An Interdisciplinary Tutorial: A Self-Healing Soft Finger with Embedded Sensor.

In the field of soft robotics, knowledge of material science is becoming more and more important. However, many researchers have a background in only one of both domains. To aid the understanding of the other domain, this tutorial describes the complete process from polymer synthesis over fabrication to testing of a soft finger. Enough background is provided during the tutorial such that researchers from both fields can understand and sharpen their knowledge. Self-healing polymers are used in this tutorial, showing that these polymers that were once a specialty, have become accessible for broader use. The use of self-healing polymers allows soft robots to recover from fatal damage, as shown in this tutorial, which increases their lifespan significantly.

Humins Blending in Thermoreversible Diels-Alder Networks for Stiffness Tuning and Enhanced Healing Performance for Soft Robotics.

Humins waste valorization is considered to be an essential pathway to improve the economic viability of many biorefinery processes and further promote their circularity by avoiding waste formation. In this research, the incorporation of humins in a Diels-Alder (DA) polymer network based on furan-maleimide thermoreversible crosslinks was studied. A considerable enhancement of the healing efficiency was observed by just healing for 1 h at 60 °C at the expense of a reduction of the material mechanical properties, while the unfilled material showed no healing under the same conditions. Nevertheless, the thermal healing step favored the irreversible humins polycondensation, thus strengthening the material while keeping the enhanced healing performance. Our hypothesis states a synergistic healing mechanism based on humins flowing throughout the damage, followed by thermal humins crosslinking during the healing trigger, together with DA thermoreversible bonds recombination. A multi-material soft robotic gripper was manufactured out of the proposed material, showing not only improved recovery of the functional performance upon healing but also stiffness-tunable features by means of humins thermal crosslinking. For the first time, both damage healing and zone reinforcement for further damage prevention are achieved in a single intrinsic self-healing system.

Content validity of the Work Rehabilitation Questionnaire (WORQ) for persons with spinal cord injury: A mixed methods study.

STUDY DESIGN: Mixed methods. OBJECTIVES: The aim of our study was to investigate the content validity of the Work Rehabilitation Questionnaire (WORQ) for use in persons with post-acute and chronic spinal cord injury (SCI). SETTING: A university-based Rehabilitation Center in The Netherlands. METHODS: Contents of the WORQ, brief ICF core sets for SCI for post-acute care and for chronic situation were compared with semi-guided interviews with persons with SCI and controlled for relevance by SCI rehabilitation professionals in two group meetings. RESULTS: Fourteen interviews with persons with SCI were performed. Two group meetings with 8 and 9 SCI rehabilitation professionals were held. Thirty seven of the 46 ICF categories (80%) of the WORQ were confirmed by both sources: mentioned in interviews with persons with SCI and considered important by the SCI professionals. The remaining 9 categories (20%) were confirmed by either the persons with SCI or the SCI professionals. Fourteen ICF categories that are part of the brief ICF core set for SCI for acute care and/or chronic situation, however are not part of the WORQ, have revealed importance by persons with SCI and SCI professionals. CONCLUSION: Our study confirms that most categories of the WORQ are important to consider for VR in persons with SCI, however, there are ICF categories that are absent in the WORQ and deemed relevant for use in VR in persons with SCI. Consequently, the content validity of the WORQ without additional items is insufficient for persons with SCI.

Processing of Self-Healing Polymers for Soft Robotics.

Soft robots are, due to their softness, inherently safe and adapt well to unstructured environments. However, they are prone to various damage types. Self-healing polymers address this vulnerability. Self-healing soft robots can recover completely from macroscopic damage, extending their lifetime. For developing healable soft robots, various formative and additive manufacturing methods have been exploited to shape self-healing polymers into complex structures. Additionally, several novel manufacturing techniques, noted as (re)assembly binding techniques that are specific to self-healing polymers, have been created. Herein, the wide variety of processing techniques of self-healing polymers for robotics available in the literature is reviewed, and limitations and opportunities discussed thoroughly. Based on defined requirements for soft robots, these techniques are critically compared and validated. A strong focus is drawn to the reversible covalent and (physico)chemical cross-links present in the self-healing polymers that do not only endow healability to the resulting soft robotic components, but are also beneficial in many manufacturing techniques. They solve current obstacles in soft robots, including the formation of robust multi-material parts, recyclability, and stress relaxation. This review bridges two promising research fields, and guides the reader toward selecting a suitable processing method based on a self-healing polymer and the intended soft robotics application.

