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Phantom limb pain (PLP) represents a significant challenge after amputation. This study investigated the use of phantom motor execution (PME) and phantom motor imagery (PMI) facilitated by extended reality (XR) for the treatment of PLP. Both treatments used XR, but PME involved overt execution of phantom movements, relying on the decoding of motor intent using machine learning to enable real-time control in XR. In contrast, PMI involved mental rehearsal of phantom movements guided by XR. The study hypothesized that PME would be superior to PMI. A multicenter, double-blind, randomized controlled trial was conducted in 9 outpatient clinics across 7 countries. Eighty-one participants with PLP were randomly assigned to PME or PMI training. The primary outcome was the change in PLP, measured by the Pain Rating Index, from baseline to treatment cessation. Secondary outcomes included various aspects related to PLP, such as the rate of clinically meaningful reduction in pain (CMRP; >50% pain decrease). No evidence was found for superiority of overt execution (PME) over imagery (PMI) using XR. PLP decreased by 64.5% and 68.2% in PME and PMI groups, respectively. Thirty-seven PME participants (71%) and 19 PMI participants (68%) experienced CMRP. Positive changes were recorded in all other outcomes, without group differences. Pain reduction for PME was larger than previously reported. Despite our initial hypothesis not being confirmed, PME and PMI, aided by XR, are likely to offer meaningful PLP relief to most patients. These findings merit consideration of these therapies as viable treatment options and alternatives to pharmacological treatments.

Purpose: The aim of this study was to investigate concurrent validity of the Swedish self-rated 36-item World Health Organization Disability Assessment Schedule (WHODAS) 2.0 by comparison with professional Global Assessment of Functioning (GAF) ratings in psychiatric outpatients. Material and methods: A cross-sectional convenience sample of 444 patients was recruited from their regular psychiatric outpatient settings. The patients filled out the WHODAS 2.0; their clinicians provided clinical information and performed GAF ratings blinded to the patients' assessments. Analyses of correlations, variance components, and ROC curves were performed to investigate the validity of the WHODAS 2.0 through comparison with the GAF. The variance component analyses included working status, psychosocial problems, number of diagnostic groups, and remission status. GAF ratings were separated as total (GAF-T), symptoms (GAF-S), and functioning (GAF-F). Results: There was significant correlation (p < 0.001) between WHODAS 2.0 total and domain scores and GAF-S, GAF-F, and GAF-T ratings. The correlations varied from r = 0.29 to r = 0.48, with the highest being between GAF-F rating and WHODAS 2.0 total score. Repeating the analyses for separate diagnostic groups replicated the findings, though not for psychotic, substance-related, and eating disorders. The WHODAS 2.0 showed good ability to distinguish impaired functioning below a fixed GAF-T cut-off of 70 (area under the curve: 0.74-0.78). The explained variance was lower for the WHODAS 2.0 than for the GAF (38.9% vs. 59.2%). Conclusions: Concurrent validity was found when comparing the Swedish self-administered 36-item version of WHODAS 2.0 with the expert-rated GAF in psychiatric outpatients.

Monika Pilch,1 Tijn van Rietschoten,2,3 Max Ortiz-Catalan,4– 6 Eva Lendaro,6,7 Corry K van der Sluis,2 Liselotte Hermansson8,9 1Centre for Health Policy & Management, School of Medicine, Trinity College Dublin, Dublin, Ireland; 2University of Groningen, University Medical Center Groningen, Department of Rehabilitation Medicine, Groningen, the Netherlands; 3University of Groningen, Faculty of Medical Sciences, Groningen, the Netherlands; 4Center for Bionics and Pain Research, Mölndal, Sweden; 5Bionics Institute, Melbourne, VC, Australia; 6Department of Electrical Engineering, Chalmers University of Technology, Gothenburg, Sweden; 7Department of Brain and Cognitive Sciences, McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, MA, USA; 8Department of Prosthetics and Orthotics, Faculty of Medicine and Health, Örebro University, Örebro, Sweden; 9University Health Care Research Center, Faculty of Medicine and Health, Örebro University, Örebro, SwedenCorrespondence: Monika Pilch, Centre for Health Policy and Management, School of Medicine, Trinity College Dublin, 3-4 Foster Place, Dublin, Ireland, Tel + 353 851614350, Email pilchm@tcd.ie Corry K van der Sluis, University of Groningen, University Medical Center Groningen, Department of Rehabilitation Medicine, Groningen, the Netherlands, Tel + 31 503612295, Email c.k.van.der.sluis@umcg.nlPurpose: Interpersonal processes, including therapeutic alliance, may modulate the impact of interventions on pain experience. However, the role of interpersonal context on the effects of technology-enhanced interventions remains underexplored. This study elicited therapists’ perspectives on how a novel rehabilitative process, involving Phantom Motor Execution (PME), may impact phantom limb pain. The mediating role of therapeutic alliance, and the way PME influenced its formation, was investigated.Methods: A qualitative descriptive design, using a framework method, was used to explore therap

