A Tangible Solution for Hand Motion Tracking in Clinical Applications

Objective real-time assessment of hand motion is crucial in many clinical applications including technically-assisted physical rehabilitation of the upper extremity. We propose an inertial-sensor-based hand motion tracking system and a set of dual-quaternion-based methods for estimation of finger segment orientations and fingertip positions. The proposed system addresses the specific requirements of clinical applications in two ways: (1) In contrast to glove-based approaches, the proposed solution maintains the sense of touch. (2) In contrast to previous work, the proposed methods avoid the use of complex calibration procedures, which means that they are suitable for patients with severe motor impairment of the hand. To overcome the limited significance of validation in lab environments with homogeneous magnetic fields, we validate the proposed system using functional hand motions in the presence of severe magnetic disturbances as they appear in realistic clinical settings. We show that standard sensor fusion methods that rely on magnetometer readings may perform well in perfect laboratory environments but can lead to more than 15 cm root-mean-square error for the fingertip distances in realistic environments, while our advanced method yields root-mean-square errors below 2 cm for all performed motions.DFG, 414044773, Open Access Publizieren 2019 - 2020 / Technische Universität Berli

Disease progression in patients with the restrictive and mixed phenotype of Chronic Lung Allograft dysfunction—A retrospective analysis in five European centers to assess the feasibility of a therapeutic trial

Pulmonary function; Graft survival; Respiratory failureFunción pulmonar; Supervivencia del injerto; Insuficiencia respiratoriaFunció pulmonar; Supervivència de l'empelt; Insuficiència respiratòriaBackground: Chronic Lung Allograft Dysfunction (CLAD) is a major obstacle for long term survival after lung transplantation (LTx). Besides Bronchiolitis Obliterans Syndrome, two other phenotypes of CLAD, restrictive allograft syndrome (RAS) and mixed phenotype, have been described. Trials to test in these conditions are desperately needed and analyzing natural outcome to plan such trials is essential. Methods: We performed a retrospective analysis of functional outcome in bilateral LTx recipients with RAS and mixed phenotype, transplanted between 2009 and 2018 in five large European centers with follow- up spirometry up to 12 months after diagnosis. Based on these data, sample size and power calculations for randomized therapeutic trial was estimated using two imputation methods for missing values. Results: Seventy patients were included (39 RAS and 31 mixed phenotype), median 3.1 years after LTx when CLAD was diagnosed. Eight, 13 and 25 patients died within 6, 9 and 12 months after diagnosis and a two patients underwent re-transplantation within 12 months leading to a graft survival of 89, 79 and 61% six, nine and 12 months after diagnosis, respectively. Observed FEV1 decline was 451 ml at 6 months and stabilized at 9 and 12 months, while FVC showed continuous decline. Using two methods of imputation, a progressive further decline after 6 months for FEV1 was noted. Conclusion: The poor outcome of these two specific CLAD phenotypes suggests the urgent need for future therapeutic randomized trials. The number of missing values in a potential trial seems to be high and most frequently attributed to death. Survival may be used as an endpoint in clinical trials in these distinct phenotypes and imputation techniques are relevant if graft function is used as a surrogate of disease progression in future trials

Intention recognition for FES in a grasp-and-release task using volitional EMG and inertial sensors

Functional Electrical Stimulation (FES) facilitates the motor recovery of the hand function after stroke. The integration of biofeedback and other strategies to actively involve a patient in the therapy is important for the rehabilitation progress. We introduce a combined control approach for a FES-driven neuroprosthesis using volitional electromyo-graphy (vEMG) and motion capturing via a novel inertial sensor network for patients that still possess a residual activity in the paralyzed muscles. A real-time vEMG measurement and signal processing in between stimulation pulses has been realized during active FES. Experiments showed that our system allows for quick adaption to individual users.BMBF, 16SV7069K, Verbundprojekt: Bewegungsfähigkeit und Mobilität wiedererlangen - BeMobil -; Teilvorhaben: Nutzerzentrierte Entwicklung technischer Methoden für eine optimale Mensch-Technik-Interaktion in der Bewegungsrehabilitatio

A new semi-automatic approach to find suitable virtual electrodes in arrays using an interpolation strategy

Functional Electrical Stimulation via electrode arrays enables the user to form virtual electrodes (VEs) of dynamic shape, size, and position. We developed a feedback-control-assisted manual search strategy which allows the therapist to conveniently and continuously modify VEs to find a good stimulation area. This works for applications in which the desired movement consists of at least two degrees of freedom. The virtual electrode can be moved to arbitrary locations within the array, and each involved element is stimulated with an individual intensity. Meanwhile, the applied global stimulation intensity is controlled automatically to meet a predefined angle for one degree of freedom. This enables the therapist to concentrate on the remaining degree(s) of freedom while changing the VE position. This feedback-control-assisted approach aims to integrate the user's opinion and the patient's sensation. Therefore, our method bridges the gap between manual search and fully automatic identification procedures for array electrodes. Measurements in four healthy volunteers were performed to demonstrate the usefulness of our concept, using a 24-element array to generate wrist and hand extension.BMBF, 16SV7069K, Verbundprojekt: Bewegungsfähigkeit und Mobilität wiedererlangen - BeMobil -; Teilvorhaben: Nutzerzentrierte Entwicklung technischer Methoden für eine optimale Mensch-Technik-Interaktion in der Bewegungsrehabilitatio

Modular finger and hand motion capturing system based on inertial and magnetic sensors

