HYPOGLYCEMIA-INDUCED COGNITIVE DYSFUNCTION IN DIABETES-MELLITUS - EFFECT OF HYPOGLYCEMIA UNAWARENESS

Hypoglycemia results in cognitive dysfunction. The aim of this study w as to assess and compare the degree of cognitive dysfunction experienc ed by insulin-dependent diabetic patients (IDDM) with hypoglycemia una wareness with patients with normal awareness of hypoglycemia. Cognitiv e function was examined in 10 patients who had normal awareness of the onset of hypoglycemia and 10 patients who had a history of impaired a wareness of hypoglycemia. A hyperinsulinemic glucose clamp was used to manipulate blood glucose concentrations. Cognitive function was asses sed using Rapid Visual Information Processing (RVIP), Trail Making B ( TMB), Paced Auditory Serial Addition Test (PASAT) and Digit Symbol Sub stitution Test (DSST). Multivariate analysis of variance demonstrated a significant effect of hypoglycemia on cognitive function (p < 0.01). A trend was observed towards an overall effect of awareness on perfor mance (p = 0.08). There were trends in the effects of awareness on RVI P correct responses across time (p = 0.07) and the interaction of awar eness by study by TMB (p = 0.08). During hypoglycemia subjects with im paired awareness were less cautious in their responses (RVIP misses p = 0.03) and on recovery from hypoglycemia, their cognitive function re mained abnormal (TMB p = 0.04, RVIP correct responses p = 0.02, RVIP m isses p = 0.04). Thus, IDDM patients with hypoglycemia unawareness exh ibited more profound cognitive dysfunction during acute hypoglycemia w hich persisted for longer following blood glucose recovery.