Distorted time perception in patients with transient global amnesia: time perception task and imaging analysis

Introduction: Transient global amnesia (TGA) is defined as a sudden and transient episode of memory loss and accompanied by temporal disorientation. However, the mechanism by which time distortion occurs is not clearly elucidated yet. Methods: Between March 2019 and November 2020, we subjected 30 TGA patients to several time perception tasks and analyzed their magnetic resonance image (MRI) scans and compared the results with age- and sex-matched control group. Results: Among the 60 recruited subjects (64.5 ± 6.3 years), 70% were women. Fourteen patients had only anterograde amnesia. Furthermore, 46% of the patients with TGA (n = 14) had a history of Valsalva maneuver, and 70% of the patients (n = 21) had a pre-attack stress factor. The MRI scans of 14 patients (46.67%) showed hippocampal hyperintensity. With regard to the time production task, patients with TGA exhibited shorter times in all trials compared with their counterparts (5 s, 4.90 ± 1.16 vs. 5.53 ± 0.87; p value = 0.02: 15 s, 12.18 ± 4.55 vs. 14.42 ± 2.54; p value = 0.021). For the time comparison task, the number of correct answers given by patients with TGA was significantly lesser than that given by the control group (6.07 ± 1.23 vs. 6.90 ± 1.24; p value = 0.006). Conclusions: This is the first study to invesgating an altered time perception in patients with TGA. Although the exact neurophysiological mechanism remains unclear, our findings could aid in the elucidation of brain function across specific time frames.