Functional Task Performance Research Articles

26 Improvement in Executive Function Following Goal-Oriented Attentional Self-Regulation Training in Veterans with mTBI

Objective:Goal-Oriented Attentional Self-Regulation (GOALS) is a cognitive rehabilitation training that targets difficulties with executive control functions. Prior research has found that GOALS training improves executive function, functional outcomes, and PTSD symptoms in Veterans with comorbid PTSD and TBI. The objective of this study is to assess the effects of GOALS training versus an active time-matched Behavioral Health Education (BHE) intervention in military Veterans with history of mTBI and executive function difficulties.Participants and Methods:Thirty-four veterans with a history of mild TBI (>6 months post-injury) and cognitive difficulties were randomized to GOALS or BHE group intervention. GOALS is a cognitive rehabilitation intervention that incorporates mindfulness-based attention regulation training, and goal management strategies applied to participant-defined goals. It consists of ten 2-hour sessions administered in small group format, and three individual 1-hour sessions. The BHE group is a matched control condition that mirrors GOALS in terms of duration and level of involvement. Participants completed a comprehensive evaluation consisting of neuropsychological and ecologically valid functional performance measures of complex attention and executive function, before and after GOALS or BHE intervention. Overall neuropsychological attention/executive functioning included measures of working memory (Letter Number Sequencing, Auditory Consonant Trigrams), mental flexibility (Design & Verbal Fluency Switching, Trails B, Stroop Inhibition/Switching), inhibition (Stroop Inhibition), and sustained attention (Digit Vigilance). The Goal Processing Scale (GPS) was used to measure ecologically valid complex functional performance.Results:Post GOALS training, but not post BHE, participants significantly improved on measures of attention /executive function including overall performance (p=.02), working memory (p=.04), sustained attention (p=.03)., and inhibition (p=.01). On measures of complex functional task performance, post GOALS participants significantly improved in the domain of planning (p=.02).Conclusions:GOALS training improved performance on neuropsychological and ecologically valid functional measures of complex attention and executive function in Veterans with mild TBI and cognitive difficulties. The current study highlights how mindfulness-based attention regulation and goalmanagement strategies applied to personal goals has positive effects across various outcomes. A percentage of individuals with mTBI continue to report persistent problems with cognition and daily functioning. Cognitive rehabilitation training such as GOALS may be beneficial for those with persistent difficulties following mTBI, even in chronic phase.

Computerized Cognitive and Skills Training in Older People With Mild Cognitive Impairment: Using Ecological Momentary Assessment to Index Treatment-Related Changes in Real-World Performance of Technology-Dependent Functional Tasks

ObjectivesCognitive and functional skills training improves skills and cognitive test performance, but the true test of efficacy is real-world transfer. We trained participants with mild cognitive impairment (MCI) or normal cognition (NC) for up to 12 weeks on six technology-related skills using remote computerized functional skills assessment and training (FUNSAT) software. Using ecological momentary assessment (EMA), we measured real-world performance of the technology-related skills over 6 months and related EMA-identified changes in performance to training gains. DesignRandomized clinical trial with post-training follow-up. SettingA total of 14 Community centers in New York City and Miami. ParticipantsOlder adults with normal cognition (n = 72) or well-defined MCI (n = 92), ranging in age from 60 to 90, primarily female, and racially and ethnically diverse. InterventionComputerized cognitive and skills training. MeasurementsEMA surveys measuring trained and untrained functional skills 3 or more days per week for 6 months and training gains from baseline to end of training. ResultsTraining gains in completion times across all 6 tasks were significant (p <0.001) for both samples, with effect sizes more than 1.0 SD for all tasks. EMA surveys detected increases in performance for both trained (p <0.03) and untrained (p <0.001) technology-related skills for both samples. Training gains in completion times predicted increases in performance of both trained and untrained technology-related skills (all p <0.001). ConclusionsComputerized training produces increases in real-world performance of important technology-related skills. These gains continued after the end of training, with greater gains in MCI participants.

