Prediction and trend of tactile acuity, pain and disability in acute LBP: a six-month prospective cohort study

Abstract

Background Chronic back pain is known to be associated with altered tactile acuity. Tactile acuity is measured using the Two-Point Discrimination (TPD) test in both clinical and research settings. In subjects with chronic low back pain, the TPD threshold (TPDT) is increased and is associated with persistent pain. It remains unknown, however, whether TPDT is also altered in cases of clinical acute pain, or whether it could be used as a predictor of future pain and disability at an early stage of LBP. The main objective of this study was to investigate the predictive value of baseline TPDT for pain and disability at 3 and 6 months after the onset of acute LBP. The TPDT in acute low back pain (LBP) and the development of TPDT over 6 months has also been assessed. Methods LBP participants (n = 124) with acute LBP (< 4 weeks) were included. Subjects were examined within 4 weeks of pain onset and followed-up after 3 and 6 months of pain onset. Horizontal and vertical TPDTs of the lower back were collected. Linear mixed models were subsequently used to evaluate the association of TPDT with pain and disability over time. Results The vertical TPDT showed a mean (SD) of 4.9 cm (1.6) and the horizontal TPDT a mean (SD) of 6.0 cm (1.5) at baseline. The vertical TPDT altered from baseline up to 6 months from 4.9 to 4.6 cm and the horizontal TPDT from 6.0 to 5.4 cm. The association between the TPDT and the Oswestry Disability Index (ODI) after 6 months was moderate. Linear mixed models revealed no association between TPDT, pain and disability over the progression of LBP. Conclusion TPDTs appear to be raised in subjects with acute LBP. However, our study revealed no predictive capability of the TPDT for disability and pain. No comparisons are possible in the absence of similar studies, indicating the need for further research is in this area.

Spatial tuning in nociceptive processing is driven by attention

“…For example, patients with CRPS 7 , or other types of chronic pain respond poorer with 2-point discrimination tasks 7 . Moreover, more recent studies have confirmed that such a tuning disruption already occurs in the acute phase of pain 27 or even immediately following noxious stimulus application 2 and preliminary data shows that intervention directed at spatial retuning may effectively reduce pain intensity 28,29 .…”

Adaptive changes in sensorimotor processing in patients with acute low back pain

“…The test battery assessed six movements and demonstrated a significant difference between patients with LBP and pain-free healthy subjects 66 . Tactile acuity was investigated by applying the vertical two-point discrimination tests performed bilaterally, and the horizontal line, the level of L4, was used as a reference 67 . A dolorimeter quantified the bilateral Pressure Pain Threshold to investigate tissue sensitivity at the same position.…”

Inter- and Intra-Examiner Reliability Study of Two-Point Discrimination Test (TPD) and Two-Point Estimation Task (TPE) in the Sacral Area of Pain-Free Individuals

“…After each measurement, present the value on the display to the assistant recording the results". Subsequently, the examiner set the caliper at a distance of 120 mm, which according to previous tests, perfectly corresponds with the sensation of two separate points [10,15]. The next step was to put the caliper on the tested person at the S3 level on one of the sides (drawn earlier), in such a way that the previously marked points (5 and 15 cm) were between the spaced caliper arms.…”

“…Research results have shown that the acuity with which touch is perceived at the painful body site is disturbed [9]. Studies have shown that tactile acuity in the acute phase of back pain only changes minimally during a 6-month follow-up [10]. Also, experimentally induced acute back pain leads to a loss of acuity, expressed as deteriorated touch sensation in the painful part of the body [11].…”