Although recent technological developments in the field of bionic upper limb prostheses, their rejection rate remains excessively high. The reasons are diverse (e.g. lack of functionality, control complexity, and comfortability) and most of these are reported only through self-rated questionnaires. Indeed, there is no quantitative evaluation of the extent to which a novel prosthetic solution can effectively address users' needs compared to other technologies. This manuscript discusses the challenges and limitations of current upper limb prosthetic devices and evaluates their functionality through a standard functional assessment, the Assessment of Capacity for Myoelectric Control (ACMC). To include a good representation of technologies, the authors collect information from participants in the Cybathlon Powered Arm Prostheses Race 2016 and 2020. The article analyzes 7 hour and 41 min of video footage to evaluate the performance of different prosthetic devices in various tasks inspired by activities of daily living (ADL). The results show that commercially-available rigid hands perform well in dexterous grasping, while body-powered solutions are more reliable and convenient for competitive environments. The article also highlights the importance of wrist design and control modality for successful execution of ADL. Moreover, we discuss the limitations of the evaluation methodology and suggest improvements for future assessments. With regard to future development, this work highlights the need for research in intuitive control of multiple degrees of freedom, adaptive solutions, and the integration of sensory feedback.

PURPOSE: Interpersonal processes, including therapeutic alliance, may modulate the impact of interventions on pain experience. However, the role of interpersonal context on the effects of technology-enhanced interventions remains underexplored. This study elicited therapists' perspectives on how a novel rehabilitative process, involving Phantom Motor Execution (PME), may impact phantom limb pain. The mediating role of therapeutic alliance, and the way PME influenced its formation, was investigated. METHODS: A qualitative descriptive design, using a framework method, was used to explore therapists' (n=11) experiences of delivering PME treatment. Semi-structured online-based interviews were conducted. RESULTS: A 3-way interaction between therapist, patient, and the PME device was an overarching construct tying four themes together. It formed the context for change in phantom limb experience. The perceived therapeutic effects (theme 1) extended beyond those initially hypothesised and highlighted the mediating role of the key actors and context (theme 2). The therapeutic relationship was perceived as a transformative journey (theme 3), creating an opportunity for communication, collaboration, and bonding. It was seen as a cause and a consequence of therapeutic effects. Future directions, including the role of expertise-informed adaptations and enabling aspects of customised solutions, were indicated (theme 4). CONCLUSION: This study pointed to intrapersonal, interpersonal, and contextual factors that should be considered in clinical implementation of novel rehabilitative tools. The results demonstrated that therapists have unique insights and a crucial role in facilitating PME treatment. The study highlighted the need to consider the biopsychosocial model of pain in designing, evaluating, and implementing technology-supported interventions.

BACKGROUND: Validity of the Ugandan version of the Pediatric Evaluation of Disability Inventory (PEDI-UG) was previously investigated on typically developing children. This study aimed to investigate the validity, test-retest reliability and minimal detectable change (MDC) of the PEDI-UG in children and youth (C&Y) with cerebral palsy (CP). METHOD: A cross-sectional study design with 118 C&Y with CP (44.7% girls) aged 10 months-22.5 years were included in the study; 37 of them completed the PEDI-UG twice to investigate test-retest reliability, determined by calculating the intraclass correlation coefficient (ICC). Additionally, data from 249 typically developing children were used for differential item functioning (DIF) analysis. The validity of the PEDI-UG was investigated by Rasch analysis. The Kruskal-Wallis test and Spearman's correlation coefficient were calculated to investigate associations between PEDI-UG scores and external classification systems. RESULTS: The principal component analysis of residuals indicated unidimensionality in all domains. The ICC values were excellent (0.98-0.99), and the MDCs were less than 6 and 13 (on a 0-100 scale) for the functional skills and caregiver assistance parts, respectively. The four-category caregiver assistance rating scale fulfilled the criteria for the analysis of rating scale functioning. In total, 78 of 189 items in the functional skills domain and two items in the caregiver assistance domain demonstrated DIF between C&Y with CP and TD children. The Kruskal-Wallis test (p<0.05) and Spearman's correlation (coefficients of -0.93 to -0.78) supported the validity of PEDI-UG. CONCLUSION: The current diagnose-specific version of PEDI-UG demonstrates evidence for validity as a measure of ability in C&Y with CP in Uganda and other similar settings, being a promising tool for use in clinical practice and research. Conversion tables and MDC values are provided to facilitate clinical adoption of the measur, Funding agency:Folke Bernadotte Stiftelsen

