Chronic pain has an effect on memory

May 21 2007

We all know that a chronic bout of pain if it goes on for any length of time stops you thinking straight but now Canadian researchers say they have found that it also has a significant effect on both attention and memory.

The researchers from the University of Alberta carried out a study with 24 patients who had all suffered from pain for a period of six months or more.

The study which was conducted at the University's Pain Centre in Edmonton, found that two-thirds of participants with chronic pain showed significant disruption of attention and memory when tested.

People who experience chronic pain over a prolonged period also experience a 'knock-on' effect, and as well as work and sleep many other activities essential for normal healthy living are jeopardised.

Researchers Dr. Bruce Dick and Dr. Saifudin Rashiq found that one of the cognitive mechanisms affected by chronic pain is the maintenance of the memory trace required to hold information for processing; they say that chronic pain causes more than physical discomfort and can impair memory and concentration.

The researchers found that of the 24 participants, two-thirds showed significant disruption of attention and memory when tested; they say their findings suggest that pain may disrupt the ability to hold, process and retain information for storage in longer-term memory stores.

For the study the participants were given computerized tests of working memory and a neuropsychological test of attention on separate "pain" and "less pain" days.

The "less pain" day involved the participants being tested after receiving a pain-reducing procedure as part of their ongoing treatment at the Centre.

On "pain" day participants were tested without having received a pain-reducing procedure, when their pain was reported to be at a high level.

The research team found that sixteen of the participants (67 per cent) demonstrated a clinical impairment due to pain on their pain testing day; the other eight participants, (33 per cent), showed no clinical impairment due to pain.

Though the study group was small the researchers say the findings are significant and indicate that the cost of chronic pain to society is great and should be recognized as a public health priority.

The findings are published in the current issue of Anesthesia and Analgesia.