Spinal kinematic variability is increased in people with chronic low back pain during a repetitive lifting task

Changes in spinal kinematic variability have been observed in people with chronic non-specific LBP (CNSLBP) during the performance of various repetitive functional tasks. However, the direction of these changes (i.e., less or more kinematic variability) is not consistent. This study aimed to assess differences in kinematic variability of the 3D angular displacement of thoracic and lumbar spinal segments in people with CNSLBP compared to asymptomatic individuals during a repetitive lifting task. Eleven people with CNSLBP and 11 asymptomatic volunteers performed 10 cycles of multi-planar lifting movements while spinal kinematics were recorded. For the three planes of motion, point-by-point standard deviations (SDs) were computed across all cycles of lifting and the average was calculated as a measure of kinematic variability for both segments. People with CNSLBP displayed higher thoracic (F = 8.00, p = 0.010, ηp2 = 0.286) and lumbar kinematic variability (F = 5.48, p = 0.030, ηp2 = 0.215) in the sagittal plane. Moreover, group differences were observed in the transversal plane for thoracic (F = 7.62, p = 0.012, ηp2 = 0.276) and lumbar kinematic variability (F = 5.402, p = 0.031, ηp2 = 0.213), as well as in the frontal plane for thoracic (F = 7.27, p = 0.014, ηp2 = 0.267) and lumbar kinematic variability (F = 6.11, p = 0.022, ηp2 = 0.234), all showing higher variability in those with CNSLBP. A significant main effect of group was not detected (p > 0.05) for spinal range of motion (ROM). Thus, people with CNSLBP completed the lifting task with the same ROM in all three planes of motion as observed for asymptomatic individuals, yet they performed the lifting task with higher spinal kinematic cycle-to-cycle variation.

Ankle dorsiflexion asymmetry and the relationship with walking performance in people with multiple sclerosis

BackgroundMultiple sclerosis (MS) is a neurological disease characterized by demyelination disrupting the central nervous system. Persons with MS may exhibit symptomatic strength asymmetry (SA) that impacts motor gait and ankle mobility. The purpose of the present study was to investigate ankle dorsiflexion SA in people with MS and its relationship to functional performance. Research QuestionIs their a difference in dorsiflexion SA in MS participants compared to healthy individuals and does it impact functional performance? Methods13 MS participants (EDSS 3.5 + 1.8) and 13 age matched NON-MS participants underwent maximal isometric (MVC) dynamometry testing for ankle dorsiflexion in both limbs to determine SA. Participants performed three functional tasks of walking performance. ResultsThere was a significant intra-limb MVC difference in the MS group, and significantly greater isometric SA (p < 0.007) and isokinetic SA (p < 0.04) in the MS group compared to healthy individuals. The MS group exhibited significant correlations between outcomes of functional walking performance with isokinetic but not isometric SA. There was no significant correlation between disability status and functional task performance. SignificanceAnkle dorsiflexion SA is negatively correlated with functional performance in MS participants. MS disability status was not a predictor of functional task performance, and symptom testing may be appropriate to assess walking ability in persons with MS.

Barriers and facilitators to community reintegration in adults following traumatic upper limb amputation: an exploratory study

Purpose To explore barriers and facilitators to community reintegration experienced by people following traumatic upper limb amputation (ULA). Methods An exploratory qualitative study was conducted with ten adults with major ULA due to trauma. Data from individual, semi-structured interviews was analysed using Braun and Clarke’s reflexive thematic analysis. Results Underlying and influencing community reintegration for participants, was a process of adjustment to the impacts of amputation on everyday function and re-establishing their identity. Participants felt social networks and peer support facilitated the return to social and community activities, as did drawing on personal attributes such as positivity, resilience and self-belief. Prosthetic devices were facilitative for community reintegration by minimising visible differences and unwanted attention through restored cosmesis and in the performance of functional tasks to fulfil social norms and meaningful roles despite issues with comfort and function. Despite the adaptation and evolution of abilities, perspectives and identities, the functional impact of ULA on everyday community activities was an ongoing challenge for all participants. Conclusion ULA has a significant and lifelong impact on an individual’s ability to complete tasks and fulfil meaningful roles in the community. Recommendations based on the study’s findings will inform clinicians to support community reintegration for people following traumatic ULA.

Poor functional task performance and compensatory trunk movements remain two years after total knee arthroplasty

Poor functional task performance and compensatory trunk movements remain two years after total knee arthroplasty

Does hip muscle strength and functional performance differ between football players with and without hip dysplasia?

