It's Not All in the Mind: Cognitive Function and Fibromyalgia

The Monday morning sessions at the 2009 American College of Rheumatology/Association of Rheumatology Health Professionals featured several presentations that focused on cognitive functioning in fibromyalgia and lupus. Researchers from the University of North Carolina presented “Cognitive Impairments in Patients Diagnosed with Fibromyalgia, Systemic Lupus Erythematosus, and Rheumatoid Arthritis,” with results from a study that enrolled 37 patients with fibromyalgia, 27 patients with systemic lupus erythematosus, 26 rheumatoid arthritis patients, and 20 healthy controls to “evaluate the contributions of demographic, physical, pain, stress, affective, and cognitive variables” to the severity of these conditions. Subjects were assessed for concentration, memory, psychomotor speed, cognitive interference, learning, and recall deficits. Subjects were also assessed for pain intensity, the presence of sleep disorders, and severity of fatigue (if present). The researchers reported that fibromyalgia patients and lupus patients experienced “significantly more cognitive impairments” compared to patients with rheumatoid arthritis and healthy controls. Fibromyalgia patients also had greater difficulty with concentration. Fibromyalgia patients and lupus patients demonstrated “significantly worse” cognitive abilities than the rheumatoid arthritis patients. The researchers said that more than 50% of the variance in impaired short-term concentration could be explained by the combined effects of impaired sleep quality and increased ACTH-production. Fatigue and “non-clinically significant depression” accounted for nearly 73% of the variance of deficits of recognition memory in patients with lupus. These results reinforce the need for clinicians to be aware of the possibility of significant cognitive deficits in fibromyalgia patients and also in patients with lupus, compared to rheumatoid arthritis patients.

Researchers from UMDNJ-Robert Wood Johnson Medical School and Rutgers University presented results from their study (“Positive Affect as a Resilience Factor in Fibromyalgia and Other Complex Symptom Disorders”) that looked at the role of positive affect (PA) in outcomes in patients with fibromyalgia, Lyme disease, chronic fatigue syndrome, and other complex symptom disorders. Study participants were evaluated using several instruments, including the Composite International Diagnostic Interview, the Positive and Negative Affect Scale, Health Assessment Questionnaire, Quick Inventory of Depressive Symptomatology, Satisfaction with Life Scale, and Symptoms Checklist. Subjects were assigned to high, normal, and low PA groups, depending on their assessment scores. The researchers revealed that “high PA” subjects reported fewer symptoms than “normal PA” participants; high PA subjects also reported less disability and greater satisfaction with quality of life compared to low PA patients, who experienced a higher incidence of depression.

Noting that other studies have reported deviations in hypothalamic-pituitary-adrenal (HPA) axis functioning in some patients with fibromyalgia, a team of researchers from UMDNJ-Robert Wood Johnson Medical School, the University of Westminster in London, and the University of Michigan studied the relationships between “positive and negative affective factors” and morning cortisol levels in patients with fibromyalgia, comparing them to healthy controls. The researchers evaluated 20 patients with fibromyalgia and 26 healthy controls using the Center for Epidemiological Studies—Depression Scale, portions of the Short Form 36 Health Survey that focus on mental health, emotional health, and social function, and the State-Trait Personality Inventory. They also measured waking cortisol levels in each patient, taking a second measure one hour after. Analysis of data revealed that in healthy controls, higher morning cortisol levels were associated with depression and anxiety, yet inversely related to positive affect variables measured by emotional health and social function scales of the Short Form 36 Health Survey. In patients with fibromyalgia, the researchers reported finding no relation between high morning cortisol levels and negative affective variables In fact, high morning cortisol was found to correlate with positive affective variables measured by Short Form 36 Health Survey. These results are interesting, given that other studies have found that lower morning cortisol levels are associated with positive affective factors, and that negative affective factors are associated with higher cortisol levels. These “paradoxical” results may be explained by the hypocortisolism frequently seen in patients with fibromyalgia – perhaps the high cortisol/high positive affective factor relationship may be due to better HPA axis function in these patients.