Transient Global Amnesia (TGA) and Migraine
Transient global amnesia (TGA) is one of the most mysterious clinical conditions in Neurology. Occurring usually only once in middle to late age, the affected person is suddenly robbed of memory, for the past, the present, and briefly, the future. Repetitive questioning without learning the answers supplied marks the typical case and frightened family members and significant others labor to bring the patient into hospital for scanning and medical evaluation. Although the cut off time for duration is 24 hours, most cases clear in 4-6 hours, with no memory of what happened during the elapsed time.
TGA is commonly found with migraine and migraine's spreading wave of depolarization sweeping across the hippocampus may be the cause of the syndrome. I have reviewed the 2 existing textbooks on TGA, the last of which was published in 1991 plus 554 articles from the rich troth of medical literature. I review the early history of amnesia and early articles in the psychiatric literature leading up to Bender's seminal article in 1955. I divided the subject into clinical, EEG, CAT scan, SPECT, PET, sonogram and MRI papers and then discussed the literature on associated medical conditions, review articles, and aetiology, ending with a chapter on clinical work up and treatment. In total the book is 306 pages and 10 chapters. This book is an extensive review of the subject with 554 bibliography references and 45 digital images written especially for the clinical behavioral neurologist, psychiatrist, or psychologist. It is the first modern review of the subject in 21 years and it discusses the exciting DWI/MRI findings which have set the neurology world on fire. No recent article or text has reviewed transient global amnesia in such detail as this book. This same painstaking and elaborate literature review style is evidenced throughout the book, placing into one compendium a body of data and references on TGA not available anywhere else.
The presented MRI scan shows one of the mysterious dots in the hippocampus at the end or the arrow that occurs a day or 2 after an attack of TGA that then disappears later.