Chronic low back pain may hamper motor control of other body parts

Sep 28 2011
While it is intuitive to assume lower back pain would make it harder to perform movements that use the back muscles, new research shows that chronic pain could also make tasks that use unrelated muscles more difficult.

The National Institutes of Health (NIH) estimate that 80 percent of Americans will experience back pain at some point in their lives. It is considered the most common neurological disorder, second only to headache, according to the Centers for Disease Control and Prevention, and is a costly burden to both the healthcare system and to the economy through lost wages.

The spinal column consists of the vertebrae, the facet joints and the intervertebral discs that cushion the spaces in between the bones. Injury, disease or degeneration of any of these structures can lead to pain. Acute back pain, the most common type of back pain, comes from a sudden injury, but should not last longer than six weeks, according to the National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), a division of the NIH. Chronic back pain can linger longer than three months.

Previous studies have shown that chronic lower back pain can make it hard to perform tasks that involve the area, such as bending and reaching for objects. This may be because of a vicious cycle between pain and a patient's fear of pain. However, there has been little research to say whether chronic pain could also make movements not involving the back more difficult. Scientists from the Netherlands were curious about whether pain, or the mere perception of it, could hamper people's ability to perform tasks unrelated to affected areas.

The researchers enrolled 30 subjects in their investigation: 15 people with chronic lower back pain and 15 healthy controls. Each person was given a test in which they were told to click a button upon hearing an auditory signal to commence the task, which involved arranging a series of cylinders. This same test was performed in three different scenarios for each subject: sitting, lying down and lying down with no trunk support, which could heighten the expectation of pain.

The results showed that overall, compared to the healthy subjects, patients with chronic lower back pain were slower to react to the auditory signal and had a harder time arranging the cylinders as instructed. Also, between lying down and lying with no trunk support, back pain patients slowed down in the arranging task, but their reaction time to the auditory signal remained the same. Together, the results suggest that both actual pain and the fear of pain can interfere with movement not related to the back.

Future studies will need to verify these findings in patients performing tasks more similar to everyday life rather than a lab setting, the researchers said.

There are several things that people can do to help avoid back pain, according to NIAMS. Exercises such as weight training, yoga and tai chi could improve the strength and balance of the back muscles. Proper lifting techniques that bear an object's weight on one's hips and legs instead of the back can help prevent injury. The bones in the spine can benefit from a diet rich in calcium and vitamin D, including dairy and green, leafy vegetables.