The assessment of hand posture and kinematicsis increasingly important in various fields. This includesthe rehabilitation of stroke survivors with restricted handfunction. This paper presents a modular, ambulatory mea-surement system for the assement of the remaining handfunction and for closed-loop controlled therapy. The de-vice is based on inertial sensors and utilizes up to fiveinterchangeable sensor strips to achieve modularity and tosimplify the sensor attachment. We introduce the modularhardware design and describe algorithms used to calculatethe joint angles. Measurements with two experimentalsetups demonstrate the feasibility and the potential of such a tracking device.BMBF, 16SV7069K, Verbundprojekt: Bewegungsfähigkeit und Mobilität wiedererlangen - BeMobil -; Teilvorhaben: Nutzerzentrierte Entwicklung technischer Methoden für eine optimale Mensch-Technik-Interaktion in der Bewegungsrehabilitatio

Clinical decision making is improved by BioFire Pneumonia Plus in suspected lower respiratory tract infection after lung transplantation: Results of the prospective DBATE‐IT * study

Background: Lower respiratory tract infections (LRTIs) are a significant cause of morbidity and mortality in lung transplant (LTx) recipients. Timely and precise pathogen detection is vital to successful treatment. Multiplex PCR kits with short turnover times like the BioFire Pneumonia Plus (BFPPp) (manufactured by bioMérieux) may be a valuable addition to conventional tests. Methods: We performed a prospective observational cohort study in 60 LTx recipients with suspected LRTI. All patients received BFPPp testing of bronchoalveolar lavage fluid in addition to conventional tests including microbiological cultures and conventional diagnostics for respiratory viruses. Primary outcome was time‐to‐test‐result; secondary outcomes included time‐to‐clinical‐decision and BFPPp test accuracy compared to conventional tests. Results: BFPPp provided results faster than conventional tests (2.3 h [2–2.8] vs. 23.4 h [21–62], p < 0.001), allowing for faster clinical decisions (2.8 [2.2–44] vs. virology 28.1 h [23.1–70.6] and microbiology 32.6 h [4.6–70.9], both p < 0.001). Based on all available diagnostic modalities, 26 (43%) patients were diagnosed with viral LRTI, nine (15 %) with non‐viral LRTI, and five (8 %) with combined viral and non‐viral LRTI. These diagnoses were established by BFPPp in 92%, 78%, and 100%, respectively. The remaining 20 patients (33 %) received a diagnosis other than LRTI. Preliminary therapies based on BFPPp results were upheld in 90% of cases. There were six treatment modifications based on pathogen‐isolation by conventional testing missed by BFPPp, including three due to fungal pathogens not covered by the BFPPp. Conclusion: BFPPp offered faster test results compared to conventional tests with good concordance. The absence of fungal pathogens from the panel is a potential weakness in a severely immunosuppressed population

Intention recognition for FES in a grasp-and-release task using volitional EMG and inertial sensors

Functional Electrical Stimulation (FES) facilitates the motor recovery of the hand function after stroke. The integration of biofeedback and other strategies to actively in-volve a patient in the therapy is important for the rehabili-tation progress. We introduce a combined control approach for a FES-driven neuroprosthesis using volitional electromyo-graphy (vEMG) and motion capturing via a novel inertial sensor network for patients that still possess a residual activity in the paralyzed muscles. A real-time vEMG measurement and signal processing in between stimulation pulses has been realized during active FES. Experiments showed that our system allows for quick adaption to individual users

Modular finger and hand motion capturing system based on inertial and magnetic sensors

The assessment of hand posture and kinematics is increasingly important in various fields. This includes the rehabilitation of stroke survivors with restricted hand function. This paper presents a modular, ambulatory measurement system for the assement of the remaining hand function and for closed-loop controlled therapy. The device is based on inertial sensors and utilizes up to five interchangeable sensor strips to achieve modularity and to simplify the sensor attachment. We introduce the modular hardware design and describe algorithms used to calculate the joint angles. Measurements with two experimental setups demonstrate the feasibility and the potential of such a tracking device

User-centered practicability analysis of two identification strategies in electrode arrays for FES induced hand motion in early stroke rehabilitation

Abstract Background Surface electrode arrays have become popular in the application of functional electrical stimulation (FES) on the forearm. Arrays consist of multiple, small elements, which can be activated separately or in groups, forming virtual electrodes (VEs). As technology progress yields rising numbers of possible elements, an effective search strategy for suitable VEs in electrode arrays is of increasing importance. Current methods can be time-consuming, lack user integration, and miss an evaluation regarding clinical acceptance and practicability. Methods Two array identification procedures with different levels of user integration—a semi-automatic and a fully automatic approach—are evaluated. The semi-automatic method allows health professionals to continuously modify VEs via a touchscreen while the stimulation intensities are automatically controlled to maintain sufficient wrist extension. The automatic approach evaluates stimulation responses of various VEs for different intensities using a cost function and joint-angles recordings. Both procedures are compared in a clinical setup with five sub-acute stroke patients with moderate hand disabilities. The task was to find suitable VEs in two arrays with 59 elements in total to generate hand opening and closing for a grasp-and-release task. Practicability and acceptance by patients and health professionals were investigated using questionnaires and interviews. Results Both identification methods yield suitable VEs for hand opening and closing in patients who could tolerate the stimulation. However, the resulting VEs differed for both approaches. The average time for a complete search was 25% faster for the semi-automatic approach (semi-automatic: 7.3min, automatic: 10.5min). User acceptance was high for both methods, while no clear preference could be identified. Conclusions The semi-automatic approach should be preferred as the search strategy in arrays on the forearm. The observed faster search duration will further reduce when applying the system repeatedly on a patient as only small position adjustments for VEs are required. However, the setup time will significantly increase for generation of various grasp types and adaptation to different arm postures. We recommend different levels of user integration in FES systems such that the search strategy can be chosen based on the users’ preferences and application scenario

Literacy in Austria. Country Report. Children and adolescents

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