Diagnosis of transient global amnesia rests on excluding more-serious conditions — stroke, seizure or head injury, for example — that can cause the same type of memory loss.
The process begins with a neurological exam, checking reflexes, muscle tone, muscle strength, sensory function, gait, posture, coordination and balance. The doctor may also ask questions to test thinking, judgment and memory.
Brain and imaging tests
The next step is to conduct tests that detect abnormalities in the brain's electrical activity and circulation. The most common of these tests are painless and take less than two hours each:
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- Magnetic resonance imaging (MRI). This technique uses a magnetic field and radio waves to create detailed, cross-sectional images of the brain. The MRI machine can combine these slices to produce 3-D images that may be viewed from many different angles.
- Electroencephalogram (EEG). An EEG records the brain's electrical activity via electrodes affixed to the scalp. People with epilepsy often have changes in their brain waves, even when they're not having a seizure.
- Computerized tomography (CT). Using special X-ray equipment, CT machines obtain images from many different angles and join them together to show cross-sectional images of the brain and skull. CT scans can reveal abnormalities in brain structure, including narrowed, overstretched or broken blood vessels and past strokes.
- Davis PH. Transient global amnesia. http://www.uptodate.com/home/index.html. Accessed May 7, 2011.
- Ropper AH, et al. Dementia and the amnesic (Korsakoff) syndrome with comments on the neurology of intelligence and memory. In: Ropper AH, et al. Adams and Victor's Principles of Neurology. 9th ed. New York, N.Y.: The McGraw-Hill Companies. 2009. http://www.accessmedicine.com/content.aspx?aID=3633470. Accessed May 9, 2011.
- Bartsch T. Transient global amnesia: Functional anatomy and clinical applications. The Lancet. 2010;9:205.
- Amnesias. The Merck Manuals: Merck Manual for Healthcare Professionals. http://www.merckmanuals.com/professional/sec16/ch210/ch210c.html. Accessed May 8, 2011.
- Kirshner HS. Approaches to intellectual and memory impairments. In: Bradley WG, et al. Neurology in Clinical Practice. 5th ed. Philadelphia, Pa.: Elsevier. 2008. http://www.mdconsult.com/books/page.do?sid=1157892467&eid=4-u1.0-B978-0-7506-7525-3..50008-X&isbn=978-0-7506-7525-3&uniqId=243694923-5. Accessed May 11, 2011.