Repetitive Transcranial Magnetic Stimulation Combined with Sling Exercise Modulates the Motor Cortex in Patients with Chronic Low Back Pain.

The study aims to explore the effects of combining repetitive transcranial magnetic stimulation (rTMS) with sling exercise (SE) intervention in patients with chronic low back pain (CLBP). This approach aims to directly stimulate brain circuits and indirectly activate trunk muscles to influence motor cortex plasticity. However, the impact of this combined intervention on motor cortex organization and clinical symptom improvement is still unclear, as well as whether it is more effective than either intervention alone. To investigate this, patients with CLBP were randomly assigned to three groups: SE/rTMS, rTMS alone, and SE alone. Motor cortical organization, numerical pain rating scale (NPRS), Oswestry Disability Index (ODI), and postural balance stability were measured before and after a 2-week intervention. The results showed statistically significant differences in the representative location of multifidus on the left hemispheres, as well as in NPRS and ODI scores, in the combined SE/rTMS group after the intervention. When compared to the other two groups, the combined SE/rTMS group demonstrated significantly different motor cortical organization, sway area, and path range from the rTMS alone group, but not from the SE alone group. These findings highlight the potential benefits of a combined SE/rTMS intervention in terms of clinical outcomes and neuroadaptive changes compared to rTMS alone. However, there was no significant difference between the combined intervention and SE alone. Therefore, our research does not support the use of rTMS as a standalone treatment for CLBP. Our study contributed to optimizing treatment strategies for individuals suffering from CLBP.

Alterations in functional connectivity in patients with non-specific chronic low back pain after motor control exercise: a randomized trial.

BACKGROUND: Motor control exercise (MCE) is effective in alleviating non-specific chronic low back pain (NCLBP). Neuro-imaging research is warranted to explore the underlying neural mechanisms of MCE. AIM: We used resting-state functional magnetic resonance imaging (rs-fMRI) to explore the central mechanism underpinning the effects of MCE in patients with NCLBP. DESIGN: A randomized, single-blinded, controlled trial. SETTING: The setting was out-patient and community. POPULATION: Fifty-eight patients with NCLBP. METHODS: Patients were randomized into the MCE or manual therapy (MT) group. All the participants completed pain-related clinical assessments and rs-fMRI scans before and after intervention. We performed exploratory whole-brain analyses in regional homogeneity (ReHo) and resting-state functional connectivity (rsFC) with significant post-pre differences in ReHo before and after intervention, and investigated associations between imaging and pain-related clinical assessments. RESULTS: Compared with the MT group, a greater alleviation in pain intensity and disability was observed in the MCE group after intervention, and was sustained at the 6-month follow-up (P<0.001). Only the MCE group showed increased ReHo values in the right pre-central gyrus and decreased ReHo values in the bilateral posterior cerebellum (voxel level P<0.001, cluster-level FWE corrected P<0.05). Decreased rsFC of the right posterior cerebellum-left superior parietal gyrus and left insula were significantly positively associated with pain-related disability (voxel level P<0.001, cluster-level FWE corrected P<0.05). CONCLUSIONS: These findings demonstrated that MCE had superior effects in relieving pain and pain-related disability, which might be associated with its modulation of rsFC between the cerebellum and areas involved in sensory-discriminative processing of noxious and somato-sensory stimuli, affection, and cognition. CLINICAL REHABILITATION IMPACT: This study provided preliminary evidence that MCE might alleviate NCLBP through its modulation of the function of brain areas related to chronic pain and postural control. Those results support MCE's clinical application and help physiotherapists to provide better multidisciplinary interventions with the combination of MCE and other first-line treatments.

Motor Control Exercise Modulates the Neural Plasticity of the Default Mode Network in Patients with Chronic Low Back Pain.