ObjectiveTo compare hip muscle strength and functional performance in football players with and without hip dysplasia and investigate if the relationships were modified by sex. DesignCross-sectional study. MethodsThis study compared football players with hip dysplasia (HD group) and without hip dysplasia (control group). Hip muscle strength (Nm/kg) and functional task performance were assessed in both groups. Linear regression with generalized estimating equations were used to assess differences between groups. Sex was assessed as a potential effect modifier. Results101 football players were included (HD group, n = 50, control group, n = 51). There was no difference in hip muscle strength or functional performance between the HD group and the control group. Results ranged from hip extension strength (Estimate −0.13.95%CI: 0.29 to 0.02, P = 0.087) to hip external rotation strength (Estimate 0.00.95%CI: 0.05 to 0.05, P = 0.918). No relationships were modified by sex or age. ConclusionsSimilar levels of hip muscle strength and functional performance were found in active football players with and without hip dysplasia. These findings differ from other studies. This may be due to our cohort having less advanced hip dysplasia than the surgical populations that have been previously investigated, or due to a beneficial effect of football participation on muscle strength and functional performance in people with hip dysplasia.

Development of a latent dementia index in the aging, demographics, and memory study: Validation and measurement invariance by sex.

Latent variable models can create a latent dementia index (LDI) using cognitive and functional ability to approximate dementia likelihood. The LDI approach has been applied across diverse cohorts. It is unclear whether sex affects its measurement properties. We use Wave A (2001-2003) of the Aging, Demographics, and Memory Study (n=856). Multiple group confirmatory factor analysis (CFA) was used to test measurement invariance (MI) using informant-reported functional ability and cognitive performance tasks, which we group into verbal, nonverbal, and memory. Partial scalar invariance was found, allowing for testing sex differences in LDI means (MDiff=0.38). The LDI correlated with consensus panel dementia diagnosis, Mini-Mental State Examination (MMSE), and dementia risk factors (low education, advanced age, and apolipoprotein ε4 [APOE-ε4] status) for men and women. The LDI validly captures dementia likelihood to permit estimation of sex differences. LDI sex differences indicate higher dementia likelihood in women, potentially due to social, environmental, and biological factors.

Harnessing Machine Learning and Physiological Knowledge for a Novel EMG-Based Neural-Machine Interface.

In this study, we aimed to develop a novel electromyography (EMG)-based neural machine interface (NMI), called the Neural Network-Musculoskeletal hybrid Model (N2M2), to decode continuous joint angles. Our approach combines the concepts of machine learning and musculoskeletal modeling. We compared our novel design with a musculoskeletal model (MM) and 2 continuous EMG decoders based on artificial neural networks (ANNs): multilayer perceptrons (MLPs) and nonlinear autoregressive neural networks with exogenous inputs (NARX networks). EMG and joint kinematics data were collected from 10 non-disabled and 1 transradial amputee subject. The offline performance tested across 3 different conditions (i.e., varied arm postures, shifted electrode locations, and noise-contaminated EMG signals) and online performance for a virtual postural matching task was quantified. Finally, we implemented the N2M2 to operate a prosthetic hand and tested functional task performance. The N2M2 made more accurate predictions than the MLP in all postures and electrode locations (p < 0.003). For estimated MCP joint angles, the N2M2 was less sensitive to noisy EMG signals than the MM or NARX network with respect to error (p < 0.032) as well as the NARX network with respect to correlation (p = 0.007). Additionally, the N2M2 had better online task performance than the NARX network (p ≤ 0.030). Overall, we have found that combining the concepts of machine learning and musculoskeletal modeling has resulted in a more robust joint kinematics decoder than either concept individually. The outcome of this study may result in a novel, highly reliable controller for powered prosthetic hands.

