Different montages of transcranial direct current stimulation on postural stability in chronic low back pain patients: A randomized sham-controlled study.

BACKGROUND: Impairment in both the motor and cognitive aspects of postural control is a critical issue in patients with chronic low back pain (CLBP) who experience high pain anxiety (HPA). OBJECTIVE: This study aimed to compare the effects of cathodal and anodal transcranial direct current stimulation (c-tDCS and a-tDCS) over the dorsolateral prefrontal cortex (DLPFC) on postural control during cognitive postural tasks in CLBP patients with HPA. METHODS: This study included 66 patients randomly assigned to three groups: DLPFC a-tDCS, DLPFC c-tDCS, and sham tDCS. All groups received 20 minutes of tDCS, but the stimulation was gradually turned off in the sham group. Postural stability indices were assessed using the Biodex Balance System. RESULTS: Both the a-tDCS and c-tDCS groups showed a significant reduction in most postural stability indices at static and dynamic levels after the interventions (immediately, 24 hours, and one-week follow-up) during the cognitive postural task (P< 0.01). Additionally, there was a significant improvement in postural balance in the a-tDCS and c-tDCS groups compared to the sham tDCS group (P< 0.01). Furthermore, the a-tDCS group showed significantly greater improvement than the c-tDCS group (P< 0.01). CONCLUSION: Based on the results, both a-tDCS and c-tDCS over the DLPFC had positive effects on postural control during cognitive postural tasks in CLBP patients with HPA.

Transcranial direct current stimulation over dorsolateral prefrontal cortex improves postural stability in non-specific chronic low back pain patients with high fear of pain: A randomized sham-controlled trial.

Deficits in postural stability in response to environmental challenges are seen in chronic low back pain (CLBP) patients with high fear of pain (HFP). Hence, it is essential to follow effective approaches to treat postural stability deficits and improve the health status of these patients. The current study aimed to compare the effects of cathodal and anodal transcranial direct current stimulation (c-tDCS and a-tDCS) over the left dorsolateral prefrontal cortex (DLPFC) on postural stability in non-specific CLBP patients with HFP. In this randomized clinical trial study, 75 patients were randomly assigned to left DLPFC a-tDCS, left DLPFC c-tDCS and sham stimulation groups (n = 25 in each group). All groups received a single-session 2 mA tDCS for 20 min, but the stimulation was slowly turned off after 30 s in the sham group. Before, immediately, 24 h and 1 week after the interventions, postural stability indices were assessed using a Biodex Balance System. A significant reduction in most indices was shown in both a-tDCS and c-tDCS groups after interventions (immediately, 24 h and 1 week follow-up) during static and dynamic postural tasks compared with the sham tDCS group (p < .01). In addition, some tests showed a significant difference between a-tDCS and c-tDCS (p < .05). The findings indicated positive effects of both a-tDCS and c-tDCS on the left DLPFC, with more efficacy of a-tDCS on postural stability in LBP patients with HFP.

Cross-cultural adaptation, validity and reliability of the Persian version of Fremantle Knee Awareness Questionnaire.

BACKGROUND: & Objective: There is strong evidence regarding impaired knee self-perception in patients with chronic knee osteoarthritis (OA). Currently, the Fremantle Knee Awareness Questionnaire (FreKAQ) has been developed to evaluate knee self-perception. This study aimed to evaluate validity and reliability of the Persian version of FreKAQ in patients with chronic knee OA. MATERIALS AND METHODS: The FreKAQ was translated via forward-backward translation. In total, 312 patients with chronic knee OA completed the questionnaire, and the construct validity of the instrument was evaluated using exploratory and confirmatory factor analyses (EFA and CFA). Moreover, its reliability was confirmed using internal consistency and Cronbach's alpha coefficient. In addition, intra-class correlation coefficient and standard error measurement (SEM) and minimal detectable change (MDC) were used to assess its relative and absolute consistency. Therefore 50 patients, completed the questionnaire twice at one-week intervals. RESULTS: In EFA, Kaiser-Meyer-Olkin (0.705) and Bartlett's tests were significant (P < 0.001), and CFA also indicated acceptable fitting with three factors. Moreover, the indices of PNFI = 0.57, PCFI = 0.60, χ2/DF = 1.14, AGFI = 0.95, GFI = 0.97, and RMSEA = 0.027 confirmed the goodness of fit of the model. The Cronbach's alpha and repeatability were estimated at 0.817 and 0.874, respectively, and the SEM and MDC was 2.13, 4.91. CONCLUSION: According to the results, the Persian version of FreKAQ had proper construct validity and reliability to evaluate the impairment of knee self-perception in patients with chronic knee OA.

