Episodic Simulation (ES) in Transient Global Amnesia (TGA)
Jessica Decker1, Ezequiel Gleichgerrcht2
1Oregon Health and Sciences University, 2Emory University
Objective:
To report the first case of temporarily impaired episodic simulation in TGA.
Background:

A 72-year-old woman presented with sudden amnesia while visiting her son, where she had stayed for the previous week. Upon awakening one evening, she struggled to recall her location and how she arrived at her son’s house. Her mental status exam showed intact semantic retrograde memory but mildly impaired episodic retrograde memory from one week prior. She exhibited anterograde amnesia while retaining her personal identity. Routine EEG, brain MRI, and MRA head and neck did not reveal significant clinical findings. Symptoms resolved by 24 hours of presentation.

Design/Methods:

Using autobiographical interviewing, the patient was shown a sequence of stock photos and asked to complete a series of tasks during and after symptom attack. The patient was asked to use an imaged to recall a personal event that had occurred in the past 2-3 years and imagine a personal event that might occur in the next 2-3 years (future) in as much specific detail as possible. Narratives were scored for amount of internal (episodic/specific) detail and external (semantic/non-specific) detail and detail subtype. 

Results:

Notably, the patient elicited 8 internal and 7 external details during attack for the future task. After symptom resolution, 15 internal and 3 external details were produced. For past recall, 17 internal and 9 external details were calculated during symptoms. 

Conclusions:

ES is a component of prospective cognition involving the ability to envision a plausible future event. ES is linked to the memory circuit, particularly the hippocampus. ES deficits were observed in a case series of 7 individuals during an attack of TGA, however, simulation capabilities were not assessed post-attack for resolution. We report the first documented case of transiently impaired ES in TGA and reversal of symptoms indicated by nearly double the internal details produced following resolution.

10.1212/WNL.0000000000211186
Disclaimer: Abstracts were not reviewed by Neurology® and do not reflect the views of Neurology® editors or staff.