Diabetes Slows Brain Function

Jan. 5, 2009 -- Mild diabetes slows mental function, even when kept under tight control, a Canadian study shows.

It's not a huge cognitive defect, but it seems to appear early in the course of type 2 diabetes. Fortunately, the defect does not snowball over time, at least for those with mild or moderate diabetes.

The finding comes from a study of 570 adults aged 53 to 90, including 41 patients with "relatively mild" type 2 diabetes, who undergo mental function exams every three years.

Earlier studies have linked diabetes to a decline in mental function. But not all mental functions are affected equally, find Roger A. Dixon, PhD, and colleagues at the University of Alberta, Edmonton, Canada.

Diabetes patients had normal reaction times and normal perceptual speed. But they were slower on tasks requiring rapid and precise processing of new verbal information. The defects involved speed and not verbal fluency.

"There could be some ways to compensate for these declines, at least early and with proper management," Dixon says in a news release.

The good news is that the gap in mental function between people with and without diabetes did not increase with age. Although the defects Dixon and colleagues detected were not "clinically significant," the researchers' more recent work suggests these small defects may foreshadow additional decline in mental function for some patients.

The findings appear in the January issue of Neuropsychology.