Browsing by Author "Imatz-Ojanguren, Eukene"
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Item Analysis of the movements generated by a multi-field functional electrical stimulation device for upper extremity rehabilitation(2022-10) Martín-Odriozola, Aitor; Rodríguez-de-Pablo, Cristina; Caceres-Salegi, Ane; García-Calleja, Andrea; Marín-Ojea, Juan Ignacio; Hernández, Erik; Imatz-Ojanguren, Eukene; Keller, Thierry; Zabaleta-Rekondo, Haritz; Martín‐Odriozola, Aitor; Rodríguez‐de‐Pablo, Cristina; Caceres‐Salegi, Ane; García‐Calleja, Andrea; Marín‐Ojea, Juan Ignacio; Imatz‐Ojanguren, Eukene; Zabaleta‐Rekondo, Haritz; Medical Technologies; Tecnalia Research & InnovationBackground: The most common chronic sequela after stroke is the loss of arm function, and functional electrical stimulation (FES) applied to the forearm muscles is one of the options to treat it. Surface multi-field electrodes have emerged, showing a great potential to improve the selectivity of the stimulation, delay muscle fatigue, and provide easier donning and doffing. The muscular selectivity takes on special relevance in the rehabilitation of the upper extremity as hand dexterity requires a wide diversity of specific muscle actions. Methods: This pilot study analyses the movements generated in the wrist and fingers using a commercial multi-field technology-based FES device (Fesia Grasp). The study included five patients with hemiplegic subacute stroke, in which scanning of all cathodes of the electrode was carried out daily for 5 days, in two different forearm positions, with the resulting movements being labeled by experienced therapists. Results: The aim of this pilot study was to determine if there were differences between subjects and between forearm positions in terms of produced movements. Movements of the wrist (two movements) and the fingers (six movements) could be achieved in two different forearm positions. Conclusions: The multi-field electrode of Fesia Grasp enables to generate a wide range of movements of the hand in different positions. This fact could allow to produce more physiological movement patterns during the rehabilitation process with FES, which could have a beneficial effect on the recovery of patients with neurological diseases.Item Evoked sensations with transcutaneous electrical stimulation with different frequencies, waveforms, and electrode configurations(2023-01) Imatz-Ojanguren, Eukene; Keller, Thierry; Imatz‐Ojanguren, Eukene; Medical Technologies; Tecnalia Research & InnovationBackground: Current Perception Threshold (CPT) is a technique used for diagnostic purposes that applies sinusoidal currents transcutaneously at 5 Hz, 250 Hz, and 2KHz to preferentially excite C, Aδ, and Aβ afferent nerve fibers correspondingly. This fact may be interesting for evoking different electrotactile sensations for a wide variety of applications. Methods: Sensations evoked by 5 Hz, 250 Hz, and 2KHz frequencies; sinusoidal, square, and 250 μs-pulsed waveforms; and conventional and concentric electrode configurations were analyzed in 19 healthy volunteers. Stimuli were applied in the dorsum of the hand in a double-blind manner and CPTs were defined based on participants' verbal feedback. After each stimulus participants filled in a form with sensation modality, irradiation, intensity, and emotion descriptors. Results: The frequency showed a significant effect on the four domains of evoked sensations and the waveform showed a significant effect on the modality domain. For most waveform and electrode configuration combinations, 5 Hz evoked mostly a low-intensity prickling sensation; 250 Hz mostly evoked an uncomfortable medium-intensity tingling sensation; and 2KHz mostly evoked a low-intensity tingling sensation. No thermal or noxious sensations were evoked. A significant interaction effect was only found between the frequency and the waveform factors. The electrode configuration did not show either a significant effect on the evoked sensations or an interaction effect with the frequency or waveform type. Conclusions: Transcutaneous electrical stimulation may evoke different sensations at different frequencies due to the preferential activation of different fiber types. The results of these analysis could be used to enhance human-machine/computer-interaction systems based on electrotactile feedback.Item Feasibility of Using Neuro-Fuzzy Subject-Specific Models for Functional Electrical Stimulation Induced Hand Movements(2015-09-01) Imatz-Ojanguren, Eukene; Irigoyen, Eloy; Valencia, David; Keller, Thierry; Tecnalia Research & Innovation; Medical TechnologiesFunctional Electrical Stimulation (FES) is a technique that artificially elicits muscle contractions and it is used to restore motor/sensory functions in both assistive and therapeutic applications. The use of multi-field surface electrodes is a novel popular approach in transcutaneous FES applications. Lately, hybrid systems that combine artificial neural networks and fuzzy logic have also been proposed for many applications in different areas. This paper presents the possibility of combining both approaches for obtaining subject-specific models of FES induced hand movements for grasping applications. Data of the hand and finger motion from two subjects affected by acquired brain injury were used to train two different approaches: coactive neuro-fuzzy inference system and recurrent fuzzy neural network. Preliminary results show that these approaches can be considered in modelling applications for their ability to learn and predict main characteristics of the system, as well as providing useful information from the original system that could be interpreted as subject-specific knowledge.Item A foot drop compensation device based on surface multi-field functional electrical