BACKGROUND: Motor control exercise (MCE) effectively alleviates nonspecific chronic low back pain (CLBP), but the neural mechanisms underlying this phenomenon are poorly understood. OBJECTIVE: To study MCE's neural mechanisms in patients with CLBP by resting-state functional magnetic resonance imaging (rs-fMRI). STUDY DESIGN: A prospective, single-blind, randomized, controlled trial. SETTING: Department of Rehabilitation Medicine, The First Affiliated Hospital, Sun Yat-sen University. METHODS: 58 patients were randomly assigned to either the MCE or the Manual Therapy (MT) group. Before and after treatment, all the patients underwent ultrasound imaging to measure transversus abdominis (TrA) activation, rs-fMRI scans and questionnaire assessments. We analyzed the activation and connectivity of the bilateral precuneus based on the fractional amplitude of low-frequency fluctuation (fALFF) and effective connectivity (EC) analyses. Further, we determined the association between imaging and clinical measures. RESULTS: Pain intensity, pain catastrophizing, and pain-related disability were alleviated significantly in both groups post-treatment. However, the MCE group showed a greater reduction in pain-related disability and a better improvement in activation of the right TrA than the MT group. After MCE, patients showed an increase in regional fALFF values in the key node of the default mode network (bilateral precuneus) and decreased EC from the bilateral precuneus to the key node of the frontoparietal network (the left dorsolateral prefrontal cortex (DLPFC)). The pre-to-post-treatment change in the EC from bilateral precuneus into the left DLPFC was significantly correlated with the pre-to-post-treatment change in visual analog scale scores and activation of the right TrA in the MCE group (r = 0.765, P < 0.001 and r = 0.481 and P = 0.043 respectively). LIMITATIONS: The present study showes the correlation between the alteration of brain functions and CLBP-related symptoms, which does not reveal the causal effect between them. Further, this study does not estimate the long-term efficacy of MCE on brain function, and the sample size was not calculated based on fMRI data. CONCLUSION: These findings demonstrate that MCE may alleviate CLBP symptoms in patients by modifying information transmission from the default mode network to the left frontoparietal network.

The effects of proprioceptive weighting changes on posture control in patients with chronic low back pain: a cross-sectional study.

Introduction: Patients with chronic low back pain (CLBP) exhibit changes in proprioceptive weighting and impaired postural control. This study aimed to investigate proprioceptive weighting changes in patients with CLBP and their influence on posture control. Methods: Sixteen patients with CLBP and 16 healthy controls were recruited. All participants completed the joint reposition test sense (JRS) and threshold to detect passive motion test (TTDPM). The absolute errors (AE) of the reposition and perception angles were recorded. Proprioceptive postural control was tested by applying vibrations to the triceps surae or lumbar paravertebral muscles while standing on a stable or unstable force plate. Sway length and sway velocity along the anteroposterior (AP) and mediolateral (ML) directions were assessed. Relative proprioceptive weighting (RPW) was used to evaluate the proprioception reweighting ability. Higher values indicated increased reliance on calf proprioception. Results: There was no significant difference in age, gender, and BMI between subjects with and without CLBP. The AE and motion perception angle in the CLBP group were significantly higher than those in the control group (JRS of 15°: 2.50 (2.50) vs. 1.50 (1.42), JRS of 35°: 3.83 (3.75) vs. 1.67 (2.00), pJRS < 0.01; 1.92 (1.18) vs. 0.68 (0.52), pTTDPM < 0.001). The CLBP group demonstrated a significantly higher RPW value than the healthy controls on an unstable surface (0.58 ± 0.21 vs. 0.41 ± 0.26, p < 0.05). Under the condition of triceps surae vibration, the sway length (pstable < 0.05; punstable < 0.001), AP velocity (pstable < 0.01; punstable < 0.001) and ML velocity (punstable < 0.05) had significant group main effects. Moreover, when the triceps surae vibrated under the unstable surface, the differences during vibration and post vibration in sway length and AP velocity between the groups were significantly higher in the CLBP group than in the healthy group (p < 0.05). However, under the condition of lumbar paravertebral muscle vibration, no significant group main effect was observed. Conclusion: The patients with CLBP exhibited impaired dynamic postural control in response to disturbances, potentially linked to changes in proprioceptive weighting.

