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We measured the bare ankle and the braced angle-torque relationships in 12 uninjured volunteers under static and dynamic conditions within the full range of inversion motion. These relationships were measured with a specially designed mechanical device that allowed inversion movements with angular velocities up to 850 deg/sec. In testing the bare ankle under static conditions, the torque showed a 10-fold increase within the full range of motion (average, from 0.9 N-m at 7 degrees to about 8 N-m at 48 degrees of inversion). The slope of the angle-torque relationship increased under dynamic conditions giving higher torque values (up to 18 N-m on average). Both orthoses induced similar additional torques that increased linearly, up to about 6 N-m at 45 degrees, with higher angles of inversion. These additional torques are small compared with the amount of stress applied to the foot during a typical ankle sprain situation, such as recovering from a jump. Therefore, we propose that orthotic devices increase the ankle torque, counteracting the inversion movement, and also prevent the start of the inversion movement by preloading and maintaining the ankle in a proper anatomic position with optimal contact between the articular surfaces. [ABSTRACT FROM AUTHOR]

Initial evidence supports the reliability of the Participation Measurement Scale (PM-Scale) in Brazil, but further exploration of its psychometric properties is needed for Brazilian stroke survivors. The aim of the study is to analyze the reliability, convergent validity, internal consistency, and accuracy of the PM-Scale Brazil. A methodological study involved three assessments over intervals of 7-14 days. Reliability was evaluated through the Intraclass Correlation Coefficient. Convergent validity was assessed using Spearman's correlation coefficient to evaluate the alignment of the PM-Scale Brazil with the SATIS-Stroke. Internal consistency was assessed through Cronbach's α. Accuracy was estimated by calculating the area under the receiver operating characteristic curve. The study involved 110 stroke survivors, revealing adequate intra-rater and inter-rater reliability. A significant weak correlation was observed between the PM-Scale and SATIS-Stroke. Internal consistency and accuracy were adequate. The PM-Scale Brazil demonstrates good reliability, internal consistency, and sensitivity. However, its weak correlation with SATIS-Stroke suggests limited convergent validity., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

During object manipulation, humans adjust the grip force to friction, such that slippery objects are squeezed more firmly than sticky ones. This essential mechanism to keep a stable grasp relies on feedback from tactile afferents innervating the fingertips, that are sensitive to local skin strains. To test if this feedback originates from the skin-object interface, we asked participants to perform a grip-lift task with an instrumented object able to monitor skin strains at the contact through transparent plates of different frictions. We observed that, following an unbeknown change in plate across trials, participants adapted their grip force to friction. After switching from high to low friction, we found a significant increase in strain inside the contact arising ~100 ms before the modulation of grip force, suggesting that differences in strain patterns before lift-off are used by the nervous system to quickly adjust the force to the frictional properties of manipulated objects.

Human dexterity requires very fine and efficient control of fingertip forces, which relies on the integration of cutaneous and proprioceptive feedback. Here, we examined the influence of gravity on isometric force control. We trained participants to reproduce isometric vertical forces on a dynamometer held between the thumb and the index finger in normal gravity and tested them during parabolic flight creating phases of microgravity and hypergravity, thereby strongly influencing the motor commands and the proprioceptive feedback. We found that gravity creates the illusion that upward forces are larger than downward forces of the same magnitude. The illusion increased under hypergravity and was abolished under microgravity. Gravity also affected the control of the grip force employed to secure the grasp. These findings suggest that gravity biases the haptic estimation of forces, which has implications for the design of haptic devices to be used during flight or space activities., Competing Interests: The authors declare no competing interests., (© 2023 The Author(s).)

Background: The prevalence of physical inactivity after stroke is high and exercise training improves many outcomes. However, access to community training protocols is limited, especially in low-income settings., Objective: To investigate the feasibility and efficacy of a new intervention: Circuit walking, balance, cycling and strength training (CBCS) on activity of daily living (ADL) limitations, motor performance, and social participation restrictions in people after stroke., Methods: Forty-six community-dwelling individuals with chronic stroke who were no longer in conventional rehabilitation were randomized into an immediate CBCS group (IG; initially received CBCS training for 12 weeks in phase 1), and a delayed CBCS group (DG) that first participated in sociocultural activities for 12 weeks. In phase 2, participants crossed over so that the DG underwent CBCS and the IG performed sociocultural activities. The primary outcome was ADL limitations measured with the ACTIVLIM-Stroke scale. Secondary outcomes included motor performance (balance: Berg Balance Scale [BBS], global impairment: Stroke Impairment Assessment Set [SIAS] and mobility: 6-minute and 10-metre walk tests [6MWT and 10mWT] and psychosocial health [depression and participation]). Additional outcomes included feasibility (retention, adherence) and safety., Results: ADL capacity significantly improved pre to post CBCS training (ACTIVLIM-stroke, +3,4 logits, p < 0.001; effect size [ES] 0.87), balance (BBS, +21 points, p < 0.001; ES 0.9), impairments (SIAS, +11 points, p < 0.001; ES 0.9), and mobility (+145 m for 6MWT and +0.37 m/s for 10mWT; p < 0.001; ES 0.7 and 0.5 respectively). Similar improvements in psychosocial health occurred in both groups. Adherence and retention rates were 95% and 100%, respectively., Conclusion: CBCS was feasible, safe and improved functional independence and motor abilities in individuals in the chronic stage of stroke. Participation in CBCS improved depression and social participation similarly to participation in sociocultural activities. The benefits persisted for at least 3 months after intervention completion., Protocol Registration Number: PACTR202001714888482., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Masson SAS. All rights reserved.)

Background: The PM-Scale was developed specifically to assess participation in individuals after stroke based on the concepts contained in the International Classification of Functioning, Disability and Health. However, this measure is only available in English and French., Objective: To translate and cross-culturally adapt the PM-Scale to Brazilian Portuguese, followed by the validation and testing of reliability of the translated version., Methods: The translation process followed standard guidelines. Preliminary test-retest reliability was determined using the intraclass correlation coefficient (ICC 2,1 ). The Rasch model was employed to analyse the validity, unidimensionality, invariance, and internal consistency of the Brazilian version of the PM-Scale., Results: The final translated version of the PM-Scale presented appropriate semantic, idiomatic, cultural, and conceptual equivalence. The preliminary analysis revealed excellent intra-observer and inter-observer reliability (ICC 2, 1  = 0.91; 95%CI: 0.83, 0.95 and ICC 2, 1  = 0.81; 95%CI: 0.64, 0.89, respectively). The analysis of the Rasch model revealed only one erratic item. An excellent overall fit was found for items (mean ± SD = 0.01 ± 1.02) and adequate fit was found for persons (mean ± SD = 1.16 ± 0.88). Internal consistency was considered adequate (person separation index = 1.77, reliability = 0.76). No significant invariance was found with regards to the personal characteristics of the sample (p > 0.05)., Conclusion: The Brazilian version of the PM-Scale is a valid, unidimensional, linear, reliable scale for measuring participation in stroke survivors and can be administered in less than five minutes., Competing Interests: Declaration of competing interest The authors report no conflicts of interest., (Copyright © 2023 Associação Brasileira de Pesquisa e Pós-Graduação em Fisioterapia. Publicado por Elsevier España, S.L.U. All rights reserved.)

