Article Summary Acute Hyperglycemia Alters Mood State and Impairs Cognitive Performance in People With Type 2 Diabetes. Sommerfield AJ, Deary IJ, Frier BM. Diabetes Care. 2004;27:2335-2340. Objective: To assess the effects of acute hyperglycemia on the cognitive function and mood states in a small cohort of people with type 2 diabetes. Methods: Twenty people with type 2 diabetes were recruited from a diabetes outpatient clinic. Baseline characteristics included median age 61.5 years, duration of diabetes 5.9 years, and A1C 7.5% recorded in the prior month. Blood glucose was maintained using a modified hyperinsulinemic glucose clamp at predetermined levels of 81 mg/dL for 30 minutes and 297 mg/dL for 20 minutes, for each study condition. Prior to cognitive testing, blood glucose concentrations were maintained at the predetermined target level for 80 minutes while tests were administered. The 2 sessions were randomized and counterbalanced. Cognitive function tests conducted during each session included assessments of complex visual scanning, psychomotor speed, verbal memory to record immediate and delayed recall, and level of attention. Changes in mood were reflected by a patient checklist to record 3 states: energetic arousal (feeling lively and active versus tired); tense arousal (feeling anxious and nervous versus relaxed); and hedonic tone (feeling happy versus sad). Results of each test were analyzed independently. Results: After controlling for sex, age, A1C levels, and glucose infusion rate, the effects of acute hyperglycemia on cognitive function were significant. In the acute hyperglycemic state, the speed of information processing, working memory, and some aspects of attention was impaired. Results of tests that measured speed of response indicated that accuracy was preserved at the expense of speed. Results of the mood questionnaire showed decreased happiness and alertness and increased agitation. Conclusion: The decrease in cognitive function and alteration in mood state implies that acute hyperglycemia may interfere significantly with activities of daily living and may influence therapeutic strategies for treating hyperglycemia.