Nondermatomal somatosensory deficits in chronic pain are associated with cerebral grey matter changes.
Widespread sensory deficits occur in 20-40% of chronic pain patients on the side of pain, independent of pain aetiology, and are known as nondermatomal sensory deficits (NDSDs). NDSDs can occur in absence of central or peripheral nervous system lesions. We hypothesised that NDSDs were associated with cerebral grey matter changes in the sensory system and in pain processing regions, detectable with voxel-based morphometry.



Twenty-five patients with NDSDs, 23 patients without NDSDs ("pain-only"), and 29 healthy controls were studied with high resolution structural MRI of the brain. A comprehensive clinical and psychiatric evaluation based on Diagnostic and Statistical Manual was performed in all patients.



Patients with NDSDs and "pain-only" did not differ concerning demographic data and psychiatric diagnoses, although anxiety scores (HADS-A) were higher in patients with NDSDs. In patients with NDSDs, grey matter increases were found in the right primary sensory cortex, thalamus, and bilaterally in lateral temporal regions and the hippocampus/fusiform gyrus. "Pain-only" patients showed a bilateral grey matter increase in the posterior insula and less pronounced changes in sensorimotor cortex.



Dysfunctional sensory processing in patients with NDSDs is associated with complex changes in grey matter volume, involving the somatosensory system and temporal regions.
a Department of Neurology , University Hospital Zurich , Switzerland.|g University of Zurich , Switzerland.|h Karl Landsteiner Institute for Clinical Epilepsy Research and Cognitive Neurology, Neurological Center Rosenhuegel , Vienna , Austria.
Franz
F
Riederer
b Centre for Pain Medicine , Swiss Paraplegic Centre , Nottwil , Switzerland.
Gunther
G
Landmann
a Department of Neurology , University Hospital Zurich , Switzerland.|f RehaClinic , Bad Zurzach/Baden , Switzerland.|g University of Zurich , Switzerland.
Andreas R
AR
Gantenbein
b Centre for Pain Medicine , Swiss Paraplegic Centre , Nottwil , Switzerland.
Lenka
L
Stockinger
c Psychosomatic Division , C.L. Lory-Haus, Department of General Internal Medicine, Inselspital, University Hospital Bern , Switzerland.
Niklaus
N
Egloff
e Arztpraxis Hottingen , Zurich , Switzerland , CH-8053.|g University of Zurich , Switzerland.
Haiko
H
Sprott
c Psychosomatic Division , C.L. Lory-Haus, Department of General Internal Medicine, Inselspital, University Hospital Bern , Switzerland.
Wolfgang
W
Schleinzer
i Department of Psychiatry , University Hospital Zurich , Switzerland.
Roberto
R
Pirrotta
b Centre for Pain Medicine , Swiss Paraplegic Centre , Nottwil , Switzerland.
Wolfgang
W
Dumat
j Institute for Biomedical Engineering , Swiss Federal Institute of Technology and the University of Zurich , Switzerland.
Roger
R
Luechinger
h Karl Landsteiner Institute for Clinical Epilepsy Research and Cognitive Neurology, Neurological Center Rosenhuegel , Vienna , Austria.
Christoph
C
Baumgartner
d Department of Neuroradiology, University Hospital Zurich , Switzerland.
Spyridon
S
Kollias
f RehaClinic , Bad Zurzach/Baden , Switzerland.|g University of Zurich , Switzerland.
Peter S
PS
Sándor
D000328:Adult; D001007:Anxiety / Q000503:physiopathology; D016022:Case-Control Studies; D059350:Chronic Pain / Q000503:physiopathology*; D003291:Conversion Disorder / Q000503:physiopathology; D005157:Facial Pain / Q000150:complications*; D005260:Female; D066128:Gray Matter / Q000000981:diagnostic imaging*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D011569:Psychiatric Status Rating Scales; D013003:Somatosensory Cortex / Q000000981:diagnostic imaging; D020886:Somatosensory Disorders / Q000503:physiopathology*; D013557:Switzerland; D013702:Temporal Lobe / Q000000981:diagnostic imaging
Nondermatomal somatosensory deficits; anxiety; chronic myofascial pain; conversion disorder; voxel-based morphometry