|
| |
| Transient Global Amnesia |
| Diagnostic criteria proposed by Caplan, Hodges and Warlow. |
 | An attack must be witnessed by an observer who can provide additional information. |
| Anterograde amnesia must be present. |
| No clouding of consciousness or loss of personal identity (i.e., patients know their
names). |
| Cognitive impairment is limited to amnesia, no apraxia or aphasia |
| No recent history of head trauma, no history of seizures in the preceding 2 years. |
| There are no focal neurologic signs, and no epileptic features. |
|
| Other clinical features |
| Most attack lasts 1 to 8 hours, mean 4.2 hours, rarely longer than a day |
| disoriented to time and place |
| 60% to 90% exhibit repetitive questioning, "Where am I?", which may last
throughout the attack |
| Attentive, can follow complex commands, and do not confabulate |
| Distant memories tend to be preserved |
| Semantic memory (long-term memory responsible for the storage and integrity of knowledge
about the world, including the meaning of words and objects) and Metamemory (the
awareness of what one should know) are usually preserved. |
|
| Precipitating factors |
| physical or emotional stress |
| sexual intercourse |
| driving an automobile |
| swimming in cold water |
|
| Incidence |
| annual incidence of 3.4 to 5.2 per 100,000 each year, 23.5 per 100,000 > 50 yo.
|
| middle-aged or elderly, but otherwise healthy |
| Recurrent attacks < 25% |
| < 3% have more than 3 attacks |
| Intervals between attacks range from 1 month to 19 years. |
| Permanent memory loss is rare, although subtle defects have been reported after only one
attack. |
|
| Differential diagnosis |
| Toxin-induced memory loss
 | Alcohol or benzodiazepines use |
| Tends to be inattentive and unable to sustain a coherent stream of thought. |
|
| Complex partial seizures, postictal state
| absence of repetitive questioning |
|
| Psychogenic amnesia
| younger age |
| known psychiatric stressor |
| more likely to have personality changes |
| does not remember personal identification |
|
|
| Further readings |
|
|
