title: Chronic back pain is associated with decreased prefrontal and thalamic gray matter density.
abstract: The role of the brain in chronic pain conditions remains speculative. We compared brain morphology of 26 chronic back pain (CBP) patients to matched control subjects, using magnetic resonance imaging brain scan data and automated analysis techniques. CBP patients were divided into neuropathic, exhibiting pain because of sciatic nerve damage, and non-neuropathic groups. Pain-related characteristics were correlated to morphometric measures. Neocortical gray matter volume was compared after skull normalization. Patients with CBP showed 5-11% less neocortical gray matter volume than control subjects. The magnitude of this decrease is equivalent to the gray matter volume lost in 10-20 years of normal aging. The decreased volume was related to pain duration, indicating a 1.3 cm3 loss of gray matter for every year of chronic pain. Regional gray matter density in 17 CBP patients was compared with matched controls using voxel-based morphometry and nonparametric statistics. Gray matter density was reduced in bilateral dorsolateral prefrontal cortex and right thalamus and was strongly related to pain characteristics in a pattern distinct for neuropathic and non-neuropathic CBP. Our results imply that CBP is accompanied by brain atrophy and suggest that the pathophysiology of chronic pain includes thalamocortical processes.
authors.affiliation: Department of Physiology and Institute of Neuroscience, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611, USA. a-apkarian@northwestern.edu
authors.forename: A Vania
authors.initials: AV
authors.lastname: Apkarian
authors.forename: Yamaya
authors.initials: Y
authors.lastname: Sosa
authors.forename: Sreepadma
authors.initials: S
authors.lastname: Sonty
authors.forename: Robert M
authors.initials: RM
authors.lastname: Levy
authors.forename: R Norman
authors.initials: RN
authors.lastname: Harden
authors.forename: Todd B
authors.initials: TB
authors.lastname: Parrish
authors.forename: Darren R
authors.initials: DR
authors.lastname: Gitelman
mesh_terms: D000375:Aging / Q000473:pathology; D001416:Back Pain / Q000473:pathology*; D002908:Chronic Disease; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D010523:Peripheral Nervous System Diseases / Q000473:pathology / Q000503:physiopathology; D017397:Prefrontal Cortex / Q000473:pathology* / Q000503:physiopathology; D012720:Severity of Illness Index; D013788:Thalamus / Q000473:pathology*