Browsing by Author "Keller, Thierry (7202537317)"

Background: Functional electrical stimulation (FES) can be applied as an assistive and therapeutic aid in the rehabilitation of foot drop. Transcutaneous multi-pad electrodes can increase the selectivity of stimulation; however, shaping the stimulation electrode becomes increasingly complex with an increasing number of possible stimulation sites. We described and tested a novel decision support system (DSS) to facilitate the process of multi-pad stimulation electrode shaping. The DSS is part of a system for drop foot treatment that comprises a custom-designed multi-pad electrode, an electrical stimulator, and an inertial measurement unit. Methods: The system was tested in ten stroke survivors (3-96 months post stroke) with foot drop over 20 daily sessions. The DSS output suggested stimulation pads and parameters based on muscle twitch responses to short stimulus trains. The DSS ranked combinations of pads and current amplitudes based on a novel measurement of the quality of the induced movement and classified them based on the movement direction (dorsiflexion, plantar flexion, eversion and inversion) of the paretic foot. The efficacy of the DSS in providing satisfactory pad-current amplitude choices for shaping the stimulation electrode was evaluated by trained clinicians. The range of paretic foot motion was used as a quality indicator for the chosen patterns. Results: The results suggest that the DSS output was highly effective in creating optimized FES patterns. The position and number of pads included showed pronounced inter-patient and inter-session variability; however, zones for inducing dorsiflexion and plantar flexion within the multi-pad electrode were clearly separated. The range of motion achieved with FES was significantly greater than the corresponding active range of motion (p < 0.05) during the first three weeks of therapy. Conclusions: The proposed DSS in combination with a custom multi-pad electrode design covering the branches of peroneal and tibial nerves proved to be an effective tool for producing both the dorsiflexion and plantar flexion of a paretic foot. The results support the use of multi-pad electrode technology in combination with automatic electrode shaping algorithms for the rehabilitation of foot drop. Trial registration: This study was registered at the Current Controlled Trials website with ClinicalTrials.gov ID NCT02729636 on March 29, 2016. © 2017 The Author(s).

We present a hand functions assessment system (BEAGLE) for kinematic tracking of hand and finger movements, envisioned as a technology-mediated rehabilitation tool. The system is custom-designed for fast and easy placement on an impaired hand (spastic or flaccid), featuring inertial sensors integrated into simple finger caps and a hand strap. An algorithm for a range of motion (ROM) estimation was implemented to provide an objective assessment of hand functions. The efficacy and feasibility of the BEAGLE system were examined in a pilot clinical study performed with ten stroke survivors in the subacute phase. Participants received therapy within two consecutive intensity-matched rehabilitation cycles. The first consisted of conventional therapy, while the second involved a combination of conventional therapy and advanced functional electrical stimulation. Assessments were performed before and after each phase. These included BEAGLE estimates of active voluntary ROM for wrist and various digits, as well as two referent clinical measures for hand functions assessment, Fugl-Meyer and Action Research Arm Test. The results indicate that the ROM assessments can detect change with sensitivity comparable to the standardized clinical scales. Statistically significant changes between the beginning and the end of the second cycle existed in all observed measures, whereas none of these measurements showed a statistically significant improvement in the first therapy cycle. The noted usability metrics indicate that the BEAGLE could be integrated into the rehabilitation workflow in a clinical environment. © 2001-2011 IEEE.

We present a hand functions assessment system (BEAGLE) for kinematic tracking of hand and finger movements, envisioned as a technology-mediated rehabilitation tool. The system is custom-designed for fast and easy placement on an impaired hand (spastic or flaccid), featuring inertial sensors integrated into simple finger caps and a hand strap. An algorithm for a range of motion (ROM) estimation was implemented to provide an objective assessment of hand functions. The efficacy and feasibility of the BEAGLE system were examined in a pilot clinical study performed with ten stroke survivors in the subacute phase. Participants received therapy within two consecutive intensity-matched rehabilitation cycles. The first consisted of conventional therapy, while the second involved a combination of conventional therapy and advanced functional electrical stimulation. Assessments were performed before and after each phase. These included BEAGLE estimates of active voluntary ROM for wrist and various digits, as well as two referent clinical measures for hand functions assessment, Fugl-Meyer and Action Research Arm Test. The results indicate that the ROM assessments can detect change with sensitivity comparable to the standardized clinical scales. Statistically significant changes between the beginning and the end of the second cycle existed in all observed measures, whereas none of these measurements showed a statistically significant improvement in the first therapy cycle. The noted usability metrics indicate that the BEAGLE could be integrated into the rehabilitation workflow in a clinical environment. © 2001-2011 IEEE.

