Comparing the effects of anodal and cathodal transcranial direct current stimulation of primary motor cortex at varying intensities on motor learning in healthy young adults.

Inconsistent results are observed in the effects of transcranial direct current stimulation (tDCS) with different montages on motor learning. This study aimed to compare the effects of anodal and cathodal tDCS (c-tDCS) over primary motor cortex (M1) at different intensities on motor learning in healthy young adults. The participants were randomly divided into: (1) 1 mA M1 c-tDCS, (2) 1 mA M1 anodal tDCS (a-tDCS), (3) 2 mA M1 c-tDCS, (4) 2 mA M1 a-tDCS and (5) M1 sham tDCS groups. The groups received 20-min stimulation with serial reaction time task (SRTT) incidentally, while the tDCS was turned off after 30 s in the sham tDCS group. Response time (RT) and error rate (ER) during SRTT were assessed prior, during and 72 h after the intervention. The results of the paired t-test indicated that online learning occurred in all groups (p < 0.05), except in M1 c-tDCS (1 mA) (p > 0.05). One-way ANOVA analysis also indicated that there were differences in offline learning (RT (F(DF) = 5.19(4); p < 0.001; and ER (F(DF) = 9(4), p < 0.0001) among groups, with more offline learning in 1 mA M1 a-tDCS, 2 mA M1 c-tDCS and 2 mA M1 a-tDCS groups (p < 0.05). On the other hand, the 1 mA M1 c-tDCS group did not indicate any consolidation effect or even a trend toward negative offline learning. M1 a-tDCS with different intensities and also 2 mA M1 c-tDCS may be helpful for the enhancement of motor learning in young healthy adults. This study enhances our understanding of tDCS intensity and polarity effects on motor learning, with potential for optimizing therapeutic protocols.

The effects of different exercises on weight loss and hormonal changes in women with polycystic ovarian syndrome: a network meta-analysis study.

BACKGROUND: Polycystic ovarian syndrome (PCOS) is one of the most common endocrine illnesses. There is evidence that exercise training positively affects on improvement of the pathogenic factors in women with PCOS. On the other hand, some studies reported similar effects of aerobic and resistance exercises or no effect of exercises on the improvement of the pathogenic factors. The aim of the current study was to perform a network meta-analysis of RCTs to evaluate the efficacy of exercises on body mass index (BMI), hormone concentrations, and regular menstruation in women with PCOS. METHODS: The search was performed from databases of PubMed, Scopus, and Web of Science with the keywords of exercise, resistance exercise, aerobic exercise, endurance exercise, yoga, polycystic ovary syndrome, randomized controlled trial based on the CONSORT, BMI, sex hormone and regular menstruation from inception until April 15, 2022. Bayesian random-effects network meta-analyses were performed to calculate mean difference and 95% credible intervals. RESULTS: Out of 1140 studies, 19 were eligible for inclusion. The results showed that moderate-intensity aerobic exercise effectively reduces BMI compared to no intervention and Yoga. No other forms of exercise led to weight loss. Additionally, exercise had no impact on sex hormones and regular menstruation. It was concluded that moderate-intensity aerobic exercise is the most effective for reducing BMI in women with PCOS. CONCLUSIONS: Due to the limitations regarding the small sample size and lack of subgroup and sensitivity analysis, the results of this study demonstrated that moderate-intensity, aerobic exercise is the most effective exercise for reducing BMI, while the other exercises were ineffective. Moderate-intensity aerobic exercise is suggested to decrease the BMI in women with PCOS. SYSTEMATIC REVIEW REGISTRATION: This systematic review and network meta-analysis study was registered in PROSPERO (CRD42022324839).

A Comparison of 2 Exercise Protocols in Athletes With Primary Subacromial Impingement Syndrome: A Randomized Clinical Trial.