BACKGROUND: Swedish social policy enables ageing in place with support from home-based care services despite high age and/or declining health. AIM: This study aims to describe the daily life experiences behind the decision to apply for a nursing home placement in older adults ageing in place. MATERIALS AND METHODS: A qualitative design was chosen, and 11 semi-structured interviews were conducted and analysed using inductive qualitative content analysis. RESULTS: The participants described a feeling of dependence in which they had to ignore their personal privacy when receiving home-based care. They reached a turning point when ageing in place was, for several reasons, no longer considered an acceptable option. This influenced their choice to apply to a nursing home where they expected that they could maintain control over their lives. DISCUSSION AND CONCLUSION: The results indicate that when enhancing ageing in place it is important to enable older adults to receive support to maintain autonomy in daily activities and to have the opportunity to age in the right place., Funding agency:Research School on Successful Ageing, Örebro University, Sweden

Introduction To support clinicians who treat children with upper-limb differences, we must first understand how these children are treated around the world. Study Design A descriptive survey was carried out in this study. Objectives The aim was to describe how treatment for children with upper-limb difference is provided in different parts of the world. Methods A web-based survey was used to gather data. The survey was shared on the Handsmart website, through providers and members using snowball sampling. Results Sixty-eight respondents from 18 countries, with most being occupational therapists and prosthetists, participated. All respondents reported that they provide prosthetic treatment and most fit a passive prosthesis before 1 year of age. Respondents from 13 countries reported having governmental funding for the provision of care for people with upper-limb loss. Intervention is guided by the presentation of the limb as well as availability of funding and other resources. In 12 countries, no treatment other than fitting of prostheses is provided for the children. The children who do not receive a prosthesis continue to see an occupational or physical therapist for other treatment (other devices, follow-up). Respondents stated that they would like to see clear treatment guidelines used by multidisciplinary teams to fit children and that treatment should include regular follow-up. Conclusions Children are treated differently in various parts of the world based on different funding, family support, and therapy resources. Further studies should encompass a geographically representative sample of children’s clinics. Clinical Relevance This study provides information regarding treatment practices for children with upper-limb loss/difference in various parts of the world; prosthetic treatment is common for children, although ages for fitting vary among clinics and countries. Results will contribute by supporting clinicians to provide better treatment for children with

OBJECTIVE: To evaluate the effect of multi-grip myoelectric prosthetic hands on performance of daily activities, pain-related disability and prosthesis use, in comparison with single-grip myoelectric prosthetic hands. DESIGN: Single-case AB design. PATIENTS: Nine adults with upper-limb loss participated in the study. All had previous experience of single-grip myoelectric prostheses and were prescribed a prosthesis with multi-grip functions. METHODS: To assess the changes in daily activities, pain-related disability and prosthesis use between single-grip and multi-grip myoelectric prosthetic hands, the Canadian Occupational Performance Measure, Pain Disability Index, and prosthesis wearing time were measured at multiple time-points. Visual assessment of graphs and multi-level linear regression were used to assess changes in the outcome measures. RESULTS: At 6 months' follow-up self-perceived performance and satisfaction scores had increased, prosthesis wearing time had increased, and pain-related disability had reduced in participants with musculoskeletal pain at baseline. On average, 8 of the 11 available grip types were used. Most useful were the power grip, tripod pinch and lateral pinch. CONCLUSION: The multi-grip myoelectric prosthetic hand has favourable effects on performance of, and satisfaction with, individually chosen activities, prostheses use and pain-related disability. A durable single-grip myoelectric prosthetic hand may still be needed for heavier physical activities. With structured training, a standard 2-site electrode control system can be used to operate a multi-grip myoelectric prosthetic hand.

