Anyone with a chronic pain condition understands that pain takes your attention away from other (more important things). This study shows that the pain is not just figuratively taking your attention away, but is literally doing so by re-routing your cognitive blood-flow. The study evaluated cerebral blood flow in relation to a mental mathematical task. The experimenters hypothesized that those with Fibromyalgia would complete the tasks at a slower rate, and that cerebral blood flow would be affected. Since mathematical tasks are associated with the left side of the brain, they expected an increase in blood flow to areas on that side, specifically to the middle cerebral arteries (MCA). They expected that severity of pain would impact performance on the mathematical tasks.
Fibromyalgia patients (45 women) were matched with 32 control group participants. Use of antidepressants, analgesics, and sleep issues were taken into account for all participants. They were presented with a series of simple arithmetic equations on the computer, where they had to respond by entering only the last digit of the answer. A warning signal was given to alert the participants prior to each equation. Responses were measured for speed and accuracy. Blood flow rates were measured on both hemispheres of the brain.
No differences were noted in the number of correct responses; however, Fibromyalgia patients did show slower responses to the equations. No performance differences were observed due to the use of antidepressants, anti anxiety medications, or pain medications. Pain intensity, and anxiety were associated with longer response times. Hypersomnia (sleepiness) was related to a higher number of incorrect answers. The comparison of blood flow rate showed the Fibromyalgia group having a lower blood flow rate. The arithmetic activity was associated with two different increases in blood flow (for both groups), an initial increase following the warning signal, and a second higher increase 5-6s following the presentation of the equation.
The results indicate that Fibromyalgia patients do process slower, and the speed of mental process is affected by pain intensity. The first change in blood flow was positively associated with correct responses, was greatly reduced in the Fibromyalgia group. This may indicate a slower reaction in those areas of the brain associated with task resolution are not quickly activated. There was also greater increase in flow through the right arterial cerebral artery (ACA), an area that is not associated with mathematical task completion. Activation of the right ACA in the healthy group was negatively associated with task performance. Increased blood flow to this area may have pulled blood flow from the area needed to accurately complete the task.
Fibromyalgia patients not only complete tasks slower, and are slower to respond, likely due to pain intensity; but, they also see an increase in blood flow to brain areas not required for task completion. This increase in blood flow to irrelevant areas is likely pulling blood flow away from areas where it is needed to accurately complete the task. It is possible that blood flow to these unrelated areas is needed to help deal with the pain. For the brain to compensate for the pain intensity it has to take resources (blood flow) away from areas where it may be needed for other processes. This actually makes sense when you consider the autonomic nervous system and the sympathetic nervous system’s response to stress and pain. When one lives with chronic pain their sympathetic nervous system is constantly activated in fight or flight mode, so the body would constantly be processing the pain before it can process other secondary issues (like solving math problems).
Melissa says
This is my favorite post you’ve done! It’s fascinating. Lack of REM sleep and chronic acute pain would probably dull the thinking ability of most people. So those of us constantly in that state would be expected to have slower response time . The blood flow component is extremely interesting. I can’t stress enough how impressive this post is. Well done!!
Julie says
Thank you Melissa. I want to do more of these types of posts on the research that is being done. There’s a lot of it out there that doesn’t get much coverage. Then we have occasional study that gets over-covered (I’m thinking the small nerve study).