Grant: Master's Award: Canada Graduate Scholarships

Pain serves as an alarm signal disrupting ongoing activities in order to immediately call attention to the source of potential injury. In some cases, however, the protective effect of pain can become problematic, such as in many chronic pain syndromes. In these instances, it may become more adaptive to ignore pain in order to resume ongoing activities. Indeed, chronic pain syndromes are nearly systematically associated with executive dysfunctions, assumed to be a disruptive consequence of the unremitting pain. This association has strong implications for the elderly, for whom a decline in cognition seems to coincide with an increased risk of developing chronic pain - indeed, a whopping one in three adults over 65 suffers from chronic pain, almost twice as many as younger adults. It now known that pain disrupts executive functioning, but could chronic pain also arise more frequently in older adults having previously shown signs of executive functions decline? More generally, is intact executive functioning vital to normal pain regulation? A recent study has found distraction by a task recruiting executive functioning can reduce the intensity of a painful stimulus experienced simultaneously. This would help explain why a patient suffering from chronic pain may easily cease to feel their pain while absorbed in a demanding activity, only to have it return while resting and idle. Although it is clear that the role of executive functions is to inhibit distractions such as pain, in order to prioritize more valued tasks, no study has yet explored the effects of executive functions integrity on pain perception and distractive effects. This could have important implications for understanding why certain individuals and populations are more at risk of developing chronic pain. If executive deficits impact pain perception, not only would pain lead to sustained disruption of cognition in the elderly, but cognitive decline or impairment would also in turn impact pain regulation - a chicken-and-egg effect. We thus propose that deficits in cognition - specifically, executive functioning, thought to be responsible for the management of cognitive processes - will impact one's ability to suppress pain during a task, in addition to impacting one's ability to perform a task while in pain, and that these effects will be particularly prevalent in aging populations. To test our hypothesis, we will recruit 40 young (ages 18-30) and 40 older (ages 60-80) healthy volunteers for a psychophysical study. We will first verify pain thresholds in order to select individual 'low' and 'high' stimulation temperatures; next, executive functioning will be measured with a modified version of the Stroop task. Finally, in the experimental portion of the study, participants will complete an 'n-back' task measuring working memory, while simultaneously receiving pain thermal stimuli; pain perception and task performance will be measured throughout the procedure. This study will allow us to assess whether the participants with lower executive functions ability have more difficulty performing on the task while in pain, and report more pain during the task, and whether the elderly are more vulnerable to these disruptive effects. Indeed, the task used is an experimental version of an everyday situation for chronic pain patients, who are to constantly try to ignore their pain in order to carry out professional activities or tasks of daily life. The results of the proposed study will allow us to identify a new risk factor to chronic pain and to its functional impacts, which can lead to better detection of pre-existing vulnerabilities in older adults, and to a tailoring of elderly care that incorporates measures of prevention and intervention.