Long-term human study shows detrimental effect diabetes has on brain plasticity.
A new neuroimaging study has shown that in just two years people with type 2 diabetes experienced negative changes in their ability to regulate blood flow in the brain This was also associated with lower scores on tests of cognition skills and their ability to perform their daily activities, according to researchers led by Harvard Medical School. The team state that normal blood flow regulation allows the brain to redistribute blood to areas of the brain that have increased activity while performing certain tasks. They go on to add that previous studies show that people with type 2 diabetes have impaired blood flow regulation. Their results suggest that diabetes and high blood sugar impose a chronic negative effect on cognitive and decision-making skills. The study is published in the journal Neurology.
The current study involved 40 people with an average age of 66. Of those, 19 had type 2 diabetes and 21 did not have diabetes. Those with diabetes had been treated for the disease for an average of 13 years. The participants were tested at the beginning of the study and again two years later. Tests included MRI scans of the brain to look at brain volume and blood flow, and blood tests to measure control of blood sugar and inflammation. This was also followed up with observational psychiatric tests such as cognition and memory tests.
The results showed that after two years, the people with diabetes had decreases in their ability to regulate blood flow in the brain. They also had lower scores on several tests of memory and thinking skills. The data findings showed that people with lower ability to regulate blood flow at the beginning of the study had greater declines in a measure of how well they could complete daily activities such as bathing and cooking. The team state that higher levels of inflammation were also associated with greater decreases in blood flow regulation, even if people had good control of their diabetes and blood pressure.
In the current study on a test of learning and memory, the scores of the people with diabetes decreased by 12 percent, from 46 points to 41 points over two years, while the scores of those without diabetes stayed the same, at 55 points. These results suggest that blood flow regulation in the brain was decreased by 65 percent in people with diabetes.
The researchers surmise that early detection and monitoring of blood flow regulation may be an important predictor of accelerated changes in cognitive and decision-making skills. They go on to conclude that additional studies involving more people and extending for a longer time period are needed to better understand the relationship and timing with blood flow regulation and changes in thinking and memory skills.