Transient global amnesia (abbreviated TGA) and transient ischemic attack (abbreviated TIA) are two differing entities. TGA is an amnesia characterized by a sudden, acute onset, and complete remission of the amnesic state within 24 hours (give or take...). The pathophysiology is not clear, but has been postulated to involve transient ischemia of subcortical brain structures (e.g., thalamus, medial temporal lobe structures) partial seizures, vasospasm associated with migaine, among other processes. During the TGA episode, the patient may be unaware of their amnesia, able to carry out complex tasks/activities, but unable to form new memories (anterograde amnesia). If queried, a retrograde amnesia may well be evident during the TGA episode (the patient may have a loss of recall for weeks/months preceding the TGA episode). TGA has been noted to occur in conjunction with multiple possible precipitators ( cold showers, intercourse, intense emotion...). Neuropsych testing performed after resolution of the TGA is typically normal. Finally, there is no evidence that folks experiencing TGA are at greater risk than the normal pop. for later occurance of adverse/permanent neurologic events.
Transient ischemic attack (TIA) is simply a term denoting the sudden onset of any focal neurologic dysfunction (not necessarily amnesia) which then resolves within 24 hours (more typically, onset and resolution are quite rapid, occuring in the 5-15 minute range, rather than the multiple hour range). TIAs often involve hemiplegia, hemianesthesia, visual field deficit; the classic stroke-like symptomology. TIAs are an indicator that all is not well, with 5% of individuals experiencing a completed stroke within the next 12 months. TIAs are attributed to atherosclerotic processes with a superimposed acute but transient event affecting the atheroscerotic vasculature. Treatment may be pharmacological (anti-platlet therapy) or neurosurgical (endarterectomy).
Any standard neurology text, text specific to stroke, or clinical neuropsych text could be consulted for more complete info and references...
Hope this helps!
Andrew A. Swihart, Ph.D.
Saginaw Valley State University
[EMAIL PROTECTED] wrote:
This term came up in class during memory unit. Student claims it is a
term for a temporary loss of ability to recall, without any apparent
physical damage. Help!David Griese'
SUNY Farmingdale
