title: Acute hypoglycemia impairs executive cognitive function in adults with and without type 1 diabetes.
abstract: OBJECTIVE
  Acute hypoglycemia impairs cognitive function in several domains. Executive cognitive function governs organization of thoughts, prioritization of tasks, and time management. This study examined the effect of acute hypoglycemia on executive function in adults with and without diabetes.
  
  
  METHODS
  Thirty-two adults with and without type 1 diabetes with no vascular complications or impaired awareness of hypoglycemia were studied. Two hyperinsulinemic glucose clamps were performed at least 2 weeks apart in a single-blind, counterbalanced order, maintaining blood glucose at 4.5 mmol/L (euglycemia) or 2.5 mmol/L (hypoglycemia). Executive functions were assessed with a validated test suite (Delis-Kaplan Executive Function). A general linear model (repeated-measures ANOVA) was used. Glycemic condition (euglycemia or hypoglycemia) was the within-participant factor. Between-participant factors were order of session (euglycemia-hypoglycemia or hypoglycemia-euglycemia), test battery used, and diabetes status (with or without diabetes).
  
  
  RESULTS
  Compared with euglycemia, executive functions (with one exception) were significantly impaired during hypoglycemia; lower test scores were recorded with more time required for completion. Large Cohen d values (>0.8) suggest that hypoglycemia induces decrements in aspects of executive function with large effect sizes. In some tests, the performance of participants with diabetes was more impaired than those without diabetes.
  
  
  CONCLUSIONS
  Executive cognitive function, which is necessary to carry out many everyday activities, is impaired during hypoglycemia in adults with and without type 1 diabetes. This important aspect of cognition has not received previous systematic study with respect to hypoglycemia. The effect size is large in terms of both accuracy and speed.
authors.affiliation: Corresponding author: Alex J. Graveling, alex.graveling@nhs.net.
authors.forename: Alex J
authors.initials: AJ
authors.lastname: Graveling
authors.forename: Ian J
authors.initials: IJ
authors.lastname: Deary
authors.forename: Brian M
authors.initials: BM
authors.lastname: Frier
mesh_terms: D000328:Adult; D001786:Blood Glucose / Q000378:metabolism; D003071:Cognition / Q000502:physiology*; D003922:Diabetes Mellitus, Type 1 / Q000097:blood / Q000503:physiopathology*; D005260:Female; D006801:Humans; D007003:Hypoglycemia / Q000097:blood / Q000150:complications* / Q000503:physiopathology*; D008297:Male
chemical_list: D001786:Blood Glucose