Mental Agility Slows With Diabetes

Some areas of cognitive function are impaired in patients with type 1 diabetes, the speed of mental processes seems to be slowed, but learning and memory are apparently almost unscathed. "The magnitude of the cognitive deficits is mild," report Dr. Augustina M. A. Brands, of University Medical Center, Utrecht, and colleagues, "but even mild forms of cognitive dysfunction might hamper everyday activities."

The researchers used MedLine and PsychLit search engines to identify studies on cognitive performance in diabetic patients. Thirty-three studies met the inclusion criteria and were included in the analysis.

The team assessed the cognitive domains of intelligence, learning and memory, psychomotor activity and information processing, attention, cognitive flexibility, visual perception, and language. In addition, they looked into the possible effects of disease variables, including recurrent episodes of hypoglycemia and metabolic control.

Compared with nondiabetic controls, subjects with type 1 diabetes had significantly lowered performance on the intelligence, speed of information processing, and psychomotor efficiency domains. Lowered performance was also observed on the domains of visual and sustained attention, cognitive flexibility, and visual perception.

"Our meta-analysis does not support the idea that there are important negative effects from recurrent episodes of severe hypoglycemia on cognitive functioning," Dr. Brands’ team reports. On the other hand, "Microvascular complications such as retinopathy and neuropathy do appear to be associated with impaired cognition."

The main unanswered questions about the effect of diabetes on cognitive dysfunction, the investigators note, relate to the relative contribution of different disease variables, such as diabetes duration and levels of glycemic control.
Diabetes Care 2005;28:726-735.

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DID YOU KNOW:
University of Miami researchers may have discovered a shortcut for turning embryonic stem cells into the insulin-producing cells destroyed by Type-1 diabetes. The technique, described in a paper published in the March issue of the journal Diabetes, could ultimately contribute to a cure for the disease by creating a limitless supply of the insulin-producing cells known as islets.
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