Differences in Neurocognitive Functions Between Healthy Controls and Anterior Cruciate Ligament-Reconstructed Male Athletes Who Passed or Failed Return to Sport Criteria: A Preliminary Study.

BACKGROUND: Only 55% of anterior cruciate ligament-reconstructed (ACLR) athletes return to competitive sports. This brings into question the usefulness of current return to sport (RTS) criteria. High cognitive demand of sport environment clarifies the value of incorporating neurocognitive tests when making decisions regarding the time of RTS. This preliminary study aimed to compare the neurocognitive functions between healthy controls and ACLR male athletes who passed or failed RTS criteria. METHODS: A total of 45 male football players, including 15 ACLR who passed RTS criteria, 15 ACLR who did not pass, and 15 healthy controls participated in this cross-sectional study. The Cambridge Neuropsychological Test Automated Battery was used to measure a battery of neurocognitive tasks, including speed of response, sustained attention, working memory, cognitive flexibility, and response inhibition. RESULTS: The results revealed that compared with both the ACLR-passed and healthy groups, the ACLR-failed group showed greater values of 5-choice movement time (P = .02, P = .01, respectively) but lower values of stop signal reaction time (P = .03, P = .001, respectively) and proportion of successful stops variables (P = .02). In addition, compared with the healthy group, both the ACLR-failed and ACLR-passed groups indicated greater values in between errors (P < .001, P = .008, respectively) and reaction latency variables (P = .002, P = .01, respectively) but lower values of A' (P < .001, P = .007, respectively), probability of hit (P < .001, P = .03, respectively), and percent correct trials variables (P = .006, P = .02, respectively). CONCLUSIONS: Our findings indicated deficits in neurocognitive functions in ACLR male athletes. In addition, poor performance in sustained attention, working memory, and cognitive flexibility measures observed in the ACLR-passed group highlighted the necessity for using a multimodal approach via implementation of neurocognitive measures in conjunction with the functional and muscular assessments when making RTS decisions.

Walking Performance during Concurrent Cognitive and Motor Tasks in Individuals with Nonspecific Chronic Low Back Pain: A Case-Control Study.

Background: The present study aimed to compare the effects of simultaneous cognitive and motor tasks on walking performance between individuals with nonspecific chronic low back pain (NSCLBP) and healthy controls. Methods: A total of 20 patients with NSCLBP and 20 healthy controls participated in this study. They walked at their self-selected speed on a treadmill under 3 walking conditions in a randomized order: walking only, walking while performing a concurrent cognitive task, and walking while performing a concurrent motor task. Two-way repeated measure analysis of variance with additional post hoc comparison (Bonferroni test) was used to evaluate the effects of group and walking conditions on gait parameters. Results: The result showed a significant main effect of the group for swing time ( P = 0.012) and double support time (P = 0.021) in those with NSCLBP compared with healthy controls. Moreover, there was a significant interaction between the group and condition for cadence ( P = 0.004) and step width variability (P = 0.016).Regarding stride length variability and stride time variability, the analysis indicated a significant effect of condition (P = 0.002 and P = 0.030, respectively). In both groups, no significant differences were observed in gait parameters between motor dual task and single walking ( P > 0.05). Conclusion: Our findings indicated that those with NSCLBP adapted successfully to walking performance to maintain the performance of the concurrent cognitive task under the cognitive dual-task walking condition. Moreover, the present study observed no dual-task interference under the motor dual-task condition.

Comparison of Cognitive Functions between Healthy Controls and Individuals with Chronic Low Back Pain with High and Low Pain Catastrophizing: A Cross-sectional Study.

