A parametric 3D printed assistive device for people with cerebral palsy - assessment of outcomes and comparison with a commercial counterpart.

This paper presents the use of a parametric design platform and 3D printing to create personalized assistive devices (ADs) for individuals with cerebral palsy, specifically a fork/spoon holder. Five subjects participated in the study, each receiving a customized device to fit their dominant hand, and they tested both the 3D printed device and a commercially available one. The devices were evaluated based on functionality and satisfaction using two standard clinical questionnaires (IPPA and QUEST 2.0). The results showed that neither the 3D printed nor the commercial device provided substantial benefits, but the questionnaires provided valuable feedback on areas for improvement. The study highlights the need for highly personalized solutions in ADs, which could be addressed by 3D printing. A configurator for generating production files from a parametric model could facilitate personalization, but a large number of model versions should be available to meet individual needs. Future research could explore clinical evaluations and guide the development of efficient and effective frameworks for digital fabrication in terms of clinically feasible AD model sourcing.

* 3D printing can be a method of creating assistive devices with dimensions fitting the user.* Standard questionnaires for measuring the effectiveness and satisfaction may efficiently identify shortcomings and suggest improvements.* Each person may have individual requirements, which calls for a large database of solutions in order to meet the person's needs.

From patient to maker - a workflow including people with cerebral palsy in co-creating assistive devices using 3D printing technologies.

Purpose: Digital fabrication, like 3D printing, is a new opportunity for rehabilitation professionals to produce customized assistive devices. It allows for empowerment and collaboration in device procurement, but practical implementations are scarcely described. We describe the workflow, discuss feasibility and propose directions for future work.Methods: We showcase a process of co-manufacturing a custom spoon handle together with two people with cerebral palsy. Our digital manufacturing process was centered around videoconferencing to remotely control the processes from design to final 3D printing. Device functionality and satisfaction were assessed using standard clinical questionnaires: the Individual Priority Problem Assessment Questionnaire (IPPA) and the Quebec User Satisfaction Assessment with Assistive Technology (QUEST 2.0).Results: IPPA was instrumental in assessing user needs and device effectiveness. QUEST revealed where to focus future design efforts.Conclusion: Involving people with disabilities in co-creation of assistive devices opens for new opportunities for healthcare providers that should be explored in depth using the described methodology. There may also be therapeutic benefits and we envisage specific actions to take in order to make it clinically viable.IMPLICATIONS FOR REHABILITATIONBest practices for co-creation of assistive devices, cost and benefits should be investigated and documented further.Standard questionnaires are useful for measuring effectiveness and satisfaction of co-created devices as well as for guiding design efforts.Co-creation may be a valuable element in therapeutic interventions as an opportunity to unfold creativity.

FITFES: A Wearable Myoelectrically Controlled Functional Electrical Stimulator Designed Using a User-Centered Approach.

Myoelectrically Controlled Functional Electrical Stimulation (MeCFES) has proven to be a useful tool in the rehabilitation of the hemiplegic arm. This paper reports the steps involved in the development of a wearable MeCFES device (FITFES) through a user-centered design. We defined the minimal viable features and functionalities requirements for the device design from a questionnaire-based survey among physiotherapists with experience in functional electrical stimulation. The result was a necklace layout that poses minimal hindrance to task-oriented movement therapy, the context in which it is aimed to be used. FITFES is battery-powered and embeds a standard low power Bluetooth module, enabling wireless control by using PC/Mobile devices vendor specific built-in libraries. It is designed to deliver a biphasic, charge-balanced stimulation current pulses of up to 113 mA with a maximum differential voltage of 300 V. The power consumption for typical clinical usage is 320 mW at 20mA stimulation current and of less than [Formula: see text] in sleep mode, thus ensuring an estimated full day of FITFES therapy on a battery charge. We conclude that a multidisciplinary user-centered approach can be successfully applied to the design of a clinically and ergonomically viable prototype of a wearable myoelectrically controlled functional electrical stimulator to be used in rehabilitation.

Sequentially applied myoelectrically controlled FES in a task-oriented approach and robotic therapy for the recovery of upper limb in post-stroke patients: A randomized controlled pilot study.