Background: Rules have been developed to simplify the understanding of researchers/clinicians and standardize the linking process between concepts contained in the items on assessment measures and the International Classification of Functioning, Disability, and Health (ICF)., Objective: Link the concepts of the SATISPART Stroke (SATIS-Stroke) and Participation Measurement Scale (PM-Scale) to ICF codes., Methods: Linking was performed by two evaluators with experience in the ICF taxonomy who applied the ten standard linking rules specifically developed and updated for this purpose. The level of agreement between the evaluators was determined using the Kappa coefficient with 95% confidence intervals., Results: The SATIS-Stroke and PM-Scale address the nine domains of the ICF "Activities and Participation" component. Adequate agreement was found between the researchers during the linking process, mainly between the 1º and 3º evaluators. Identified 41 ICF codes were found among the SATIS-Stroke items and 24 ICF codes were found among the items of the PM-Scale., Conclusion: SATIS-Stroke addresses more issues regarding the domains of Learning and Applying Knowledge, Mobility, Self-Care, Domestic Life, and Major Life Areas, whereas the PM-Scale addresses more issues regarding the General Tasks and Demands, Communication, and Community, Social and Civic Life. Both instruments equally address issues related to Interpersonal Interactions and Relationships.

Background: Reduced walking speed because of a stroke may limit activities of daily living (ADLs) and restrict social participation., Objectives: To describe the level of balance impairment, activity limitations, and participation restrictions and to investigate their relationship with walking speed in Burundians with chronic stroke., Methods: This cross-sectional study involved adult stroke survivors. Walking speed, balance, ADLs and social participation were assessed with the 10-meter walk test (10 mWT), the Berg balance scale (BBS), the activity limitation stroke scale and the participation measurement scale, respectively. In order to determine ambulatory independence status, participants were stratified into three walking speed groups (household ambulation, limited ambulation and full-community ambulation), based on the Perry classification., Results: Fifty-eight adults (mean age 52.1 ± 11.4 years) with chronic stroke were included in our study. Most participants had severe balance impairments (median BBS score, 27). Their mean (± standard deviation [SD]) walking speeds, ADL levels and social participation levels were 0.68 ± 0.34 m/s, 50.8% ± 9.3% and 52.8% ± 8.6%, respectively. Walking speed correlated moderately with balance (rho = 0.5, p < 0.001) and strongly with ADL level ( r = 0.7, p < 0.001) but not with participation level ( r = 0.2, p = 0.25)., Conclusion: Using socio-culturally suitable tools, our study showed that walking speed correlates robustly with balance and ADL ability, but not with social participation, in Burundi, a low-income country., Clinical Implications: Exercises targeting walking speed would be very useful for people with chronic stroke living in low-resource countries, in order to promote their functional independence., Competing Interests: The authors declare that they have no financial or personal relationships that may have inappropriately influenced them in writing this article., (© 2022. The Authors.)

Background: Chronic low back pain (CLBP) is an increasing burden worldwide. The biopsychosocial factors associated with CLBP-related activity limitations have not yet been investigated in Burundi., Objective: The aim of our study was to investigate the biopsychosocial factors that influence the CLBP-related activity limitations in a Burundian sample population., Method: We carried out a cross-sectional study of 58 adults with nonspecific CLBP from Bujumbura city. Univariate and bivariate analyses were used to investigate the association between biopsychosocial factors and CLBP activity limitations. Sequential multiple regression analyses were subsequently used to predict CLBP activity limitations., Results: Fifty-eight individuals with a mean age of 41.3 ± 10.20, 58.6% of female gender, were recruited. The univariate and bivariate analyses demonstrated that educational level, gender, healthcare coverage, profession, height, pain intensity, depression and physical fitness were significantly associated with CLBP-related activity limitations ( p range, < 0.001 to < 0.05). The multivariate regression analysis showed that the significant biopsychosocial factors accounted for 49% of the variance in self-reported activity limitations. Predictors of activity limitations were education level (β = -0.369; p = 0.001), abdominal muscle endurance (β = -0.339; p = 0.002) and depression (β = 0.289; p = 0.011)., Conclusions: Our study provides evidence of biopsychosocial factor associations with CLBP-related activity limitations in Burundi. Evidence-based management and prevention of CLBP in Burundi should incorporate a biopsychosocial model., Clinical Implications: Biopsychosocial factors should be regularly evaluated in people with chronic low back pain and efforts to improve the burden of chronic low back pain in Burundi should take these factors into account., Competing Interests: The authors declare that they have no financial or personal relationships that may have inappropriately influenced them in writing this article., (© 2022. The Authors.)

Purpose: To review and quantify the effects of walking training for the improvement of various aspects of physical function of people with chronic stroke., Methods: We conducted a systematic search and meta-analysis of randomized controlled trials (RCTs) of chronic stroke rehabilitation interventions published from 2008 to 2020 in English or French. Of the 6476-screened articles collated from four databases, 15 RCTs were included and analyzed. We performed a meta-regression with the total training time as dependent variable in order to have a better understanding of how did the training dosage affect the effect sizes., Results: Treadmill walking training was more effective on balance and motor functions (standardized mean difference (SMD)=0.70[0.02, 1.37], p  = 0.04) and 0.56[0.15, 0.96], p  = 0.007 respectively). Overground walking training improved significantly walking endurance (SMD = 0.38[0.16, 0.59], p  < 0.001), walking speed (MD = 0.12[0.05, 0.18], p  < 0.001), participation (SMD = 0.35[0.02, 0.68], p  = 0.04) and quality of life (SMD = 0.46[0.12, 0.80], p  = 0.008). Aquatic training improved balance (SMD = 2.41[1.20, 3.62], p  < 0.001). The Meta-regression analysis did not show significant effect of total training time on the effect sizes., Conclusion: Treadmill and overground walking protocols consisting of ≥30 min sessions conducted at least 3 days per week for about 8 weeks are beneficial for improving motor impairments, activity limitations, participation, and quality of life in people with chronic stroke.Implications for rehabilitationTreadmill walking training is effective for improving balance and motor functions.Overground walking training improved significantly walking endurance, walking speed, participation and quality of life.Treadmill and overground walking protocols consisting of ≥30 min sessions conducted at least 3 days per week for about 8 weeks are beneficial for improving motor impairments, activity limitations, participation, and quality of life in patient with chronic stroke.