Examining the Use of Kinesiology Tape During Weight Bearing Exercises on Proprioception in Participants With Functional Ankle Instability.

The aim of this study was to examine the effect of tape worn during weight bearing exercises on proprioception (i.e., ankle angle repositioning error) in participants with functional ankle instability. We employed a randomized, controlled clinical study in a laboratory setting, with 56 participants with functional ankle instability. Participants were randomly assigned to three groups: (a) weight bearing exercises without tape (n = 18), (b) weight bearing exercises with tape (n = 19) and controls not engaged in weight bearing exercises (n = 19). Weight bearing exercises included six weeks of bilateral squats in partial form with up to 45 degrees of knee flexion, and unilateral partial squats with full heel raise, and with full toe raise. In the taped condition, participants wore tape for six weeks with up to three tape replacements per week. Proprioception was measured as ankle repositioning error. Results showed that the mean angle repositioning error among participants in the active weight bearing groups was decreased by the taping intervention, relative to the control group's performance (p = 0.042). There were no significant differences between weight bearing exercise groups and control groups. The addition of kinesiology tape in weight bearing exercises can improve proprioception in active conditions.

Cognitive Behavioral Therapy With Stabilization Exercises Affects Transverse Abdominis Muscle Thickness in Patients With Chronic Low Back Pain: A Double-Blinded Randomized Trial Study.

OBJECTIVE: Nonspecific chronic low back pain (NCLBP) is a major public health and global socioeconomic burden with a variety of symptoms, such as fear-avoidance behaviors. This study aimed to evaluate the effect of cognitive behavioral therapy (CBT) associated with stabilization exercise (SE) on thickness of transverse abdominis (TrA) muscle in patients with NCLBP. METHODS: Forty patients with NCLBP were randomly assigned into experimental CBT associated with SE (n = 20) and control groups without SE (n = 20). Transverse abdominis muscle thickness was assessed during abdominal drawing in maneuver (ADIM) and active straight leg raise (ASLR) of the right lower limb using ultrasound imaging. Fear-avoidance belief and disability were evaluated using a fear-avoidance belief questionnaire (FABQ) and a Roland-Morris disability questionnaire (RMDQ) before and after intervention. RESULTS: Mixed-model analysis of variance indicated that the effect of time was significant for the right and left TrA contraction thickness during ADIM and left TrA contraction thickness during ASLR (P < .05). However, the experimental group exhibited higher right and left TrA muscle thickness compared with the control group during ADIM (P = .001). Moreover, there were no significant differences between groups in the thickness of TrA muscle during ASLR (P > .05). The effect of time was significant for FABQ (P = .02) and RMDQ (P = .01); however, the effect of group was significant for the FABQ after intervention (P = .04). CONCLUSIONS: Stabilization exercise associated with CBT is more effective than SE alone in improving fear avoidance belief and in increasing the thickness of the TrA muscle during ADIM task.

The immediate effect of whole body vibration training on the electromyographic activity of contralateral hand muscles; a randomized controlled trial.

Whole Body Vibration (WBV) has been used as a useful adjunct to improve the neuromuscular function of the upper limb. Cross-transfer of strength plays an important role in rehabilitation of unilateral injuries. The present research intended to evaluate the acute effect of low frequency WBV training on cross-transfer of electromyographic activity and hand muscles strength when the measurement was performed on the contralateral limb. This was a randomized crossover trial conducted in a clinical biomechanics laboratory. Twenty-eight healthy participants aging between 20 and 35 years were included who were involved in two sessions with two weeks of rest. The participants were randomly assigned in two groups as follows: 1) active WBV/sham WBV; 2) sham WBV/active WBV. The participants were asked to stand on the vibrating plate and pull its belt in a vibrating mode using their dominant hand. Then, after a two-week rest, they performed the same task in the vibrating mode (35 Hz). Grip strength and electromyography (root mean square) in flexor digitorum profundus (FDP), flexor digitorum superficialis (FDS), extensor carpi radialis (ECR), and extensor carpi ulnaris (ECU) muscles of the contralateral limb were measured before and after exercise in both phases. No significant change was observed in the electrical activity of FDP, FDS, ECR, ECU muscles, and hands' grip strength of the contralateral limb (P > 0.05). WBV (35 Hz) was not able to augment cross-transfer in electromyographic activity and neuromuscular performance of the upper limb. Further studies would help to explore these results for several sessions of WBV on cross-transfer of training.

