On the moderating role of age in the relationship between pain and cognition.

BACKGROUND: A relationship between pain perception and cognitive function is evident. However, the directionality of this association is unclear and may be influenced by age. That is, inverse associations between pain and cognition have been reported in young and middle-aged chronic pain patients, whereas higher clinical pain ratings have been associated with better cognitive performance in older chronic pain patients. Therefore, this study examined the possible moderating role of age in the pain-cognition relationship.
METHOD: Twenty-two younger and 24 older chronic pain participants completed neuropsychological tests of psychomotor speed, memory and executive function. They also completed the McGill Pain Questionnaire to evaluate clinical pain.
RESULTS: Interaction analyses revealed that age indeed moderates the relationship between clinical pain ratings and cognitive functions. In the younger age group, pain ratings were inversely related to memory and executive function. In the older age group, a positive relationship was found between pain ratings and executive function, whereas the inverse association of clinical pain with memory was no longer present.
CONCLUSIONS: This study was the first to confirm the hypothesis that age is an important moderator of the relationship between pain and cognition. An important finding is that in older adults, most inverse effects of pain on cognition are either no longer present or may even be reversed. The positive relationship between pain and executive function may indicate age-related reduced integrity of a shared underlying neural substrate.