Fibromyalgia, a disease that is still not completely understood, is the subject of much research. Besides the fatigue associated with fibromyalgia, many people with fibromyalgia experience chronic pain that is difficult to treat. Other hallmark complaints are difficulty sleeping and depression. Now, along with these problems, researchers believe that many people with fibromyalgia also experience significant changes in their mental function.
Earlier research has found that cognitive disruptions in fibromyalgia seem to focus around memory and vocabulary. Another study found that people with fibromyalgia had difficulty doing tasks in a stimulus competition, with their ability declining as the stimulus competition increased. Yet another study that investigated the effect of chronic pain in general, found that people who lived with chronic pain also showed less ability to perform higher level tasks.
The authors of this article investigated the association of working memory disruption and declining performance in patients with fibromyalgia. The authors believed they would find that there would be a decline in this patient group and that how well they did would depend on the stimulus competition and the working memory.
Researchers studied 30 women with fibromyalgia and matched them with 30 women (controls) who did not have the syndrome. The women were assessed for pain using the Numerical Rating Scale (NRS), which asks the patients to draw a line across a horizontal line to illustrate their current pain level. The women also completed the McGill Pain Questionnaire (MPQ), which measures different qualities of pain. To assess attention functioning, both groups of women took the Test of Everyday Attention (TEA) and the Auditory Consonant Trigram (ACT), which asks for study subjects to remember three items lists of consonants after they had performed a task that was meant to distract them. Another test, the Reading Span Test (RST) assessed linguistic and nonlinguistic abilities. The researchers also assessed the quality of life using the 15D test. Finally, mental health was assessed using the Hospital Anxiety and Depression (HAD) scale and sleep was assessed by the patients recording how many of hours they slept each night.
After all the data were collected and analyzed, the researchers found that there were significant differences between the fibromyalgia group and the control group in terms of cognitive disruption, including depression, anxiety, how many hours of sleep per night, and how often wakening occurred at night. Women with fibromyalgia performed more poorly in tests for overall attention, stimulus interference, and working memory. But, the researchers did not find differences between the two groups regarding cognitive measures. The researchers did divide the fibromyalgia group into patients who took opioids (strong, controlled pain medications) and those who did not. The found that the patients who were taking regular, stable doses of opioids did do a bit better than those who were not. The authors pointed out that their study group was relatively small so it could be difficult to obtain a strong showing either way.
The authors wrote that there were some very strong differences between the fibromyalgia group and the control group in terms of mood, sleep disruption and pain that they experienced. There was also a link between cognitive disruption and the difficulties associated with depression, sleep deprivation, and anxiety. The authors went on to write that their beliefs going into the study were confirmed with their findings; that working memory is affected by chronic pain. They did point out, however, that there are some flaws to the study. These include the differences in medications that the patients may have been taking, the relationship between pain and fatigue that can be difficult to separate, as well as the small study size.
As more research points to the relationship between fibromyalgia and cognitive decline, research into the actual causes is moving forward. Using brain imaging, researchers have found that patients who have fibromyalgia also have higher levels of certain types of brain activity, but what this means remains to be learned.