OBJECTIVES: Researchers suggested that the interruptive effects of chronic pain on cognitive functions may be modulated by the level of pain catastrophizing (PC). However, in individuals with chronic low back pain (CLBP), domains of cognitive function that may be affected by the level of PC remain largely unclear. Therefore, this study was aimed to compare cognitive functions between healthy controls and individuals with CLBP with high and low PC. METHODS: This cross-sectional study examined cognitive functions of 42 individuals with CLBP and 21 healthy controls. The PC scale was used to stratify participants with CLBP into high and low PC. Participants performed 5 cognitive tests from the Cambridge Neuropsychological Test Automated Battery, namely five-choice reaction time, rapid visual processing, spatial working memory, attention switching task, and stop signal task. RESULTS: The statistical analyses revealed that compared to individuals with CLBP with low PC and healthy controls, individuals with high PC demonstrated greater values of the between errors (P=0.01), reaction latency (P<0.001), and stop signal reaction time variables (P=0.004, P=0.003, respectively) but lower values of probability of hit (P=0.02, P=0.01, respectively), A' (P=0.01, P<0.001, respectively), and percent correct trials variables (P=0.002, P<0.001, respectively). DISCUSSION: The results of the current study showed deficits in sustained attention, working memory, cognitive flexibility, and inhibitory control in individuals with CLBP with high PC. From a clinical perspective, therapeutic interventions targeting PC should be considered to decrease catastrophic thinking about pain in individuals with CLBP. Additional research is warranted to explore cognitive functioning as an outcome of these interventions in individuals with CLBP.

Immediate effects of local muscle vibration on static and dynamic balance control in individuals with chronic ankle instability.

OBJECTIVES: To investigate the immediate effects of local muscle vibration (LMV) on static and dynamic balance control in individuals with and without chronic ankle instability (CAI). DESIGN: Quasi-experimental study. SETTING: Research laboratory. PARTICIPANTS: Twenty-six individuals with CAI and 26 healthy controls. MAIN OUTCOME MEASURES: Center of pressure variables (mean total velocity and displacement in anteroposterior (AP) and mediolateral (ML) directions) during single-leg standing with eyes open and eyes closed and also reach distances in anterior (ANT), posteromedial (PM), and posterolateral (PL) directions of the modified star excursion balance test (MSEBT) were assessed before and after LMV. RESULTS: Statistical analyses showed a significant decrease in mean total velocity and displacement in AP direction from before to after LMV in eyes open condition for both individuals with CAI (p = 0.025, p = 0.041, respectively) and healthy controls (p = 0.001, p = 0.003, respectively). Similar results were observed in eyes closed condition for both individuals with CAI (p < 0.001, p < 0.001, respectively) and healthy controls (p = 0.040, p = 0.014, respectively). The results also showed increased reach distances in ANT (p < 0.001), PM (p < 0.001), and PL directions (p < 0.001) in all participants after LMV. CONCLUSION: Our results suggest that LMV may be a useful tool in rehabilitation of static and dynamic balance deficits in individuals with CAI.

Effects of attentional focus on quiet standing balance control in individuals with non-specific chronic low back pain.

Despite the widespread research about the effects of attentional focus on balance control in different populations, to the best of our knowledge, no study has yet investigated the effects of attentional focus instructions on balance control in individuals with chronic low back pain (CLBP). Therefore, this study was aimed to compare the effects of internal focus (IF) and external focus (EF) of attention on quiet standing balance control between individuals with CLBP and healthy controls. Twenty individuals with CLBP and 20 healthy controls were enrolled in this quasi-experimental study. The participants were asked to stand still with eyes open and eyes closed while performing three tasks: baseline standing with no focus instructions, internally focusing on their feet, and externally focusing on two markers were placed on the force platform. Statistical analyses showed a significant main effect of group for mean total velocity (p = 0.02), area (p = 0.01), and displacement in mediolateral (ML) direction (p = 0.003). Moreover, a significant main effect of vision was observed for mean total velocity (p < 0.001), area (p < 0.001), and displacement in anteroposterior (AP) (p < 0.001) and ML directions (p < 0.001). Also, the results revealed a significant main effect of attentional focus for mean total velocity (p < 0.001), area (p < 0.001), and displacement in AP (p < 0.001) and ML directions (p = 0.01). Our results showed that in both healthy controls and individuals with CLBP, EF led to improve quiet standing balance control compared to IF and control conditions. From a clinical perspective, it may be useful for physical therapists to consider the use of instruction cues that direct performer's attention away from the body for improving quiet standing balance control in individuals with CLBP.