BACKGROUND: Functional recovery of the plegic upper limb in post-stroke patients may be enhanced by sequentially applying a myoelectrically controlled FES (MeCFES), which allows the patient to voluntarily control the muscle contraction during a functional movement, and robotic therapy which allows many repetitions of movements. OBJECTIVE: Evaluate the efficacy of MeCFES followed by robotic therapy compared to standard care arm rehabilitation for post-stroke patients. METHODS: Eighteen stroke subjects (onset ⩾ 3 months, age 60.1 ± 15.5) were recruited and randomized to receive an experimental combination of MeCFES during task-oriented reaching followed by robot therapy (MRG) or same intensity conventional rehabilitation care (CG) aimed at the recovery of the upper limb (20 sessions/45 minutes). Change was evaluated through Fugl-Meyer upper extremity (FMA-UE), Reaching Performance Scale and Box and Block Test. RESULTS: The experimental treatment resulted in higher improvement on the FMA-UE compared with CG (P= 0.04), with a 10-point increase following intervention. Effect sizes were moderate in favor of the MRG group on FMA-UE, FMA-UE proximal and RPS (0.37-0.56). CONCLUSIONS: Preliminary findings indicate that a combination of MeCFES and robotic treatment may be more effective than standard care for recovery of the plegic arm in persons > 3 months after stroke. The mix of motor learning techniques may be important for successful rehabilitation of arm function.

From patient to maker - a case study of co-designing an assistive device using 3D printing.

Commercially available assistive devices (AD) may not always match the individual needs of the patient. Sometimes substantial customizations or a new design is needed. New ideas, arising by involving the patient, could help many, but product development and marketing is hard. We hypothesize that digital fabrication (DF), e.g. 3D printing, may be an opportunity to involve patients in the process of custom design and creation of personalized ADs. As DF is minimizing the requirement for manual activities, DF has the potential to enable people in creating ADs for personal use, despite physical limitations. However, co-design and the use of DF in AD provision is still in its infancy and scarcely reported in scientific literature. We studied the literature, performed a mini survey and then conducted a case story of a person with severe upper extremity impairment who became a maker of her personal AD using 3D printing. Implications of using DF as a key enabling technology empowering patients with physical limits to become active in personal AD provision are discussed. We conclude that this topic merits a proper scientific investigation of systematically engaging patients as competent participants in the development and realization of assistive devices and technologies.

Myoelectrically Controlled FES to Enhance Tenodesis Grip in People With Cervical Spinal Cord Lesion: A Usability Study.

People with tetraplegia are often lacking grip strength, causing impairment in activities of daily living. For them, improving hand function is a priority because it is important for autonomy and participation in daily life. A tendon transfer surgery may be an option to improve the tenodesis grip, but it is an invasive procedure. Alternatively a similar effect can be produced, using a non-invasive method. We have previously described how myoelectrically controlled functional electrical stimulation (MeCFES) can be efficient for enhancing grip strength, using a one channel research prototype with wired connections to surface electrodes. In this paper we focus on the usability for activities of daily living and how it can fulfill an actual need. We recruited 27 participants with a cervical spinal cord lesion (C5-C7) for this trial. They tested the device in 12 sessions of 2 h each, in which the participants performed self selected activities involving the tenodesis grip. User centered outcomes were validated questionnaires: the Individually Prioritized Problem Assessment (IPPA) and the Quebec User Evaluation of Satisfaction with Assistive Technology (QUEST). Furthermore, they were asked if they found the device useful for continued use in daily life. The device facilitated prioritized activities for all participants. The IPPA change score was 4.6 on average (STD:3.5, effect size:1.3), meaning that the system greatly facilitated problematic tasks and the large effect size evinces that this was a meaningful improvement of hand function. It compares to the impact that a mobility device like a wheelchair has on daily living. Fourteen subjects found the system useful, expressing the need for such a neuroprosthesis. Examples of acquiring new abilities while using the device, indicate that the method could have a therapeutic use as well. Furthermore, results from the IPPA questionnaire are indicating what issues people with tetraplegia may hope to solve with a neuroprosthesis for the hand. The satisfaction of the device (QUEST) indicates that further effort in development should address wearability, eliminate wires, and improve the fitting procedure.

