Does acupuncture/dry needling applied as a sensory discrimination training tool decrease pain in chronic low back pain patients more than acupuncture alone?

Acupuncture of lumbar spine (same points as the control) with sensory discrimination (subjects watch the acupuncture point via a mirror) Detail: All the chosen points are designed to represent the most common and practical local acupuncture points for the treatment of low back pain. A total of 14 points will be inserted for each intervention. Considering subjects will be in different sizes and shapes, instead of using metric system to standardise points their thumb width (cun, unit of measuring points in acupuncture) will be measured by using a cunometer (a measuring instrument similar to a clipper that is used to find thumb width/cun). The spinous processes of lumbar spine will be used as the point of reference and the cunometer will be employed to find the acupuncture points. The points will be marked on the subjects lumbar region with skin safe pen and left for the duration of both intervention. The points are mostly traditional points thus they run over a meridian (Urinary Bladder). Four of the points do not run over the meridian and they are common Trigger or Ah Shi points.All these points have been used in numerous large trials of acupuncture for low back pain. The Depth of penetration will be standardised to only 15mm and insertion will be directed obliquely towards the spinous process. To standardise the depth all needles will be exactly 15mm in length and they are completely inserted in both interventions. In the experimental intervention arm subjects will participate in a sensory discrimination training programme similar to that used by Moseley et al. (2008b) in the management of CRPS. Subjects will be shown a picture of the back with the position of each needle numbered. The clinician will manipulate a single needle for a few seconds in random order and the subject will be required to nominate which needle is being stimulated. This will be performed with visualisation of the back via a mirror in the first 10 minutes and progressed to without a mirror in the last 10 minutes. Each intervention sesssion is 20 minutes in duration with a 10 minutes wash out periods between each intervention. Subjects will have to attend one appointment. During the appointment they will recieve the two interventions.