Differences in dynamic balance control based on pain catastrophizing level in individuals with nonspecific chronic low back pain.

BACKGROUND: Pain catastrophization (PC) is related to motor control changes in individuals with nonspecific chronic low back pain (NSCLBP). However, differences in dynamic balance control based on the level of PC still remain unclear in these individuals. OBJECTIVE: The aim of this study was to compare the dynamic balance control between healthy controls and individuals with NSCLBP with high and low PC. METHODS: Forty individuals with NSCLBP and 20 healthy participants were enrolled in this cross-sectional study. Individuals with NSCLBP were classified into two groups of high and low PC. Dynamic balance control was assessed using the Modified Star Excursion Balance Test (MSEBT), Five-Time Sit-to-Stand Test (FTSST), and Timed Up and Go Test (TUGT). RESULTS: Statistical analyses showed that mean values of reach distances in the anterior, posteromedial, and posterolateral directions of the MSEBT were significantly lower in individuals with NSCLBP with high PC compared to low PC (p = .04, p = .01, and p = .04, respectively) and healthy controls (p < .001, p = .001, and p = .006, respectively). In addition, for both the FTSS and TUG tests, the mean time was significantly greater in individuals with NSCLBP with high PC compared to low PC (p < .001 and p = .004, respectively) and healthy controls (p < .001). CONCLUSIONS: Our results showed poor dynamic balance control in individuals with NSCLBP with high PC. This suggests that PC could contribute to the impaired dynamic balance control in individuals with NSCLBP. Combining balance exercises and cognitive-behavioral treatments targeting PC may be useful for the improvement of dynamic balance control in individuals with NSCLBP with high PC.

Can a rigid antipronation foot orthosis change the effects of prolonged standing on postural control in men with patellofemoral pain?

BACKGROUND: Pronated foot posture is known as a contributing factor for patellofemoral pain (PFP) development. Patients with patellofemoral pain often experience poor postural control. Implementation of optimal management strategies for enhancing their postural performance is important. OBJECTIVES: The aim of this study was to determine whether a rigid antipronation foot orthosis changes prolonged standing effects on postural control in men with PFP. STUDY DESIGN: Case-control study. METHODS: Twenty-eight men with PFP and pronated foot and 28 healthy men were enrolled in this study. Center-of-pressure parameters were measured during short trials (60 seconds) of single-leg standing before and immediately after prolonged standing (20 minutes) using force platform. In patients with PFP, postural control was examined on 2 separate days with and without rigid antipronation foot orthosis. RESULTS: Findings showed that the pre-post differences of sway area (t(48) = -2.22, p = 0.03), mediolateral (ML) displacement (t (48) = -2.51, p = 0.01), and mean velocity (t(48) = -2.01, p = 0.04) were significantly greater in patients with PFP without foot orthosis compared with those in the healthy group. Significant intervention main effect ( p = 0.04) and time-by-intervention interaction ( p = 0.006) for sway area were shown. Significant intervention main effects were noted for ML displacement ( p = 0.007) and mean velocity ( p = 0.003). For these variables, significant time-by-intervention interactions were found. Further analysis showed greater values of ML displacement and mean velocity parameters before the prolonged standing in patients with PFP without foot orthosis compared with patients with PFP with orthosis. CONCLUSIONS: Rigid antipronation foot orthosis can improve the postural performance after prolonged standing in young adult men with PFP.

Quantifying lower extremity inter-segmental coordination variability during walking in people with multiple sclerosis with high and low fear of falling.

