Executive Function in Chronic Pain Patients and Healthy Controls: Different Cortical Activation During Response Inhibition in Fibromyalgia

Abstract

The primary symptom of fibromyalgia (FM) is chronic, widespread pain; however, patients report additional symptoms including decreased concentration and memory. Performance based deficits are seen mainly in tests of working memory and executive function. Neural correlates of executive function were investigated in 18 FM patients and 14 age-matched HCs during a simple go/no-go task (response inhibition) while they underwent functional magnetic resonance imaging (fMRI). Performance was not different between FM and HC, in either reaction time or accuracy. However, fMRI revealed that FM patients had lower activation in the right pre-motor cortex, supplementary motor area (SMA), mid cingulate cortex (MCC), putamen and, after controlling for anxiety, in the right insular cortex (IC) and right inferior frontal gyrus (IFG). A hyper-activation in FM patients was seen in the right inferior temporal gyrus/fusiform gyrus. Despite the same RTs and accuracy, FM patients show less brain activation in cortical structures in the inhibition network (specifically in areas involved in response selection/motor preparation) and the attention network along with increased activation in brain areas not normally part of the inhibition network. We hypothesize that response -inhibition and pain perception may rely on partially overlapping networks, and that in chronic pain patients resources taken up by pain processing may not be available for executive functioning tasks such as response inhibition. Compensatory cortical plasticity may be required to achieve performance on par with control groups.

Fibromyalgia patients and controls are equally accurate in detecting tactile stimuli while observing another in pain: an experimental study

“…Another possibility may be that FM patients lack response inhibition as they detect vibrotactile stimuli on both hands, whereas healthy controls tend to report only the vibrotactile stimulus congruent to the visual stimulus and inhibit the detection of the incongruent vibrotactile stimulus. This is consistent with the results of a study by Glass et al (2011) reporting that FM patients showed lower activation in the inhibition and attention networks and increased activation in other areas. Further research could explore whether this inhibition theory played a role in the different number of neglect errors reported in the two groups tested here.…”

A case-matched study of neurophysiological correlates to attention/working memory in people with somatic hypervigilance

“…That we did not find any evidence for between group differences suggests people with somatic hypervigilance are no slower (ART), no more impulsive (for example increased false positives), nor less accurate (for example overall errors) in identifying the stimulus in the presented paradigms than case-matched controls. A mismatch between neurophysiological and behavioural outcome measures as reported in this study, has been also been reported in the existing fibromyalgia literature (Glass, et al, 2011;Mercado, et al, 2013), albeit during tasks of inhibition. Here the task was thought to be too simple to tax the remaining cortical resources beyond their capacity to perform the task accurately and with speed.…”

Probiotics for Fibromyalgia: Study design for a pilot double-blind, randomized controlled trial.

“…Self-reported cognitive deficits include forgetfulness, concentration difficulties, loss of vocabulary and mental slowness (13)(14)(15)(16)(17)(18). Emotional and mood problems are also common in FMS.…”