Humans need to accurately process the contact forces that arise as they perform everyday haptic interactions such as sliding the fingers along a surface to feel for bumps, sticky regions, or other irregularities. Several different mechanisms are possible for how the forces on the skin could be represented and integrated in such interactions. In this study, we used a force-controlled robotic platform and simultaneous ultrasonic modulation of the finger-surface friction to independently manipulate the normal and tangential forces during passive haptic stimulation by a flat surface. To assess whether the contact pressure on their finger had briefly increased or decreased during individual trials in this broad stimulus set, participants did not rely solely on either the normal force or the tangential force. Instead, they integrated tactile cues induced by both components. Support-vector-machine analysis classified physical trial data with up to 75% accuracy and suggested a linear perceptual mechanism. In addition, the change in the amplitude of the force vector predicted participants' responses better than the change of the coefficient of dynamic friction, suggesting that intensive tactile cues are meaningful in this task. These results provide novel insights about how normal and tangential forces shape the perception of tactile contact., (© 2022. The Author(s).)

Dexterous manipulation of objects heavily relies on the feedback provided by the tactile afferents innervating the fingertips. Previous studies have suggested that humans might take advantage of partial slip, localized loss of grip between the skin and the object, to gauge the stability of a contact and react appropriately when it is compromised, that is, when slippage is about to happen. To test this hypothesis, we asked participants to perform point-to-point movements using a manipulandum. Through optical imaging, the device monitored partial slip at the contact interface, and at the same time, the forces exerted by the fingers. The level of friction of the contact material was changed every five trials. We found that the level of grip force was systematically adjusted to the level of friction, and thus partial slip was limited to an amount similar across friction conditions. We suggest that partial slip is a key signal for dexterous manipulation and that the grip force is regulated to continuously maintain an upper bound on partial slip across friction conditions.

Background: SATIS-Stroke questionnaire has been translated and adapted for use in the Brazilian population, however, it is necessary to test the measurement properties in Brazilian population., Objective: To test the reliability, agreement, concurrent validity, and diagnostic accuracy of the SATIS-Stroke., Methods: Chronic stroke survivors were included. The calculations were made using scores in logits (Rasch Model). Reliability was tested using the intraclass correlation coefficient (ICC 2,1 ), standard error of measurement (SEM), minimal detectable change (MDC), and Bland-Altman plots. Concurrent validity was analyzed using Spearman's correlation coefficient. For such, the correlation between SATIS-Stroke and Stroke Specific Quality of Life (SS-QOL) questionnaires was determined. Diagnostic accuracy was estimated based on the area under the receiver operating characteristic (ROC) curve with a 95% confidence interval and considering the sensitivity and specificity of SATIS-Stroke in differentiating different types of activity and participation., Results: Eighty stroke survivors were analyzed. Mean age was 57.98±13.85 years and 45.2% had severe impairment. Excellent reliability was found (intra-observer ICC 2,1  = 0.90; 95% CI: 0.84, 0.93; inter-observer ICC 2,1  = 0.89; 95% CI: 0.83, 0.93). The Bland-Altman plot demonstrated satisfactory agreement. In the analysis of concurrent validity, a strong, positive, significant correlation was found between SATIS-Stroke and SS-QOL (r s = 0.74; p <0.001 with an r 2 =0.44; p=0.001). Diagnostic accuracy was satisfactory, with 80.8% sensitivity and 85.2% specificity., Conclusion: The Brazilian version of the SATIS-Stroke questionnaire exhibited adequate reliability, concurrent validity, and diagnostic accuracy. Therefore, this is a valid, reproducible measure for the assessment of satisfaction with regard to activities and participation following a stroke., Competing Interests: Conflict of interest The authors declare no conflicts of interest., (Copyright © 2021 Associação Brasileira de Pesquisa e Pós-Graduação em Fisioterapia. Publicado por Elsevier España, S.L.U. All rights reserved.)

During active object manipulation, the finger-object interactions give rise to complex fingertip skin deformations. These deformations are in turn encoded by the local tactile afferents and provide rich and behaviorally relevant information to the central nervous system. Most of the work studying the mechanical response of the finger to dynamic loading has been performed under a passive setup, thereby precisely controlling the kinematics or the dynamics of the loading. However, to identify aspects of the deformations that are relevant to online control during object manipulation, it is desirable to measure the skin response in an active setup. To that end, we developed a device that allows us to monitor finger forces, skin deformations, and kinematics during fine manipulation. We describe the device in detail and test it to precisely describe how the fingertip skin in contact with the object deforms during a simple vertical oscillation task. We show that the level of grip force directly influences the fingerpad skin strains and that the strain rates are substantial during active manipulation (norm up to 100%/s). The developed setup will enable us to causally relate sensory information, i.e. skin deformation, to online control, i.e. grip force adjustment, in future studies. NEW & NOTEWORTHY We present a novel device, a manipulandum, that enables to image the contact between the finger and the contact surface during active manipulation of the device. The device is tested in a simple vertical oscillation task involving 18 participants. We demonstrate that substantial surface skin strains take place at the finger-object interface and argue that those deformations provide essential information for grasp stability during object manipulation.

The ability to monitor activities of daily living in the natural environments of patients could become a valuable tool for various clinical applications. In this paper, we show that a simple algorithm is capable of classifying manual activities of daily living (ADL) into categories using data from wrist- and finger-worn sensors. Six participants without pathology of the upper limb performed 14 ADL. Gyroscope signals were used to analyze the angular velocity pattern for each activity. The elaboration of the algorithm was based on the examination of the activity at the different levels (hand, fingers and wrist) and the relationship between them for the duration of the activity. A leave-one-out cross-validation was used to validate our algorithm. The algorithm allowed the classification of manual activities into five different categories through three consecutive steps, based on hands ratio (i.e., activity of one or both hands) and fingers-to-wrist ratio (i.e., finger movement independently of the wrist). On average, the algorithm made the correct classification in 87.4% of cases. The proposed algorithm has a high overall accuracy, yet its computational complexity is very low as it involves only averages and ratios.

Human tactile afferents provide essential feedback for grasp stability during dexterous object manipulation. Interacting forces between an object and the fingers induce slip events that are thought to provide information about grasp stability. To gain insight into this phenomenon, we made a transparent surface slip against a fixed fingerpad while monitoring skin deformation at the contact. Using microneurography, we simultaneously recorded the activity of single tactile afferents innervating the fingertips. This unique combination allowed us to describe how afferents respond to slip events and to relate their responses to surface deformations taking place inside their receptive fields. We found that all afferents were sensitive to slip events, but fast-adapting type I (FA-I) afferents in particular faithfully encoded compressive strain rates resulting from those slips. Given the high density of FA-I afferents in fingerpads, they are well suited to detect incipient slips and to provide essential information for the control of grip force during manipulation., Competing Interests: BD, EJ, AB, JT, BE, PL No competing interests declared, (© 2021, Delhaye et al.)

