title: Changes in pain perception and descending inhibitory controls start at middle age in healthy adults.
abstract: OBJECTIVE
  Previous studies have shown a reduction of diffuse noxious inhibitory controls (DNICs) in elderly adults compared with younger adults. Unfortunately, little is known regarding the developmental course of DNIC deficits and so it is still unclear whether middle-aged adults also show a DNIC deficit. The aims of the present study were to better characterize the developmental time course of the change in DNIC response by adding a middle-aged group. The role of expectations was also investigated.
  
  
  METHODS
  The pain thresholds (PTs) of 20 young, 20 middle-aged, and 20 healthy elderly volunteers were assessed before and during a cold pressor task (water at 7 degrees C). Acute nociceptive stimuli were administered using a thermode and consisted of a range of painless and painful heat pulses.
  
  
  RESULTS
  Analyses showed that thermal PTs increase by middle age but that the DNIC-induced increase in PT dampens progressively with advancing age. DNIC response was negatively correlated with advancing age, however, expectations regarding DNIC efficacy did not vary with age. This suggests that age-related changes in the size of the DNIC response are not best explained by an age-related change in expectation.
  
  
  CONCLUSIONS
  The findings tell us that changes in pain perception and endogenous pain modulation arrive earlier than previously suggested. Studies on aging and pain should include a middle-aged group when comparing pain measures across the adult lifespan.
authors.affiliation: Département des Sciences de la Santé, Université du Québec en Abitibi-Témiscamingue, Rouyn-Noranda, Québec, Canada.
authors.forename: Marianne
authors.initials: M
authors.lastname: Larivière
authors.forename: Philippe
authors.initials: P
authors.lastname: Goffaux
authors.forename: Serge
authors.initials: S
authors.lastname: Marchand
authors.forename: Nancy
authors.initials: N
authors.lastname: Julien
mesh_terms: D000328:Adult; D000368:Aged; D000375:Aging / Q000523:psychology*; D000698:Analgesia / Q000523:psychology; D003080:Cold Temperature; D003213:Conditioning, Psychological; D005260:Female; D006358:Hot Temperature; D006801:Humans; D006930:Hyperalgesia / Q000523:psychology; D007101:Immersion; D008297:Male; D008875:Middle Aged; D010146:Pain / Q000523:psychology*; D010147:Pain Measurement; D017288:Pain Threshold / Q000502:physiology; D011312:Pressure