title: Frequency and timing of severe hypoglycemia affects spatial memory in children with type 1 diabetes.
abstract: OBJECTIVE
  Repeated severe hypoglycemia has been reported to reduce long-term spatial memory in children with type 1 diabetes. Early exposure to hypoglycemia may be more damaging to cognitive function than later exposure. Our goal was to determine whether the age at which severe hypoglycemia occurs modulates the impact of severe hypoglycemia frequency on long-term spatial memory.
  
  
  METHODS
  We combined data from three independent studies to obtain a sample of children aged 6-18 years with type 1 diabetes (n = 103) and nondiabetic control subjects (n = 60). Each study evaluated previous severe hypoglycemia and tested short (5 s)- and long (60 s)-delay spatial memory with the spatial delayed response task. Type 1 diabetic participants were categorized as having zero, one to two, or three or more severe hypoglycemic episodes and as having their first severe hypoglycemic episode before or after 5 years of age. Information on chronic hyperglycemia (HbA1c values) was also collected.
  
  
  RESULTS
  We found that repeated severe hypoglycemia (more than three episodes) reduced long-delay spatial delayed response performance, particularly when severe hypoglycemic episodes began before the age of 5 years. Age of type 1 diabetes onset and estimates of chronic hyperglycemia did not influence performance.
  
  
  CONCLUSIONS
  High frequency of and early exposure to severe hypoglycemia during development negatively affects spatial long-term memory performance.
authors.affiliation: Department of Psychiatry, Campus Box 8225, 4525 Scott Ave., Washington University School of Medicine, St. Louis, MO 63110, USA. tammy@wustl.edu
authors.forename: Tamara
authors.initials: T
authors.lastname: Hershey
authors.forename: Dana C
authors.initials: DC
authors.lastname: Perantie
authors.forename: Stacie L
authors.initials: SL
authors.lastname: Warren
authors.forename: Emily C
authors.initials: EC
authors.lastname: Zimmerman
authors.forename: Michelle
authors.initials: M
authors.lastname: Sadler
authors.forename: Neil H
authors.initials: NH
authors.lastname: White
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D002908:Chronic Disease; D003072:Cognition Disorders / Q000209:etiology; D003922:Diabetes Mellitus, Type 1 / Q000150:complications*; D004827:Epilepsy / Q000209:etiology; D006801:Humans; D006943:Hyperglycemia / Q000150:complications; D007003:Hypoglycemia / Q000150:complications*; D008569:Memory Disorders / Q000209:etiology*; D012720:Severity of Illness Index; D013028:Space Perception