In humans, practically all movements are learnt and performed in a constant gravitational field. Yet, studies on arm movements and object manipulation in parabolic flight have highlighted very fast sensorimotor adaptations to altered gravity environments. Here, we wondered if the motor adjustments observed in those altered gravity environments could also be observed on Earth in a situation where the body is upside-down. To address this question, we asked participants to perform rhythmic arm movements in two different body postures (right-side-up and upside-down) while holding an object in precision grip. Analyses of grip-load force coordination and of movement kinematics revealed distinct adaptation patterns between grip and arm control. Grip force and load force were tightly synchronized from the first movements performed in upside-down posture, reflecting a malleable allocentric grip control. In contrast, velocity profiles showed a more progressive adaptation to the upside-down posture and reflected an egocentric planning of arm kinematics. In addition to suggesting distinct mechanisms between grip dynamics and arm kinematics for adaptation to novel contexts, these results also suggest the existence of general mechanisms underlying gravity-dependent motor adaptation that can be used for fast sensorimotor coordination across different postures on Earth and, incidentally, across different gravitational conditions in parabolic flights, in human centrifuges, or in Space. NEW & NOTEWORTHY During rhythmic arm movements performed in an upside-down posture, grip control adapted very quickly, but kinematics adaptation was more progressive. Our results suggest that grip control and movement kinematics planning might operate in different reference frames. Moreover, by comparing our results with previous results from parabolic flight studies, we propose that a common mechanism underlies adaptation to unfamiliar body postures and adaptation to altered gravity.

Background: Patients treated in hand surgery (HS) belong to different demographic groups and have varying impairments related to different pathologies. HS outcomes are measured to assess treatment results, complication risks and intervention reliability. A one-dimensional and linear measure would allow for unbiased comparisons of manual ability between patients and different treatment effects., Objective: To adapt the ABILHAND questionnaire through Rasch analysis for specific use in HS patients and to examine its validity., Methods: A preliminary 90-item questionnaire was presented to 216 patients representing the diagnoses most frequently encountered in HS, including distal radius fracture (n = 74), basal thumb arthritis (n = 66), carpal tunnel syndrome (n = 53), and heavy wrist surgery (n = 23). Patients were assessed during the early recovery and in the late follow-up period (0-3 months, 3-6 months and >6 months), leading to a total of 305 assessments. They rated their perceived difficulty with queried activities as impossible, difficult, or easy. Responses were analyzed using the RUMM2030 software. Items were refined based on item-patient targeting, fit statistics, differential item functioning, local independence and item redundancy. Patients also completed the QuickDASH, 12-item Short Form Survey (SF-12) and a numerical pain scale., Results: The rating scale Rasch model was used to select 23 mostly bimanual items on a 3-level scale, which constitute a unidimensional, linear measure of manual ability with good reliability across all included diagnostic groups (Person-Separation Index = 0.90). The resulting scale was found to be invariant across demographic and clinical subgroups and over time. ABILHAND-HS patient measures correlated significantly (p<0.001) with the QuickDASH (r = -0.77), SF-12 Physical Component Summary (r = 0.56), SF-12 Mental Component Summary (r = 0.31), and pain scale (r = -0.49)., Conclusion: ABILHAND-HS is a robust person-centered measure of manual ability in HS patients., Competing Interests: The authors have declared that no competing interests exist.

Purpose: Walking and mind-body therapies (MBTs) are commonly recommended to relieve pain and improve function in patients with chronic low back pain (CLBP). The purpose of this study was to compare the effectiveness of walking and MBTs in CLBP., Methods: We included randomized controlled trials (RCTs) comparing walking or MBTs to any other intervention or control in adults with CLBP. Studies were identified through PubMed, Cochrane Library, PsycINFO, Scopus, and ScienceDirect databases. The research was limited to studies published in English and French between January 2008 and December 2018. Two reviewers independently selected the studies, extracted data, and assessed studies quality using the Physiotherapy Evidence Database (PEDro) scale. Statistical analyses were performed under a random-effects model. We analyzed pain and activity limitation, with the calculation of standardized mean differences and 95% confidence intervals for the different treatment effects., Results: Thirty one randomized controlled trials involving 3193 participants were analyzed. Walking was as effective as control interventions in the short-term and slightly superior in the intermediate term with respect to pain (Standardized mean differences (SMD)  = -0.34; 95% CI, -0.65 to -0.03; P = .03) and activity limitation (SMD = -0.30; 95% CI, -0.50 to -0.10; P = .003). In contrast, yoga was more effective than control interventions in the short term in terms of pain (SMD = -1.47; 95% CI, -2.26 to -0.68; P = .0003) and activity limitation (SMD = -1.17; 95% CI, -1.80 to -0.55; P = .0002). Yoga was no longer superior to the control interventions for pain at the 6-month follow-up., Conclusion: MBTs, especially yoga, seem to be more effective in the short term, and walking seems to be more effective in the intermediate term, for the relief of pain and activity limitation in patients with CLBP. A combination of walking and MBTs fits the biopsychosocial model and might be valuable therapy for CLBP throughout follow-up due to combined effects.

To appraise available International Classification of Functioning, Disability and Health (ICF)-based tools for the measurement of participation after stroke and to examine their applicability in the African sociocultural context. Pubmed/Medline, Science Direct, Cochrane Library, and Hinari databases were systematically searched. The literature search was limited to studies published in the English or French language from January 2001 up to May 2019. Two reviewers independently screened all identified studies and selected eligible articles. Disagreements about inclusion or exclusion of studies were resolved by consensus. Two reviewers independently extracted the psychometric properties of each instrument using the Consensus-based Standard for the Selection of Health Measurement Instruments checklist and examined the methodological quality of each selected study using the MacDermid checklist. A total of 1030 articles were systematically reviewed for relevance, yielding 22 studies that met inclusion criteria. These studies were related to nine participation tools. The MacDermid scores ranged from 13 to 21 out of 24. The number of investigated psychometric properties and the number of ICF participation domains covered by each tool varied among studies. This systematic review revealed nine ICF-based tools for the measurement of participation after stroke. We examined the content of these tools and provided valuable information that can be used to guide researchers in Africa in their selection of the most appropriate tool for the measurement of participation after stroke.

Humans and other animals adapt motor commands to predictable disturbances within tens of trials in laboratory conditions. A central question is how does the nervous system adapt to disturbances in natural conditions when exactly the same movements cannot be practiced several times. Because motor commands and sensory feedback together carry continuous information about limb dynamics, we hypothesized that the nervous system could adapt to unexpected disturbances online. We tested this hypothesis in two reaching experiments during which velocity-dependent force fields (FFs) were randomly applied. We found that within-movement feedback corrections gradually improved, despite the fact that the perturbations were unexpected. Moreover, when participants were instructed to stop at a via-point, the application of a FF prior to the via-point induced mirror-image after-effects after the via-point, consistent with within-trial adaptation to the unexpected dynamics. These findings suggest a fast time-scale of motor learning, which complements feedback control and supports adaptation of an ongoing movement., (Copyright © 2020 Crevecoeur et al.)