We designed a new surface multi-pad electrode for the electrical stimulation of the forearm that is effective in controlling functional grasp in hemiplegic patients. The electrode shape and size were designed on the basis of the surface stimulation map of the forearm, determined from measurements in seven hemiplegic patients who had limited or absent voluntary movements of the fingers, thumb and wrist. The stimulation map for each patient was assessed with a conventional set of single pad Pals Platinum electrodes. Since the sites for the stimulation varied greatly between patients, the end result was a rather large multi-pad electrode. Modulating multi-pad electrode size, shape, position and individual pad stimulation parameters allows us to accommodate the diversity of the neural tissues in patients that need to be activated for functional grasp. This also allows asynchronous activation of different portions of the muscle and dynamic adaptation of the stimulation sites to appropriate underlying tissues during functional use. The validity of the determined stimulation map was tested in the same group of hemiplegic patients. The selected set of active pads resulted in fully functional and reproducible palmar and lateral grasps similar to healthy-like grasps. © 2001-2011 IEEE.

We designed a new surface multi-pad electrode for the electrical stimulation of the forearm that is effective in controlling functional grasp in hemiplegic patients. The electrode shape and size were designed on the basis of the surface stimulation map of the forearm, determined from measurements in seven hemiplegic patients who had limited or absent voluntary movements of the fingers, thumb and wrist. The stimulation map for each patient was assessed with a conventional set of single pad Pals Platinum electrodes. Since the sites for the stimulation varied greatly between patients, the end result was a rather large multi-pad electrode. Modulating multi-pad electrode size, shape, position and individual pad stimulation parameters allows us to accommodate the diversity of the neural tissues in patients that need to be activated for functional grasp. This also allows asynchronous activation of different portions of the muscle and dynamic adaptation of the stimulation sites to appropriate underlying tissues during functional use. The validity of the determined stimulation map was tested in the same group of hemiplegic patients. The selected set of active pads resulted in fully functional and reproducible palmar and lateral grasps similar to healthy-like grasps. © 2001-2011 IEEE.

BACKGROUND: Foot drop is common gait impairment after stroke. Functional electrical stimulation (FES) of the ankle dorsiflexor muscles during the swing phase of gait can help correcting foot drop. OBJECTIVE: To evaluate efficacy of additional novel FES system to conventional therapy in facilitating motor recovery in the lower extremities and improving walking ability after stroke. METHODS: Sixteen stroke patients were randomly allocated to the FES group (FES therapy plus conventional rehabilitation program) (n=8), and control group (conventional rehabilitation program) n=8. FES was delivered for 30min during gait to induce ankle plantar and dorsiflexion. Main outcome measures: Gait speed using 10 Meter Walk Test (10 MWT), Fugl-Meyer Assessment (FMA), Berg Balance Scale (BBS) and modified Barthel Index (MBI). RESULTS: Results showed a significant increase in gait speed in FES group (p<0.001), higher than the minimal detected change. The FES group showed improvement in functional independence in the activities of daily living, motor recovery and gait performance. CONCLUSIONS: The findings suggest that novel FES therapy combined with conventional rehabilitation is more effective on walking speed, mobility of the lower extremity, balance disability and activities of daily living compared to a conventional rehabilitation program only. © 2017 - IOS Press and the authors.

BACKGROUND: Foot drop is common gait impairment after stroke. Functional electrical stimulation (FES) of the ankle dorsiflexor muscles during the swing phase of gait can help correcting foot drop. OBJECTIVE: To evaluate efficacy of additional novel FES system to conventional therapy in facilitating motor recovery in the lower extremities and improving walking ability after stroke. METHODS: Sixteen stroke patients were randomly allocated to the FES group (FES therapy plus conventional rehabilitation program) (n=8), and control group (conventional rehabilitation program) n=8. FES was delivered for 30min during gait to induce ankle plantar and dorsiflexion. Main outcome measures: Gait speed using 10 Meter Walk Test (10 MWT), Fugl-Meyer Assessment (FMA), Berg Balance Scale (BBS) and modified Barthel Index (MBI). RESULTS: Results showed a significant increase in gait speed in FES group (p<0.001), higher than the minimal detected change. The FES group showed improvement in functional independence in the activities of daily living, motor recovery and gait performance. CONCLUSIONS: The findings suggest that novel FES therapy combined with conventional rehabilitation is more effective on walking speed, mobility of the lower extremity, balance disability and activities of daily living compared to a conventional rehabilitation program only. © 2017 - IOS Press and the authors.