CONTEXT: To stabilize the humeral head within the glenoid fossa during arm elevation, the rotator cuff muscles may contribute through internal and external rotation. The main purpose of the current study was to compare the acromiohumeral distance between athletes with primary subacromial impingement syndrome who received progressive resistance exercises consisting of either shoulder internal or external rotation. DESIGN: A randomized and controlled clinical study. METHODS: Thirty athletes with primary subacromial impingement syndrome were enrolled and randomly divided into 2 experimental groups. The progressive resistance exercise protocol in experimental group I comprised shoulder internal rotation, while in experimental group II consisted of shoulder external rotation. The experimental groups worked out 3 days a week for 6 weeks. The experimental groups were compared with the control group consisting of 15 healthy athletes. The acromiohumeral distance was measured before and after the intervention using an ultrasound machine under the passive and active across no arm elevation and 45°of arm elevation. RESULTS: The acromiohumeral distance significantly increased in both experimental groups under the passive and active arm positions following the intervention (P < .001), with no significant differences detected between the experimental groups (P > .665). The paired comparisons of the acromiohumeral distance discrepancy indicated a significant difference between the control group and each experimental group under the active and passive arm positions (P < .001), while no significant difference was observed between the experimental groups (P > .999). CONCLUSIONS: The present study revealed, for the first time, that both progressive resistance exercise protocols involving either the shoulder internal or the external rotation increased the acromiohumeral distance in individuals with primary subacromial impingement syndrome and improved associated pain and disabilities.

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.

Concurrent multi-session anodal trans-cranial direct current stimulation enhances pelvic floor muscle training effectiveness for female patients with multiple sclerosis suffering from urinary incontinence and pelvic floor dysfunction: a randomized clinical trial study.

INTRODUCTION AND HYPOTHESIS: Urinary incontinence following a pelvic floor muscle (PFM) dysfunction is a common disorder in women with multiple sclerosis (MS). Concurrent anodal transcranial direct current stimulation (a-tDCS) of the primary motor cortex (M1) may prime the effects of PFM training (PFMT) in MS patients. This study was aimed at investigating the effects of M1 a-tDCS on the effectiveness of PFMT in the treatment of female MS patients with urinary incontinence and PFM dysfunctions. METHODS: In a randomized double-blinded, control trial study, 30 women with MS were divided into two groups (experimental group: concurrent active M1 a-tDCS and PFMT; control group: concurrent sham M1 a-tDCS and PFMT). Over the course of 8 weeks, these patients received 20-min interventions three times a week. As an indication of PFM function, the bladder base displacement was measured by ultrasonography before, during the 4th week, immediately, and 1 month after the intervention ended. Urinary incontinence was also measured by Incontinence Questionnaire-Urinary Incontinence Short Form (ICIQ-UISF) before, immediately, and 1 month after the intervention ended. RESULTS: A significant improvement in PFM function occurred in the 4th week of intervention and remained 1 month after the intervention in the experimental group when compared with the control group (p<0.05). Compared with baseline, both groups reported significant improvements in PFM function at 8 weeks (p<0.05). Also, both groups were found to have decreased ICIQ-UIS scores after the intervention and at 1-month follow-up (p<0.05). CONCLUSIONS: In MS patients, M1 a-tDCS can significantly enhance the effects of PFMT on the PFM function and urinary incontinence.

Effect of Functional Electrical Stimulation on Muscle Mass, Fatigue, and Quality of Life in Older Patients With COVID-19: A Randomized Clinical Trial Study.

OBJECTIVE: This study aimed to evaluate the effects of functional electrical stimulation (FES) on muscle strength, fatigue, muscle mass, and quality of life (QoL) in older patients with COVID-19. METHODS: Older patients with COVID-19 were randomly divided into the following 2 groups: real FES (intervention group, n = 20) and sham FES (control group, n = 20). These patients received FES concurrent with the voluntary contraction of muscles for 10 consecutive sessions. Ultrasound imaging, pressure biofeedback, Chalder fatigue scale, and QoL were utilized to measure muscle mass, muscle strength, chronic fatigue, and QoL, respectively. Evaluations were performed at the beginning, immediately, and 1 month after the end of intervention. RESULTS: All variables showed statistically significant improvement immediately and 1 month after the intervention in the real FES group (P < .05). However, the tibialis anterior muscle mass and fatigue significantly improved immediately after the intervention in the sham FES group. However, the tibialis anterior and rectus femoris muscles strength and rectus femoris muscle mass were not significantly changed immediately and 1 month after the intervention (P > .05). There were significant differences in muscle mass, physical fatigue, muscle strength, and QoL between groups with more efficacy of real FES (P < .05). CONCLUSION: For this sample of patients, FES improved fatigue, muscle strength, muscle mass, and QoL in older adults with COVID-19.

Priming Effects of Anodal Transcranial Direct Current Stimulation on the Effects of Conventional Physiotherapy on Balance and Muscle Performance in Athletes With Anterior Cruciate Ligament Injury.