Objective: To build a model of prediction of social participation of community-dwelling stroke survivors in Benin at 1 month, 3 months, and 6 months., Design: An observational study with evaluations at 1 month, 3 months, and 6 months poststroke. Correlational analyses and multivariate linear regressions were performed., Setting: Outpatient rehabilitation centers in Benin., Participants: A volunteer sample of 91 stroke patients was enrolled at baseline; 64 (70%) patients completed all the study (N=64): 70% male and 52% right hemiparesis., Intervention: Not applicable., Main Outcome Measures: Participants were evaluated with the Participation Measurement Scale, ACTIVLIM-Stroke (activities of daily living [ADL]), Stroke Impairment Assessment Set, 6-minute walk test, Hospital Anxiety and Depression Scale, and the modified Rankin Scale., Results: The significant predictors of social participation after controlling the confounders were the following: at 1 month ADL (0.4 [0.3, 0.6]) and depression (‒0.6 [‒0.8, ‒0.2]) with total model R 2 =0.44; at 3 months ADL (0.58 [0.4, 0.7]) and depression (‒0.58 [‒0.5, ‒0.7]) with total model R 2 =0.65; and at 6 months ADL (0.31 [0.2, 0.5]), impairments (‒0.82 [‒0.5, ‒0.7]), and depression (‒0.94 [‒0.8, ‒0.2]) with total model R 2 =0.78., Conclusions: Using socioculturally tailored tools, the present study identified ADL performance (ACTIVLIM-Stroke), depression (Hospital Anxiety Depression Scale), and overall impairments (Stroke Impairment Assessment Set) as the significant determinants of social participation (Participation Measurement Scale) poststroke in Benin. These findings will be a valuable resource for rehabilitation stakeholders in evaluating interventions, programs, and policies designed to encourage social participation for stroke patients., (Copyright © 2019 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.)

Displaying tactile feedback through a touchscreen via electrovibration has many potential applications in mobile devices, consumer electronics, home appliances and automotive industry though our knowledge and understanding of the underlying contact mechanics are very limited. An experimental study was conducted to investigate the contact evolution between the human finger and a touch screen under electrovibration using a robotic set-up and an imaging system. The results show that the effect of electrovibration is only present during full slip but not before slip. Hence, the coefficient of friction increases under electrovibration as expected during full slip, but the apparent contact area is significantly smaller during full slip when compared to that of no electrovibration condition. It is suggested that the main cause of the increase in friction during full slip is due to an increase in the real contact area and the reduction in apparent area is due to stiffening of the finger skin in the tangential direction.

Introduction: SATIS-Stroke was developed to measure satisfaction regarding activities and participation among stroke survivors based on the concepts contained in the International Classification of Functioning, Disability, and Health. However, this measure is only available in English and French., Objective: Perform the translation and cross-cultural adaptation of SATIS-Stroke to Brazilian Portuguese and test the preliminary reliability of this measure., Methods: The translation process followed standardized guidelines and consisted of six phases: initial translation, back-translation, analysis of expert committee, test of final version, submission, and assessment of all written reports. To test the preliminary test-retest reliability, the measure was administered by a single observer on two occasions with an interval of 7 to 14 days for the determination of intraobserver agreement and administered again by a second observer for the determination of interobserver agreement. Reliability was analyzed using the intraclass correlation coefficient (ICC 2,1 ) and respective 95% confidence intervals (CI)., Results: All stages of the cross-cultural adaptation process were respected and the final translated version of SATIS-Stroke exhibited semantic, idiomatic, cultural, and conceptual equivalence to the original version. The preliminary analysis revealed excellent intraobserver and interobserver reliability (ICC = 0.93; 95% CI: 0.83-0.97, p = 0.001 and ICC = 0.90; 95% CI: 0.74-0.96; p = 0.001, respectively). The items demonstrated adequate internal consistency, although ceiling and floor effects were considered beyond acceptable standards for some items. In the exploratory factor analysis, three factors were extracted that aggregated more than one construct to each component, but all were related to the "Activities and Participation" component of the International Classification of Functioning, Disability, and Health., Conclusion: The final version of the SATIS-Stroke scale in Brazilian Portuguese proved to be adequate and reliable for use on the Brazilian population. Further studies are underway to give continuity to the validation process and analyze the others measurement properties of the scale in the Brazilian population.

Objective: To investigate responsiveness of the Participation Measurement Scale (PM-Scale) for the measurement of participation of stroke survivors., Design: A 6-month observational study with 3 evaluation time points. Responsiveness of the PM-Scale was investigated over a period of 6 months., Setting: Rehabilitation centers., Participants: Stroke survivors (N =64); mean age ± SD, 56.9±12.6 years; sex, 45 men (70%)., Interventions: Not applicable., Main Outcome Measures: Participants were evaluated using the PM-Scale. The modified Rankin Scale was used to categorize the overall disability level for each participant., Results: The mixed-effect model analysis showed a significant difference in the participation over time (χ 2 =35.04; df=2; P<.001). In addition, the model exhibited significant effects of the sex, age, and disability at enrollment on the subjects' participation levels. Furthermore, the PM-Scale detected different levels of changes in the entire cohort over time (small change, effect size [ES]=0.33; moderate change, ES=0.67; and large change, ES=1). The PM-Scale also facilitated the classification of the participants into discriminative categories such as important improvement (t score≥1.96; 1.8≤ES≤2.13), moderate improvement (0

Aim: To investigate the responsiveness of the ACTIVLIM-CP questionnaire after two evidence-based interventions for children with cerebral palsy (CP)., Method: Seventy-five children with CP either participated in an intensive motor-skill learning intervention (hand-arm bimanual intensive therapy including lower extremities [HABIT-ILE], n=47) or received botulinum neurotoxin-A (BoNT-A) injection(s) into lower extremities combined with conventional physical therapy (n=28). All children were assessed three times: at baseline (T 0 ; before HABIT-ILE/the day of BoNT-A injection), at T 1 (last day of HABIT-ILE/6wks after BoNT-A injection), and at follow-up (T 2 ; 3-4mo after the beginning of intervention). Parents completed ACTIVLIM-CP and three other activity questionnaires. Responsiveness was analysed using group (based on intervention), subgroup (based on gross motor function level), and individual approaches., Results: For the HABIT-ILE group, significant improvements in ACTIVLIM-CP were observed for the T 0 -T 1 period (p<0.001) but not for the T 1 -T 2 period. No significant changes were found in the BoNT-A group during assessments (p=0.84). In the subgroup analysis for the HABIT-ILE group (T 0 -T 1 ), greater changes were demonstrated for children in Gross Motor Function Classification System levels III and IV (p<0.001, effect size=1.36). The individual approach was congruent with the group approach., Interpretation: ACTIVLIM-CP demonstrated high responsiveness after HABIT-ILE, showing that this scale may be used to investigate global activity performance in clinical trials focusing on improving daily life activities., What This Paper Adds: Good responsiveness of ACTIVLIM-CP questionnaire during intensive motor-skill learning intervention. Higher responsiveness for children in Gross Motor Function Classification System (GMFCS) levels III and IV versus I and II after intensive intervention. ACTIVLIM-CP is useful to identify children improving their performance after botulinum neurotoxin-A injection., (© 2018 Mac Keith Press.)