BACKGROUND: Fear of falling (FOF) is associated with gait disturbances in people with multiple sclerosis (PwMS). However, previous studies mostly assessed FOF-related changes in gait patterns of PwMS using spatio-temporal gait parameters. Considering the complex nature of gait control, investigation of the higher order properties of the human movement system, particularly inter-segmental coordination variability may provide valuable information about underlying deficits in motor control patterns in PwMS with different levels of FOF. Therefore, the purpose of this study was to clarify the differences in lower extremity inter-segmental coordination variability between healthy controls and PwMS with high and low FOF. METHODS: This cross-sectional study examined gait patterns of 40 PwMS and 20 age-and-sex-matched healthy controls during treadmill walking at a preferred walking speed for 3 min. The falls efficacy scale-international questionnaire was used to stratify PwMS into high and low FOF subgroups. Variability in coordinative relationships between shank-thigh and foot-shank segments was determined using deviation phase (DP), which is the average standard deviation calculated from all points of the ensemble continuous relative phase (CRP) curve during the stance and swing phases of gait. RESULTS: DP values for shank-thigh (p = 0.005 and p < 0.001, respectively) and foot-shank inter-segmental relationships (p < 0.001) during the stance phase as well as for foot-shank inter-segmental relationships during the swing phase (p = 0.03) were significantly greater in PwMS with high FOF compared to those with low FOF and healthy controls. In addition, both groups of PwMS with high and low FOF indicated greater shank-thigh DP values compared to healthy controls during the swing phase (p < 0.001 and p = 0.002, respectively). CONCLUSION: The findings suggest unsteadiness in neuromuscular organization during walking in PwMS with high FOF. Rehabilitative interventions targeting impairments in lower extremity inter-segmental coordination and FOF may be useful to improve walking and reduce risk of falls in PwMS with high FOF.

Psychometric properties of the Persian-version of the Activities-specific Balance Confidence scale and Fall Efficacy Scale-International in Iranian patients with multiple sclerosis.

BACKGROUND AND PURPOSE: Balance impairment and fear of falling are two common risk factors for falls in people with multiple sclerosis (PwMS). Clinicians should use valid, reliable, and responsive tools to assess these risk factors and identify individuals at increased risk for falls. So, this study aimed to examine psychometric properties of the Persian-version of the Activities-specific Balance Confidence (ABC) scale and Fall Efficacy Scale-International (FES-I) in Iranian PwMS. METHODS: One hundred and fifty-three PwMS completed the Persian versions of ABC, FES-I, Multiple Sclerosis Walking Scale-12 (MSWS-12), and Berg Balance Scale (BBS) in the first session. To assess the test-retest reliability, 50 PwMS filled out ABC, and FES-I in retest session with an interval of 2-7 days. Also, for evaluating responsiveness, 50 PwMS completed ABC and FES-I before and after a 4-week treatment. RESULTS: Intra-class Correlation Coefficients were 0.96 and 0.93 and Cronbach's alpha coefficients were 0.96 and 0.99 for the ABC and FES-I, respectively. There were significant correlations (p < .001) between ABC and BBS (r = 0.55), FES-I and BBS (r = -0.56), ABC and MSWS-12 (r = -0.72), and FES-I and MSWS-12 (r = 0.76). No floor or ceiling effect was found. ABC and FES-I had acceptable responsiveness (AUC > 0.70), and their minimally important difference (MID) were 10.5 and 9.5 points, respectively. CONCLUSION: The Persian-versions of ABC and FES-I are reliable, valid, and responsive measures to quantify balance confidence and fear of falling in PwMS at both clinical and research settings. The MID can help clinicians to make a decision based on the clinical significance of changes in patients' status.

Potential Prophylactic and Therapeutic Effects of Respiratory Physiotherapy for COVID-19.

