title: Central sensitization and changes in conditioned pain modulation in people with chronic nonspecific low back pain: a case-control study.
abstract: Quantitative sensory testing is widely used in human research to investigate the state of the peripheral and central nervous system contributions in pain processing. It is a valuable tool to help identify central sensitization and may be important in the treatment of low back pain. The aim of this study was to evaluate changes in local and segmental hypersensitivity and endogenous pain inhibition in people with chronic nonspecific low back pain. Thirty patients with chronic low back pain and thirty healthy subjects were studied. Pressure pain thresholds (PPTs) were measured from the lumbar region and over the tibialis anterior muscle (TA). A cold pressor test was used to assess the activation of conditioned pain modulation (CPM), and PPTs in the lumbar region were recorded 30 s after immersion of participant's foot in a bucket with cold water. People with chronic low back pain have significantly lower PPT than controls at both the lumbar region [89.5 kPa (mean difference) 95 % CI 40.9-131.1 kPa] and TA [59.45 kPa (mean difference) 95 % CI 13.49-105.42 kPa]. During CPM, people with chronic low back pain have significantly lower PPT than controls in lumbar region [118.6 kPa (mean difference) 95 % CI 77.9-159.2 kPa]. Women had significantly lower PPTs than men in both lumbar region [101.7 kPa (mean difference) 95 % CI 37.9-165.7 kPa] and over the TA [189.7 kPa (mean difference) 95 % CI 14.2-145.2 kPa]. There was no significant difference in PPTs in men between healthy controls and those with low back pain, suggesting the significant differences are mediated primarily by difference between women.
authors.affiliation: Master's and Doctoral Programs in Physical Therapy, Universidade Cidade de São Paulo, Rua Cesário Galeno 448, Tatuapé, São Paulo, CEP 03071-000, Brazil.
authors.forename: Juliana Barbosa
authors.initials: JB
authors.lastname: Corrêa
authors.forename: Leonardo Oliveira Pena
authors.initials: LO
authors.lastname: Costa
authors.forename: Naiane Teixeira Bastos
authors.initials: NT
authors.lastname: de Oliveira
authors.forename: Kathleen A
authors.initials: KA
authors.lastname: Sluka
authors.forename: Richard Eloin
authors.initials: RE
authors.lastname: Liebano
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D059333:Central Nervous System Sensitization / Q000502:physiology*; D059350:Chronic Pain; D005260:Female; D006801:Humans; D006930:Hyperalgesia / Q000503:physiopathology*; D017116:Low Back Pain / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D058748:Pain Perception / Q000502:physiology*; D017288:Pain Threshold / Q000502:physiology*; D012737:Sex Factors