CONTEXT: In athletes, postural control impairment and knee muscle dysfunction are the most common disorders following anterior cruciate ligament (ACL) injury. Because of functional changes in the motor cortex following ACL injury, physiotherapy (PT) is not enough for treatment and using neuromodulators, such as trans-cranial direct current stimulation (tDCS) may be necessary. The present study focused on the effects of anodal tDCS (a-tDCS) over the primary motor cortex (M1) concurrent with PT on postural control and muscular performance in the athletes with ACL injury. DESIGN: In this study, 34 athletes with ACL injury were randomly assigned in 2 groups of intervention group (active M1 a-tDCS concurrent with PT, n = 16) and control group (sham M1 a-tDCS concurrent with PT, n = 16). METHODS: The participants of all groups received 20-minute 2 mA M1 a-tDCS with PT during 10 sessions, while tDCS was turned off after 30 seconds in the sham group. Before, immediately following, and 1 month after the interventions, the center of pressure and the average of power of flexor and extensor muscles at 2 velocities of 30°/s and 60°/s were measured by force plate and isokinetic devices, respectively. RESULTS: One month after treatment, the displacement of center of pressure was decreased in the intervention group (P < .05), while there were no changes in the control group. Y-axis of center of pressure decreased in the intervention group relative to the control group, although average of power of flexor and extensor muscles increased immediately in both groups, but the rise in the intervention group was larger than that in the control group (P < .05). CONCLUSION: The findings indicated that M1 a-tDCS can induce the efficacy of PT, which has a lasting effect on the improvement of the postural control in athletes with ACL injury.

The effects of concurrent M1 anodal tDCS and physical therapy interventions on function of ankle muscles in patients with stroke: a randomized, double-blinded sham-controlled trial study.

One of the most common symptoms in stroke patients is spasticity. The aims were to investigate the effects of anodal trans-cranial direct current stimulation (a-tDCS) over the affected primary motor cortex (M1) on ankle plantar flexor spasticity and dorsiflexor muscle activity in stroke patients. The design of this study was a randomized sham-controlled clinical trial. Thirty-two participants with stroke were randomly assigned to three groups (experimental, sham, control groups). Participants in the experimental and sham groups received 10-session 20-min M1 a-tDCS concurrent with physical therapy (PT), while the control group only received 10-session PT. All groups were instructed to perform home stretching exercises and balance training. Berg Balance Scale (BBS), Modified Ashworth Scale (MAS) of plantar flexors, and EMG activity of lateral gastrocnemius (LG) and tibialis anterior (TA) were recorded during active and passive ankle dorsiflexion immediately and 1 month after interventions. A significant reduction was shown in MAS and EMG activity of LG during dorsiflexion, immediately and 1 month after intervention in the M1 a-tDCS group (p <0.001). BBS also significantly increased only in the M1 a-tDCS group (p <0.001). In addition, EMG activity of TA during active dorsiflexion increased immediately and 1 month after intervention in the M1 a-tDCS group (p <0.001). However, in the sham and control groups, EMG activity of TA increased immediately (p<0.001), while this was not maintained 1 month after intervention (p >0.05). PT concurrent with M1 a-tDCS can significantly prime lasting effects of decreasing LG spasticity, increasing TA muscle activity, and also balance in stroke patients.

Does anodal trans-cranial direct current stimulation of the damaged primary motor cortex affects wrist flexor muscle spasticity and also activity of the wrist flexor and extensor muscles in patients with stroke?: a Randomized Clinical Trial.

Spasticity is a common symptom in stroke survivors. This study is double-blinded, sham-controlled randomized, clinical trial with three parallel arms. The aim of the study was to investigate the effects of anodal trans-cranial direct current stimulation (a-tDCS) over the damaged primary motor cortex (M1) on spasticity of the wrist flexor and also the activity of wrist flexor and extensor muscles in sub-acute stroke patients. This study was performed on 32 stroke patients. The patients are assigned to three groups (intervention, sham, and control). All participants in the first two groups received 20-min concurrent M1 a-tDCS or sham tDCS and functional electrical stimulation (FES) for 10 sessions (5 sessions per week), while participants in control group were given only 20-min FES for 10 sessions. Modified Ashworth scale of wrist flexors and also electromyography (EMG) activity of flexor carpi radialis (FCR) and extensor carpi radialis (ECR) were recorded before, immediately, and 1 month after the interventions. A significant reduction was shown in the MAS and EMG activity of FCR muscle at passive rest position of the wrist, immediately and 1 month after the intervention in M1 a-tDCS compared to sham and control groups (p < 0.001). Also, the EMG activity of FCR and ECR muscles during active wrist flexion and extension increased immediately and 1 month after intervention in M1 a-tDCS compared to the other groups, respectively (p < 0.001). M1 a-tDCS can significantly decrease the spasticity of wrist flexor muscle and also increase the wrist flexor and extensor muscles activity in stroke patients during active flexion and extension.