Background: Children with congenital limb reduction deficiency live with the decisions made by their parents and healthcare professionals about treatments to be carried out during the first years of life. To understand better the meaning of treatment during childhood, it is necessary to listen to adolescents who have had this experience. The aim of this study was to investigate the perceptions of adolescents with congenital limb reduction deficiency concerning the treatment they received during childhood and what it meant to them currently and in the future. Methods: A descriptive design with a qualitative approach was used. Semi-structured interviews were conducted with 10 adolescents (six girls and four boys) with upper and/or lower limb reduction deficiency, median age 17.5 years (range 16–19). The interview data were analysed using a phenomenographic approach. Results: The treatment received during childhood had contributed to shaping the adolescents, as shown in the emerging description categories Creating opportunities, Choosing one's own path and Belonging in a context. Their current situation fell into three categories: A continuous journey, indicating that they still used the skills learned during childhood; Leaving the door open, indicating that they were not currently using the skills learned during childhood, but felt that there could be opportunities ahead; and Closing a chapter, indicating that they had stopped using their prosthesis or assistive devices and no longer needed those skills. Further, the adolescents' thoughts about the future are portrayed in the categories Uncertainty about the future and Confidence about the future. Conclusions: An understanding of the meaning of treatment received during childhood may help improve the delivery of treatment and continued support to meet the needs of children with congenital limb reduction deficiency in the short and long term., Funding agencies:Faculty of Medicine and Health, Örebro University, Örebro, SwedenResearch Committee, Region Örebro County, Sweden

Background: Validated outcome measures are essential for assessment and treatment of children with disabilities. The Children's Hand-use Experience Questionnaire (CHEQ) was developed and validated for use in Western countries for children with unilateral hand dysfunction. This study aimed to perform a cross-cultural adaptation and investigate reliability for the Arabic CHEQ. Methods: Translation and cross-cultural adaptation were performed in four phases: (i) forward-translation and reconciliation with feedback from parents and typically developing children from Jordan (n = 14); (ii) backward-translation and review; (iii) cognitive debriefing with parents and/or their children with unilateral hand dysfunction (n = 17); and (iv) review and proofreading. In the psychometric analyses, 161 children from Jordan (mean age [SD] 10y 8 m [5y 8 m]; 88 males) participated. Internal consistency was evaluated with Cronbach's alpha. Test-retest reliability was evaluated in 39 children with intraclass correlation coefficient (ICC) and weighted kappa (kappa). Results: Synonyms of four words were added to accommodate for different Arabic dialects. On average, 93% of children with unilateral hand dysfunction and their parents understood the CHEQ items. One response alternative, 'Get help', to the opening question was unclear for 70% of the respondents and need further explanation. Two items about using a knife and fork were difficult to comprehend and culturally irrelevant. High internal consistency was demonstrated (Cronbach's alphas 0.94- 0.97) and moderate to excellent ICC (0.77-0.93). For 18 individual items, kappa indicated poor to good agreement (kappa between 0.28 and 0.66). Conclusions: After the suggested minor adjustments, the Arabic CHEQ will be comprehensible, culturally relevant and reliable for assessing children with unilateral hand dysfunction in Jordan., Funding agencies:Riksförbundet for Rörelsehindrade Barn och UngdomarFolke Bernadotte stiftelsenFaculty Scientific Research at Jordan University of Science and Technology, Irbid, Jordan MA 84/2017

