EFFECTS OF ACUTE HYPERGLYCEMIA ON MENTAL EFFICIENCY AND COUNTERREGULATORY HORMONES IN ADOLESCENTS WITH INSULIN-DEPENDENT DIABETES-MELLITUS

Objective: To determine whether acute hyperglycemia adversely affects menial efficiency to the same extent as acute mild hypoglycemia. Study design: We administered a battery of cognitive tests to adolescents s tudied at hyperglycemic (20 mmol/L (360 mg/dl)), hypoglycemic (3.3 mmo l/L (60 mg/dl)), or euglycemic (5.5 mmol/L (100 mg/dl)) targets, which were maintained by an insulin-glucose clamp, The study included 36 ch ildren, 9 to 19 years of age (mean = 14.7 years), with diabetes durati on more than 2 years (mean = 6.9 years). Results: Cognitive test perfo rmance did not deteriorate during hyperglycemia, In contrast, there wa s a significant decline in performance on all cognitive tests during m ild hypoglycemia. Autonomic symptoms did not change significantly duri ng hyperglycemia or during the rapid return from hyperglycemia to eugl ycemia. Although significant increments in epinephrine and pancreatic polypeptide levels occurred during mild hypoglycemia, no changes in co unterregulatory hormones occurred during hyperglycemia, An exploratory regression analysis demonstrated that changes in mental efficiency we re best predicted by increases in pancreatic polypeptide, a marker of autonomic activation. Conclusion: These results confirm our previous f inding that mild hypoglycemia causes transient decrements in cognitive function, In contrast, neither hyperglycemia, nor the rapid drop from acute hyperglycemia to euglycemia, affected symptoms, cognitive funct ion, or counterregulatory hormone secretion.