Stroke Reduces Concentration Ability

A special study will help assess the risks of developing cognitive impairments in patients who have suffered a stroke.

A group of scientists led by Professor Chunsui Yu, who study brain processes during a stroke, published their findings in the online journal "Radiology". The researchers' conclusions will allow doctors to determine with high probability which patients may develop cognitive impairments and take necessary measures to provide effective treatment at an early stage.

During a stroke, processes occur that disrupt blood circulation in the brain, leading to damage to the pathways that transmit information to different parts of the brain. In some patients suffering from chronic ischemia, changes occur in the subcortical structures of the right hemisphere of the brain. These patients suffer from a reduced ability to concentrate. A stroke provokes damage to areas of the cerebral cortex (specifically the gray matter that lines its surface) and selectively affects subcortical structures, disrupting the white matter pathways that connect various parts of the brain. In acute blood circulation disorders in subcortical structures, a subcortical stroke occurs. Studies have shown that about one-third of patients who have suffered a stroke experience reduced attention concentration, which negatively impacts both work and the ability to perform daily tasks.

Essence of the Study

To study the mechanisms responsible for the decline in cognitive functions of the brain resulting from subcortical stroke, scientists employed two approaches simultaneously:

• Diffusion tensor tractography (DTT) – a method that is a type of MRI, which allows for three-dimensional visualization of selected segments of the brain's white matter.
• Voxel-based lesion-symptom mapping (VLSM) – a method that enables neuroimaging of damaged areas of the brain and investigates the behavioral disorders they provoke.

Dr. Chunsui Yu and his colleagues observed two groups of patients: the first consisted of 49 individuals diagnosed with "subcortical stroke", while the second was a control group of fifty individuals. The ages of patients in both groups ranged from forty to seventy years.

The scientists conducted tests to evaluate the speed of visual image assessment, which depends on the ability to concentrate. During the experiments, it was found that patients with impaired function of the right hemisphere of the brain had significantly worse results. DTT and VLSM testing showed that this was due to disruptions in blood circulation function in the caudate nucleus of the right hemisphere and the adjacent white matter.

It was previously believed that cognitive function impairment was a result of weakened connections between brain structures caused by the natural aging process. The new study showed that the cause of reduced attention concentration is often not age, but rather a previous stroke.

According to the author of the scientific study, Dr. Chunsui Yu, the work conducted by his team will help doctors better organize prevention efforts. If after diagnostic examinations doctors find damage to the thalamic and caudally-prefrontal pathways of the right hemisphere, this will signal the need to initiate a comprehensive set of measures at early stages to prevent deterioration of cognitive abilities.