stimulation—Usability study in a clinical environment(2019) Imatz-Ojanguren, Eukene; Sánchez-Márquez, Gema; Asiain-Aristu, Jose Ramón; Cueto-Mendo, Joxean; Jaunarena-Goicoechea, Edurne; Zabaleta, Haritz; Keller, Thierry; Tecnalia Research & InnovationFunctional electrical stimulation applies electrical pulses to the peripheral nerves to artificially achieve a sensory/motor function. When applied for the compensation of foot drop it provides both assistive and therapeutic effects. Multi-field electrodes have shown great potential but may increase the complexity of these systems. Usability aspects should be checked to ensure their success in clinical environments. We developed the Fesia Walk device, based on a surface multi-field electrode and an automatic calibration algorithm, and carried out a usability study to check the feasibility of integrating this device in therapeutic programs in clinical environments. The study included 4 therapists and 10 acquired brain injury subjects (8 stroke and 2 traumatic brain injury).Item Neuro-fuzzy models for hand movements induced by functional electrical stimulation in able-bodied and hemiplegic subjects(2016-11-01) Imatz-Ojanguren, Eukene; Irigoyen, Eloy; Valencia-Blanco, David; Keller, Thierry; Tecnalia Research & Innovation; Medical TechnologiesFunctional Electrical Stimulation (FES) may be effective as a therapeutic treatment for improving functional reaching and grasping. Upper-limb FES models for predicting joint torques/angles from stimulation parameters can be useful to support the iterative design and development of neuroprostheses. Most such models focused on shoulder or elbow joints and were defined for fixed electrode configurations. This work proposes the use of a Recurrent Fuzzy Neural Network (RFNN) for modeling FES induced wrist, thumb, and finger movements based on surface multi-field electrodes and kinematic data from able-bodied and neurologically impaired subjects. Different combinations of structure parameters comprising fuzzy term numbers and feedback approaches were tested and analyzed in order to see their effect on the model performance for six subjects. The results showed mean success rates in the range from 60% to 99% and best success rates in the range from 78% to 100% on test data for all subjects. No common trend was found across subjects regarding structure parameters. The model showed the ability to successfully reproduce the response to FES for both able-bodied and hemiplegic subjects at least with one of the tested combinations.Item Reinforcement Learning for Hand Grasp with Surface Multi-field Neuroprostheses(Springer International Publishing, 2017) Imatz-Ojanguren, Eukene; Irigoyen, Eloy; Keller, Thierry; Lopez-Guede, Jose Manuel; Herrero, Alvaro; Quintian, Hector; Grana, Manuel; Etxaniz, Oier; Corchado, Emilio; Tecnalia Research & InnovationHand grasp is a complex system that plays an important role in the activities of daily living. Upper-limb neuroprostheses aim at restor- ing lost reaching and grasping functions on people su ering from neural disorders. However, the dimensionality and complexity of the upper-limb makes the neuroprostheses modeling and control challenging. In this work we present preliminary results for checking the feasibility of using a re- inforcement learning (RL) approach for achieving grasp functions with a surface multi- eld neuroprosthesis for grasping. Grasps from 20 healthy subjects were recorded to build a reference for the RL system and then two di erent award strategies were tested on simulations based on neuro- fuzzy models of hemiplegic patients. These rst results suggest that RL might be a possible solution for obtaining grasp function by means of multi- eld neuroprostheses in the near future.Item Stimulation Discomfort Comparison of Asynchronous and Synchronous Methods with Multi-Field Surface Electrodes(2013-06) Imatz-Ojanguren, Eukene; Hoffmann, Ulrich; Veneman, Jan; Malešević, Nebojša; Keller, Thierry; Tecnalia Research & InnovationFunctional Electrical Stimulation (FES) is a technique that artificially stimulates motor nerves in order to restore motor/sensory functions for assistive and therapeutic applications. Recently, multi-field surface electrodes for transcutaneous electrical stimulation have been suggested to overcome problems of single channel surface stimulation. This study compares sensation perceived by 15 healthy subjects on upper limb when two different stimulation methods are applied by means of multi-field electrodes. Asynchronous and synchronous stimulation methods are compared for four different cases: activation of two neighbor fields, three neighbor fields, two distant fields and three distant fields. Two descriptors rated from 1 to 5 are used to describe discomfort: superficial discomfort and deep discomfort. Results expressed no differences in superficial discomfort for any case, but showed significant differences in deep discomfort for distant field activations. In these cases, synchronous stimulation resulted in higher perceived deep discomfort than asynchronous stimulation and affected its efficacy.Item Transcutaneous FES-induced pain maps on post-stroke upper limb(2014-09) Imatz-Ojanguren, Eukene; Cuesta, Alicia; Iglesias, Javier; Carratala, María; Keller, Thierry; Tecnalia Research & InnovationFunctional Electrical Stimulation (FES) is a technique to artificially stimulate motor nerves in order to restore motor/sensory functions for assistive and therapeutic applications. This preliminary study attempts to detect differences in the perception of transcutaneous FES in upper limbs. Three chronic stroke survivors participated in the study. Multi-field electrodes were used to selectively activate the targeted areas over the wrist-finger flexors, wrist-finger extensors, biceps, and