Glucose Changes in Type 1 Diabetes May Affect Thinking Speed

In type 1 diabetes, glucose fluctuations were related to cognitive processing speed, but not sustained attention, the researchers reported.

Based on data collected every 5 minutes from continuous glucose monitors, large fluctuations in glucose were associated with slower processing speed as measured by digital symptom matching reaction time, found Zoë Hawks, PhD, of McLean Hospital in Belmont, Massachusetts, and colleagues.

This link was significant at three different cut-points for ecological momentary assessment completion for digital symptom matching reaction time (≥50%, ≥66%, and ≥80%), they detailed in npj Digital Medicine.

Glucose fluctuations were not associated with sustained attention, as measured by a gradual-onset continuous performance test.

“We don’t think large glucose fluctuations are healthy for the body, but our results further suggest that when your glucose is very different from what your body is used to, your thinking may be slower or slower,” co- Author Laura Germine, PhD, of the McLean Institute of Psychiatric Technology, explained to MedPage today. “Keeping glucose stable is important for overall health and will likely also result in more stable cognitive function from hour to hour and day to day.”

There were also individual differences when it came to cognitive vulnerability to glucose fluctuations, showing that they may affect some more than others.

“Although most patients had slower thinking speed when their glucose was low or very high, people differed greatly in how much their thinking was affected by changes in glucose,” Germine added. “For some people, everyday changes in glucose made their response noticeably slower. For other people, these same changes in glucose didn’t make much of a difference.”

For example, when glucose was one standard deviation below its mean, patients with high vulnerability to glucose fluctuations responded 0.76 ms and 3.24 ms slower on the gradual-onset continuous performance test. in digital symptom matching reaction times, respectively, than those with low vulnerability. Similarly, when glucose was two standard deviations below its mean, patients with high vulnerability to glucose fluctuations responded 1.8 ms and 9.30 ms slower in the two tests, respectively, than those with low vulnerability.

Germine said doctors should be aware that patients can have very different responses to the same glucose level and that the same glucose level may be associated with thinking difficulties for one patient but not another.

Overall, participants consistently had their fastest digital symbol matching reaction time when glucose levels were slightly higher than their individual average level. The fastest performance on average occurred 0.72 standard deviations (47.49 mg/dL) above the individual’s mean glucose and was associated with a 0.57% (5.30 ms) performance increase. , in relation to their cognitive averages.

“This was an important finding because people with diabetes often report feeling better at a higher glucose level than is considered healthy,” co-author Naomi Chaytor, PhD, of Washington State University, said in a statement. in Spokane.

“It could be that your brain gets habituated to a glucose level it’s used to,” Chaytor said. “So the next step in this research is to see if the glucose level associated with peak performance drops to the normal range when the amount of time spent above the range is reduced, which can be achieved by using systems automated diabetes control systems.

In a post hoc analysis, neck circumference emerged as an unexpected variable that impacted the link between individual differences in cognitive vulnerability to glucose fluctuations. According to correlation tests, the risk of sleep apnea (r=0.43, P<0.001) and upper body adiposity (r=0.16, P=0.051) were associated with individual estimates of cognitive vulnerability to glucose fluctuations, whereas gender was not (r=0.11, P=0.17).

The study included 200 adults with type 1 diabetes and an average age of about 46 years. A little more than half were women, the average HbA1c was 7.5% and the glucose was 182.3 mg/dL. Based on continuous glucose measurements, glucose was in the target range (70-180 mg/dL) on average 54.6% of the time and was above 180 mg/dL 42.5% of the time.

For the digital symbol matching test, patients were presented with a target symbol pairing key and a digit-symbol pairing key and used a touch screen to press the digit that was paired with the target symbol on the key. . Each ecological momentary assessment session lasted 30 seconds. For the gradual-onset continuous performance test, patients viewed a gray-scale circular image of a city or mountain and were instructed to press their touchscreen device when the image represented a city and withhold a response when the image represented a mountain. Each session lasted 60 seconds and consisted of 75 trials.