Objective: Today's health care system faces challenges in meeting the needs of older people with multimorbidity. To better cope with these needs, tailored primary health care with geriatric competence and person-centred care has been suggested. The aim of this study was to explore older patients' experiences of a tailored primary health care unit. Design: This was a qualitative study using semi-structured individual interviews and qualitative content analysis. Setting and patients: Nineteen patients were recruited from a tailored PHC unit for people aged 75 years or older in a region in central Sweden. Methods: The interview data were analysed using inductive category development. Results: In the analysis, the theme In safe hands when in need of primary health care emerged. The interviewees expressed a desire to participate in their own care. Easy access, enough consultation time and a calm environment, along with the PHC professionals' welcoming and attentive approach enhanced their feeling of being in safe hands. PHC professionals were perceived as having geriatric knowledge and taking responsibility for the care of older patients. Although the interviewees experienced that they received attention for their health conditions, a need for a more preventive approach to care emerged. Conclusion: Older patients highly appreciated their tailored PHC unit and they emphasised that it was an improvement compared to the ordinary PHC centre. This study provides insights into older patients' experiences, which may be helpful in the ongoing process of improving care for older patients in PHC. Older patients attending a tailored Primary health care (PHC) unit felt acknowledged, unlike in the ordinary PHC centre, which facilitated their participation in their care. The calm environment, specialist geriatric competence and ample patient contact time enabled them to feel secure and taken care of. Older patients expressed a need for an incorporation of social services and health pr, Funding agency:Research Committee OLL-731751

Purpose: To explore spouses’ experiences of the value of mobility scooters prescribed to their partner. Material and Methods: A descriptive design with a qualitative approach was used. Thirteen spouses (11 females) aged 65–86 years participated. Semi-structured interviews were conducted when the spouse’s partner had had the mobility scooter for 4–6 months. The interviews were analysed using qualitative content analysis. Results: The interviews showed primarily that the spouses experienced that their everyday lives and life situation had improved since their partner had received a mobility scooter. They reported that they could engage in activities of their own choice to a greater extent. The prescription of a mobility scooter to their partner had also yielded a sense of freedom related to shared activities. On the other hand, the spouses described some of the scooter’s limitations. Three categories emerged: a sense of freedom related to thespouse’s own activities, a sense of freedom related to shared activities and a somewhat restricted freedom. Conclusion: Prescription of a powered mobility scooter was of value to the users’ spouses because it facilitated independent and shared activities and participation in the community. The value was mainly expressed as a sense of freedom when doing things on their own or together with their partner. Spouses are key persons in the rehabilitation of people with mobility restrictions. Their views on the assistive device may influence the rehabilitation process. Knowledge of spouses’ experiences is thus crucial, as this may influence the future rehabilitation outcome., Funding Agencies:Swedish Institute of Assistive Technology Promobilia Foundation, Sweden

Aim The aim of this study was to evaluate the reliability and validity of the Swedish version of the self-rated 36-item WHODAS 2.0 in patients from Swedish psychiatric outpatient settings, using classical test theory. Methods The 36-item WHODAS 2.0, together with the Sheehan Disability Scale (SDS), was filled in by a sample of 780 participating psychiatric patients: 512 (65.6%) women, 263 (33.7%) men, and 5 (0.6%) who did not report any sex. Results The internal consistency, measured by Cronbach’s alpha, for the different domains of functioning were between 0.70 and 0.94, and interpreted as good. The confirmatory factor analysis (CFA) revealed two levels: the first level consisted of a general disability factor, while the second level consisted of the six domains of the scale, respectively. The model had borderline fit. There was a significant correlation between WHODAS 2.0 36-item and SDS (n = 395). The WHODAS 2.0 differed significantly between diagnostic groups. Conclusion The present study demonstrates that the Swedish self-rated 36-item version of WHODAS 2.0, within a psychiatric outpatient population, showed good reliability and convergent validity. We conclude that the self-rated 36-item Swedish version of WHODAS 2.0 can be used for valid interpretations of disability in patients with psychiatric health conditions.

Background: Training is crucial to develop the ability to operate a myoelectric prosthetic hand and use it in daily life. Multigrip prostheses, with their wider repertoire of functions, require further training. Because studies show that prosthesis abandonment is an issue and the advanced functions are not used to the expected extent, the question of what training should be offered to patients arises. If the available training methods were synthesized, the training could be improved to the benefit of the people who are fitted with a multigrip prosthesis. Objective: To critically examine the content of published sources for training of users with myoelectric multigrip hand prostheses. Study design: Scoping review. Methods: A literature search covering the period 2007-2020 in the databases PubMed, CINAHL, and Allied and Complementary Medicine Database, as well as gray literature from prosthesis manufacturers, identified 2,005 sources. After full-text review of 88 articles and four user manuals from manufacturers, nine sources were included and analyzed in their entirety. Results: We found few descriptions of multigrip prosthesis training, and no source described all training phases in detail. Integration of the prosthesis and training in daily activities was described least. Few sources actually described how to perform training in multigrip functions, and none described how to integrate these functions in daily life. Conclusions: Existing training instructions for using multigrip prosthetic hands are inadequate, providing poor guidance to clinicians and insufficient training for patients. Further research is needed into the efficiency of various training methods.