Multi-session anodal transcranial direct current stimulation enhances lower extremity functional performance in healthy older adults.

The aim of this study was to examine the effects of 5 days of anodal-transcranial direct current stimulation (a-tDCS) over the primary motor cortex (M1) on lower extremity functional performance in healthy elderly people. This was a randomized, double-blinded, sham-controlled study whereby 32 healthy older individuals participated in two groups. The intervention group received 20 min of a-tDCS (1 mA) over the M1 on five consecutive days. The sham group received the same stimulation, but the tDCS device was turned off after 30 s of stimulation. Participants were asked to perform the Timed Up and Go (TUG), 30-s Chair Stand Test (30-s CST), and a Modified Figure of Eight Walk Test (MFEWT) on the first day before tDCS application, immediately, 30 min, and 1 week after the last session of stimulation. Results of the a-tDCS group showed that most of the test values had significant changes in post-test assessments compared to the pre-test (p < 0.05). When comparing the anodal and sham tDCS groups, the results showed a significant improvement in TUG and time-MFEWT immediately after (p = 0.02, p = 0.01), 30 min after (p = 0.04, p = 0.01) and 1 week after the last session of stimulation (p = 0.01, p = 0.01). Improvements in performance of the 30-s CST and the number of steps-MFEWT were not significant, except at 1 week after the last session for the steps-MFEWT (p = 0.04). The application of 20 min a-tDCS over the M1 for 5 consecutive days improves lower extremity functional performance in the healthy older participants.

Stabilization exercise affects function of transverse abdominis and pelvic floor muscles in women with postpartum lumbo-pelvic pain: a double-blinded randomized clinical trial study.

INTRODUCTION AND HYPOTHESIS: Lumbo-pelvic pain (LPP) is a common disorder in women after pregnancy due to ligament laxity and postural changes. Transverse abdominis (TrA) and pelvic floor muscle (PFM) activity is important for lumbo-pelvic stability. The purpose of this study was to compare the effect of stabilization exercise (SE) and general exercise (GE) on TrA and PFM muscle activity and pain intensity in women with postpartum LPP. METHODS: A randomized controlled trial study was conducted on 68 women with postpartum LPP. Patients were randomly divided into two groups of stabilization exercise (SE) and general exercise (GE) and received either SE or GE exercise for 8 weeks three times a week. Ultrasound imaging was utilized to measure the thickness change of TrA muscles during abdominal hollowing (AH) and bladder base displacement. These measurements were used as an indicator of TrA and PFM muscle activity. Pain intensity, thickness changes of the TrA muscle and bladder base displacement were measured pre- and post-intervention. RESULTS: The results showed that there was no significant difference in pain relief after intervention between groups. The differences in TrA and PFM activity between groups were significant (P < 0.05). PFM and TrA muscle activity was significantly increased after SE in women with postpartum LPP (P < 0.05). CONCLUSIONS: SE improved both PFM and TrA muscle function more than GE in women with postpartum LPP. However, the clinical outcome of pain relief was not greater in the SE group.

Does M1 anodal transcranial direct current stimulation affects online and offline motor learning in patients with multiple sclerosis?

OBJECTIVE: Multiple Sclerosis (MS) is one of the most common neurological diseases in the world. Due to structural and functional changes in central nerves system, the patients with MS may affected by sensory-motor learning deficits. The aims of the current study was to assess the effect of primary motor cortex (M1) anodal transcranial direct current stimulation (a-tDCS) on online and offline motor learning in patients with MS. MATERIALS AND METHODS: Thirty-nine patients with MS were randomly assigned in three groups: concurrent M1 a-tDCS and serial response time test (SRTT) (n=13), concurrent sham a-tDCS and SRTT (n=13) and SRTT-only control (n=13). The participants in all groups were asked to concurrently perform 20 minutes of SRTT. M1 a-tDCS group received 20-minute M1 a-tDCS (2 mA) concurrent with SRTT, while the a-tDCS was turned off after 30 seconds in the sham a-tDCS group. Response time (RT) and error rate (ER) during SRTT were assessed prior, during and 48 hours after the intervention. RESULTS: Online learning happened in all groups (P < 0.05), with more significant learning in M1 a-tDCS group as compared to the other groups (P < 0.05). However, offline learning was occurred only in M1 a-tDCS group (P < 0.05). CONCLUSIONS: The findings indicate offline motor learning impairment in patients with MS. M1 a-tDCS may be used for enhancement of motor learning especially offline learning in patients with MS.

