Cognitive Impairment in Patients with Diabetes

I've been following Nicolas Bolo's work at Harvard since I first saw this video of a presentation he gave almost a decade ago in which he explained that changes in the brain's default mode network was correlated to glycemic control.

The major factor limiting improved glucose control in type 1 diabetes is the significant increase in hypoglycemia associated with insulin treatment. Repeated exposure to hypoglycemia alters patients' ability to recognize the autonomic and neuroglycopenic symptoms associated with low plasma glucose levels. We examined brain resting state networks during the induction of hypoglycemia in diabetic and control subjects and found differences in networks involved in sensorimotor function, cognition, and interoceptive awareness that were related to chronic levels of glycemic control. These findings identify brain regions that are sensitive to variations in plasma glucose levels and may also provide a basis for understanding the mechanisms underlying the increased incidence of cognitive impairment and affective disorders seen in patients with diabetes. -- Nicolas Bolo, et al

In other words, the treatment of Type 1 diabetes with insulin is correlated with a significant increase in hypoglycemia.

Worse, chronic exposure to hypoglycemia makes it more difficult to recognize the symptoms of hypoglycemia.

Worse yet, increased incidence of affective disorders seen in patients with diabetes are likely explained by these changes in the brain.