Chronic Pain Can Impair Memory

In a study recently conducted at the university's Multidisciplinary Pain Centre in Edmonton, Canada, two-thirds of participants with chronic pain showed significant disruption of attention and memory when tested.

After studying 24 patients, Drs. Bruce D. Dick and Saifudin Rashiq seem to have zeroed in on one of the cognitive mechanisms affected by chronic pain. Their findings, published in the latest issue of Anesthesia and Analgesia, suggest that pain may disrupt the maintenance of the memory trace that is required to hold information for processing and retain it for storage in longer-term memory stores. In other words, chronic pain can, quite literally, drive people to distraction.

Participants in the study--all of whom had pain lasting six months or longer--were given computerized tests of working memory and a neuropsychological test of attention on separate "pain" and "less pain" days.

On the "less pain" day, participants were tested after receiving a pain-reducing procedure as part of their ongoing treatment at the Centre. On the "pain" day, participants were tested without having received a pain-reducing procedure, when their pain was reported to be at a high level. Sixteen participants--a startling 67 per cent--showed clinical impairment due to pain on their pain testing day. The remaining eight participants, or 33 per cent, showed no clinical impairment due to pain.

The sample of individuals included in the study may be small, but the statistically significant findings are "robust", Dick and Rashiq said.

"Prevalence studies indicate that as much as 44 per cent of the population--in Canada as well as in the U.S. and Europe--experience pain on a regular basis, and that in approximately one-quarter of this group the pain is severe", said Dick. The cost of chronic pain to society is great, and Dick and Rashiq argue that the matter needs to be recognized as a public health priority.