The immediate effects of iTBS on the muscle activation pattern under challenging balance conditions in the patients with chronic low back pain: A preliminary study.

Background: The patients with chronic low back pain (CLBP) showed impaired postural control, especially in challenging postural task. The dorsolateral prefrontal cortex (DLPFC) is reported to involve in the complex balance task, which required considerable attentional control. The effect of intermittent theta burst stimulation (iTBS) over the DLPFC to the capacity of postural control of CLBP patients is still unknown. Methods: Participants diagnosed with CLBP received a single-session iTBS over the left DLPFC. All the participants completed the postural control tasks of single-leg (left/right) standing before and after iTBS. The activation changes of the DLPFC and M1 before and after iTBS were recorded by functional near-infrared spectroscopy (fNIRS). The activation pattern of the trunk [transversus abdominis (TrA), superficial lumbar multifidus (SLM)] and leg [tibialis anterior (TA), gastrocnemius medialis (GM)] muscles including root mean square (RMS) and co-contraction index (CCI) during single-leg standing were measured by surface electromyography (sEMG) before and after the intervention. The paired t-test was used to test the difference before and after iTBS. Pearson correlation analyses were performed to test the relationship between the oxyhemoglobin concentration and sEMG outcome variables (RMS and CCI). Results: Overall, 20 participants were recruited. In the right-leg standing condition, compared with before iTBS, the CCI of the right TrA/SLM was significantly decreased (t = -2.172, p = 0.043), and the RMS of the right GM was significantly increased (t = 4.024, p = 0.001) after iTBS. The activation of the left DLPFC (t = 2.783, p = 0.012) and left M1 (t = 2.752, p = 0.013) were significantly decreased and the relationship between the left DLPFC and M1 was significant after iTBS (r = 0.575, p = 0.014). Correlation analysis showed the hemoglobin concentration of M1 was negatively correlated with the RMS of the right GM (r = -0.659, p = 0.03) and positively correlated between CCI of the right TrA/SLM (r = 0.503, p = 0.047) after iTBS. There was no significant difference in the brain or muscle activation change in the left leg-standing condition between before and after iTBS. Conclusion: Intermittent theta burst stimulation over the left DLPFC seems to be able to improve the muscle activation pattern during postural control ability in challenging postural task, which would provide a new approach to the treatment of CLBP.

Changes in cortical activation during upright stance in individuals with chronic low back pain: An fNIRS study.

Introduction: Postural control deficits are a potential cause of persistent and recurrent pain in patients with chronic low back pain (CLBP). Although some studies have confirmed that the dorsolateral prefrontal cortex (DLPFC) contributes to pain regulation in CLBP, its role in the postural control of patients with CLBP remains unclear. Therefore, this study aimed to investigate the DLPFC activation of patients with CLBP and healthy controls under different upright stance task conditions. Methods: Twenty patients with CLBP (26.50 ± 2.48 years) and 20 healthy controls (25.75 ± 3.57 years) performed upright stance tasks under three conditions: Task-1 was static balance with eyes open; Task-2 was static balance with eyes closed; Task-3 involved dynamic balance on an unstable surface with eyes open. A wireless functional near-infrared spectroscopy (fNIRS) system measured cortical activity, including the bilateral DLPFC, pre-motor cortex (PMC) and supplementary motor area (SMA), the primary motor cortex (M1), the primary somatosensory cortex (S1), and a force platform measured balance parameters during upright stance. Results: The two-way repeated measures ANOVA results showed significant interaction in bilateral PMC/SMA activation. Moreover, patients with CLBP had significantly increased right DLPFC activation and higher sway 32 area and velocity than healthy controls during upright stance. Discussion: Our results imply that PMC/SMA and DLPFC maintain standing balance. The patients with CLBP have higher cortical activity and upright stance control deficits, which may indicate that the patients with CLBP have low neural efficiency and need more motor resources to maintain balance.