Transient global amnesia

Abstract

Transient global amnesia (TGA) is a memory dysfunction characterized by a sudden onset of dense anterograde amnesia (AA)that gradually resolves across several hours. TGAis typically accompanied by repeated questions (concerning present circumstances) with retrograde amnesia for events preceding the attack, and it usually strikes individuals in their late 50s and early 60s. The etiology of TGA remains unclear, although it probably reflects a temporary disruption of the blood supply to the temporallobe. The physical and psychological events preceding the attack are diverse, but they often include acute emotional and physical stressors. TGA appears to be benign, with low risk for recurrence or residual complications. While systematic memory research on TGApatients is rare, these individuals present a unique opportunity to study amnestic behaviors in otherwise normal individuals. A guide to conducting future research is provided. 401Over the last 4 decades, a considerable literature has accumulated concerning transient global amnesia (TGA). Originally described by Hague (1954; see Haas, 1983), the term TGA was coined by Fisher and Adams (1958) to describe a reversible, short-term (several hour) inability to store and/or retrieve new information most commonly observed in older adults (50-70 years old). Its onset is sudden, and its resolution is gradual. A period of retrograde amnesia (RA) is usually observed, the duration of which is highly variable (hours to years) across individuals and shrinks during the recovery period. TGA victims often ask the same question(s) repeatedly and are generally confused regarding time, place, and circumstances. Despite the inability to retain new information, general intellectual function (reading, writing, speaking, calculation) and selfidentity are preserved, and obvious neurological abnormalities are absent. Oddly, most TGA victims experience only one episode in a lifetime. TGA appears to be unassociated with any obvious physical or psychological disease process or residual disability, contrasting with other memory maladies, such as Alzheimer's dementia, Korsakoff's disease, drug addiction, or hysterical fugue states (Markowitsch, 1995).The primary purpose ofthe present review is to acquaint behavioral researchers with a common malady that is relatively unknown among psychology professionals. Despite a large literature on TGA, the phenomenon is poorly understood, and no consensus has emerged on its psychological or physiological cause. The present literature summary will hopefully allow cognitive, clinical, and healthThe author wishes to extend special thanks to Billie Stovall in the Interlibrary Loan Office of Southern Methodist University for her herculean efforts in procuring hundreds of articles from medical journals at other universities.

Transient Global Amnesia in a 60-year-old female with Post-traumatic Stress Disorder

“…This shows the close association between stress and TGA. Other reported causes include sexual intercourse, migraines, orgasms, emotional stress, swimming, sudden temperature change, and coughing [2-3,7]. There is a report of a TGA triggered by a nightmare [8] which has resemblance with our case report.…”

“…There is also no report linking the emergence of TGA from psychotherapy treatment of PTSD. However, sources identify stress as a key precipitant of TGA [2-6]. The rate of stress-related TGA varies between 14% [4] and 50% [6] of the total TGA.…”

“…In this clinical syndrome, patients demonstrate repetitive questioning due to the inability to encode new memories [1]. This condition is seen mostly in individuals between the ages, 50 to 70 [2] and often resolves within 24 hours [1-2]. Diagnostic criteria include witness of an attack by a capable observer, presence of anterograde amnesia, no loss of personal identity, no neurological symptoms during or after an attack, absence of epileptic features, resolution of TGA within 24 hours, no recent head injury, and no history of seizures or active epilepsy [1].…”

What does transient global amnesia really mean? Review of the literature and thorough study of 142 cases

“…We compared the age distribution of our patients with that of the French population as a whole (INSEE, 1999), using individuals from the 31-85 age bracket to compose a 100% baseline (see Brown, 1998 for the method). When the overall population percentages were subtracted from the percentage of TGA patients, we found that people aged 56--75 have a higher risk of experiencing TGA (see Fig.…”

The dynamic time course of memory recovery in transient global amnesia

“…3 8-10 This neuropsychological variability from case to case may be due to both interindividual differences and the stage of recovery at which the testing is carried out. 11 Few studies have focused on the memory recovery process because of the methodological difficulties arising from the briefness of this disorder. TGA is a short lived syndrome (only a few hours) and neuropsychological investigations rely on specific logistics which notably require the presence of a neurologist and a neuropsychologist at the emergency unit.…”