Bidirectional Associations Between Adiposity and Cognitive Function and Mediation by Brain Morphology in the ABCD Study

Most epidemiologic studies examine the brain as an outcome in relation to adiposity (ie, the brain-as-outcome perspective), but it is also a potential risk factor associated with adiposity accumulation over time (ie, the brain-as-risk factor perspective). The bidirectionality hypothesis has not been fully explored in adolescent samples previously. To assess bidirectional associations between adiposity and cognitive function in youth and test mediational pathways through brain morphology (specifically the lateral prefrontal cortex [LPFC]), lifestyle behaviors, and blood pressure. This cohort study uses data (wave 1-3; 2 years of follow-up) from the Adolescent Brain Cognitive Development (ABCD) Study, a long-term longitudinal investigation of brain development in the United States launched in 2015, which recruited 11 878 children aged 9 to 10 years at inception. Data analysis was performed from August 2021 to June 2022. Multivariate multivariable regression analyses were used to assess bidirectional associations of indicators of cognitive function (eg, executive function, processing speed, episodic memory, receptive vocabulary and reading skills) and adiposity (eg, body mass index z scores [zBMI] and waist circumference [WC]). Mediators considered for this investigation were lifestyle variables (eg, diet and physical activity), blood pressure, and the morphology of the LPFC and its subregions. A total of 11 103 individuals (mean [SD] age, 9.91 [0.6] years; 5307 females [48%]; 8293 White individuals [75%] and 2264 Hispanic individuals [21%]) were included in the current study. Multivariate multivariable regression analyses revealed that higher baseline zBMI and WC were associated with worse follow-up episodic memory (β, -0.04; 95% CI, -0.07 to -0.01) and better vocabulary (β, 0.03; 95% CI, 0.002 to 0.06) task performance, in covariate adjusted models. Similarly, superior baseline executive function (zBMI: β, -0.03; 95% CI, -0.06 to -0.01; WC: β, -0.04; 95% CI, -0.07 to -0.01) and episodic memory (zBMI: β, -0.04; 95% CI, -0.07 to -0.02; WC: β, -0.03; 95% CI, -0.06 to -0.002) task performance were associated with better follow-up adiposity status in covariate adjusted models. Cross-lagged panel models with latent variable modeling had a bidirectional association with executive function task performance (brain-as-outcome: β, -0.02; 95% CI, -0.05 to -0.001; brain-as-risk factor: β, -0.01; 95% CI, -0.02 to -0.003). The hypothesized associations were statistically mediated by LPFC volume and thickness, physical activity, and blood pressure. In this cohort study, executive function and episodic memory were bidirectionally associated with adiposity indices over time in this adolescent sample. These findings suggest that the brain can be both a risk factor and an outcome of adiposity; this complex bidirectional association should be taken into account in future research and clinical practice.

Effectiveness of a Single Prolonged Aerobic Exercise Session on Executive Function Task Performance in Physically Active Adults (21-70 Years of Age).

We sought to examine the effectiveness of an acute prolonged exercise session on post-exercise executive function in physically active adults and to assess if age or pre-exercise cognitive performance was predictive of the magnitude of change in executive task performance. Self-registered cyclists were recruited prior to participating in a 161-km mass-participation cycling event. Cyclists were excluded if they had not previously participated in a similar endurance event, were young (<18 y), or were cognitively impaired (Mini CogTM < 3 units). Immediately after completing the exercise session, the time taken to complete Trail Making Test Part A and Part B (TMT A + B) was assessed. A faster time to complete the TMT A + B was observed after exercise (+8.5%; p = 0.0003; n = 62; age range = 21-70 y). The magnitude of change in TMT A + B performance (pre vs. post) was influenced by pre-exercise TMT A + B performance (r2 = 0.23, p < 0.0001), not age (r2 =0.002; p = 0.75). Prolonged exercise had a small-to-moderate effect on post-exercise compared to pre-exercise executive function task performance (Cohen's d = 0.38-0.49). These results support the effectiveness of a single prolonged exercise bout to augment executive function in physically active adults, irrespective of age.

Shoulder Performance Activity Test (SPAT) for People With Shoulder Pain: Feasibility, Reliability, and Validity.