Comparing the effects of multi-session anodal trans-cranial direct current stimulation of primary motor and dorsolateral prefrontal cortices on fatigue and quality of life in patients with multiple sclerosis: a double-blind, randomized, sham-controlled trial.

OBJECTIVE: To compare the effects of anodal trans-cranial direct current stimulation (a-tDCS) over primary motor and dorsolateral prefrontal cortices on Fatigue Severity Scale and its lasting effect on fatigue reduction and improvement in quality of life in patients with multiple sclerosis. DESIGN: A randomized, double-blinded, sham-controlled parallel clinical trial study. SETTING: Neurological physiotherapy clinics. SUBJECTS: Thirty-nine participants were randomly assigned to three groups: dorsolateral prefrontal cortex a-tDCS, primary motor a-tDCS (experimental groups) and sham a-tDCS. Finally, 36 participants completed the whole study (n = 12 in each group). INTERVENTIONS: Participants in the experimental groups received six-session a-tDCS (1.5 mA, 20 minutes) during two weeks (three sessions per week). The sham group received six sessions of 20-minute sham stimulation. MAIN MEASURES: The Fatigue Severity Scale and quality of life were assessed before, immediately and four weeks after the intervention. RESULTS: Findings indicated a significant reduction in the Fatigue Severity Scale and a significant increase in the quality of life in both experimental groups, immediately after the intervention (P < 0.001), while Fatigue Severity Scale and quality of life changes were not significant in the sham a-tDCS group (P > 0.05). In addition, improvement of the variables remained four weeks after the intervention in dorsolateral prefrontal cortex a-tDCS (mean differences (95% confidence interval): 0.03 (-0.63 to 0.68) as compared to primary motor (-0.62 (-0.11 to -1.14) and sham a-tDCS groups (-0.47 (-1.37 to 0.43)). CONCLUSION: Both primary motor and dorsolateral prefrontal cortex a-tDCS as compared to sham intervention can immediately improve fatigue and quality of life. However, the effects last up to four weeks only by the dorsolateral prefrontal cortex a-tDCS.

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 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.

Online and offline effects of cerebellar transcranial direct current stimulation on motor learning in healthy older adults: a randomized double-blind sham-controlled study.

The aim of this randomized double blinded sham-controlled study was to determine the effect of cerebellar anodal transcranial direct current stimulation (a-tDCS) on online and offline motor learning in healthy older individuals. Thirty participants were randomly assigned in experimental (n = 15) or sham tDCS (n = 15) groups. Participants in experimental group received 2 mA cerebellar a-tDCS for 20 min. However, the tDCS was turned off after 30 seconds in sham group. Response time (RT) and error rate (ER) in serial RT test were assessed before, during 35 minutes and 48 h after the intervention. Reduction of RT and ER following the intervention session was considered as short-term (35 min post intervention) and long-term offline learning (48 h post intervention), respectively. Online RT and ER reduction were similar in both groups (P > 0.05). RT was significantly reduced 48 hours post intervention in cerebellar a-tDCS group (P = 0.03). Moreover, RT was significantly increased after 35 minutes and 48 hours in sham tDCS group (P = 0.03, P = 0.007), which indicates a lack of short-term and long-term offline learning in older adults. A-tDCS on cerebellar region produced more short-term and long-term offline improvement in RT (P = 0.014, P = 0.01) compared to sham tDCS. In addition, online, short-term and long-term (48 h) offline error reduced in cerebellar a-tDCS as compared to sham-control group, although this reduction was not significant (P > 0.05). A deficit suggests that a direct comparison to a younger group was made. The findings suggested that cerebellar a-tDCS might be useful for improvement of offline motor learning in older individuals.

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.

Knee muscle activity during gait in patients with anterior cruciate ligament injury: a systematic review of electromyographic studies.

