removed and tested to determine if there is an infection or other problems. CSF is the fluid that bathes the brain and spinal cord.
• Myelogram is a procedure in which dye is injected into the spinal canal to make that structure clearly visible on x-rays.
• Evoked potentials are procedures that record the brain's electrical response to visual, auditory and sensory stimuli.
• Arteriogram, or angiogram, is an x-ray of the veins and arteries to detect blockage or narrowing of these vessels.
• Neurosonography is a procedure utilizing ultra high-frequency sound waves that enable analysis of blood flow in possible stroke cases.
• Ultrasound, or sonography, is a diagnostic imaging technique which uses high-frequency sound waves and a computer to create images of blood vessels, tissues and organs. Ultrasounds are used to view internal organs as they function, and to assess blood flow through various vessels.