Trunk-Pelvis Kinematics Variability During Gait and Its Association With Trunk Muscle Endurance in Patients With Chronic Low Back Pain.

The first purpose was to investigate the trunk muscle endurance, the second aim was to evaluate the trunk-pelvis kinematics during gait, and the third was to evaluate the relationship between trunk-pelvis kinematics and the trunk muscle endurance. Thirty participants (15 nonspecific chronic low back pain [NCLBP] and 15 healthy) were included. The authors first assessed trunk muscle endurance on endurance testing protocols. The authors next measured the trunk-pelvis kinematics during gait using a 3-dimensional motion capture system. Angular displacement, waveform pattern (CVp), and offset variability (CVo) were also examined. Statistical analysis revealed a significant difference in (1) the trunk muscle endurance and (2) sagittal, frontal, and transverse planes CVp between groups (P < .05). A significant moderate correlation was found between supine double straight-leg raise and frontal CVp (r = .521, P = .03) and transverse planes CVp (r = .442, P = .05). However, a significant moderate correlation was observed between prone double straight-leg raise and sagittal plane CVp (r = .528, P = .03) and transverse plane CVp (r = .678, P = .001). The relationship between (1) lower trunk extensor endurance with transverse and sagittal planes CVp and (2) lower abdominal muscle endurance with transverse and frontal planes CVp suggests that gait variability in these planes may result because of trunk muscle deconditioning accompanying NCLBP.

The Effects of Stabilization Exercise on the Thickness of Lateral Abdominal Muscles During Standing Tasks in Women With Chronic Low Back Pain: A Randomized Triple-Blinded Clinical Trial Study.

CONTEXT: Chronic low back pain (CLBP) often presents with a dysfunction in deep abdominal muscles activity during standing tasks. Although some studies indicated that deep abdominal muscle activity improved during some functional tasks following stabilization exercise (SE), there is no study to evaluate the effect of SE on lateral abdominal muscles thickness during standing postural tasks. OBJECTIVE: The purpose of this study was (1) to evaluate the lateral abdominal muscles thickness in the participants with CLBP while standing on a balance board and (2) to compare the effects of SE and a general exercise (GE) program on the lateral muscles thickness changes. METHODS: This was a between-groups, triple-blinded randomized controlled trial design. In total, 40 females with CLBP were randomly assigned into 2 groups:  GE (control group) and supervised progressive SE (experimental group). Diagnostic ultrasound imaging was used before and after the intervention to measure lateral abdominal muscles thickness during standing on 2 different levels of platform in the Biodex Balance System. Visual analog scale and Roland-Morris Disability Questionnaire were used to evaluate changes in pain intensity and disability. RESULTS: The results indicated significant increases in transverse abdominis muscle thickness during all standing tasks (P = .02) and significant decreases in pain intensity and disability following SE intervention (P < .001). However, the lateral abdominal muscle thicknesses were not changed after GE intervention while standing postural tasks (P > .05). The GE group revealed only significant decreases in pain intensity after intervention (P = .03). CONCLUSION: Supervised progressive SE improved the activity of deep abdominal muscles in standing postural tasks in the patients with CLBP.

Relationships Between Hoffman Reflex Parameters, Trait Stress, and Athletic Performance.