Predicting the consequences of one's own movements can be challenging when confronted with completely novel environmental dynamics, such as microgravity in space. The absence of gravitational force disrupts internal models of the central nervous system (CNS) that have been tuned to the dynamics of a constant 1- g environment since birth. In the context of object manipulation, inadequate internal models produce prediction uncertainty evidenced by increases in the grip force (GF) safety margin that ensures a stable grip during unpredicted load perturbations. This margin decreases with practice in a novel environment. However, it is not clear how the CNS might react to a reduced, but non-zero, gravitational field, and if adaptation to reduced gravity might be beneficial for subsequent microgravity exposure. That is, we wondered if a transfer of learning can occur across various reduced-gravity environments. In this study, we investigated the kinematics and dynamics of vertical arm oscillations during parabolic flight maneuvers that simulate Mars gravity, Moon gravity, and microgravity, in that order. While the ratio of and the correlation between GF and load force (LF) evolved progressively with practice in Mars gravity, these parameters stabilized much quicker to subsequently presented Moon and microgravity conditions. These data suggest that prior short-term adaptation to one reduced-gravity field facilitates the CNS's ability to update its internal model during exposure to other reduced gravity fields.

During tactile exploration, partial slips occur systematically at the periphery of fingertip-object contact prior to full slip. Although the mechanics of partial slips are well characterized, the perception of such events is unclear. Here, we performed psychophysical experiments to assess partial slip detection ability on smooth transparent surfaces. In these experiments, the index fingertip of human subjects was stroked passively by a smooth, transparent glass plate while we imaged the contact slipping against the glass. We found that subjects were able to detect fingertip slip before full slip occurred when, on average, only 48% of the contact area was slipping. Additionally, we showed that partial slips and plate displacement permitted slip detection, but that the subjects could not rely on tangential force to detect slipping of the plate. Finally, we observed that, keeping the normal contact force constant, slip detection was impeded when the plate was covered with a hydrophobic coating dramatically lowering the contact friction and therefore the amount of fingertip deformation. Together, these results demonstrate that partial slips play an important role in fingertip slip detection and support the hypothesis that the central nervous system relies on them to adjust grip force during object manipulation.

Objective: To develop a valid stroke-specific tool, named the Participation Measurement Scale (PM-Scale), for the measurement of participation after stroke., Design: Observational study and questionnaire development., Setting: Outpatient rehabilitation centers., Participants: Patients with stroke (N=276; mean age, 58.5±11.1y; 57% men)., Interventions: Not applicable., Main Outcome Measures: Participants completed a 100-item experimental questionnaire of the PM-Scale. Items were scored as "not at all," "weakly," or "strongly." The Hospital Anxiety and Depression Scale was used to evaluate depression, and the modified Rankin Scale was used to categorize the severity of disability on the basis of observation., Results: After successive Rasch analyses using unrestricted partial credit parameterization, a valid, unidimensional, and linear 22-item scale for the measurement of participation was constructed. All 22 items fulfilled the measurement requirements of overall and individual item and person fits, category discrimination, invariance, and local response independence. The PM-Scale showed good internal consistency (person separation index, .93). The test-retest reliability of item difficulty hierarchy (r=.96; P<.001) and patient location (r=.99; P<.001) were excellent. This patient-based scale covers all 9 International Classification of Functioning, Disability and Health domains of participation., Conclusions: The PM-Scale has good psychometric qualities and provides accurate measures of participation in patients with stroke in Africa., (Copyright © 2017 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.)

Bimanual tasks involve the coordination of both arms, which often offers redundancy in the ways a task can be completed. The distribution of control across limbs is often considered from the perspective of handedness. In this context, although there are differences across dominant and nondominant arms during reaching control ( Sainburg 2002 ), previous studies have shown that the brain tends to favor the dominant arm when performing bimanual tasks ( Salimpour and Shadmehr 2014 ). However, biomechanical factors known to influence planning and control in unimanual tasks may also generate limb asymmetries in force generation, but their influence on bimanual control has remained unexplored. We investigated this issue in a series of experiments in which participants were instructed to generate a 20-N force with both arms, with or without perturbation of the target force during the trial. We modeled the task in the framework of optimal feedback control of a two-link model with six human-like muscles groups. The biomechanical model predicted a differential contribution of each arm dependent on the orientation of the target force and joint configuration that was quantitatively matched by the participants' behavior, regardless of handedness. Responses to visual perturbations were strongly influenced by the perturbation direction, such that online corrections also reflected an optimal use of limb biomechanics. These results show that the nervous system takes biomechanical constraints into account when optimizing the distribution of forces generated across limbs during both movement planning and feedback control of a bimanual task. NEW & NOTEWORTHY Here, we studied a bimanual force production task to examine the effects of biomechanical constraints on the distribution of control across limbs. Our findings show that the central nervous system optimizes the distribution of force across the two arms according to the joint configuration of the upper limbs. We further show that the underlying mechanisms influence both movement planning and online corrective responses to sudden changes in the target force.

Humans have a remarkable ability to adjust the way they manipulate tools through a genuine regulation of grip force according to the task. However, rapid changes in the dynamical context may challenge this skill, as shown in many experimental approaches. Most experiments adopt perturbation paradigms that affect only one sensory modality. We hypothesize that very fast adaptation can occur if coherent information from multiple sensory modalities is provided to the central nervous system. Here, we test whether participants can switch between different and never experienced dynamical environments induced by centrifugation of the body. Seven participants lifted an object four times in a row successively in 1, 1.5, 2, 2.5, 2, 1.5, and 1 g. We continuously measured grip force, load force and the gravitoinertial acceleration that was aligned with body axis (perceived gravity). Participants adopted stereotyped grasping movements immediately upon entry in a new environment and needed only one trial to adapt grip forces to a stable performance in each new gravity environment. This result was underlined by good correlations between grip and load forces in the first trial. Participants predictively applied larger grip forces when they expected increasing gravity steps. They also decreased grip force when they expected decreasing gravity steps, but not as much as they could, indicating imperfect anticipation in that condition. The participants' performance could rather be explained by a combination of successful scaling of grip force according to gravity changes and a separate safety factor. The data suggest that in highly unfamiliar dynamic environments, grip force regulation is characterized by a combination of a successful anticipation of the experienced environmental condition, a safety factor reflecting strategic response to uncertainties about the environment and rapid feedback mechanisms to optimize performance under constant conditions.

