Increased cortical activation upon painful stimulation in fibromyalgia syndrome.
BACKGROUND
Fibromyalgia syndrome (FMS) is a chronic condition characterized by widespread pain and associated symptoms. We investigated cerebral activation in FMS patients by functional near-infrared spectroscopy (fNIRS).


METHODS
Two stimulation paradigms were applied: a) painful pressure stimulation at the dorsal forearm; b) verbal fluency test (VFT). We prospectively recruited 25 FMS patients, ten patients with unipolar major depression (MD) without pain, and 35 healthy controls. All patients underwent neurological examination and all subjects were investigated with questionnaires (pain, depression, FMS, empathy).


RESULTS
FMS patients had lower pressure pain thresholds than patients with MD and controls (p <  .001) and reported higher pain intensity (p < 0.001). Upon unilateral pressure pain stimulation fNIRS recordings revealed increased bilateral cortical activation in FMS patients compared to controls (p < 0.05). FMS patients also displayed a stronger contralateral activity over the dorsolateral prefrontal cortex in direct comparison to patients with MD (p < 0.05). While all three groups performed equally well in the VFT, a frontal deficit in cortical activation was only found in patients with depression (p < 0.05). Performance and cortical activation correlated negatively in FMS patients (p < 0.05) and positively in patients with MD (p < 0.05).


CONCLUSIONS
Our data give further evidence for altered central nervous processing in patients with FMS and the distinction between FMS and MD.


BACKGROUND
ISRCTN registry ID ISRCTN15015327 (24.09.2015).
Department of Neurology, University of Würzburg, Josef-Schneider-Str. 11, Würzburg, 97080, Germany. ueceyler_n@ukw.de.
Nurcan
N
Üçeyler
Department of Psychiatry, University of Würzburg, Würzburg, Germany. Zeller_J1@ukw.de.
Julia
J
Zeller
Department of Neurology, University of Würzburg, Josef-Schneider-Str. 11, Würzburg, 97080, Germany. Susanne.Kewenig@t-online.de.
Susanne
S
Kewenig
Department of Psychiatry, University of Würzburg, Würzburg, Germany. Sarah.Kittel-Schneider@kgu.de.
Sarah
S
Kittel-Schneider
Department of Psychiatry, University of Tübingen, Tübingen, Germany. Andreas.Fallgatter@med.uni-tuebingen.de.
Andreas J
AJ
Fallgatter
Department of Neurology, University of Würzburg, Josef-Schneider-Str. 11, Würzburg, 97080, Germany. sommer@uni-wuerzburg.de.
Claudia
C
Sommer
D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D002540:Cerebral Cortex / Q000503:physiopathology*; D003865:Major Depressive Disorder / Q000503:physiopathology*; D005260:Female; D005356:Fibromyalgia / Q000503:physiopathology*; D059907:Functional Neuroimaging; D006801:Humans; D008297:Male; D008875:Middle Aged; D009460:Neurologic Examination; D010146:Pain / Q000503:physiopathology*; D017288:Pain Threshold; D010812:Physical Stimulation; D011312:Pressure; D011446:Prospective Studies; D019265:Spectroscopy, Near-Infrared; D011795:Surveys and Questionnaires