This study evaluated the relationships between trait stress, Hoffman reflex, and performance among 36 healthy amateur male athletes. We first obtained a trait stress questionnaire from participants and then assigned them to high- and low-stress groups. We next recorded Hoffman reflex data from the soleus and lateral gastrocnemius muscles and then examined their athletic performance on testing protocols separated by a 72-hour washout period. Performance testing utilized vertical jump height, 20 -m sprint time, and standing stork tests. There were significant correlations between (a) the standing stork test, vertical jump height, and trait stress and (b) Hmax/ Mmax ratios, threshold intensity ( Hth), the intensity of the Hmax, and the intensity of the Hlast. Hth, the intensity of Hmax, and the intensity of Hlast were significantly higher among the low-stress compared with the high-stress participant groups ( p < .05), despite participants' similar training history. We suggest that self-perceived psychological stress affects performance through neural adaptation.

The effects of cerebellar transcranial direct current stimulation on static and dynamic postural stability in older individuals: a randomized double-blind sham-controlled study.

The aging population is growing rapidly. Risk of falling is higher in older people compared to young adults due to several reasons including poor posture and balance. The main aim of this study was to investigate the effect of cerebellar anodal transcranial direct current stimulation (a-tDCS) on static and dynamic postural stability in older individuals. Twenty-nine older adults participated in this study and were randomly allocated to two groups of active a-tDCS (experimental; n = 14) or sham tDCS group (n = 15). Experimental group received cerebellar a-tDCS for 20 min with intensity of 1.5 mA. Anterior-posterior and medial-lateral postural stability indices (postural sway) in addition to Berg Balance Score were measured before and after the intervention. Postural sways in static and dynamic postural tasks were significantly decreased (P < 0.05) after cerebellar a-tDCS, in addition to Berg Balance Score that increased significantly in active cerebellar a-tDCS group (P < 0.05). However, there were no significant changes in postural stability indices or Berg Balance Score in sham group (P > 0.05). The findings indicated immediate effect of cerebellar a-tDCS on improvement of postural control and balance in older individuals.

The study of the variability of anticipatory postural adjustments in patients with recurrent non-specific low back pain.

BACKGROUND AND OBJECTIVES: Intrinsic variability is present in all actions, including repetitive tasks. The aim of this study was to evaluate the variability of anticipatory postural adjustments (APAs) of trunk muscles in participants with low back pain (LBP). MATERIAL AND METHOD: The study included 21 participants with recurrent non-specific LBP (15 men, 6 women) and 21 healthy volunteers. Standard deviation of electromyographic activity of the external oblique (EO), transverse abdominis/internal oblique (TrA/IO), and erector spinae (ES) muscles onset relative to deltoid muscle onset was recorded in 75 rapid arm flexions, and the correlation with the participants' avoidance belief (the FABQ score) and disability (the Roland-Morris Questionnaire score) was statistically analyzed. RESULTS: participants with LBP exhibited less variability in timing of APAs of the TrA/IO muscle compared with the control group (P=0.047). The timing of APAs of the TrA/IO muscle was significantly correlated with the FABQ score (P=0.006). There was no significant correlation between this variable and disability (P=0.09). Decrease in variability of the timing of APA of the EO (P=0.45) and ES (P=0.6) muscles was not significant. CONCLUSION: The variability of the postural responses of participants with LBP decreased. Restoring variability in postural control responses might be a goal in rehabilitating these patients.

Multiplying linear dimension techniques may predict the cross-sectional area of multifidus muscle at all levels of lumbar spine.

OBJECTIVE: This study was designed to find out the relationship between the multiplied linear dimensions (MLD) measurement and the cross-sectional area (CSA) measurement of the lumbar multifidus muscle. METHODS: Sixty healthy female subjects participated in this study. The CSA of the lumbar multifidus muscle from L2 to L5 was bilaterally measured by tracing around the muscle margins with an on- screen cursor. The linear dimensions including lateral dimension (LD), anteroposterior dimension (APD) and MLD of the muscles were also calculated at the same levels of lumbar vertebrae. RESULTS: The linear regression between CSA and MLD for each vertebral level was significant (r=0.89 to 0.97, p<0.0001). In addition, there was significant correlation between CSA and APD (r=0.69 to 0.87, p<0.05). CONCLUSIONS: MLD method can be used to predict the CSA of the lumbar multifidus muscle. The method described for assessing the multifidus muscle is a potentially valuable, quick and easy way to evaluate muscle size at different levels of the lumbar vertebrae in clinical practice.