Aim: To compare grip force (GF) and load force (LF) coordination while walking down a step between children with unilateral cerebral palsy (UCP) and typically developing (TD) children., Methods: Twenty-five children with UCP (age 9.3±1.7 y) and 25 TD controls (age 9.4±2.1 y) walked down a step while holding a grip-lift manipulandum. Dynamic and temporal variables were analyzed. The maximum voluntary contraction (MVC) was also assessed., Results: The temporal course was perturbed mainly in the more affected hand of children with UCP when compared to TD children because the increases in GF and LF onset occurred in a reversed order. Compared with the TD controls, the children with UCP presented higher LF values on both hands and a higher GF on the less affected hand. In children with UCP, the GF to LF adaptation was adequate on the less affected hand but overestimated on the more affected hand. Furthermore, children with UCP presented a lower MVC in the more affected hand, leading to a higher percentage of MVC used during the task., Interpretation: Our findings highlight an anticipatory control of precision grip during a stepping down task in children with UCP that is adequate for the less affected hand but altered for the more affected hand.

When we touch an object or explore a texture, frictional strains are induced by the tactile interactions with the surface of the object. Little is known about how these interactions are perceived, although it becomes crucial for the nascent industry of interactive displays with haptic feedback (e.g. smartphones and tablets) where tactile feedback based on friction modulation is particularly relevant. To investigate the human perception of frictional strains, we mounted a high-fidelity friction modulating ultrasonic device on a robotic platform performing controlled rubbing of the fingertip and asked participants to detect induced decreases of friction during a forced-choice task. The ability to perceive the changes in friction was found to follow Weber's Law of just noticeable differences, as it consistently depended on the ratio between the reduction in tangential force and the pre-stimulation tangential force. The Weber fraction was 0.11 in all conditions demonstrating a very high sensitivity to transient changes in friction. Humid fingers experienced less friction reduction than drier ones for the same intensity of ultrasonic vibration but the Weber fraction for detecting changes in friction was not influenced by the humidity of the skin., (© 2017 The Authors.)

Simultaneous execution of cognitive and sensorimotor tasks is critical in daily life. Here, we examined whether dexterous manipulation, a highly habitual and seemingly automatic behavior, involves high order cognitive functions. Specifically, we explored the impact of reducing available cognitive resources on the performance of a precision grip-lift task in healthy participants of three age groups (18-30, 30-60 and 60-75 years). Participants performed a motor task in isolation (M), in combination with a low-load cognitive task (M + L), and in combination with a high-load cognitive task (M + H). The motor task consisted in grasping, lifting and holding an apparatus instrumented with force sensors to monitor motor task performance. In the cognitive task, a list of letters was shown briefly before the motor task. After completing the motor task, one letter of the list was shown, and participants reported the following letter of the list. In M + L, letters in the list followed the alphabetical order. In M + H, letters were presented in random order. Performing the high-load task thus required maintaining information in working memory. Temporal and dynamic parameters of grip and lift forces were compared across conditions. During the cognitive tasks, there was a significant alteration of movement initiation and a significant increase of grip force (GF) throughout the grip-lift task. There was no interaction with "age". Our results demonstrate that planning and the on-line control of dexterous manipulation is not an automatic behavior and, instead, that it interacts with high-level cognitive processes such as those involved in working memory.

Tactile and muscle afferents provide critical sensory information for grasp control, yet the contribution of each sensory system during online control has not been clearly identified. More precisely, it is unknown how these two sensory systems participate in online control of digit forces following perturbations to held objects. To address this issue, we investigated motor responses in the context of fingertip loading, which parallels the impact of perturbations to held objects on finger motion and fingerpad deformation, and characterized surface recordings of intrinsic (first dorsal interosseous, FDI) and extrinsic (flexor digitorum superficialis, FDS) hand muscles based on statistical modeling. We designed a series of experiments probing the effects of peripheral stimulation with or without anesthesia of the finger, and of task instructions. Loading of the fingertip generated a motor response in FDI at ~60 ms following the perturbation onset, which was only driven by muscle stretch, as the ring-block anesthesia reduced the gain of the response occurring later than 90 ms, leaving responses occurring before this time unaffected. In contrast, the motor response in FDS was independent of the lateral motion of the finger. This response started at ~90 ms on average and was immediately adjusted to task demands. Altogether these results highlight how a rapid integration of partially distinct sensorimotor circuits supports rapid motor responses to fingertip loading. NEW & NOTEWORTHY To grasp and manipulate objects, the brain uses touch signals related to skin deformation as well as sensory information about motion of the fingers encoded in muscle spindles. Here we investigated how these two sensory systems contribute to feedback responses to perturbation applied to the fingertip. We found distinct response components, suggesting that each sensory system engages separate sensorimotor circuits with distinct functions and latencies., (Copyright © 2017 the American Physiological Society.)

Aim: ABILHAND-Kids is a parent-reported questionnaire measuring manual ability in children with cerebral palsy (CP). Its psychometric properties have been established, with the exception of responsiveness, which is examined here., Method: In this cohort study, 98 children (46 males, 52 females; range 6-19y, mean 11y, standard deviation [SD] 3.3y) with unilateral CP underwent three assessments of upper extremity function: at baseline (T1); after 80 to 90 hours of intensive training (T2); and at follow-up (T3). The responsiveness was analyzed using global, group (based on age and on Manual Ability Classification System [MACS] level), and individual approaches during two time periods (T1-T2 and T2-T3). Effect size was used to quantify magnitude of changes., Results: The global approach showed significant improvements between T1 and T2 (p<0.001) but not between T2 and T3 (p=0.222). In the group analyses, effect size and SRM demonstrated large changes in younger children (6-12y, n=52, mean change=1.06 logit, effect size >0.8) and small changes in the older children (13-19y, n=46, mean change=0.71 logit, effect size >0.4). Children in MACS level II demonstrated larger changes than children in MACS level I or III., Interpretation: The ABILHAND-Kids exhibited responsiveness in detecting changes after intensive training. Therefore, this scale is potentially useful in assessing the functional status of children with unilateral CP in clinical trials., (© 2016 Mac Keith Press.)

Objective: Children with cerebral palsy (CP) often have upper extremity (UE) and lower extremity (LE) impairments. While tools measuring separately UE and LE abilities are currently used, activities in which UE and LE are used in combination - numerous in everyday life - cannot be assessed because no instrument allows capturing global activity performance in children with CP. This study aimed to develop a clinical tool for measuring their global activity performance using the Rasch model., Study Design: The caregivers of 226 children with CP (2-18 years old) answered a 154-item experimental questionnaire. Within 4-6 weeks, 129 of them filled in the questionnaire a second time. Responses were analyzed using the Rasch RUMM2020 software., Results: The final 43 item scale presented a high reliability (R=0.98) and reproducibility (R=0.97). The item difficulty hierarchy was consistent over time and did not vary according to age, gender, or clinical form, allowing the follow-up of children from 2 to 18 years old., Conclusions: ACTIVLIM-CP is a unidimensional scale specifically developed to measure global activity performance in children with CP providing a reliable tool to follow children's evolution and document changes related to neurorehabilitation, especially where a combination of UE and LE is targeted. Its responsiveness is still to be tested., (Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.)