Trajectories of Self-Efficacy, Depressed Mood, and Anxiety From Admission to Spinal Cord Injury Rehabilitation to 1 Year After Discharge.

OBJECTIVE: Self-efficacy (SE) is an important determinant for the psychological adjustment of people with spinal cord injury (SCI). However, little is known about the course of SE during inpatient rehabilitation up to 1 year after discharge. The aim of this study was to determine latent trajectory classes of SE, depressive mood, and anxiety in people with SCI, as well as the interrelationships between these trajectories. DESIGN: Longitudinal inception cohort study. SETTING: Eight specialized SCI rehabilitation centers. PARTICIPANTS: The participants (N=268) were mainly men 183 of 268 (68.3%) with a mean age of 55.6 years. Almost half had a traumatic SCI 135 of 268 (50.4%) and tetraplegia (53.7%), and the minority had a motor complete SCI (32.2%). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: SE was measured using the University of Washington Self-Efficacy Scale. In addition, the Hospital Anxiety and Depression Scale was used to asses distress and perform dual trajectory modeling analyses. RESULTS: Three trajectories of SE, indicating low, middle, and high SE, could be distinguished. Furthermore, a 2-class trajectory solution for depressive mood and a 4-class solution for anxiety were found to be most suitable. All trajectories were stable over time. Developmental connections between SE and depressive mood and between SE and anxiety were revealed. In particular, participants who adjusted well, reporting low scores on depressive mood and anxiety, could be identified by their high SE scores. However, the group of participants with high depressive mood scores and anxiety scores could not always be identified based on their SE trajectory. CONCLUSIONS: In accordance with our hypotheses, distinct trajectories of SE, depressive mood, and anxiety were identified and high probabilities that SE trajectories were interrelated to the trajectories from depressive mood and anxiety were confirmed. Concurrent screening for SE and distress might best detect people at risk for adjustment problems.

Integration of 3D Printed Flexible Pressure Sensors into Physical Interfaces for Wearable Robots.

Sensing pressure at the physical interface between the robot and the human has important implications for wearable robots. On the one hand, monitoring pressure distribution can give valuable benefits on the aspects of comfortability and safety of such devices. Additionally, on the other hand, they can be used as a rich sensory input to high level interaction controllers. However, a problem is that the commercial availability of this technology is mostly limited to either low-cost solutions with poor performance or expensive options, limiting the possibilities for iterative designs. As an alternative, in this manuscript we present a three-dimensional (3D) printed flexible capacitive pressure sensor that allows seamless integration for wearable robotic applications. The sensors are manufactured using additive manufacturing techniques, which provides benefits in terms of versatility of design and implementation. In this study, a characterization of the 3D printed sensors in a test-bench is presented after which the sensors are integrated in an upper arm interface. A human-in-the-loop calibration of the sensors is then shown, allowing to estimate the external force and pressure distribution that is acting on the upper arm of seven human subjects while performing a dynamic task. The validation of the method is achieved by means of a collaborative robot for precise force interaction measurements. The results indicate that the proposed sensors are a potential solution for further implementation in human-robot interfaces.

Measurement Properties of the Full and Brief Version of the Work Rehabilitation Questionnaire in Persons with Physical Disabilities.

Purpose The Work Rehabilitation Questionnaire (WORQ) is a self-report vocational rehabilitation assessment. A comprehensive (WORQ-FULL) and a brief version (WORQ-BRIEF) are available. The purpose of this study was to investigate measurement properties of both versions in persons with physical disabilities. Methods Cross sectional and test-retest design. Adults with physical disabilities in vocational rehabilitation were included. Internal consistency (Cronbach's alpha), test-retest reliability (intra-class correlation; ICC), agreement between sessions (Bland-Altman Plots), criterion validity (ICC and agreement with Bland-Altman Plots between WORQ-FULL and WORQ-BRIEF) and convergent validity with the Work Ability Index -Single item (WAS) and the EuroQOL 5D-5L were analyzed. Results Out of the 91 individuals who agreed to participate, 74 (81%) returned questionnaire T1 and 49 (54%) participants returned questionnaire T2 within the maximum time interval (= 27 days). At T2, 28 (57%) participants reported no medical changes compared to T1. Median age was 49 (IQR 40-60), 57% were male, 47% had experienced a stroke and 27% a spinal cord injury (n = 49). Internal consistency was good: 0.95/0.95/0.94 for the WORQ-FULL and 0.88/0.89/0.85 for the WORQ-BRIEF (n = 74/n = 48/n = 28, respectively). Test-retest reliabilitywas good: ICC = 0.86/0.85 for the WORQ-FULL and ICC = 0.87/0.86 for the WORQ-BRIEF (n = 49/ n = 28). Bland Altman plots suggested a higher score at T1. As for criterion validity of the WORQ-FULL versus the WORQ-BRIEF, ICC was good (ICC = 0.84; n = 74), however Bland Altman plots indicated potential bias. Correlations with the WAS/EuroQOL 5D-5L were variable: r = -0.24/r = -0.57 (WORQ-FULL) and r = -0.28/-0.65 (WORQ-BRIEF). Conclusions The WORQ showed good internal consistency and test-retest reliability. Agreement demonstrated large score differences are needed to indicate change beyond random chance at individual level, whereas small changes are sufficient at group level. Criterion validity of the WORQ-FULL versus the WORQ-BRIEF was supported, however, agreement demonstrated moderate to large score differences are needed to indicate change beyond random chance at individual level, whereas small changes are sufficient at group level. This indicates the WORQ-FULL and WORQ-BRIEF are better not used interchangeably. Correlation analyses provided better insight in the validity of the WORQ. Convergent validity was supported for the WORQ-BRIEF with the EuroQoL 5D-5L (r = -0.65).