The goal of this study was to investigate surface motor activation zones and their temporal variability using an advanced multi-pad functional electrical stimulation system. With this system motor responses are elicited through concurrent activation of electrode matrix pads collectively termed “virtual electrodes” (VEs) with appropriate stimulation parameters. We observed VEs used to produce selective wrist, finger, and thumb extension movements in 20 therapy sessions of 12 hemiplegic stroke patients. The VEs which produce these three selective movements were created manually on the ergonomic multi-pad electrode by experienced clinicians based on visual inspection of the muscle responses. Individual results indicated that changes in VE configuration were required each session for all patients and that overlap in joint movements was evident between some VEs. However, by analyzing group data, we defined the probability distribution over the electrode surface for the three VEs of interest. Furthermore, through Bayesian logic we obtained preferred stimulation zones that are in accordance with our previously reported heuristically obtained results. We have also analyzed the number of active pads and stimulation amplitudes for these three VEs. Presented results provide a basis for an automated electrode calibration algorithm built on a priori knowledge or the starting point for manual selection of stimulation points. © 2017 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

The goal of this study was to investigate surface motor activation zones and their temporal variability using an advanced multi-pad functional electrical stimulation system. With this system motor responses are elicited through concurrent activation of electrode matrix pads collectively termed “virtual electrodes” (VEs) with appropriate stimulation parameters. We observed VEs used to produce selective wrist, finger, and thumb extension movements in 20 therapy sessions of 12 hemiplegic stroke patients. The VEs which produce these three selective movements were created manually on the ergonomic multi-pad electrode by experienced clinicians based on visual inspection of the muscle responses. Individual results indicated that changes in VE configuration were required each session for all patients and that overlap in joint movements was evident between some VEs. However, by analyzing group data, we defined the probability distribution over the electrode surface for the three VEs of interest. Furthermore, through Bayesian logic we obtained preferred stimulation zones that are in accordance with our previously reported heuristically obtained results. We have also analyzed the number of active pads and stimulation amplitudes for these three VEs. Presented results provide a basis for an automated electrode calibration algorithm built on a priori knowledge or the starting point for manual selection of stimulation points. © 2017 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

The ArmAssist is a low-cost robotic system for post-stroke upper-limb telerehabilitation based on serious games. The system incorporates a set of games for the assessment of arm function, the ArmAssist Assessment (AAA), which allows a remote monitoring of the progress of the patient and an automatic adaptation of the therapy. In this study, different components of the AAA are compared against three widely-used clinical tests, the Fugl-Meyer Assessment (FMA) [1], the Action Research Arm Test (ARAT) [2] and the Wolf Motor Function Test (WMFT) [3] in order to select the most clinically meaningful ones for the final score provided to patients and therapist, and evaluate their capability to predict or even improve some aspects of these standard scales. All four tests were performed in 38 separate sessions in 19 post-stroke individuals in their sub-acute phase, as part of a broader study. Statistically significant correlation could be shown with the three clinical tests. These preliminary results are promising for the validation of AAA as a fast, automatic and clinically meaningful tool for remote progress assessment and therapy adaptation; however, more data and further analysis is needed to confirm this. © 2015 IEEE.

The ArmAssist is a low-cost robotic system for post-stroke upper-limb telerehabilitation based on serious games. The system incorporates a set of games for the assessment of arm function, the ArmAssist Assessment (AAA), which allows a remote monitoring of the progress of the patient and an automatic adaptation of the therapy. In this study, different components of the AAA are compared against three widely-used clinical tests, the Fugl-Meyer Assessment (FMA) [1], the Action Research Arm Test (ARAT) [2] and the Wolf Motor Function Test (WMFT) [3] in order to select the most clinically meaningful ones for the final score provided to patients and therapist, and evaluate their capability to predict or even improve some aspects of these standard scales. All four tests were performed in 38 separate sessions in 19 post-stroke individuals in their sub-acute phase, as part of a broader study. Statistically significant correlation could be shown with the three clinical tests. These preliminary results are promising for the validation of AAA as a fast, automatic and clinically meaningful tool for remote progress assessment and therapy adaptation; however, more data and further analysis is needed to confirm this. © 2015 IEEE.