Fibromyalgia Patients Show Worse Cognitive Function in Their Everyday Lives, Small Study Finds

Fibromyalgia Patients Show Worse Cognitive Function in Their Everyday Lives, Small Study Finds

People with fibromyalgia display significantly poorer perceived cognitive function and objective working memory in their daily lives, according to the results of a small study.

The study, “Fibrofog in daily life: An examination of ambulatory subjective and objective cognitive function in fibromyalgia,” was published in the journal Arthritis Care & Research.

While chronic and widespread pain is a hallmark of fibromyalgia, cognitive impairment — also called “fibro fog” or “brain fog” — is reported in approximately 70% of people with the condition.

A previous study showed that the most common cognitive difficulties for those with fibromyalgia include learning and memory problems, difficulty paying attention, and inability to control movement.

Cognitive dysfunction contributes to “negative health perceptions and difficulty maintaining relationships, working, communicating, driving, organizing, and initiating activities of daily life,” the researchers wrote.

However, fibromyalgia’s effect on cognitive function has only been studied in a clinical environment, with no studies to date on its impact on patients’ cognitive function in daily life.

Therefore, the researchers evaluated the daily-life perceived (subjective) and objective cognitive function in 50 people with fibromyalgia, compared with a control group of 50 people who were unaffected by the condition.

Participants were recruited in the Michigan area, and their mean age was 44.9 years for the fibromyalgia group and 45.2 years for the control group. Each group consisted of 44 women (88%) and six men (12%).

Those with fibromyalgia were taking significantly more medications that could potentially alter their cognitive function, and they were more likely to be unemployed (40%) than those in the control group (22%).

At the beginning of the study (baseline), participants underwent a battery of patient-reported (subjective) and standardized (objective) tests of cognitive function in the lab. Then, they were given mini smartphones programmed with a study-specific app that alerted them to complete subjective and objective assessments five times a day over eight days.

Daily subjective cognitive function was assessed with two rating scales measuring cognitive clarity and speed, followed by two brief validated objective tests of processing speed and working memory (short-term storage of information while performing other mental tasks).

At baseline, results revealed that people with fibromyalgia reported significantly worse cognitive function, depressed mood, pain, and fatigue, and showed moderately poorer cognitive function (in attention, working memory and processing speed) than those in the control group.

Daily-life data showed that fibromyalgia patients had significantly worse perceived cognitive function, compared with the other group. While they also showed poorer working memory and processing speed, their working memory scores were significantly worse.

The researchers hypothesized that the lack of significant differences in daily-life processing speed between the two groups might be related to the test itself, which may not be adequately sensitive to fibromyalgia-associated deficits.

Both groups showed a similar association between subjective and objective measures of cognitive function at baseline and in daily life.

However, in daily-life measurements, only “momentary changes in processing speed, but not working memory, were associated with subjective reports of cognitive function,” the researchers wrote. They noted that this might be due to the fact that “perceived memory ability was not assessed in the [daily subjective] items, which assessed cognitive clarity and speed.”

“This study provides initial evidence of the characteristics of subjective (‘fibro fog’) and objective cognitive dysfunction in the daily lives of those with [fibromyalgia],” the researchers added.

However, they noted that the tests did not measure performance in real-world cognitive tasks, and assessed only a limited number of cognitive domains. Future and larger studies are required to confirm these findings and to evaluate other cognitive domains and the association between cognitive function and fibromyalgia symptoms, the researchers said.

They also called for future studies to differentiate the aspects of “fibro fog” that are associated with general chronic pain from those that are specific to fibromyalgia.