Prediction of Psychological Distress Among Persons With Spinal Cord Injury or Acquired Brain Injury and Their Significant Others.

OBJECTIVES: To identify intra- and interpersonal sociodemographic, injury-related, and psychological variables measured at admission of inpatient rehabilitation that predict psychological distress among dyads of individuals with spinal cord injury (SCI) or acquired brain injury (ABI) and their significant others (ie, individuals close to the individual with a disability, mostly family members) 6 months after discharge. Differences in predictors were investigated for persons with SCI or ABI and their significant others and were compared between diagnoses. DESIGN: Prospective longitudinal study. SETTING: Twelve Dutch rehabilitation centers. PARTICIPANTS: Dyads (N=157) consisting of adults with SCI or ABI who were admitted to inpatient rehabilitation and their adult significant others. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Psychological distress (Hospital Anxiety and Depression Scale). RESULTS: Sociodemographic and injury-related variables were not or were only weakly associated with psychological distress among individuals with SCI or ABI and their significant others 6 months after discharge. Bivariately, higher baseline psychological distress, lower scores on adaptive psychological characteristics (combination of self-efficacy, proactive coping, purpose in life, resilience), and higher scores on maladaptive psychological characteristics (combination of passive coping, neuroticism, appraisals of threat and loss) were related to higher psychological distress, as well as crosswise between individuals with SCI or ABI and their significant others, although less strongly. Combined prediction models showed that psychological distress among persons with SCI or ABI was predicted by education level of their significant other, their own baseline psychological distress, and their own maladaptive psychological characteristics (explained variance, 41.9%). Among significant others, only their own baseline psychological distress predicted psychological distress (explained variance, 40.4%). Results were comparable across diagnoses. CONCLUSIONS: Although a dyadic connection was shown, primarily one's own baseline psychological distress and psychological characteristics were important in the prediction of later psychological distress among both individuals with SCI or ABI and their significant others. Screening based on these variables could help to identify persons at risk for psychological distress.

Additive Manufacturing for Self-Healing Soft Robots.

The field of self-healing soft robots was initiated a few years ago. A healing ability can be integrated in soft robots by manufacturing their soft membranes out of synthetic self-healing polymers, more specifically elastomeric Diels-Alder (DA) networks. As such they can recover completely from macroscopic damage, including scratches, cuts, and ruptures. Before this research, these robots were manufactured using a technique named "shaping-through-folding-and-self-healing." This technique requires extensive manual labor, is relatively slow, and does not allow for complex shapes. In this article, an additive manufacturing methodology, fused filament fabrication, is developed for the thermoreversible DA polymers, and the approach is validated on a soft robotic gripper. The reversibility of their network permits manufacturing these flexible self-healing polymers through reactive printing into the complex shapes required in soft robotics. The degree of freedom in the design of soft robotics that this new manufacturing technique offers is illustrated through the construction of adaptive DHAS gripper fingers, based on the design by FESTO. Being constructed out of self-healing soft flexible polymer, the fingers can recover entirely from large cuts, tears, and punctures. This is highlighted through various damage-heal cycles.

International Comparison of Vocational Rehabilitation for Persons With Spinal Cord Injury: Systems, Practices, and Barriers.

