Chronic pain may impede short-term memory

By Amy Norton

NEW YORK (Reuters Health) - People who suffer from chronic pain may find their memory taxed by everyday "multitasking," a new study suggests.

The study, of 24 men and women treated at a pain clinic, found that chronic pain appeared to impair patients' working, or short-term, memory.

Specifically, many had trouble maintaining a "memory trace" of one piece of information while simultaneously performing another task. In real life, this might translate into, for instance, difficulty remembering a phone number while searching for a pen and holding your baby, study co-author Dr. Bruce D. Dick told Reuters Health.

It's possible, according to Dick, that chronic pain disrupts a person's attention and essentially "eats up" some of the resources the brain would otherwise devote to working memory -- the temporary "holding tank" where information is processed before being stored in long-term memory.

"Many of us in our day-to-day activities multitask, and we divide up our working memory resources between a variety of tasks," explained Dick, an assistant professor of anesthesiology and pain medicine at the University of Alberta in Edmonton, Canada.

But the new findings suggest that chronic bodily pain can drain the resources available for such mental multitasking.

Dick and colleague Saifudin Rashiq report the findings in the journal Anesthesia & Analgesia.

For the study, the researchers recruited 24 patients from the university pain clinic who'd been suffering pain in their joints, back, limbs or elsewhere in the body for at least 6 months.

Based on standard tests of attention and working memory, 16 patients were categorized as being impaired due to their pain. Of these patients, those who were most impaired specifically showed problems in maintaining a memory trace.

According to Dick, the findings support what many chronic pain patients have long maintained -- that their memory suffers as a result of their physical condition.

"Our findings also point to a specific cognitive mechanism that is disrupted by pain," he noted.

The hope, according to Dick, is to eventually help chronic pain patients recognize when their cognitive function is being affected, and offer them ways to overcome those disruptions.

SOURCE: Anesthesia & Analgesia, May 2007.