triceps muscles. Results showed no significant correlation between the applied current and pain ratings. Differences in the rating of pain in different fields over the four targeted areas were observed. The initial results suggest that here is a common pattern to most subjects for each area of the upper limb.Item Usability study of a device for compensation of foot drop based on FES and surface multi-field electrodes in a clinical environment(2017-07) Imatz-Ojanguren, Eukene; Sánchez-Márquez, Gema; Asiain-Aristu, Jose Ramón; Cueto-Mendo, Joxean; Jaunarena-Goicoechea, Edurne; Zabaleta, Haritz; Keller, Thierry; Tecnalia Research & InnovationFunctional Electrical Stimulation (FES) has shown successful assistive and rehabilitation effects in people affected by foot drop dysfunction caused by neurological disorders [1]. Still, FES-based foot drop devices are not present in regular therapy programs of many countries due to barriers caused by technological, usability or reliability issues [2]. FES devices based on surface multi-field electrodes bring new broader stimulation possibilities and features like compensation of eversion/inversion and thus, potentially increase the configuration options. In this study, the satisfaction and usability aspects of a multi-field based FES device were analyzed in a clinical environment. Method The FES device used in this study was the Fesia Walk device for compensation of foot drop, which is based on a multi-field surface electrode and an inertial sensor for gait phase detection. 10 acquired brain injury subjects in chronic stage and 4 therapists participated in the study. The therapists received a two-hour training session prior to the therapy sessions. Every subject was assigned to one therapist and received 3 sessions of habituation and 6 sessions of over ground walking with the Fesia Walk during three weeks. Both therapists and users were evaluated with the Quebec User Evaluation of Satisfaction with Assistive Technology (QUEST). Additionally, the therapists were evaluated with the System Usability Scale (SUS). An individual interview was carried out with each of the participants. Results The device received good scores in both the QUEST and SUS scales, with mean scores of 4.14 out of 5 and 85.6 out of 100 respectively. Furthermore, most users and all therapists showed interest to continue using the device after the study. Discussion and conclusions This usability study indicated that it is possible to include surface multi-field based FES devices for the compensation of foot drop in practical therapeutic programs and that they can be used as regular tools by therapists in clinical environments.Item The Use of Functional Electrical Stimulation on the Upper Limb and Interscapular Muscles of Patients with Stroke for the Improvement of Reaching Movements: A Feasibility Study: A feasibility study(2017-05-10) Cuesta-Gómez, Alicia; Molina-Rueda, Francisco; Carratala-Tejada, Maria; Imatz-Ojanguren, Eukene; Torricelli, Diego; Miangolarra-Page, Juan Carlos; Tecnalia Research & Innovation; Medical TechnologiesIntroduction: Reaching movements in stroke patients are characterized by decreased amplitudes at the shoulder and elbow joints and greater displacements of the trunk, compared to healthy subjects. The importance of an appropriate and specific contraction of the interscapular and upper limb (UL) muscles is crucial to achieving proper reaching movements. Functional electrical stimulation (FES) is used to activate the paretic muscles using short-duration electrical pulses. Objective: To evaluate whether the application of FES in the UL and interscapular muscles of stroke patients with motor impairments of the UL modifies patients’ reaching patterns, measured using instrumental movement analysis systems. Design: A cross-sectional study was carried out. Setting: The VICON Motion System® was used to conduct motion analysis. Participants: Twenty-one patients with chronic stroke. Intervention: The Compex® electric stimulator was used to provide muscle stimulation during two conditions: a placebo condition and a FES condition. Main outcome measures: We analyzed the joint kinematics (trunk, shoulder, and elbow) from the starting position until the affected hand reached the glass. Results: Participants receiving FES carried out the movement with less trunk flexion, while shoulder flexion elbow extension was increased, compared to placebo conditions. Conclusion: The application of FES to the UL and interscapular muscles of stroke patients with motor impairment of the UL has improved reaching movements.Item Uso de redes neuro-borrosas RFNN para la aproximación del comportamiento de una neuroprótesis de antebrazo en pacientes con daño cerebral(2015-09) Imatz-Ojanguren, Eukene; Irigoyen Gordo, Eloy; Valencia Blanco, David; Zabaleta, Haritz; Keller, Thierry; Tecnalia Research & InnovationLas neuroprótesis son sistemas basados en la técnica de estimulación eléctrica funcional que provocan contracciones musculares mediante la excitación artificial de nervios periféricos, y son utilizadas para sustituir funciones motrices/sensoriales en aplicaciones tanto asistivas como terapéuticas. Este trabajo presenta la posibilidad de utilizar redes neuro-borrosas recurrentes para obtener modelos capaces de extraer las características principales del resultado de la aplicación de una neuroprótesis de miembro superior en distintos pacientes. Se ha entrenado una Recurrent Fuzzy Neural Network (RFNN) con datos reales obtenidos de pacientes crónicos de daño cerebral adquirido. Se han analizado distintas estrategias y estructuras y los resultados preliminares muestran la capacidad de estas redes de aprender las características principales de distintos sujetos y de proporcionar información fácilmente interpretable.