Effects of hypoglycemia on cognition were studied using event-related brain-potential (ERP) measures and reaction times at the Otto-von-Guericke University, Magdeburg, Germany. ERP measures of selective attention, response choice and reaction time were delayed during hypoglycemia compared to baseline performance. After restoration of euglycemia, total-error frequencies were still higher than at baseline and recovery of the quality of task performance was delayed. Hypoglycemia impairs both the stimulus and the motor-response selection. Large negative shifts in cortical potentials were distributed over frontal areas during hypoglycemia, suggesting that the frontal cortex is involved in the control of attention and stimulus selection. 
COMMENT. Hypoglycemia has an adverse effect on attentional behavior by increasing reaction times and error frequencies. After restoration of normal blood sugar levels there is a delay in recovery of quality of task performance. The frontal cortex is more highly activated during acute hypoglycemia as a compensatory mechanism for the reduced energy supply to the brain. Frontal location brain mechanisms, important in control of attention, are particularly affected by the impaired energy supply associated with hypoglycemia.