Patients with nonspecific low back pain (NSLBP) rely more on the ankle compared with the lower back proprioception while standing, perform sit-to-stand-to-sit (STSTS) movements slower, and exhibit perceptual impairments at the lower back. However, no studies investigated whether these sensorimotor impairments relate to a reorganization of the primary and secondary somatosensory cortices (S1 and S2) and primary motor cortex (M1) during proprioceptive processing.
Proprioceptive stimuli were applied at the lower back and ankle muscles during functional magnetic resonance imaging in 15 patients with NSLBP and 13 controls. The location of the activation peaks during the processing of proprioception within S1, S2, and M1 were determined and compared between groups. Proprioceptive use during postural control was evaluated, the duration to perform 5 STSTS movements was recorded, and participants completed the Fremantle Back Awareness Questionnaire (FreBAQ) to assess back-specific body perception.
The activation peak during the processing of lower back proprioception in the right S2 was shifted laterally in the NSLBP group compared with the healthy group (P=0.007). Moreover, patients with NSLSP performed STSTS movements slower (P=0.018), and reported more perceptual impairments at the lower back (P<0.001). Finally, a significant correlation between a more lateral location of the activation peak during back proprioceptive processing and a more disturbed body perception was found across the total group (ρ=0.42, P=0.025).
The results suggest that patients with NSLBP show a reorganization of the higher-order processing of lower back proprioception, which could negatively affect spinal control and body perception.
*KU Leuven Department of Rehabilitation Sciences, Leuven
†Biomedical Research Institute, Rehabilitation Sciences, Hasselt University, Diepenbeek, Belgium
Supported by the Flanders Innovation & Entrepreneurship (VLAIO) (PhD Grant for Strategic Basic Research Nina Goossens, Grant Number ZKC9172-00-W01), Brussels, Belgium and the Research Foundation Flanders (FWO) (Postdoctoral Fellowship Lotte Janssens, Grant Number 12M9815N), Brussels, Belgium. The authors declare no conflict of interest.
Reprints: Nina Goossens, PhD, KU Leuven Department of Rehabilitation Sciences—Musculoskeletal Rehabilitation Research Group, Tervuursevest 101, P.O. Box 1501, Leuven 3001, Belgium (e-mail: firstname.lastname@example.org).
Received August 9, 2018
Received in revised form December 24, 2018
Accepted January 15, 2019