Arm rehabilitation in post stroke subjects: A randomized controlled trial on the efficacy of myoelectrically driven FES applied in a task-oriented approach.

PURPOSE: Motor recovery of persons after stroke may be enhanced by a novel approach where residual muscle activity is facilitated by patient-controlled electrical muscle activation. Myoelectric activity from hemiparetic muscles is then used for continuous control of functional electrical stimulation (MeCFES) of same or synergic muscles to promote restoration of movements during task-oriented therapy (TOT). Use of MeCFES during TOT may help to obtain a larger functional and neurological recovery than otherwise possible. STUDY DESIGN: Multicenter randomized controlled trial. METHODS: Eighty two acute and chronic stroke victims were recruited through the collaborating facilities and after signing an informed consent were randomized to receive either the experimental (MeCFES assisted TOT (M-TOT) or conventional rehabilitation care including TOT (C-TOT). Both groups received 45 minutes of rehabilitation over 25 sessions. Outcomes were Action Research Arm Test (ARAT), Upper Extremity Fugl-Meyer Assessment (FMA-UE) scores and Disability of the Arm Shoulder and Hand questionnaire. RESULTS: Sixty eight subjects completed the protocol (Mean age 66.2, range 36.5-88.7, onset months 12.7, range 0.8-19.1) of which 45 were seen at follow up 5 weeks later. There were significant improvements in both groups on ARAT (median improvement: MeCFES TOT group 3.0; C-TOT group 2.0) and FMA-UE (median improvement: M-TOT 4.5; C-TOT 3.5). Considering subacute subjects (time since stroke < 6 months), there was a trend for a larger proportion of improved patients in the M-TOT group following rehabilitation (57.9%) than in the C-TOT group (33.2%) (difference in proportion improved 24.7%; 95% CI -4.0; 48.6), though the study did not meet the planned sample size. CONCLUSION: This is the first large multicentre RCT to compare MeCFES assisted TOT with conventional care TOT for the upper extremity. No adverse events or negative outcomes were encountered, thus we conclude that MeCFES can be a safe adjunct to rehabilitation that could promote recovery of upper limb function in persons after stroke, particularly when applied in the subacute phase.

Myoelectrically driven functional electrical stimulation may increase motor recovery of upper limb in poststroke subjects: a randomized controlled pilot study.

The objective of this randomized controlled pilot study was to assess the feasibility and effectiveness of myoelectrically controlled functional electrical stimulation (MeCFES) for rehabilitation of the upper limb in poststroke subjects. Eleven poststroke hemiparetic subjects with residual proximal control of the arm, but impaired volitional opening of the paretic hand, were enrolled and randomized into a treated and a control group. Subjects received 3 to 5 treatment sessions per week until totaling 25 sessions. In the experimental group, myoelectric activity from wrist and finger extensors was used to control stimulation of the same muscles. Patients treated with MeCFES (n = 5) had a significant (p = 0.04) and clinically important improvement in Action Research Arm Test score (median change 9 points), confirmed by an Individually Prioritized Problem Assessment self-evaluation score. This improvement was maintained at follow-up. The control group did not show a significant improvement (p = 0.13). The reduced sample size of participants, together with confounding factors such as spontaneous recovery, calls for larger studies to draw definite conclusions. However, the large and persistent treatment effect seen in our results indicate that MeCFES could play an important role as a clinical tool for stroke rehabilitation.

A noninvasive neuroprosthesis augments hand grasp force in individuals with cervical spinal cord injury: the functional and therapeutic effects.

OBJECTIVES: The primary purpose of this study was to evaluate myoelectrically controlled functional electrical stimulation (MeCFES) for enhancing the tenodesis grip in people with tetraplegia. The second aim was to estimate the potential number of candidates for the MeCFES device. The application of MeCFES provides the user with direct control of the grasp force as opposed to triggered FES systems. METHODS: Screening 253 medical records of C5 to C7 spinal cord injury resulted in 27 participants who trained activities of daily living for 12 × 2 hours, using the MeCFES. Hand function was evaluated by the Action Research Arm Test (ARAT). Primary outcome was the ARAT change score with/without the device, before/after the intervention period. Secondary outcome was the number of positive or clinically relevant change scores with respect to the cohort. RESULTS: The MeCFES improved hand test score in 63% of the subjects at first application. Training resulted in a significant therapeutic effect, which resulted in an overall increase of hand function in 89% of the participants and 30% experienced a clinically relevant change (6 points or more). CONCLUSIONS: Clinical relevance was found both as an assistive aid and as a therapeutic tool in rehabilitation. The therapeutic effect deserves further investigation in clinical studies.

