Cognitive impairment in fibromyalgia syndrome: The impact of cardiovascular regulation, pain, emotional disorders and medication

Abstract

This study investigated cognitive performance in fibromyalgia syndrome (FMS) and its association with cardiovascular and clinical parameters. Thirty-five patients with FMS and 29 matched healthy controls completed a neuropsychological test measuring attention and arithmetic processing. As possible factors underlying the expected cognitive impairment, clinical pain intensity, co-morbid depression and anxiety disorders, sleep complaints, medication use, as well as blood pressure parameters were investigated. The patients' test performance was substantially reduced, particularly in terms of lower speed of cognitive processing and restricted improvement of performance in the course of the task. While the extent of depression, anxiety, fatigue and sleep complaints was unrelated to test performance, better performance was observed in patients showing lower pain ratings and those using opiate medication. The data corroborate the presence of substantial cognitive impairment in FMS. While the experience of chronic pain is crucial in mediating the deficits, co-morbid depression, anxiety, fatigue and sleep complaints play only a subordinate role. In the control group, but not in the patients, blood pressure was inversely associated with mental performance. This finding is in line with the well known cognitive impairment in hypertension. The lack of this association in FMS confirms previous research showing aberrances in the interaction between blood pressure and central nervous function in the affected patients.

Fibromyalgia: A Critical and Comprehensive Review

“…It should be pointed out that there are also numerous tests on which FMS patients perform similar to healthy subjects, and that the results for the same tests may not always agree between different investigations [186,191,192,195,196]. In addition, the comparison of FMS patients to healthy subjects may reveal relatively subtle deficits, even though the patients perform within the normal range compared to normative data.…”

“…Significant decrements in processing speed have been documented in FMS patients using a variety of tests [186,192,202,203], even though normal results have also been obtained with certain tasks [204,205], and occasionally, FMS patients perform even better than controls [202]. However, it is often not possible to clearly distinguish between reduced mental processing speed, decreased psychomotor speed, or a combination of both [206].…”

“…Depression or depressive symptoms show associations with some of the cognitive dysfunction in FMS, but they fully explain them in only a few studies, partly explain them in others, and do not show any association in the remainder [187,191,192,198,200,206]. These discrepancies may arise because the effects of depressive symptoms appear to be domain-or even task-specific [183,198,209] and because different instruments were used for assessing depressive symptoms.…”

“…As a matter of fact, there are indications that cognitive deficits in FMS patients become most obvious in the presence of a distractor or source of stimulus competition, not only in tests of attention but also in tests of working memory [193,194]. Working memory is another cognitive domain where FMS patients very consistently perform more poorly compared to healthy controls [186,187,192,195,196]. While addressed in fewer studies, certain measures of semantic memory also show impairments in FMS, including decreased verbal fluency, naming speed, and vocabulary [187,195,197].…”

“…Unfortunately, this concept has been rather broadly or incompletely defined in many studies. When attention is broken down into processes of alerting, orienting, and executive functioning, FMS patients show deficits in alerting and temporal orienting, but not visual orienting, and in various aspects of executive control [125,186,187,[189][190][191][192]. Cognitive inhibition, i.e., the ability to keep focused despite distractions, can be conceptualized as a component of executive function and is quite consistently found to be impaired in FMS patients.…”