Adaptation at cognitive function to hypoglycemia in healthy men

OBJECTIVE - Antecedent hypoglycemia reduces hypoglycemic counterregulation and symptoms, thereby provoking the hypoglycemia unawareness syndrome. The effects of antecedent hypoglycemia on hypoglycemia-induced cognitive dysfun ction are less well established. RESEARCH DESIGN AND METHODS - To determine whether antecedent hypoglycemia also reduces hypoglycemic cognitive dysfunction, we performed stepwise hypo glycemic clamp experiments (4.1, 3.6, 3.1, and 2.6 mmol/l) during a 6-h per iod in 30 young healthy men. A total of 15 subjects additionally received a 2.5-h antecedent hypoglycemic clamp (3.1 mmol/l) on the preceding day (pri or-hypo group), whereas the other 15 subjects did not (control group). Cogn itive function was assessed by auditory-evoked brain potentials (AEBPs) and reaction time during a vigilance task and short-term memory recall. Tests were performed during the stepwise hypoglycemic clamp at baseline and at ea ch hypoglycemic plateau. RESULTS - In both groups, performance on all measures of cognitive function deteriorated during stepwise hypoglycemia (all P < 0.01). However, after a ntecedent hypoglycemia, the hypoglycemia-induced decrease in the amplitude of the P3 of the AEBP was distinctly reduced compared with the control cond ition (P < 0.05). Also, short-term memory performance was less impaired in the prior-hypo group than in the control group (P < 0.005), and a minor hyp oglycemic impairment of reaction time (P < 0.05) was evident in the prior-h ypo group. CONCLUSIONS - Data provide evidence that a single episode of mild anteceden t hypoglycemia (3.1 mmol/l) attenuates several aspects of cognitive dysfunc tion during subsequent hypoglycemia 18-24 h later.