New coronavirus disease 2019 (COVID-19) has succeeded in surprising the world with infecting more than 12 million people and claiming 560,000 lives in only six months. COVID-19 is associated with a spectrum of respiratory symptoms, especially dyspnea. Patients who progress to severe or critical condition display peripheral and posterior lung lesions bilaterally. These patients require admission to the intensive care unit (ICU); therefore, they are prone to ICU-related complications during disease and after recovery. Respiratory physiotherapy techniques, in particular, active techniques, might help the improvement of airway clearance and lung capacity in addition to the reduction of breathing effort during the active disease. In parallel, it might lead to the prevention of disabilities, resulting from infection and extended hospitalization in patients who recovered from COVID-19. This supports physiotherapy both as a prophylactic and therapeutic strategy for COVID-19.

Comparison of the lower limb inter-segmental coordination during walking between healthy controls and people with multiple sclerosis with and without fall history.

BACKGROUND: This research aims to compare lower limb inter-segmental coordination, a higher order property of the human movement system, during walking between healthy controls and people with multiple sclerosis (PwMS) with and without fall history. METHODS: Fifty PwMS (25 patients with fall history and 25 patients without fall history) and 25 healthy controls participated in the present study. Three-dimensional coordinate data of the lower limbs were collected during treadmill walking at a preferred walking speed. The phasing relationship and its variability between lower limb segments were evaluated using the mean absolute relative phase (MARP) and deviation phase (DP) during the stance and swing phases of gait. RESULTS: Compared to healthy controls, both groups of PwMS demonstrated significantly greater shank-thigh MARP values during the stance phase (p < 0.001). In addition, MARP values of foot-shank coordination were significantly smaller in both groups of PwMS than the healthy controls during both the stance and swing phases (p < 0.001). For the DP of shank-thigh coordination, our analysis revealed greater values in both MS fallers and non-fallers compared to healthy controls during the stance (p < 0.001) and swing phases (p < 0.001, p = 0.004, respectively). Moreover, MS fallers demonstrated greater DP values than non-fallers in swing phase (p = 0.02). For the DP of foot-shank coordination, MS fallers showed greater values compared to non-fallers and healthy controls during the stance (p = 0.009, p = 0.001, respectively) and swing phases (p = 0.01, p = 0.006, respectively). CONCLUSION: Our results suggest that in addition to traditional gait parameters, examining and also facilitating lower limb inter-segmental coordination should be considered in future studies aimed at improving gait performance and reducing risk of falling in PwMS.

Impaired local dynamic stability during treadmill walking predicts future falls in patients with multiple sclerosis: A prospective cohort study.

BACKGROUND: Falling is a significant problem in patients with multiple sclerosis (MS) and the majority of falls occur during dynamic activities. Recently, there have been evidences focusing on falls and local stability of walking based on dynamic system theory in the elderly as well as patients with cerebral concussion. However, in patient with MS, this relationship has not been fully investigated. The aim of this study was to investigate local stability of walking as a risk factor for falling in patients with MS. METHODS: Seventy patients were assessed while walking at their preferred speed on a treadmill under single and dual task conditions. A cognitive task (backward counting) was used to assess the importance of dual tasking to fall risk. Trunk kinematics were collected using a cluster marker over the level of T7 and a 7-camera motion capture system. To quantify local stability of walking, maximal finite-time Lyapunov exponent was calculated from a 12-dimensional state space reconstruction based on 3-dimensional trunk linear and angular velocity time series. Participants were classified as fallers (≥1) and non-fallers based on their prospective fall occurrence. FINDINGS: 30 (43%) participants recorded ≥1 falls and were classified as fallers. The results of multiple logistic regression analysis revealed that short-term local dynamic stability in the single task condition (P<0.05, odds ratio=2.214 (1.037-4.726)) was the significant fall predictor. INTERPRETATION: The results may indicate that the assessment of local stability of walking can identify patients who would benefit from gait retraining and fall prevention programs.

Effects of cognitive versus motor dual-task on spatiotemporal gait parameters in healthy controls and multiple sclerosis patients with and without fall history.

