Differences in brain processing of proprioception related to postural control in patients with recurrent non-specific low back pain and healthy controls

Patients with non-specific low back pain (NSLBP) show an impaired postural control during standing and a slower performance of sit-to-stand-to-sit (STSTS) movements. Research suggests that these impairments could be due to an altered use of ankle compared to back proprioception. However, the neural correlates of these postural control impairments in NSLBP remain unclear. Therefore, we investigated brain activity during ankle and back proprioceptive processing by applying local muscle vibration during functional magnetic resonance imaging in 20 patients with NSLBP and 20 controls. Correlations between brain activity during proprioceptive processing and (Airaksinen et al., 2006) proprioceptive use during postural control, evaluated by using muscle vibration tasks during standing, and (Altmann et al., 2007) STSTS performance were examined across and between groups. Moreover, fear of movement was assessed. Results revealed that the NSLBP group performed worse on the STSTS task, and reported more fear compared to healthy controls. Unexpectedly, no group differences in proprioceptive use during postural control were found. However, the relationship between brain activity during proprioceptive processing and behavioral indices of proprioceptive use differed significantly between NSLBP and healthy control groups. Activity in the right amygdala during ankle proprioceptive processing correlated with an impaired proprioceptive use in the patients with NSLBP, but not in healthy controls. Moreover, while activity in the left superior parietal lobule, a sensory processing region, during back proprioceptive processing correlated with a better use of proprioception in the NSLBP group, it was associated with a less optimal use of proprioception in the control group. These findings suggest that functional brain changes during proprioceptive processing in patients with NSLBP may contribute to their postural control impairments

The development of the Dutch version of the Fremantle Back Awareness Questionnaire

Background: Disturbed body perception may play a role in the aetiology of chronic low back pain (LBP). The Fremantle Back Awareness Questionnaire (FreBAQ) is currently the only self-report questionnaire to assess back-specific body perception in individuals with LBP. Objectives: To perform a cross-cultural adaptation of the FreBAQ into Dutch. Design: Psychometric study. Methods: A Dutch version of the FreBAQ was generated through forward-backward translation, and was completed by 73 patients with LBP and 73 controls to assess discriminant validity. Structural validity was assessed by principal component analysis. Internal consistency was assessed by the Cronbach\u27s alpha coefficient. Construct validity was assessed by examining the relationship with clinical measures (Numerical Rating Scale pain, Oswestry Disability Index (ODI), Tampa Scale for Kinesiophobia). Test-retest reliability was assessed in a subgroup (n = 48 with LBP and 48 controls) using intraclass correlation coefficients (ICC), standard error of measurement (SEM) and minimal detectable change (MDC 95%) Results: The Dutch FreBAQ showed one component with eigenvalue \u3e2. Cronbach\u27s alpha values were respectively 0.82 and 0.73 for the LBP and control group. ICC values were respectively 0.69 and 0.70 for the LBP and control group. In the LBP group, the SEM was 3.9 and the MDC (95%) was 10.8. The LBP group (ODI 22 ± 21%) scored significantly higher on the Dutch FreBAQ than the control group (ODI 0%) (11 ± 7 vs. 3 ± 9, p \u3c 0.001). Within the LBP group, higher Dutch FreBAQ scores correlated significantly with higher ODI scores (rho = 0.30, p = 0.010), although not with pain (rho = 0.10, p = 0.419) or kinesiophobia (r = 0.14, p = 0.226). Conclusions: The Dutch version of the FreBAQ can be considered as unidimensional and showed adequate internal consistency, sufficient test-retest reliability and adequate discriminant and construct validity in individuals with and without LBP. It can improve our understanding on back-specific perception in the Dutch-speaking population with LBP

Postural strategy and back muscle oxygenation during inspiratory muscle loading.

Most healthy individuals show a multisegmental control strategy during challenging standing conditions, whereas others show a rigid ankle-steered strategy, which is assumed as suboptimal. Respiratory-demanding tasks exert a perturbing effect on balance, although the underlying mechanisms remain poorly understood. The purpose of this study was to investigate whether inspiratory resistive loading (IRL) affects postural strategy, back muscle oxygenation, and blood volume during postural control

Inspiratory muscle training affects proprioceptive use and low back pain.

We have shown that individuals with recurrent nonspecific low back pain (LBP) and healthy individuals breathing against an inspiratory load decrease their reliance on back proprioceptive signals in upright standing. Because individuals with LBP show greater susceptibility to diaphragm fatigue, it is reasonable to hypothesize that LBP, diaphragm dysfunction, and proprioceptive use may be interrelated. The purpose of this study was to investigate whether inspiratory muscle training (IMT) affects proprioceptive use during postural control in individuals with LBP

Distinction of non-specific low back pain patients with proprioceptive disorders from healthy individuals by linear discriminant analysis

The central nervous system (CNS) dynamically employs a sophisticated weighting strategy of sensory input, including vision, vestibular and proprioception signals, towards attaining optimal postural control during different conditions. Non-specific low back pain (NSLBP) patients frequently demonstrate postural control deficiencies which are generally attributed to challenges in proprioceptive reweighting, where they often rely on an ankle strategy regardless of postural conditions. Such impairment could lead to potential loss of balance, increased risk of falling, and Low back pain recurrence. In this study, linear and non-linear indicators were extracted from center-of-pressure (COP) and trunk sagittal angle data based on 4 conditions of vibration positioning (vibration on the back, ankle, none or both), 2 surface conditions (foam or rigid), and 2 different groups (healthy and non-specific low back pain patients). Linear discriminant analysis (LDA) was performed on linear and non-linear indicators to identify the best sensory condition towards accurate distinction of non-specific low back pain patients from healthy controls. Two indicators: Phase Plane Portrait ML and Entropy ML with foam surface condition and both ankle and back vibration on, were able to completely differentiate the non-specific low back pain groups. The proposed methodology can help clinicians quantitatively assess the sensory status of non-specific low back pain patients at the initial phase of diagnosis and throughout treatment. Although the results demonstrated the potential effectiveness of our approach in Low back pain patient distinction, a larger and more diverse population is required for comprehensive validation

Greater diaphragm fatigability in individuals with recurrent low back pain.

