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. 2022 Jan;269(1):361-367.
doi: 10.1007/s00415-021-10639-x. Epub 2021 Jun 8.

Chronobiology of transient global amnesia

Carolin Hoyer #  1 , Kyoko Higashida #  2 , Fabio Fabbian  3 , Alfredo De Giorgi  3 , Vesile Sandikci  1 , Anne Ebert  1 , Michael Platten  1 , Shuhei Okazaki  2 , Roberto Manfredini #  3 , Kristina Szabo #  4
Affiliations

Chronobiology of transient global amnesia

Carolin Hoyer et al. J Neurol. 2022 Jan.

Abstract

Introduction: The etiology of transient global amnesia (TGA) is still a matter of debate. Based, among others, on the observation of a close temporal relation between certain events and subsequent TGA episodes, recent proposals discuss the relevance of stress-associated processes impacting on hippocampal functioning. Circadian, infra- and ultradian rhythmicity has been found to play a relevant role in the multifactorial pathomechanisms of various disorders but has not been thoroughly studied in TGA.

Methods: Data of patients with a final diagnosis of TGA were collected in Mannheim, Germany (06/1999-01/2018, n = 404), and in the Kansai district, Japan (04/2006-03/2018, n = 261). Chronological patterns of TGA occurrence were determined.

Results: Significant circadian rhythmicity of TGA occurrence with bimodal peaks (mid-morning, late afternoon) was found for the entire population (p = 0.002) and for either sub-cohort (Mannheim: p = 0.003, Kansai: p = 0.007). This finding was confirmed for either sex (women: p = 0.004, men: p = 0.004) and different age groups (< 65 years: p = 0.0009, ≥ 65 years: p = 0.003). There was no variation according to day of the week, month or season, but the proportion of patients with a weekday episode was significantly higher in the Mannheim cohort (p = 0.002).

Discussion: We identified a robust circadian rhythm in TGA occurrence which remarkably applied to either of the two study sites located on different continents and which was independent of sex and age. In light of abundant evidence of circadian rhythmicity of both, components of the human stress response system and memory, chronobiological analyses may provide an opportunity to further uncover the mechanisms underlying TGA.

Keywords: Chronobiology; Circadian rhythm; Day-of-week; Infradian rhythm; Season; Transient global amnesia.

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Conflict of interest statement

Not applicable.

Figures

Fig. 1
Fig. 1
Time-of-day distribution in our cohort of 646 transient global amnesia cases from Japan (Kansai district) and Germany (Mannheim) with known time of onset
Fig. 2
Fig. 2
Distribution according to day of the week in our cohort of 665 transient global amnesia cases from Japan (Kansai district) and Germany (Mannheim)
Fig. 3
Fig. 3
Monthly distribution in our cohort of 665 transient global amnesia cases from Japan (Kansai district) and Germany (Mannheim)
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Comment in

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