The purpose of this study was to assess feasibility, reliability, and validity of a new performance-based test, the Shoulder Performance Activity Test (SPAT). People with shoulder pain (n = 93) and without shoulder pain (n = 43) were included. The SPAT consists of overhead reach, hand behind head, and hand behind back tasks, each performed with 20 repetitions and rated by time, pain, and effort. The SPAT scores were summed for time, pain, and effort, and a total score across the 3 tasks. Feasibility was assessed by the percentage of SPAT task completion, test-retest reliability by intraclass correlation coefficient (ICC), standard error measurement, minimal detectable change, and known-groups construct validity by comparing between groups (shoulder pain and no pain) and between shoulders in those with pain. All participants performed the 3 SPAT tasks. The ICC was 0.74-0.91, and the minimal detectable change was 3.1-4.7 for task scores and 10.0 points for the total score. Individuals with pain presented higher tasks and total scores compared with those without pain. The moderate/severe pain group had higher scores than the low pain and no shoulder pain groups, and the low pain group had higher scores than the no pain group. Scores were higher in the involved shoulder compared with the uninvolved shoulder. The SPAT is a feasible and reliable performance-based test for use in patients with shoulder pain and can differentiate between individuals with and without pain, among different levels of pain, and between involved and uninvolved shoulders. The SPAT provides a standardized method for clinicians to assess shoulder functional performance tasks, which can enable a comprehensive assessment of shoulder disability and clinical decision making. The error metrics can be used to determine meaningful changes in performance.

Piloting a Novel Daily Living Skills Assessment in Autistic Adolescents and Young Adults.

There are a few ecologically valid measurements of Daily Living Skills (DLS)-a critical component of adaptive functioning (AF)-for autistic adolescents and young adults. This is particularly important given that DLS predict outcomes as autistic adolescents transition to adulthood. We pilot-tested the assessment section of two modules of the Computerized Functional Skills Assessment and Training program (CFSAT) in 25 autistic (n = 4 female) and 25 non-autistic (n = 6 female) adolescents and young adults to evaluate preliminary feasibility in an autistic sample. Tasks involved using an ATM and ticket-buying machine. We also assessed AF and DLS with a well-validated self-report questionnaire. We examined group differences in performance and relationships between performance on CFSAT and an existing measure of AF and DLS. We also conducted regression analyses to investigate the associations between age, IQ, executive functioning (EF), and CFSAT task performance. All but one autistic participant were able to complete the CFSAT tasks. Autistic participants made more errors, but did not take longer to complete the task, than non-autistic participants. Performance correlated strongly with self-reported AF generally and DLS specifically. The regression analyses revealed that task performance was associated with EF in the autistic group, but not the non-autistic group. These results provide preliminary support for the use of a new performance-based ecologically valid assessment of DLS in an autistic population. Two CFSAT modules were well-tolerated and detected differences in DLS ability. Strong correlations with an existing measure of AF suggest evidence of construct validity. The EF was associated with CFSAT task performance in autistic individuals. Such a tool could help identify individuals who would benefit from a DLS intervention.

How limb dominance influences limb symmetry in ACL patients: effects on functional performance

BackgroundTiming for return to sport (RTS) after anterior cruciate ligament (ACL) injury is paramount for the avoidance of a secondary injury. A common criterion in RTS decision-making is the limb symmetry index (LSI) which quantifies (a)symmetries between the affected and unaffected limb. Limb dominance is one of many factors that may contribute to the recovery of the LSI after ACL reconstruction. The purpose of this study was to examine how limb dominance affects the LSI of functional performance tasks nine months following ACL reconstruction (time of RTS).MethodsAt time of return to sport, n = 100 patients (n = 48 injured the dominant limb, n = 52 injured the non-dominant limb, n = 34 female, n = 66 male) with ACL reconstruction surgery performed isokinetic strength measurements of the knee extensors and flexors, and drop jumps (DJ), single leg hop for distance (SHD) and 6 m timed hop (6MTH) testings.ResultsThe findings indicated that injury of the dominant leg led to significantly higher LSI values in maximal isokinetic knee extensor strength (p = 0.030). No significant differences were observed for maximal isokinetic knee flexor strength, DJ, SHD or 6MTH performance. Stratifying for sex revealed no significant differences. Simple regression analyses demonstrated that LSI in maximal knee extensor strength significantly predicted LSIs in DJ and SHD while explaining 14% and 18% of the respective variance.ConclusionsGiven that limb dominance affects the LSI of muscle strength suggests that a differentiated interpretation of the LSI with respect to limb dominance should be considered for a safe return to sport. Monoarticular knee extensor strength and multiarticular hop test performance are interrelated and thus can show asymmetries which are not maladaptive but established during years of habituation or training.

