Lumbar tactile acuity is near identical between sides in healthy pain-free participants.
A growing body of literature suggests that alterations in brain structure and function are a feature of chronic back pain. Tactile acuity is considered a clinical signature of primary somatosensory representation and offers a simple measure of cortical reorganisation. Clinical interpretation of test scores from an individual patient is hampered by variance in published normative values and less than ideal inter-rater reliability. These problems might be mitigated in people with unilateral back pain by using the patient as their own control and comparing tactile acuity at the painful site to performance at the corresponding position on the non-painful side. The first step in exploring this approach is to quantify the normal side-to-side difference in healthy populations. We pooled data from three previous studies that measured lumbar tactile acuity bilaterally in healthy controls using similar protocols. We calculated the mean and variance of the absolute error between sides, the standard error of measurement and the reliable change index (RCI). The mean difference between sides was 3.2 mm (±5.2) when assessed vertically and 1.9 mm (±3.2) when assessed horizontally. The standard error of measurement was 4.2 mm when assessed vertically and 2.7 mm when assessed horizontally. The RCI suggests that differences of greater than 13 mm when assessed horizontally and 17 mm when assessed vertically equate to 95% confidence that a difference truly exists. Several assumptions related to the application of this approach need to be investigated further.
The School of Physiotherapy, The University of Notre Dame Australia, 19 Mouat Street, Fremantle, WA 6959, Australia. Electronic address: benedict.wand@nd.edu.au.
Benedict Martin
BM
Wand
Sansom Institute for Health Research, University of South Australia, Adelaide, Australia.
Mark Jon
MJ
Catley
Institute of Physiotherapy, Department of Health, Zürich University of Applied Sciences, Winterthur, Switzerland.
Hannu Antero
HA
Luomajoki
Department of Clinical Therapies, University of Limerick, Ireland.
Kieran James
KJ
O'Sullivan
Neuroscience Research Australia, Sydney, Australia; The Prince of Wales Clinical School, University of New South Wales, Sydney, Australia.
Flavia
F
Di Pietro
Centre for Research in Rehabilitation, School of Health Sciences and Social Care, Brunel University, Uxbridge, UK.
Neil Edward
NE
O'Connell
Sansom Institute for Health Research, University of South Australia, Adelaide, Australia.
G Lorimer
GL
Moseley
D000328:Adult; D059350:Chronic Pain / Q000503:physiopathology; D004193:Discrimination Learning; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D017116:Low Back Pain / Q000503:physiopathology; D008161:Lumbosacral Region / Q000503:physiopathology*; D008297:Male; D055698:Touch Perception / Q000502:physiology*
Body image; Chronic low back pain; Sensory acuity; Two-point discrimination