Battery powered neuromuscular stimulator circuit for use during simultaneous recording of myoelectric signals.

Surface Functional Electrical Stimulation (FES) requires high stimulation voltages. A step-up transformer in the output stage of the stimulation circuit is often used. In the present technical paper a voltage controlled current source (VCCS) is presented as an alternative to the transformer coupling. Two (master-slave) coupled transconductance amplifiers (TAs)--in series with pre-charged capacitors--are used to drive the output current. After each stimulation pulse the capacitors are recharged to a high voltage by a switch mode power supply (SMPS). A multiplexer in the output stage is used to provide biphasic output. Output rise-time (10-90%) was less than 2 micros at 100 mA output. Biphasic charge balanced stimulation current can be produced with a net current to ground of less than 20 nA, thus virtually separated from ground. The circuit permits recording of the volitional myoelectric signal from the stimulated muscle. It is part of a portable myoelectrically controlled FES system powered by 2 AA batteries and currently used in clinical trials.

Functional electrical stimulation reinforced tenodesis effect controlled by myoelectric activity from wrist extensors.

We demonstrated a method for enhancing the tenodesis grip in individuals with sustained tetraplegia at the 6th cervical vertebra neurological level. Subjects used the myoelectric activity from wrist extensor muscles to directly control the electrical stimulation of the extrinsic finger and thumb flexors (flexor pollicis longus and flexor digitorum superficialis/ profondus) with the use of a specially designed system, Myoelectrically Controlled Functional Electrical Stimulation (MeCFES). We screened 20 medical records and selected 9 subjects. Of the nine subjects, five showed a positive response to the surface stimulation and could test the system; the other four failed to achieve functional finger flexion because of skin sensitivity or inadequate movement. We evaluated hand function, with and without the MeCFES system, using tests involving three everyday objects: manipulating a videocassette with the key grip, drinking from a bottle with the palmar grasp, and writing with a pen using the tripod grip. Without the system, none of the five subjects could complete all three tasks; but, when assisted with MeCFES, all subjects completed all the tasks. The system proved simple and intuitively easy to use, and no training was needed for subjects to obtain immediate functionality. We will need further research to evaluate the usefulness of the system in activities of daily living.

Can the F-Response be Volitionally Repressed during Functional Electrical Stimulation?

Objective The purpose of this study was to test if the F-response can be repressed volitionally. Normally, the F-response is used for clinical diagnostics but it also has an important influence on the design of a neural prosthesis involving functional electrical stimulation (FES) and the use of volitional myoelectric signal (MES) for control. Methods Ten neurologically normal subjects were trained to reduce the level of the F-response from the anterior tibial muscle. The nerve to the anterior tibial (TA) muscle was stimulated with constant intensity and frequency (16.6 pulses per second) and the surface myoelectric signal (MES) from the muscle was digitally processed to estimate the F-level. Training was carried out by giving the subject visual feedback on a computer screen of the F-level during the stimulation with the task of keeping the level as low as possible. Each subject had five sessions consisting of 20 stimulation tests, lasting 30 sec each. The subjects acted as their own control and changes in the F-level during the stimulation tests, sessions, and trials, were analyzed. Results There was a significant (p < 0.001) increase in the F-response level within the test period of constant stimulation, but a significant (p < 0.001) decrease from the first to the last test in the session was found. From the first to the last session of a trial, the change was found not significant. Conclusion The level of the F-response may change locally, but there is no indication that a subject can volitionally learn to repress the response, even when given feedback information about the actual level. Therefore the F-waves in the myoelectric signal from a stimulated muscle has to be accounted for when designing devices using a stimulated muscle response for myoelectric control such as eliminating the F-interval from the recorded signal.