Exploring Cognitive Dysfunction in Rheumatology

Scientists have also studied the specific domains of cognition that seem to be most affected. These results should be interpreted in the light of tests and analyses in specific studies; however, broadly speaking, symptoms seem to most affect executive function and working memory, causing difficulties with concentration, attention, planning and organization.

Fibromyalgia

Dr. Daniel Whibley

Daniel Whibley, PhD, assistant professor in the Department of Physical Medicine and Rehabilitation at the University of Michigan, addressed some of these questions in the context of fibromyalgia. Around 70% of patients with fibromyalgia report cognitive symptoms, nicknamed fibrofog by the patient community.²

Dr. Whibley shared results of a study of 50 patients with fibromyalgia matched with 50 people without fibromyalgia. In a lab setting, the patients with fibromyalgia performed objectively worse across four different tests of cognitive function. In a real-word ambulatory setting, the patients with fibromyalgia reported poorer subjective cognition and performed more poorly on remote assessments of objective working memory via a smartphone app.²

Dr. Whibley also found that pain levels over the day in patients with fibromyalgia tracked with both poorer perceived cognitive functioning and slower processing speed. This is in line with other research showing the potential negative impact of chronic pain on cognitive functioning.³

This relates to the complicated nature of cognitive dysfunction, both in fibromyalgia and other conditions that can cause chronic pain. Dr. Whibley pointed out that pain, poor sleep, fatigue and mood can all interact in complex ways, and all can have negative impacts on cognitive function.

“Addressing cognitive symptoms may well have an impact on other troublesome symptoms of fibromyalgia,” said Dr. Whibley. “I’d argue that addressing cognition doesn’t only sharpen thinking, but it can also ease the experience of the illness itself.”

Rheumatoid Arthritis

Dr. Katz

Patti Katz, PhD, emerita professor in the Division of Rheumatology at the University of California, San Francisco, extensively reviewed the existing literature on perceived and objectively validated cognitive dysfunction in rheumatoid arthritis. “It’s a really understudied issue,” she said.

Dr. Katz pointed out several flaws, holes and potential biases in the scientific literature, for example, lack of consistency in assessment approaches and definitions of cognitive impairment, small sample sizes and lack of consideration of confounding variables. Because of this, the true prevalence is not well understood. Summarizing and synthesizing existing research, Dr. Katz said that cognitive dysfunction does appear to be more common in people with RA compared with people of a similar age in the general population.^4-9