The effects of acute insulin-induced hypoglycemia on spatial abilities in adults with type 1 diabetes

  1. Rohana J Wright, MRCP#,
  2. Brian M Frier, MD# and
  3. Ian J Deary, PhD (i.j.deary{at}*
  1. #Department of Diabetes, Royal Infirmary of Edinburgh, UK
  2. * Department of Psychology, University of Edinburgh, UK
  3. † Centre for Cognitive Ageing and Cognitive Epidemiology, University of Edinburgh, UK


    Objective: To examine the effects of acute insulin-induced hypoglycemia on spatial cognitive abilities in adult humans with type 1 diabetes.

    Research Design and Methods: Sixteen adults with type 1 diabetes underwent two counterbalanced experimental sessions: euglycemia (blood glucose 4.5mmol/l; 81mg/dl) and hypoglycemia (2.5mmol/l; 45mg/dl). Arterialized blood glucose levels were maintained using a hyperinsulinemic glucose clamp technique. During each session, subjects underwent detailed assessment of spatial abilities from the Kit of Factor-Referenced Cognitive Tests, and two tests of general cognitive function.

    Results: Spatial ability performance deteriorated significantly during hypoglycemia. The Hidden Patterns, Card Rotations, Paper Folding, and Maze Tracing tests were all impaired significantly (p≤0.001) during hypoglycemia, as was the Cube Comparisons test (p=0.03). The Map Memory test was not significantly affected by hypoglycemia.

    Conclusions: Hypoglycemia is a common side-effect of insulin therapy in people with type 1 diabetes, and spatial abilities are of critical importance in day-to-day functioning. The deterioration in spatial abilities observed during modest experimental hypoglycemia provides novel information on the cerebral hazards of hypoglycemia that has potential relevance to everyday activities.


      • Received February 4, 2009.
      • Accepted April 30, 2009.