Canadian and American researchers tested the reaction times of 36 people with lesions in their frontal lobes and other parts of their brains. The lesions were caused by trauma, hemorrhage, surgery for benign tumors, and other acute disorders.
The reaction times of the people with the brain lesions were compared to reaction times of 12 healthy people in a control group.
The tests included measuring speed, sensitivity and response differences between study participants as they did tasks such as pressing a button in response to a specific signal. They also gauged how the people in the study sped up or slowed down in response to increasing distraction and redundant information.
When they analyzed the results, the researchers found that different types of attention problems were associated with injuries in different parts of the brain. In particular, they determined that the ability to screen out irrelevant information seems to be based in the frontal lobes' right side.
The results show that attention involves at least three distinct processes that appear to be functionally and anatomically different, the study says. The findings add to scientific evidence that attention is a complex, multi-faceted process.
The findings could help lead to better treatment for people with attention disorders.
For more on attention and the human brain, visit the Massachusetts Institute of Technology.