Abnormal proximal-distal interactions in upper-limb of stroke survivors during object manipulation: A pilot study.

Despite its importance, abnormal interactions between the proximal and distal upper extremity muscles of stroke survivors and their impact on functional task performance has not been well described, due in part to the complexity of upper extremity tasks. In this pilot study, we elucidated proximal-distal interactions and their functional impact on stroke survivors by quantitatively delineating how hand and arm movements affect each other across different phases of functional task performance, and how these interactions are influenced by stroke. Fourteen subjects, including nine chronic stroke survivors and five neurologically-intact subjects participated in an experiment involving transport and release of cylindrical objects between locations requiring distinct proximal kinematics. Distal kinematics of stroke survivors, particularly hand opening, were significantly affected by the proximal kinematics, as the hand aperture decreased and the duration of hand opening increased at the locations that requires shoulder abduction and elbow extension. Cocontraction of the extrinsic hand muscles of stroke survivors significantly increased at these locations, where an increase in the intermuscular coherence between distal and proximal muscles was observed. Proximal kinematics of stroke survivors was also affected by the finger extension, but the cocontraction of their proximal muscles did not significantly increase, suggesting the changes in the proximal kinematics were made voluntarily. Our results showed significant proximal-to-distal interactions between finger extension and elbow extension/shoulder abduction of stroke survivors exist during their functional movements. Increased cocontraction of the hand muscles due to increased neural couplings between the distal and proximal muscles appears to be the underlying mechanism.

Movement compensation is driven by the deltoid and teres minor muscles following severe rotator cuff tear

BackgroundRotator cuff tears are common in older adults, negatively affecting function. Previous simulation-based studies reported more posterior and superior oriented glenohumeral loading with increased cuff tear severity and task performance, although corresponding muscle compensation strategies are unclear. Our objective is to determine how shoulder muscle forces change with increased rotator cuff tear severity during functional task performance. MethodsEight musculoskeletal models of increasing tear severity were developed to represent no rotator cuff tear to massive three-tendon tears. Simulations were performed using each combination of model and kinematics for five functional tasks. Individual muscle forces were averaged for each task and tear severity, then normalized by the sum of the muscle forces across the shoulder. Forces were compared across tear severity and muscle. FindingsFor muscle force contribution, interactions between tear severity and muscle and a main effect of muscle were seen for all tasks (P < 0.0001). Middle deltoid increased force contribution by >10% in the greatest tear severity model compared to no cuff tear model for all tasks (all P < 0.0001). Teres minor contribution increased by 7.7%, 5.6%, and 11% in the greatest tear severity model compared to the no cuff tear model for forward reach, axilla wash, and upward reach 105° tasks, respectively (all P < 0.0001). InterpretationFunctional tasks elicit compensatory responses from uninjured muscles following severe cuff tears, notably in middle deltoid and teres minor, leading to posterior-superior glenohumeral loading. The muscles are potential targets for strengthening to avoid injury from sustained increased muscle force.

Flexible and Dynamic Scheduling of Mixed-Criticality Systems.

A mixed-criticality system refers to an integrated embedded system in which tasks with different criticality levels run on a shared computing platform. In the design and development of mixed-criticality systems, how to schedule tasks to ensure that high-criticality tasks are executed in time and low-criticality tasks are served as much as possible is a major problem to be studied. Existing studies tend to consider pessimistic processing strategies to ensure the schedulability of functional tasks with high-criticality requirements. However, excessive pessimistic processing can lead to waste of system resources, thereby reducing the performance of functional tasks with low-criticality requirements. In this paper, we propose an adaptive-service-level adjustment strategy for low-criticality tasks, which solves the problem of waste of resources caused by invalid compensation in the low-criticality task compensation method of flexible mixed-criticality systems. In view of the problem that the existing methods mostly use static budget allocation and static independent mode switching without considering the actual operation of the task, this paper also proposes a flexible and dynamic mixed-criticality system scheduling scheme and designs a system execution framework, scheduling algorithm, and dynamic allocation strategy of maximum execution budget, in order to reduce unnecessary redundant resource expenditures and system switching costs and to improve the performance of low-criticality tasks. Experiments show that the proposed methods are effective compared to the state-of-the-art.

