Diagnositc Tests:

Below is a list of diagnostic tests used to diagnose neurological disorders. To read more information on a specific test please click on the name.

  • CBC (Complete Blood Count)
    Hemoglobin/Hematocrit-used to measure the oxygen carrying capacity of the blood and its thickness. Important in many conditions, especially those that impact cerebral circulation.
  • WBC (White Blood Cell count)
    Especially important in infections, leukemia, and AIDS.
  • Electrolytes
    Sodium and Potassium levels are critical for nervous system function.
  • BUN/Creatinine
    Measure of kidney function. Kidney failure leads to confusion, seizures, coma, tremor and other problems.
  • Glucose
    Too much or too little can cause confusion, seizures, coma. Diabetes is the most common cause of peripheral neuropathy.
  • Magnesium, Calcium
    Important in seizures and muscle problems. Protime/PTT- Measures of blood clotting, especially important in stroke management.
  • ESR (sed rate)
    General measure of inflammation in the body. Especially important in headaches in elderly patients and collagen vascular diseases.
    Diagnoses syphilis and false positives help diagnose collagen vascular disease. Syphilis can cause dementia, nerve and blood vessel damage.
  • ANA/RF
    Helps to diagnose lupus and rheumatoid arthritis which can affect the peripheral nerves and central nervous system.
    Protein and Immune globulin measurements used to rule disorders of white blood cells that lead to nerve damage.
  • Skull X-Ray
    Useful to check for intracranial calcification, midline brain shift, pituitary gland enlargement, and fractures. Largely replaced by CT imaging where available.
  • Cranial Ultrasound
    Used in infants with openings between skull bones to diagnose brain hemorrhage.
  • CT (computerized axial tomography or cat scan)
    A computer generated image from x-rays that is excellent for harder tissues, good for most soft tissues, excellent for fresh blood. Newer techniques available for vessels. Fast but uses ionizing radiation. Best for trauma and subarachnoid hemorrhage.
  • MRI (magnetic resonance imaging)
    Computer generated image based on alignment of molecules in a magnetic field. Excellent for brain and spinal cord. Excellent for soft tissues and white matter diseases. Best for cervical disks and multiple sclerosis. Gives more detail than CT. Takes longer and claustrophobia a problem with closed units. Pacemakers and some metal in the body, especially in the eye, restrict its use. New techniques can image vessels (MRA) and replace invasive angiography.
  • Cerebral Angiography
    Injection of contrast dye directly into arteries after insertion of a catheter followed by x-ray picture. Best for aneurysm and carotid artery blockage. There is a small risk of stroke. MRA and CT may replace this soon.
  • EEG (Electroencephalogram)
    Measures brain waves with safe scalp surface electrodes. Mainly used for analysis of seizure disorders but also useful with dementia and confused, encephalopathic or comatose patients. Main test for brain death.
  • Lumbar Puncture (LP or spinal tap)
    Insertion of a long thin needle into the spinal canal and sample fluid and measure opening pressure. A must if infection is suspected. Also needed if ruptured aneurysm is suspected and CT is normal. Helps diagnose multiple sclerosis and other inflammatory diseases of the central nervous system. CT needed first to rule out a brain mass if suspected.
  • EMG/NCV (Electromyography/Nerve Conduction Velocity)
    Electrodes are placed over nerves and electrical shocks are used to measure nerve conduction speed and delays. Acupuncture like needles are inserted into certain muscles to measure electrical activity and wave formation. Often painful but excellent for diagnosis of muscle and nerve diseases. Risk of bleeding if on anticoagulants. Very useful in localizing pinched cervical and lumbosacral nerve roots.
  • Evoked Potentials
    A measure of nerve conduction time from peripheral to central nervous system from eye, ear, or limbs. Information is gathered about brain and nerve function. Formerly very useful as aid in multiple sclerosis, largely replaced by MRI. Still useful for 8th cranial nerve problems by brain stem auditory evoked potential. Sometimes used to monitor brain function under anesthesia.
  • Carotid Duplex Ultrasound
    Safe test using sonar to generate a picture of carotid arteries in the neck and to estimate blood velocity. Greater than 70% blockage carries a risk of stroke that surgery and/or medicine can reduce.
  • Transcranial Doppler Ultrasound
    Safe test that uses sonar to measure intracranial artery blood velocity. Mainly used to check for spasm after subarachnoid hemorrhage. May be useful for spotting clots to brain and measuring adequacy of collateral cerebral blood flow.
  • Brain mapping
    A computer generated picture of the brain based on EEG activity. Not of proven use clinically at this time.
  • Myelography/CT
    A myelogram is a LP with contrast dye inserted into the spinal canal followed by x-ray to check for blocks especially from disks or tumors. MRI can do this without needles. Myelography followed by CT is the most accurate test for imaging disk herniation.
  • SPECT (Single Photon Emission Computed Tomography)
    Computer generated image based on brain function at time of test. Image produced based on distribution of radioactive tracers injected into blood and pickup by active brain tissue. Reflects blood flow, glucose uptake, receptor binding locally in brain. Mainly of academic interest at this time.
  • PET (Positron Emission Tomography)
    Like SPECT but can check on more than glucose metabolism with various other tracers. Technically more difficult, more expensive, need a particle accelerator on site to make tracers. Promising for certain seizure patients.
  • MRS (Magnetic Resonance Spectroscopy)
    A biochemical measurement of specific brain metabolites with MRI technology that promises to help measure the neuronal number and function. Used in seizure research.
  • Functional MRI
    A new rapid scanning MRI technique that demonstrates alteration in blood oxygenation. Used in seizure research.