Transient Global Amnesia - Prognosis

Prognosis

The prognosis of "pure" TGA is very good. It does not affect mortality or morbidity and unlike earlier understanding of the condition, TGA is not a risk factor for stroke or ischemic disease. Rates of recurrence are variously reported, with one systematic calculation suggesting the rate is under 6% per year. TGA “is universally felt to be a benign condition which requires no further treatment other than reassurance to the patient and their family.” "The most important part of management after diagnosis is looking after the psychological needs of the patient and his or her relatives. Seeing a once competent and healthy partner, sibling or parent become incapable of remembering what was said only a minute ago is very distressing, and hence it is often the relatives who will require reassurance."

TGA may have multiple etiologies and prognoses. Atypical presentations may masquerade as epilepsy and be more properly considered TEA. In addition to such probable TEA cases, some people experiencing amnestic events diverging from the diagnostic criteria articulated above may have a less benign prognosis than those with "pure" TGA.

Recently, moreover, both imaging and neurocognitive testing studies question whether TGA is as benign as has been thought. MRI scans of the brain in one study showed that among people who had experienced TGA, all had cavities in the hippocampus, and these cavities were far more numerous, larger, and more suggestive of pathological damage than in either healthy controls or a large control group of people with tumor or stroke. Verbal and cognitive impairments have been observed days after TGA attacks, of such severity that the researchers estimated the effects would be unlikely to resolve within a short time frame. A large neurocognitive study of patients more than a year after their attacks has shown persistent effects consistent with amnestic mild cognitive impairment (MCI-a) in a third of the people who had experienced TGA. In another study, "selective cognitive dysfunctions after the clinical recovery" were observed, suggesting a prefrontal impairment. These dysfunctions may not be in memory per se but in retrieval, in which speed of access is part of the problem among people who have had TGA and experience ongoing memory problems.