Adaptation of cognitive function to hypoglycemia in healthy men.
OBJECTIVE
Antecedent hypoglycemia reduces hypoglycemic counterregulation and symptoms, thereby provoking the hypoglycemia unawareness syndrome. The effects of antecedent hypoglycemia on hypoglycemia-induced cognitive dysfunction are less well established.


METHODS
To determine whether antecedent hypoglycemia also reduces hypoglycemic cognitive dysfunction, we performed stepwise hypoglycemic clamp experiments (4.1, 3.6, 3.1, and 2.6 mmol/l) during a 6-h period in 30 young healthy men. A total of 15 subjects additionally received a 2.5-h antecedent hypoglycemic clamp (3.1 mmol/l) on the preceding day (prior-hypo group), whereas the other 15 subjects did not (control group). Cognitive function was assessed by auditory-evoked brain potentials (AEBPs) and reaction time during a vigilance task and short-term memory recall. Tests were performed during the stepwise hypoglycemic clamp at baseline and at each hypoglycemic plateau.


RESULTS
In both groups, performance on all measures of cognitive function deteriorated during stepwise hypoglycemia (all P < 0.01). However, after antecedent hypoglycemia, the hypoglycemia-induced decrease in the amplitude of the P3 of the AEBP was distinctly reduced compared with the control condition (P < 0.05). Also, short-term memory performance was less impaired in the prior-hypo group than in the control group (P < 0.005), and a minor hypoglycemic impairment of reaction time (P < 0.05) was evident in the prior-hypo group.


CONCLUSIONS
Data provide evidence that a single episode of mild antecedent hypoglycemia (3.1 mmol/l) attenuates several aspects of cognitive dysfunction during subsequent hypoglycemia 18-24 h later.
Department of Internal Medicine, University of Luebeck, Germany. fruehwal@kfg.mu-luebeck.de
B
B
Fruehwald-Schultes
J
J
Born
W
W
Kern
A
A
Peters
H L
HL
Fehm
D000222:Adaptation, Physiological; D000328:Adult; D001143:Arousal; D001786:Blood Glucose / Q000378:metabolism*; D003071:Cognition / Q000502:physiology*; D003072:Cognition Disorders / Q000209:etiology*; D004644:Emotions; D004837:Epinephrine / Q000097:blood; D005221:Fatigue; D015309:Glucose Clamp Technique; D019382:Human Growth Hormone / Q000097:blood; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D007003:Hypoglycemia / Q000503:physiopathology* / Q000523:psychology*; D008297:Male; D008570:Memory, Short-Term / Q000502:physiology*; D009638:Norepinephrine / Q000097:blood; D011930:Reaction Time / Q000502:physiology; D012044:Regression Analysis; D011795:Surveys and Questionnaires
D001786:Blood Glucose; D019382:Human Growth Hormone; D006854:Hydrocortisone; D009638:Norepinephrine; D004837:Epinephrine