Biofeedback in chronic back pain

A recent journal paper in the International Journal of Behavioural Medicine presented a meta-analysis of the efficacy of biofeedback in chronic back pain. The authors identified some 21 "eligible" studies covering 23 treatemnt conditions and 1062 patients. 

The study suggests a significant effect on a number of related factors - for example

Detection of EMG from the trapezius muscles. The ground electrode is in the centre over the spine

  • pain intensity over an average follow-up duration of eight months
  • reducing depression and disability,
  • reduction of muscle tension and improving cognitive coping

The authors concluded that biofeedback treatment can lead to improvements in various pain-related outcomes in the short and long terms, both as a standalone and as an adjunctive intervention.

NeXus 10 biofeedback system utilising EMG biofeedback from the trapezius muscles

Some research on low back pain shows significant surface EMG (electromyographic) activity differences between persons with back pain compared with a control group of persons without pain. The surface EMG also shows differences based on the underlying cause of the back pain.

Surface EMG is a non-invasive way of monitoring tension in a muscle group by using surface electrodes. The EMG instrumentation picks up the weak electrical signals generated when a muscle contracts. Each muscle consists of many muscle fibers with motor neurons that are electrically connected to higher levels of the nervous system. As muscle contraction occurs some electrical energy leaves the muscle and migrates through surrounding tissue to the skin surface where it can be detected.  More EMG equals more muscle tension - less EMG equals less muscle tension. The NeXus range of biofeedback systems are all capable of plug and play interventions in this application area.

In the case of low back pain, experience suggests three possible muscle tension abnormalities

  • Unusually low muscle tension levels that are perhaps due to nerve damage and the resulting muscle atrophy
  • Unusually high muscle tension levels - which is the most frequently seen abnormality
  • Asymmetry in which one side of the back or hamstring muscles has normal EMG levels whils tthe other side has abnormally high or low levels.

How is biofeeback used?
The principles of biofeedback depend upon being able to measure a physiological signal (in this case EMG from a muscle of interest) then make the state of this signal (feedback) available to the client in a simple and meaningful manner. The client learns to decrease muscle tension for example, or in the case of asymmetry increase or decrease the abnormal muscle tension as appropriate. One goal would be balanced bilateral values within normal ranges. The images above show EMG biofeedback applied to the trapezius muscles which frequently exhibit tension abnormalities in cases of stress and migraine. The principles of application in lower-back pain are the same.

Reference
Robert Sielski , Winfried Rief, Julia Anna Glombiewski
"Efficacy of Biofeedback in Chronic back Pain: a Meta-Analysis"
International Journal of Behavioral Medicine, pp 1-17
First online: 15 June 2016
http://link.springer.com/article/10.1007%2Fs12529-016-9572-9