title: Cognitive function is disrupted by both hypo- and hyperglycemia in school-aged children with type 1 diabetes: a field study.
abstract: OBJECTIVE
  We developed a field procedure using personal digital assistant (PDA) technology to test the hypothesis that naturally occurring episodes of hypo- and hyperglycemia are associated with deterioration in cognitive function in children with type 1 diabetes.
  
  
  METHODS
  A total of 61 children aged 6-11 years with type 1 diabetes received a PDA programmed with two brief cognitive tests (mental math and choice reaction time), which they completed just before home glucose readings. The computer recorded time to complete each test and number of correct responses. Children completed several trials per day over 4-6 weeks for a total of 70 trials. Performance variables were compared across glucose ranges. Individual impairment scores (IISs) were also computed for each child by calculating the SD between performance during euglycemia and that during glucose extremes.
  
  
  RESULTS
  Time to complete both mental math and reaction time was significantly longer during hypoglycemia. During hyperglycemia, time to complete math was significantly longer and reaction time was marginally significant (P = 0.053). There were no differences on task accuracy. Decline in mental math performance was equivalent at glucose levels <3.0 and >22.2 mmol/l. IISs varied greatly across children, with no age or sex differences.
  
  
  CONCLUSIONS
  A decrease in mental efficiency occurs with naturally occurring hypo- and hyperglycemic glucose fluctuations in children with type 1 diabetes, and this effect can be detected with a field procedure using PDA technology. With blood glucose levels >22.2 mmol/l, cognitive deterioration equals that associated with significant hypoglycemia.
authors.affiliation: Behavioral Medicine Center, Department of Psychiatry and Neurobehavioral Sciences, University of Virginia Health Sciences Center, Charlottesville, Virgina, USA. Linda Gonder-Frederick, lag3g@virginia.edu
authors.forename: Linda A
authors.initials: LA
authors.lastname: Gonder-Frederick
authors.forename: John F
authors.initials: JF
authors.lastname: Zrebiec
authors.forename: Andrea U
authors.initials: AU
authors.lastname: Bauchowitz
authors.forename: Lee M
authors.initials: LM
authors.lastname: Ritterband
authors.forename: Joshua C
authors.initials: JC
authors.lastname: Magee
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Cox
authors.forename: William L
authors.initials: WL
authors.lastname: Clarke