Autonomous Learning of Page Flipping Movements via Tactile Feedback

Robotic manipulation is challenging when both the objects being manipulated and the tactile sensors are deformable. In this article, we addressed the interplay between the manipulation of deformable objects, tactile sensing, and model-free reinforcement learning on a real robot. We showed how a real robot can learn to manipulate a deformable, thin-shell object via feedback from deformable, multimodal tactile sensors. We addressed the learning of a page flipping task using a two-stage approach. For the first stage, we learned nominal page flipping trajectories for two page sizes by constructing a reward function that quantifies functional task performance from the perspective of tactile sensing. For the second stage, we learned adapted trajectories using tactile-driven perceptual coupling, with an intuitive assumption that, while the page flipping trajectories for different task contexts (page sizes) might differ, similar tactile feedback should be expected from functional trajectories for each context. We also investigated the quality of information encoded by two different representations of tactile sensing data: one based on the artificial apical tuft of bio-inspired tactile sensors, and another based on principal component analysis eigenvalues. The results and effectiveness of our learning framework were demonstrated on a real seven-degree of freedom robot arm and gripper outfitted with tactile sensors.

Hip Adductor, Abductor Muscles Strength, and Performance in Participants with and without Low Back Pain

Introduction: Weakness of hip muscles is common in individuals with chronic non- specific low back pain (CNSLBP). Also, hip joint performance can be influenced by the weakness of hip muscles. This study aimed to compare the strength and performance of hip adductor and abductor muscles between subjects with and without CNSLBP and to investigate their association with disability level.&#x0D; Materials and Methods: This case-control study included 41 participants with CNSLBP and 41 healthy participants. The strength of hip abductor and adductor muscles were measured using a dynamometer and their performance was assessed using the one-leg hop test. The disability level in the CNSLBP group was assessed using the oswestry disability index (ODI). Data were analyzed using an independent sample t test and Pearson correlation coefficient.&#x0D; Results: No significant differences were observed between groups for hip muscle strength. One-leg hop test scores of the left lower extremity in the lateral direction were significantly higher in the CNSLBP group compared to the control group. Also, no significant relationships were observed between the total score of ODI and hip muscle strength or performance in the CNSLBP group.&#x0D; Conclusion: It’s recommended that evaluation and exercise therapy of participants with CNSLBP be performed during functional performance tasks.

Neuroendocrine effects of a single bout of functional and core stabilization training in women with chronic nonspecific low back pain: A crossover study.

Exercise‐induced hypoalgesia (EIH) is characterized as the pain reduction after an exercise session and it seems to be related to the release of plasma β‐endorphin. In this sense, the core stabilization training (CT) has been suggested for patients with chronic nonspecific low back pain (CNSLBP), but it is unclear whether it induces EIH. Patients with CNSLBP have neuromotor dysfunctions that can affect the performance of functional tasks, thus, performing functional training (FT) could improve motor control and promote EIH, since functional training uses multi‐joint exercises that aim to improve the functionality of actions performed in daily life. EIH is usually assessed using quantitative sensory tests (QST) such as conditioned pain modulation, pressure pain threshold, and temporal summation. Thus, the sum of parameters from quantitative sensory tests and plasma β‐endorphin would make it possible to understand what the neuroendocrine effects of FT and CT session are. Our study compared the acute effect of CT and FT on the EIH and plasma β‐endorphin release, and correlated plasma β‐endorphin with quantitative sensory testing in patients with CNSLBP. Eighteen women performed two training sessions (CT and FT) with an interval of 48 h between sessions. EIH was assessed by QST and plasma β‐endorphin levels. Results showed that only FT significantly increased plasma β‐endorphin (FT p < 0.01; CT p = 0.45), which correlated with pain pressure threshold (PPT) and conditioned pain modulation (CPM). However, QST values were not different in women with CNSLBP after CT or FT protocols. Plasma β‐endorphin correlated with PPT and CPM, however, the same did not occur with a temporal summation.