Background: Parents of children with congenital limb reduction deficiency have an essential role in making treatment decisions during their child's first years of life. Treatment options usually concern surgical and/or prosthetic treatment. To tailor treatment options to fit different family values and priorities, the family‐centred approach indicates the importance of understanding the parental role in partnership with health care professionals. The aim of this study was to describe parents' experiences of their role in decision‐making and treatment for children with congenital limb reduction deficiency. Methods: A descriptive design with a qualitative approach was used. Semi‐structured interviews were conducted with 17 parents (12 mothers and 5 fathers) of children with upper and/or lower limb deficiency (mean age 5.9 years). The interview data were analysed using qualitative content analysis with an inductive approach. Results: Two major themes emerged from the data. The first theme, being a decision maker for someone else, was described as an ambivalent parental role, including collaboration within the family and with health care professionals. The second theme, becoming and being a treatment supporter in the child's everyday life, was made up of four categories: being a supporter of the child in everyday activities, mentoring the child to handle encounters with others, becoming a coordinator of information and being an ‘extended arm’ of the health care provision for the child. Conclusions: This study enhances our understanding of the parental role in decision‐making and treatment for children with congenital limb reduction deficiency. The results may contribute to the continued development of the family‐centred service approach by providing guidelines for treatment programmes, with the goal of improving decision support and broadening the support for parents during treatment for these children., Funding Agencies:Faculty of Medicine and Health, Örebro University, Örebro, Sweden Research Committee, Region Örebro County, Sweden Norrbacka-Eugenia Foundation, Stockholm, Sweden

Introduction: Different factors in the environment influence the use of powered wheelchairs or powered scooters, i.e. powered mobility devices (PMDs), but there is limited knowledge about how these factors interact and if any factor has a greater impact. According to the ICF the environment consists of five areas. Aim: To describe users' experiences of how environmental factors from all ICF areas influence the use of PMDs. Methods: Descriptive qualitative design including 14 interviews with PMD users, analyzed using inductive qualitative content analysis. Findings: Use of PMDs means a conditional freedom depending on the interaction of several environmental factors. Regardless of environmental factor the societal attitudes were always present, directly or indirectly, and influenced the participants' feeling of being included and involved in society. The environmental factors and how they influence PMD use are described in four categories, comprising the following subjects: societal attitudes, the service delivery process, accessibility to the physical environment and financial resources. Conclusion: The findings show that societal attitudes influence all other factors, directly by others people's attitudes, or indirectly by how legislation and guidelines are formulated, interpreted and applied. Therefore, a change of societal attitudes seems necessary to increase accessibility and participation for PMD users., Funding Agencies:Uppsala-Örebro Regional Research Council Research Committee of Örebro County Council, Sweden

A custom-made prosthetic product is unique for each patient. Fossil-based thermoplastics are the dominant raw materials in both prosthetic and industrial applications; there is a general demand for reducing their use and replacing them with renewable, biobased materials. A transtibial prosthesis sets strict demands on mechanical strength, durability, reliability, etc., which depend on the biocomposite used and also the additive manufacturing (AM) process. The aim of this project was to develop systematic solutions for prosthetic products and services by combining biocomposites using forestry-based derivatives with AM techniques. Composite materials made of polypropylene (PP) reinforced with microfibrillated cellulose (MFC) were developed. The MFC contents (20, 30 and 40 wt%) were uniformly dispersed in the polymer PP matrix, and the MFC addition significantly enhanced the mechanical performance of the materials. With 30 wt% MFC, the tensile strength and Young´s modulus was about twice that of the PP when injection molding was performed. The composite material was successfully applied with an AM process, i.e., fused deposition modeling (FDM), and a transtibial prosthesis was created based on the end-user's data. A clinical trial of the prosthesis was conducted with successful outcomes in terms of wearing experience, appearance (color), and acceptance towards the materials and the technique. Given the layer-by-layer nature of AM processes, structural and process optimizations are needed to maximize the reinforcement effects of MFC to eliminate variations in the binding area between adjacent layers and to improve the adhesion between layers.