Background: Employment rates among people with spinal cord injury or spinal cord disease (SCI/D) show considerable variation across countries. One factor to explain this variation is differences in vocational rehabilitation (VR) systems. International comparative studies on VR however are nonexistent. Objectives: To describe and compare VR systems and practices and barriers for return to work in the rehabilitation of persons with SCI/D in multiple countries. Methods: A survey including clinical case examples was developed and completed by medical and VR experts from SCI/D rehabilitation centers in seven countries between April and August 2017. Results: Location (rehabilitation center vs community), timing (around admission, toward discharge, or after discharge from clinical rehabilitation), and funding (eg, insurance, rehabilitation center, employer, or community) of VR practices differ. Social security services vary greatly. The age and preinjury occupation of the patient influences the content of VR in some countries. Barriers encountered during VR were similar. No participant mentioned lack of interest in VR among team members as a barrier, but all mentioned lack of education of the team on VR as a barrier. Other frequently mentioned barriers were fatigue of the patient (86%), lack of confidence of the patient in his/her ability to work (86%), a gap in the team's knowledge of business/legal aspects (86%), and inadequate transportation/accessibility (86%). Conclusion: VR systems and practices, but not barriers, differ among centers. The variability in VR systems and social security services should be considered when comparing VR study results.

Progress of the Dutch Spinal Cord Injury Database: Completeness of Database and Profile of Patients Admitted for Inpatient Rehabilitation in 2015.

Background: In the Dutch International Spinal Cord Injury (SCI) Data Sets project, we translated all International SCI Data Sets available in 2012 and created a Dutch SCI Database (NDD). Objective: To describe the number of included patients and completeness of the NDD, and to use the NDD to provide a profile of people with traumatic SCI (T-SCI) and non-traumatic SCI (NT-SCI) in the Netherlands. Methods: The NDD includes patients admitted for their first inpatient rehabilitation after onset of SCI to 1 of the 8 rehabilitation centers with a specialty in SCI rehabilitation in the Netherlands. Data of patients admitted in 2015 were analyzed. Results: Data for 424 patients were available at admission; for 310 of these patients (73.1%), discharge data were available. No significant differences were found between patients with and without data at discharge. Data were nearly complete (>90%) for lower urinary tract, bowel, pain, and skin. Data on sexual function has the lowest completion rate. Complete neurological and functional data were available for 41.7% and 38%, respectively. Most patients were male (63.4%), had NT-SCI (65.5%), and had incomplete SCI (58.4% D). Patients with T-SCI differed from patients with NT-SCI on most characteristics, and they stayed considerably longer in the rehabilitation center (112 days vs 65 days, p < .001). Place of discharge was not different between both groups. Conclusion: With the NDD, we collect important data on the majority of Dutch SCI patients, although much work needs to be done to improve the completeness of the data collection.

Relationships between type of pain and work participation in people with long-standing spinal cord injury: results from a cross-sectional study.

STUDY DESIGN: Multicentre, cross-sectional study. OBJECTIVES: To describe the relationships between the presence of (different types of) pain and participation in paid work in people with long-standing spinal cord injury (SCI). Furthermore, the associations of pain-related work limitations, age, gender, relationship, education, lesion level, and time since injury (TSI) with work participation (WP) were investigated. SETTING: The Netherlands. METHODS: Individuals (n = 265) with SCI for ≥ 10 years were included. Data were collected through a structured consultation with a rehabilitation physician and self-report questionnaire. Descriptive statistics and logistic regression analysis were performed. RESULTS: Median age of participants was 47.9 years, median time since injury was 22 years, 73% were male, 69% had complete SCI and 59% had paraplegia, 50% had paid work, 63% reported musculoskeletal pain, 49% reported neuropathic pain, and 31% reported other pain. Self-reported pain-related work limitations were significantly (V = 0.26 and V = 0.27) related to WP. In bivariable logistic regression analyses, no statistically significant relationships between type of pain and WP were observed. Younger age (OR=0.96), male gender (OR=0.52), a stable relationship (OR = 1.70), and shorter time since SCI (OR = 0.97) were significantly associated with a higher chance of being employed. Multivariable analysis confirmed these findings and in addition showed a higher level of education to be positively related with WP. CONCLUSION: Age, gender, relationship, education, TSI and self-reported work limitations showed a relationship with WP. Different types of pain were unrelated to WP. SPONSORSHIP: Fonds NutsOHRA through the Dutch Organization for Health Research and Development (ZonMw), Project number 89000006.