You don't need to be a scientist to know that chronic back pain can have a negative impact on your life, often bringing with it anxiety and depression. It can affect your ability to work, sleep, and perform other daily activities.
Until recently, it has been assumed that whatever changes occurred in the brain as a result of chronic back pain were only temporary and that the brain would revert to a normal state once the pain stopped.
Recent findings by researchers from Northwestern University have turned this assumption on its head. What they found was that chronic back pain - defined as pain lasting six months or longer - can cause significant and long-lasting damage to the brain, aging it up to 20 times faster than normal.
Shades of gray
In fact, chronic back pain actually shrinks the gray matter of the brain - the part responsible for memory and information processing - by as much as 11 percent each year. In contrast, normal aging of the brain results in just a 0.5 percent loss of gray matter a year.
Scientists compared 26 healthy volunteers with 26 patients who had been suffering with chronic lower back pain (some with sciatica) for more than a year. Those with chronic back pain with sciatica had the largest decrease in gray matter. Another significant finding: The longer a subject had had chronic back pain, the more brain loss he suffered.
One theory on why there is such a large decrease in gray matter is that chronic pain forces nerve cells to work overtime. Even more troubling is the possibility that if chronic back pain is allowed to continue, it may become harder to reverse and less responsive to treatment due to these changes in the brain. Experts say the findings should sound a warning to patients with back pain to seek care as soon as possible.
Driven to distraction
The Northwestern study is consistent with other research on chronic pain and cognitive ability. Scientists at the University of Alberta have confirmed that chronic pain can impair your memory and concentration.
In testing done by Drs. Bruce D. Dick and Saifudin Rashiq at the university's Multidisciplinary Pain Centre in Edmonton, Canada, two-thirds of participants who suffered with chronic pain had a difficult time paying attention and remembering simple facts.
Participants in the study - all of whom had pain lasting six months or longer - were given computerized memory tests, along with a neuropsychological test of attention on what were identified as "pain" and "less pain" days.
On a "less pain" day, participants were tested after they received a pain-reducing procedure as part of their ongoing treatment at the Centre. On a "pain" day, participants were tested without getting any pain-reducing procedure. Sixteen of the 24 participants - 67 per cent - showed signs of cognitive impairment on their pain-testing day. Although the sample of participants was small, the findings were statistically significant, according to the lead researchers.
You must remember this
Further evidence of a link between chronic pain and brain function comes from a study done at Keele University in the United Kingdom. Scientists compared the "prospective" memory - such as remembering to pick up groceries or keep a doctor's appointment - of 50 subjects with chronic back pain to the memory of 50 subjects who were pain-free.
Investigators used something called the Prospective Memory Questionnaire, a self-rating scale that requires users to record the number of times their prospective memory fails in a given period of time. The scale measures three types of prospective memory: long-term habitual, short-term episodic, and internally cued.
Those with chronic pain had significantly impaired short-term memory compared with subjects who were pain-free. No differences were observed in the other types of prospective memory.
"One explanation for the observation of short-term prospective memory deficits may be related to the link between pain and stress and the impact of this relationship on cognitive function," Ling's team reported.
The ideas is that when pain kicks in, it triggers a region of the brain known as the lateral occipital complex (LOC). When this happens, it overrides a person's ability to concentrate and accurately recognize images.