Hyperglycemia is associated with simultaneous alterations in electrical brain activity in youths with type 1 diabetes mellitus

Objective: To assess the association between hyperglycemia and electrical brain activity in type 1 diabetes mellitus (T1DM). Methods: Nine youths with T1DM were monitored simultaneously and continuously by EEG and continuous glucose monitor system, for 40 h. EEG powers of 0.5-80 Hz frequency bands in all the different brain regions were analyzed according to interstitial glucose concentration (IGC) ranges of 4-11 mmol/l, 11-15.5 mmol/l and >15.5 mmol/l. Analysis of variance was used to examine the differences in EEG power of each frequency band between the subgroups of IGC. Analysis was performed separately during wakefulness and sleep, controlling for age, gender and HbA1c. Results: Mean IGC was 11.49 ± 5.26 mmol/l in 1253 combined measurements. IGC > 15.5 mmol/l compared to 4-11 mmol/l was associated during wakefulness with increased EEG power of low frequencies and with decreased EEG power of high frequencies. During sleep, it was associated with increased EEG power of low frequencies in all brain areas and of high frequencies in frontal and central areas. Conclusions: Asymptomatic transient hyperglycemia in youth with T1DM is associated with simultaneous alterations in electrical brain activity during wakefulness and sleep. Significance: The clinical implications of immediate electrical brain alterations under hyperglycemia need to be studied and may lead to adaptations of management.