Reduced sensation matches reduced movement control in people with back pain

This study looked at sensory acuity at the back and the ability to perform specific movements of the back and pelvis.  By sensory acuity we mean how precise can we be about a stimulus applied to the skin of the back. We used a measure called two point discrimination threshold. That is, if one is touched in two locations at once, how far apart do those two locations have to be for us to detect two points instead of one.  We compared people with back pain to people without back pain.  Those with back pain were less precise – their tactile acuity was less than that of those without back pain.  What is more, the degree to which their tactile acuity was reduced related to how difficult it was for them to perform certain voluntary movements of their back.  Read about it in the paper here.

Tactile acuity and lumbopelvic motor control in patients with back pain and healthy controls

Hannu Luomajoki(a) and G Lorimer Moseley(b)
(a) Zürich University of Applied Sciences, Switzerland
(b) Prince of Wales Medical Research Institute, Australia

Abstract

Background Voluntary lumbo-pelvic control is compromised in patients with back pain. Loss of proprioceptive acuity is one contributor to decreased control. Several reasons for decreased proprioceptive acuity have been proposed, but the integrity of cortical body maps has been overlooked. We investigated whether tactile acuity, a clear clinical signature of primary sensory cortex organisation, relates to lumbopelvic control in people with back pain.

Methods Forty-five patients with back pain and 45 age and gender matched healthy controls participated in this cross sectional study. Tactile acuity at the back was assessed using two-point discrimination (TPD) threshold in vertical and horizontal directions. Voluntary motor control was assessed using an established battery of clinical tests.

Results Patients performed worse on the voluntary lumbopelvic tasks than healthy controls did (p<0.001). TPD threshold was larger in patients (mean ± SD = 61mm ± 13mm) than in healthy controls (44mm ± 10mm). Moreover, larger TPD threshold was positively related to worse performance on the voluntary lumbopelvic tasks (Pearsons r= 0.49; p<0.001).

Discussion Tactile acuity, a clear clinical signature of primary sensory cortex organisation, relates to voluntary lumbopelvic control. This relationship raises the possibility that the former contributes to the latter, in which case training tactile acuity may aid recovery and assist in achieving normal motor performance after back injury.

See full article at British Journal of Sports Medicine