Hypoglycemia Awareness Impacts Brain Function

Restoration of hypoglycemia awareness is linked to increased blood flow to areas of the brain associated with internal self-awareness and decision making, according to the results of a recent study.

“Impaired awareness of hypoglycemia (IAH) in type 1 diabetes (T1D) is a major risk factor for severe hypoglycemia and is associated with atypical responses to hypoglycemia in brain regions involved in arousal, decision making, and memory. Whether restoration of hypoglycemia awareness alters these responses is unknown,” the researchers wrote.

They conducted a study involving 12 adults with T1D and IAH who underwent pseudocontinuous arterial spin labeling functional MRI during hypoglycemic clamp (5-2.6 mmol/L) prior to and following a hypoglycemia avoidance program involving education, specialist support, and sensor-augmented pump therapy. The researchers compared participants’ pre- and post-intervention hypoglycemic cerebral blood flow in the thalamus, anterior cingulate cortex, orbitofrontal cortex, and hippocampus.

Overall, the rates of severe hypertension were reduced (1.5 ± 2 to 0.3 ± 0.5 episodes per year, P = 0.03) and hypoglycemic symptom scores increased (18.8 ± 6.3 to 27.3 ± 12.7, P = 0.02) following intervention, and greater anterior cingulate cortex cerebral blood flow was observed with hypoglycemia, while thalamic and orbitofrontal cortex activity remained the same.

“Increased blood flow is seen within brain pathways involved in internal self-awareness and decision making after restoration of hypoglycemia awareness, suggesting partial recovery of brain responses lost in IAH. Resistance of frontothalamic networks, involved in arousal and emotion processing, may explain why not all individuals with IAH achieve awareness restoration with education and technology alone,” the researchers concluded.

—Michael Potts

Reference:

Nwokolo M, Amiel SA, O’Daly O, et al. Restoration of hypoglycemia awareness alters brain activity in type 1 diabetes. Diabetes Care. 2021 Feb;44(2):533-540.

doi: 10.2337/dc20-1250.