Cognitive dysfunction during hypoglycemia in an elderly subject without diabetes.

The aim of the present study was to examine whether an elderly subject without diabetes experiences hypoglycemia during his daily life or after an oral glucose tolerance test (OGTT), and investigate whether hypoglycemic episodes affect cognitive function. The 85-year-old healthy subject, who is a sports enthusiast, showed lower than normal (< 80 mg/dl) blood glucose levels on two occasions over 6 days in the early morning. The subject also experienced hypoglycemic episodes and blood glucose levels of 65 and 74 mg/dl, respectively, during the 6-h OGTT given after a 13-h fast. Cognitive function, as assessed using a numeracy test and a driving simulator test, deteriorated during the hypoglycemic episodes but recovered 0.5 h after ingestion of a confectionary product (two pieces of Dorayaki containing 247 kcal and 51.5 g of carbohydrate each). Cognitive dysfunction caused by mild hypoglycemia can be involved in a part of traffic accidents in elderly drivers.