Cognitive Dysfunction in Fibromyalgia Patients: Specific Neuro-psychological Dysfunctions, Psychiatric Comorbidity and Integrative Assessments

Cognitive dysfunction in Fibromyalgia patients: specific neuro-psychological dysfunctions, psychiatric comorbidity and integrative assessments - Can the investigators help them?

Scientific and Technological Background

1. General Clinical characteristics FM is a common rheumatologic disorder (ranges from 2%-12% in the general population) with complex symptom presentation that include: chronically painful, soft tissue pain. Those affected suffer widespread pain and tenderness at anatomically defined tender points in soft tissue musculoskeletal structures. Associated symptoms include depression, anxiety, fatigue, sleep disturbances, and other somatic complaints (headaches, irritable bowel or bladder, morning stiffness, dysesthesia) and severe cognitive impairment. Cognitive impairment in FM has both subjective elements: "forgetfulness", "concentration difficulties" or "a failing memory".
2. Cognitive impairment in FM 2.1 Subjective Cognitive impairment in FM The subjective cognitive impairments have been described in several studies. Zachrisson and colleagues reported a 95% incidence rate for ''Concentration Difficulties'' and a 93% incidence rate for ''Failing Memory'' on their Fibro-Fatigue scale. Additionally, patients who have FM report more cognitive problems and dissociative states than other rheumatology patients. Arnold and colleagues reported the results of patient focus groups that assessed important symptoms and the impact of these symptoms from a patient perspective. Patients reported that memory and concentration problems were very disruptive-affecting their ability to express themselves due to word-finding difficulties, their ability to organize and plan ahead, their ability to respond quickly to questions, and their ability to drive.

2.2 Objective Cognitive impairment in FM Objective cognitive dysfunction is assessed through a broad range of neuro-cognitive testing. The mechanisms found to have the most marked impairment in FM are: working memory, followed by episodic memory and access to semantic memory. In addition findings points to a particular difficulty in dealing with distracting information so that patients have an enhanced sensitivity to distraction and difficulty in filtering sensory stimuli.

2.2.1 Working memory Working memory is a system of short-term memory storage system (on the order of seconds) combined with other mental processes, that allows for example, to briefly remember two numbers and add them together mentally. A quick assessment of working memory function is: how many digits an individual can listen to and then repeat in backward order. Working memory is a basic cognitive mechanism that underlies successful performance on many other cognitive tasks. There are now several studies that have reported impairment in this important cognitive function in subjects who have FM, using a variety of different tests of working memory.