J Clin Neurol.  2016 Oct;12(4):403-406. 10.3988/jcn.2016.12.4.403.

Seasonal Changes in the Incidence of Transient Global Amnesia

• Keret O
• Lev N
• Shochat T
• Steiner I

• KMID: 2385102
• DOI: http://doi.org/10.3988/jcn.2016.12.4.403

Abstract

BACKGROUND AND PURPOSE
Transient global amnesia (TGA) is a stereotypic condition characterized by anterograde and retrograde amnesia that typically resolves within 24 hours. The pathophysiology of TGA is still unclear. We noted that patients hospitalized with TGA tend to appear in seasonal clusters, and decided to investigate this phenomenon.
METHODS
Every patient with acute presentation of amnesia at our medical center is hospitalized for observation and evaluation. We reviewed the monthly occurrence of TGA in our patient population between 2000 and 2014, and compared this to non-TGA hospitalizations during the same time period.
RESULTS
During the analysis period, 154 patients who met the criteria for TGA were hospitalized, as well as 259,007 non-TGA hospitalizations. The annual occurrence of TGA ranged from 5 to 16 hospitalizations. There were 91 TGA events in women and 63 in men, in subjects aged 62.8±10.6 years (mean±SD). The incidence was maximal during December [odds ratio (OR)=2.83, 95% confidence interval (CI)=1.20-6.67] and March (OR=2.77, 95% CI=1.17-6.56), and minimal from April to August. The incidence exhibited an increase followed by a decrease from October to February. A seasonal trend was observed as well, with incidence peaks occurring in winter (OR=1.82, 95% CI=1.12-2.96) and spring (OR=1.80, 95% CI=1.10-2.94).
CONCLUSIONS
Our findings suggest that the incidence of TGA exhibits seasonal variations. This observation may help to improve the understanding of the pathophysiology underlying TGA.

Keyword

transient global amnesia; amnesia; seasonality; incidence

MeSH Terms

Amnesia
Amnesia, Retrograde
Amnesia, Transient Global*
Female
Hospitalization
Humans
Incidence*
Male
Seasons*

Figure

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  Fig. 1 Incidence rate of TGA per month (numbers are in the scale of 10-6). TGA: transient global amnesia.

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  Fig. 2 Incidence rate of TGA per season (numbers are in the scale of 10-6). TGA: transient global amnesia.

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