The diaphragm plays an important role in spinal control. Increased respiratory demand compromises spinal control, especially in individuals with low back pain (LBP). The objective was to determine whether individuals with LBP exhibit greater diaphragm fatigability compared to healthy controls. Transdiaphragmatic twitch pressures (TwPdi) were recorded in 10 LBP patients and 10 controls, before and 20 and 45 min after inspiratory muscle loading (IML). Individuals with LBP showed a significantly decreased potentiated TwPdi, 20 min (-20%) (p=0.002) and 45 min (-17%) (p=0.006) after IML. No significant decline was observed in healthy individuals, 20 min (-9%) (p=0.662) and 45 min (-5%) (p=0.972) after IML. Diaphragm fatigue (TwPdi fall ≥ 10%) was present in 80% (20 min after IML) and 70% (45 min after IML) of the LBP patients compared to 40% (p=0.010) and 30% (p=0.005) of the controls, respectively. Individuals with LBP exhibit propensity for diaphragm fatigue, which was not observed in controls. An association with reduced spinal control warrants further study

Ankle proprioception is not targeted by exercises on an unstable surface

Item does not contain fulltextLaboratory study using a repeated measures design. The aim of this study was to determine if ankle proprioception is targeted in exercises on unstable surfaces. Lateral ankle sprain (LAS) has recurrence rates over 70%, which are believed to be due to a reduced accuracy of proprioceptive signals from the ankle. Proprioceptive exercises in rehabilitation of LAS mostly consist of balancing activities on an unstable surface. The methods include 100 healthy adults stood barefoot on a solid surface and a foam pad over a force plate, with occluded vision. Mechanical vibration was used to stimulate proprioceptive output of muscle spindles of triceps surae and lumbar paraspinal musculature. Each trial lasted for 60 s; vibration was applied from the 15th till the 30th second. Changes in mean velocity and mean position of the center of pressure (CoP) as a result of muscle vibration were calculated. Results show that on foam, the effect of triceps surae vibration on mean CoP velocity was significantly smaller than on a solid surface, while for paraspinal musculature vibration the effect was bigger on foam than on solid surface. Similar effects were seen for mean CoP displacement as outcome. Exercises on unstable surfaces appear not to target peripheral ankle proprioception. Exercises on an unstable surface may challenge the capacity of the central nervous system to shift the weighting of sources of proprioceptive signals on balance

Altered interpretation of neck proprioceptive signals in persons with subclinical recurrent neck pain

OBJECTIVE: To evaluate whether subjects with subclinical recurrent neck pain have an altered interpretation of neck proprioceptive signals. DESIGN: A comparative group design. SUBJECTS: Twelve subjects with recurrent neck pain and 12 control subjects. METHODS: The shoulder, head, trunk and whole-body position were measured under the following conditions: active and passive elevation and depression of the right shoulder and vibration of the trapezius muscle. RESULTS: During passive shoulder movements both groups moved their head in the opposite direction (p<0.05). During passive elevation subjects with recurrent neck pain showed a significant over-appraisal of shoulder position. Both groups responded similarly to active movements. Subjects with recurrent neck pain and control subjects showed similar trunk and head-to-trunk movements during shoulder movements. Subjects with recurrent neck pain, however, made larger movements compared with healthy subjects (p<0.05). During trapezius muscle vibration similar whole-body movements were found in both groups. CONCLUSION: These results show a modified interpretation of neck proprioceptive signals in subjects with recurrent neck pain and may reflect an offset in the egocentric reference frame or a decreased capacity to switch between reference frames. Better insight into these mechanisms might lead to better evaluation and treatment of subjects with recurrent neck pain and to a reduction in recurrent episodes.status: publishe

The effectiveness of technology-supported exercise therapy for low back pain: a systematic review

Various technological systems have been developed to assist exercise therapy for low back pain. The aim of this systematic review was to provide an overview and to assess the effectiveness of the available technology-supported exercise therapy (TSET) programs for low back pain. The electronic databases Pubmed, Embase, Cochrane Central Register of Controlled Trials, PEDro, IEEE, and ACM were searched until January 2016. Randomized controlled trials (RCTs) using electronic technological systems simultaneously with exercise therapy for patients with low back pain were included. Twenty-five RCTs met the inclusion criteria. Seventeen studies involved patients with chronic low back pain, and electromyography biofeedback was the most prevalent type of technological support. This review shows that TSET seems to improve pain, disability, and quality of life for patients with low back pain, and that a standard treatment combined with an additional TSET program might be superior to a standard treatment alone. However, TSET seems not more effective compared to other interventions or a placebo intervention for improving these outcomes, which may partially be explained by the analytical approach of the current TSET-programs. For most technologies, only a limited number of RCTs are available, making it difficult to draw firm conclusions about the effectiveness of individual technological systems.status: publishe

Changes in the organization of the secondary somatosensory cortex while processing lumbar proprioception and the relationship with sensorimotor control in low back pain

OBJECTIVES: 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. MATERIALS AND METHODS: 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. RESULTS: 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). CONCLUSIONS: 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.status: publishe