Acute hyperglycaemia impairs cognitive function in children with IDDM.
OBJECTIVE
The effects of acute hyperglycaemia on cognitive function in children remain controversial. This study was designed to investigate the suggestion that acute hyperglycaemia impairs cognition in IDDM children.


METHODS
To examine this question we studied 12 randomly selected children with IDDM (6 boys, 6 girls, mean age 12.4 years). Cognitive performance was assessed on two occasions at least six months apart (7.4 +/- 1.4 mths, range: 6.3-11.1 mths) under randomised conditions of hyperglycaemia (20-30 mmol/l) on one occasion and euglycaemia (5-10 mmol/l) on the other. Target glucose levels were achieved using a modified clamp technique with subjects and psychologist blinded to the glycaemic level. Cognitive tests chosen to assess performance skills were subtests from the Wechsler Intelligence Scale for Children-3rd Edition (WISC-111).


RESULTS
No significant learning effect was present. However, there was a reduction in performance IQ at hyperglycaemia compared with euglycaemia (106 +/- 4.3 vs 112 +/- 4.5 IQ points respectively, p < 0.05). Under hyperglycaemic conditions the mean decrease in percentile score for performance IQ was 9.5%. Of the 12 children tested, 8 had a decrease in IQ when hyperglycaemic, which was independent of duration of diabetes and long term metabolic control assessed by HbA1c.


CONCLUSIONS
Acute hyperglycaemia results in impairment of complex cognitive function in children with IDDM. This may have important implications for school performance.
Department of Diabetes/Endocrinology, Princess Margaret Hospital for Children, Perth, Western Australia.
E A
EA
Davis
S A
SA
Soong
G C
GC
Byrne
T W
TW
Jones
D000293:Adolescent; D001786:Blood Glucose / Q000378:metabolism; D002648:Child; D003071:Cognition; D018592:Cross-Over Studies; D003922:Diabetes Mellitus, Type 1 / Q000097:blood / Q000150:complications*; D005260:Female; D015309:Glucose Clamp Technique; D006801:Humans; D006943:Hyperglycemia / Q000503:physiopathology*; D008297:Male; D014888:Wechsler Scales
D001786:Blood Glucose