We have previously reported deterioration of cognitive function in children with IDDM during mild hypoglycemia. We now have examined the relationship between age, anxiety and cognitive functioning during mild hypoglycemia (HYPO) in 25 individuals with IDDM (age=18.6±5.4 yrs; duration=8.9±9.5 yrs; M±SD) and 16 age-matched nondiabetic controls. Each subject participated in a euglycemic (Eu) and a Hypo clamp, in random order, 2 months apart. During the Hypo clamp, plasma glucose was dropped from 100 mg/dl to 60 mg/dl and maintained for 60 min. Comparing both clamps, we found that during Hypo, significant (p≤0.5) increases in self-reported anxiety (Spielberger State Anxiety Inventory) occured in both groups, whereas significant declines on cognitive tests of attention (Letter Rotation Reaction Time Test; Digit Vigilance) and mental flexibility (Trail Making B) were limited to IDDM subjects. In controls cognitive change correlated with age but not anxiety levels. In diabetics, there was a small relationship between Trail Making B and anxiety (r=0.3; p=0.017) but not age.

Conclusion: Studied under identical conditions, unlike controls, children and adults with IDDM showed similar levels of cognitive decline during mild hypoglycemia which minimally affected their level of anxiety. The differences between subjects with and without IDDM may relate to differences in autonomic nervous system responses even prior to clinical autonomic neuropathy.