Correlating cognition and cortical excitability with pain in fibromyalgia: a case control study

Abstract

Background Fibromyalgia is a chronic pain disorder characterized by widespread musculoskeletal symptoms, primarily attributed to sensitization of somatosensory system carrying pain. Few reports have investigated the impact of fibromyalgia symptoms on cognition, corticomotor excitability, sleepiness, and the sleep quality — all of which can deteriorate the quality of life in fibromyalgia. However, the existing reports are underpowered and have conflicting directions of findings, limiting their generalizability. Therefore, the present study was designed to compare measures of cognition, corticomotor excitability, sleepiness, and sleep quality using standardized instruments in the recruited patients of fibromyalgia with pain-free controls. Methods Diagnosed cases of fibromyalgia were recruited from the Rheumatology department for the cross-sectional, case-control study. Cognition (Mini-Mental State Examination, Stroop color-word task), corticomotor excitability (Resting motor threshold, Motor evoked potential amplitude), daytime sleepiness (Epworth sleepiness scale), and sleep quality (Pittsburgh sleep quality index) were studied according to the standard procedure. Results Thirty-four patients of fibromyalgia and 30 pain-free controls were recruited for the study. Patients of fibromyalgia showed decreased cognitive scores (p = 0.05), lowered accuracy in Stroop color-word task (for color: 0.02, for word: 0.01), and prolonged reaction time (< 0.01, < 0.01). Excessive daytime sleepiness in patients were found (< 0.01) and worsened sleep quality (< 0.01) were found. Parameters of corticomotor excitability were comparable between patients of fibromyalgia and pain-free controls. Conclusions Patients of fibromyalgia made more errors, had significantly increased reaction time for cognitive tasks, marked daytime sleepiness, and impaired quality of sleep. Future treatment strategies may include cognitive deficits and sleep disturbances as an integral part of fibromyalgia management.

Non-Invasive Electric and Magnetic Brain Stimulation for the Treatment of Fibromyalgia

“…Stimulation parameters, specific protocols, outcome measures, sample sizes, and evaluated symptoms are somehow heterogeneous between studies, which limits their comparability. Table 1 (TMS) and Table 2 (rTMS) summarize the principal protocols and results of these studies [ 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 ]. Overall findings for TMS and rTMS are described in the following subsections.…”

“…On the other hand, reduced intracortical facilitation (ICF) has also been described in fibromyalgia [ 14 ], but this finding has not been as consistent as that observed with inhibitory processes. Although the specific pathophysiology of fibromyalgia that affects cortical excitability is not well understood [ 16 ], empirical results show that M1 stimulation via rTMS reduces pain intensity and modulates intracortical inhibition processes [ 25 ]. Further studies are needed to elucidate whether these cortical excitability alterations are a primary central mechanism of fibromyalgia and its relationship to chronic pain and other symptoms.…”

Impact of being physically active on the brain electrocortical activity, brain volumetry and performance in the Stroop color and word test in women with fibromyalgia

“…To our knowledge, no previous studies have investigated the brain electrocortical activity during the SCWT in people with FM. In this regard, other studies have correlated the performance 43 to cortical excitability or investigated brain activity using functional magnetic resonance imaging 5 . Furthermore, a previous study has investigated the effect of a long-term intervention on SCWT performance 5 .…”