The aim of this study was to determine whether the internal model regulating grip force (GF)/load force (LF) coordination during a brisk load increase is preserved when the lower extremities produce a perturbation during a single step-down task. We observed the coordination of the vertical ground reaction force (vGRF), GF and LF while holding a handheld object during a single step-down task. The 3 forces (vGRF, GF and LF) decreased during the start of the task. While the subject was descending, LF and GF became dissociated from vGRF and increased in value, probably to anticipate the first foot contact. Coordination of LF and GF was maintained until the maximal vGRF (knee extension). LF peaked in the same time window as vGRF, whereas GF peaked about 70 ms later. This desynchronization, which was previously observed in direct load increase on a handheld object, was interpreted to be a predictive action to ensure the smooth management of the brisk increase in load induced by the lower extremities. Incidentally, in this group, kinematic and dynamic differences were observed between men and women, which may highlight a gender-specific strategy to perform the step-down task. In conclusion, these results suggest that the internal model of precision grip is able to integrate a brisk load change, whatever its origin, and regulate the forces to provide an ideal GF to dampen a brisk load increase and secure the object., Competing Interests: The authors have declared that no competing interests exist.

Objective: Stroke is a major public health problem in developing countries. However, few studies have quantified the functional recovery of stroke patients in sub-Saharan Africa. This study examined the functional recovery of stroke patients in the Republic of Benin., Methods: A total of 68 patients with acute stroke were recruited from hospitals and health centres in Benin. Patients were evaluated at enrolment and 1, 3 and 6 months post-stroke. The ACTIVLIM-Stroke scale, Barthel Index, and modified Rankin Scale were used to assess activity limitations, functional autonomy, and overall level of disability, respectively., Results: Over the 6-month follow-up period, 18 patients died and 9 dropped out. Overall, the 3 measures highlighted progressive and significant functional recovery during the first 6 months. At enrolment, the mean score on ACTIVLIM-Stroke was 16% (standard deviation (SD) 9), indicating that patients were almost totally dependent and unable to perform most activities of daily living. At 6 months, the mean score for activity limitation reached 67% (SD 15) and most patients were able to perform some basic tasks easily. Patients had difficulty with tasks requiring walking and remained unable to perform certain activities requiring manual dexterity., Conclusion: The study sample showed significant functional recovery (~50%) during the first 6 months post-stroke. We recommend the integration of group-based brisk walking into a cost-effective rehabilitation programme as a suitable way to increase functional recovery of chronic stroke patients in sub-Saharan Africa after hospital discharge.

The static coefficient of friction (µ static ) plays an important role in dexterous object manipulation. Minimal normal force (i.e., grip force) needed to avoid dropping an object is determined by the tangential force at the fingertip-object contact and the frictional properties of the skin-object contact. Although frequently assumed to be constant for all levels of normal force (NF, the force normal to the contact), µ static actually varies nonlinearly with NF and increases at low NF levels. No method is currently available to measure the relationship between µ static and NF easily. Therefore, we propose a new method allowing the simple and reliable measurement of the fingertip µ static at different NF levels, as well as an algorithm for determining µ static from measured forces and torques. Our method is based on active, back-and-forth movements of a subject's finger on the surface of a fixed six-axis force and torque sensor. µ static is computed as the ratio of the tangential to the normal force at slip onset. A negative power law captures the relationship between µ static and NF. Our method allows the continuous estimation of µ static as a function of NF during dexterous manipulation, based on the relationship between µ static and NF measured before manipulation.

The THESEUS project (Towards Human Exploration of Space: a European Strategy), initiated within the seventh Framework Programme by the European Commission, aimed at providing a cross-cutting, life-science-based roadmap for Europe's strategy towards human exploration of long space missions, and its relevance to applications on Earth. This topic was investigated by experts in the field, in the framework of the THESEUS project whose aim was to develop an integrated life sciences research roadmap regarding human space exploration. In particular, decades of research have shown that altered gravity impairs neurological responses at large, such as perception, sleep, motor control, and cognitive factors. International experts established a list of key issues that should be addressed in that context and provided several recommendations such as a maximal exploitation of currently available resources on Earth and in space., Competing Interests: The authors declare no conflict of interest.

In a forced-choice task, we asked human participants to discriminate by touch alone glass plates from transparent polymethyl methacrylate (PMMA) plastic plates. While the surfaces were flat and did not exhibit geometric features beyond a few tens of nanometres, the materials differed by their molecular structures. They produced similar coefficients of friction and thermal effects were controlled. Most participants performed well above chance and participants with dry fingers discriminated the materials especially well. Current models of tactile surface perception appeal to surface topography and cannot explain our results. A correlation analysis between detailed measurements of the interfacial forces and discrimination performance suggested that the perceptual task depended on the transitory contact phase leading to full slip. This result demonstrates that differences in interfacial mechanics between the finger and a material can be sensed by touch and that the evanescent mechanics that take place before the onset of steady slip have perceptual value.

Suppose that someone bumps into your arm at a party while you are holding a glass of wine. Motion of the disturbed arm will engage rapid and goal-directed feedback responses in the upper-limb. Although such responses can rapidly counter the perturbation, it is also clearly desirable not to destabilize your grasp and/or spill the wine. Here we investigated how healthy humans maintain a stable grasp following perturbations by using a paradigm that requires spatial tuning of the motor response dependent on the location of a virtual target. Our results highlight a synchronized expression of target-directed feedback in shoulder and hand muscles occurring at ∼60 ms. Considering that conduction delays are longer for the more distal hand muscles, these results suggest that target-directed responses in hand muscles were initiated before those for the shoulder muscles. These results show that long-latency feedback can coordinate upper limb and hand muscles during object manipulation tasks.

This study aims to investigate the clinimetric properties of ACTIVLIM, a measure of activity limitations, when it is used in daily practice in a large nationwide representative cohort of patients with neuromuscular diseases. A cohort of 2986 patients was assessed at least once over 2 years in 6 national neuromuscular diseases reference centers. Successive Rasch analyses were conducted in order to investigate the scale validity, reliability, consistency across demographic and clinical sub-groups and its sensitivity to change. ACTIVLIM confirmed excellent fit to a unidimensional scale, with stable but 3-times more accurate item calibrations compared to the original publication. It showed a good reliability (R = 0.95), an appropriate targeting for 87% of the sample and an excellent invariance across age, gender, language and time. Despite some variations in the item difficulty hierarchy across diagnoses, ACTIVLIM exhibited a good capability to quantify small but significant changes in activity for various diagnostic groups. Overall, ACTIVLIM demonstrated very good clinimetric properties, allowing accurate quantitative measurement of activity limitations in both children and adults with a variety of neuromuscular diseases., (Copyright © 2016 Elsevier B.V. All rights reserved.)