BACKGROUND: The purpose of the current study was to compare the effects of cognitive or motor tasks on gait performance between healthy controls and multiple sclerosis (MS) patients with and without fall history. METHODS: The investigation included MS patients with fall history (n = 25) and without fall history (n = 25) and matched healthy controls (n = 25). Participants walked at their preferred speed on a motorized treadmill under three walking conditions in a randomized order: walking only, walking while performing a concurrent cognitive task (counting backward aloud by 3s), and walking while performing a concurrent motor task (carrying a tray with glasses). RESULTS: The findings showed that in patients with MS, regardless of fall history, spatiotemporal gait parameters were different compared to healthy controls. In contrast to average gait parameters, variability in stride length and stride time could discriminate between MS fallers and non-fallers. Simultaneous performance of cognitive task and walking resulted in higher dual-task costs (DTC) in gait performance compared to the motor dual-task. However, the pattern of change was not different among the three groups. All participants responded to the cognitive task challenges by increasing stride length and decreasing cadence and stride length variability while maintaining cognitive task performance. CONCLUSIONS: The findings may reflect successful adaptation of locomotor system to preserve cognitive task performance under cognitive dual-task condition. Future studies should examine more complex concurrent cognitive and motor tasks to better understand the dual-task-related gait changes and their contribution to falls in patients with MS.

Nonlinear dynamical structure of sway path during standing in patients with multiple sclerosis and in healthy controls is affected by changes in sensory input and cognitive load.

Although several studies have applied traditional linear measures to evaluate postural control of patients with multiple sclerosis (MS), little is known about the nonlinear dynamics of this patient group. In this study, recurrence quantification analysis (RQA), a well documented nonlinear method, was used to compare the nonlinear dynamical structure of postural sway in two groups consisting of MS patients (n=23) and healthy matched controls (n=23). The study focuses on three levels of postural difficulty consisting of (1) standing on a rigid surface (force platform) with eyes open, (2) standing on a rigid surface with eyes closed, and (3) standing on a foam surface with eyes closed. The two levels of cognitive difficulty measured, consisted of a single postural task and a dual postural-cognitive task. It was observed that as the postural conditions became more difficult, the center of pressure (COP) time series of both groups became less regular as recorded in lower recurrence rate, less complex in deterministic structure as reflected in lower RQA entropy, and less nonstationary as reflected in the recording of lower Trend. Moreover, as cognitive conditions became more difficult, COP time series became less regular (lower %Rec in the anteroposterior direction and lower %Det in both directions), less complex in deterministic structure (lower RQA Ent in the anteroposterior direction), and less nonstationary (lower trend in the anteroposterior direction). The analytical results of the research show that there is a similar dynamical structure for both the MS patients and the control group; however, the nonlinear behavior of both groups was different under various experimental conditions.

The effects of cognitive loading on balance control in patients with multiple sclerosis.

The aim of this study was to compare the effects of concurrent cognitive task (silent backward counting) on balance performance between two groups of multiple sclerosis (MS) (n=23) and healthy (n=23) participates. Three levels of postural difficulty were studied on a force platform, i.e. rigid surface with eyes open, rigid surface with eyes closed, and foam surface with eyes closed. A mixed model analysis of variance showed that under difficult sensory condition of foam surface with eyes closed, execution of concurrent cognitive task caused a significant decrement in variability of sway velocity in anteroposterior direction for the patient group (P<0.01) while this was not the case for healthy participants (P=0.22). Also, the variability of sway velocity in mediolateral direction was significantly decreased during concurrent execution of cognitive task in patient group (P<0.01) and not in healthy participants (P=0.39). Furthermore, in contrast to single tasking, dual tasking had the ability to discriminate between the 2 groups in all conditions of postural difficulty. In conclusion, findings of variability in sway velocity seem to confirm the different response to cognitive loading between two groups of MS and healthy participants.