Incidence of transient global amnesia in the Belluno province, Italy: 1985 through 1995. Results of a community-based study.

INTRODUCTION: We sought to determine the incidence rate of all the new cases of first-ever-in-a-lifetime transient global amnesia in the Belluno province, Italy. Only two prospective epidemiological studies on TGA incidence have been performed to date, non in Italy. Our study aimed to provide reliable and comparable information on TGA incidence.

MATERIAL AND METHODS: We undertook a prospective population-based study in the territory of the province of Bulluno, Italy, between June 1, 1992 and December 31, 1995. We also retrospectively reviewed the clinical records of all the patients with a diagnosis of amnesia seen in the hospitals of the study area from January 1, 1985 through May 31, 1992.

RESULTS: During the prospective study period we identified 77 patients who experienced a first-ever TGA. The crude annual incidence rate was 10.4/100,000 (9.35/100,000 for men and 11.37/100,000 for women). After adjustment to the European population, the incidence rate decreased to 8.60/100,000 per year. The crude annual incidence rate during the retrospective study period was 5.81/100,000. The demographic and clinical features of the two groups did not differ one to the other.

CONCLUSIONS: The incidence rate of first-ever TGA registered in the province of Belluno, Italy, was closely similar to that reported in Turku, Finland and confirms that TGA is more common than has been usually proposed. We emphasize the usefulness of prospective, rather than retrospective, epidemiological studies for research on TGA.