PURPOSE: This review compared knee muscle activity between ACL-deficient (ACLD) patients and healthy controls during gait, to find out whether the available electromyography (EMG) studies support Quadriceps (Q-ceps) inhibition or hamstring facilitation during gait in ACLD patients. METHOD: A systematic review was conducted to retrieve the EMG studies of knee muscles during gait in ACLD patients. Cochrane library, PubMed, Medline, Ovid, CINAHL and Science Direct databases were searched entries from 1995 through October 2014 using the terms "anterior cruciate ligament" OR "ACL", "electromyography" Or "EMG" "gait" Or "walking". Articles that assessed subjects with ACL rupture that used surface EMG to assess the knee muscle activity were included. The quality of the included papers was assessed using the Critical Appraisal Skills Programme tool for observational studies. RESULT: In total, 13 studies met the inclusion criteria. Seven studies consistently found no significant difference in magnitude of activity or timing of Q-ceps muscle between the chronic ACLD patients and control subjects. Two studies on acute ACLD patients and three studies on ACLD patients with unstable knee found the significantly reduced Q-ceps activity compared to control subjects. Six studies showed the significantly greater hamstring activity, and three studies found prolonged duration of activity in ACLD patients compared to the control subjects. CONCLUSION: This review highlighted that the results of the studies are in favour of increased hamstring muscular activity. However, decreased Q-ceps activation exists in the acute stage and in ACLD patients that experience knee instability (non-copers). LEVEL OF EVIDENCE: III.

Interference Effect of Prior Explicit Information on Motor Sequence Learning in Relapsing-Remitting Multiple Sclerosis Patients.

BACKGROUND: Multiple sclerosis (MS) is the most widespread disabling neurological condition in young adults around the world. The purpose of this study was to investigate the impact of explicit information (EI) on motor-sequence learning in MS patients. METHODS: Thirty patients with relapsing-remitting MS (RRMS), age: 29.5 (SD = 5.6) years and 30 healthy gender-, age-, and education-matched control group participants, age: 28.8 (SD = 6.0) years, were recruited for this study. The participants in the healthy group were then randomly assigned into an EI (n = 15) group and a no-EI (n = 15) group. Similarly, the participants in the control group were then randomly assigned into EI (n = 15) and no-EI (n = 15) groups. The participants performed a serial reaction time (SRT) task and reaction times. A retention test was performed after 48 hours. RESULTS: All participants reduced their reaction times across acquisition (MS group: 46.4 (SD = 3.3) minutes, P < 0.001, and healthy group: 39.4 (SD = 3.3) minutes, P < 0.001). The findings for the within-participants effect of repeated measures of time were significant (F(5.06, 283.7) = 71.33. P < 0.001). These results indicate that the interaction between group and time was significant (F(5.06, 283.7) = 6.44. P < 0.001), which indicated that the reaction time in both groups was significantly changed between the MS and healthy groups across times (B1 to B10). The main effect of the group (MS and healthy) (F(1, 56) = 22.78. P < 0.001) and also the main effect of no-EI vs EI (F(1, 56) = 4.71. P < 0.001) were significant. CONCLUSION: This study demonstrated that that RRMS patients are capable of learning new skills, but the provision of EI prior to physical practice is deleterious to implicit learning. It is sufficient to educate MS patients on the aim and general content of the training and only to provide feedback at the end of the rehabilitative session.

Occupational low back pain in primary and high school teachers: prevalence and associated factors.

OBJECTIVE: The purposes of this study were to investigate the prevalence of and risk factors for low back pain (LBP) in teachers and to evaluate the association of individual and occupational characteristics with the prevalence of LBP. METHODS: In this cross-sectional study, 586 asymptomatic teachers were randomly selected from 22 primary and high schools in Semnan city of Iran. Data on the personal, occupational characteristics, pain intensity, and functional disability as well as the prevalence and risk factors of LBP were collected using different questionnaires. RESULTS: Point, last month, last 6 months, annual, and lifetime prevalence rates of LBP were 21.8%, 26.3%, 29.6%, 31.1%, and 36.5%, respectively. The highest prevalence was obtained for the high school teachers. The prevalence of LBP was significantly associated with age, body mass index, job satisfaction, and length of employment (P < .05 in all instances). Prolonged sitting and standing, working hours with computer, and correcting examination papers were the most aggravating factors, respectively. Rest and participation in physical activity were found to be the most relieving factors. CONCLUSION: The prevalence of LBP in teachers appears to be high. High school teachers were more likely to experience LBP than primary school teachers. Factors such as age, body mass index, length of employment, job satisfaction, and work-related activities were significant factors associated with LBP in this teacher population.