Showing papers by "Paolo Bonato published in 2014"

The effect of arm weight support on upper limb muscle synergies during reaching movements

Abstract: Background: Compensating for the effect of gravity by providing arm-weight support (WS) is a technique often utilized in the rehabilitation of patients with neurological conditions such as stroke to facilitate the performance of arm movements during therapy. Although it has been shown that, in healthy subjects as well as in stroke survivors, the use of arm WS during the performance of reaching movements leads to a general reduction, as expected, in the level of activation of upper limb muscles, the effects of different levels of WS on the characteristics of the kinematics of motion and of the activity of upper limb muscles have not been thoroughly investigated before. Methods: In this study, we systematically assessed the characteristics of the kinematics of motion and of the activity of 14 upper limb muscles in a group of 9 healthy subjects who performed 3-D arm reaching movements while provided with different levels of arm WS. We studied the hand trajectory and the trunk, shoulder, and elbow joint angular displacement trajectories for different levels of arm WS. Besides, we analyzed the amplitude of the surface electromyographic (EMG) data collected from upper limb muscles and investigated patterns of coordination via the analysis of muscle synergies. Results: The characteristics of the kinematics of motion varied across WS conditions but did not show distinct trends with the level of arm WS. The level of activation of upper limb muscles generally decreased, as expected, with the increase in arm WS. The same eight muscle synergies were identified in all WS conditions. Their level of activation depended on the provided level of arm WS. Conclusions: The analysis of muscle synergies allowed us to identify a modular organization underlying the generation of arm reaching movements that appears to be invariant to the level of arm WS. The results of this study provide a normative dataset for the assessment of the effects of the level of arm WS on muscle synergies in stroke survivors and other patients who could benefit from upper limb rehabilitation with arm WS.

The effect of arm weight support on upper limb muscle synergies during reaching movements

Abstract: Background: Compensating for the effect of gravity by providing arm-weight support (WS) is a technique often utilized in the rehabilitation of patients with neurological conditions such as stroke to facilitate the performance of arm movements during therapy. Although it has been shown that, in healthy subjects as well as in stroke survivors, the use of arm WS during the performance of reaching movements leads to a general reduction, as expected, in the level of activation of upper limb muscles, the effects of different levels of WS on the characteristics of the kinematics of motion and of the activity of upper limb muscles have not been thoroughly investigated before. Methods: In this study, we systematically assessed the characteristics of the kinematics of motion and of the activity of 14 upper limb muscles in a group of 9 healthy subjects who performed 3-D arm reaching movements while provided with different levels of arm WS. We studied the hand trajectory and the trunk, shoulder, and elbow joint angular displacement trajectories for different levels of arm WS. Besides, we analyzed the amplitude of the surface electromyographic (EMG) data collected from upper limb muscles and investigated patterns of coordination via the analysis of muscle synergies. Results: The characteristics of the kinematics of motion varied across WS conditions but did not show distinct trends with the level of arm WS. The level of activation of upper limb muscles generally decreased, as expected, with the increase in arm WS. The same eight muscle synergies were identified in all WS conditions. Their level of activation depended on the provided level of arm WS. Conclusions: The analysis of muscle synergies allowed us to identify a modular organization underlying the generation of arm reaching movements that appears to be invariant to the level of arm WS. The results of this study provide a normative dataset for the assessment of the effects of the level of arm WS on muscle synergies in stroke survivors and other patients who could benefit from upper limb rehabilitation with arm WS.

Robotic Gait Rehabilitation Trainer

Abstract: This paper presents the basic principle of operation, the mechanical design, and the control system of the Robotic Gait Rehabilitation (RGR) Trainer. This novel single-actuator mechatronic system targets secondary gait deviations affecting patterns of movement of the pelvis in stroke survivors. These deviations arise as compensatory movements associated with primary gait deviations, such as the lack of sufficient knee flexion during the swing phase of the gait cycle. Using an expanded impedance control strategy, the device generates a force field that affects the obliquity of the pelvis (rotation of the pelvis around the anteroposterior axis) via a lower body exoskeleton while the patient ambulates on a treadmill. Preliminary healthy human subject testing demonstrated that the RGR Trainer can effectively guide the pelvis in the frontal plane via force fields to alter pelvic obliquity.

Designing auditory cues for Parkinson's disease gait rehabilitation.

Abstract: Recent works have proved that Parkinson's disease (PD) patients can be largely benefit by performing rehabilitation exercises based on audio cueing and music therapy. Specially, gait can benefit from repetitive sessions of exercises using auditory cues. Nevertheless, all the experiments are based on the use of a metronome as auditory stimuli. Within this work, Human-Computer Interaction methodologies have been used to design new cues that could benefit the long-term engagement of PD patients in these repetitive routines. The study has been also extended to commercial music and musical pieces by analyzing features and characteristics that could benefit the engagement of PD patients to rehabilitation tasks.

Triggering motor adaptations at the pelvis using the RGR trainer

Abstract: The ability to generate motor adaptations in response to a perturbation is directly related to the capacity of a person to process the feedback related to the perturbation and to generate an adequate motor plan in response. In this work, we investigated the possibility to generate motor adaptations in response to perturbations in the pelvis trajectory in a pool of healthy subjects. Subjects experienced up- and downward force field perturbations at the pelvic area with and without visual feedback on the actual and desired pelvic trajectories. Results showed that it is possible to trigger a motor adaptation behavior while perturbing pelvis obliquity only in response to a downward pushing force field and in the presence of visual feedback, thus indicating a) that pelvic perturbations are not deemed as task relevant by the central nervous system while walking on a treadmill; b) that visual feedback can trigger adaptation to non-task relevant perturbations; c) that hip abductors and extensors cannot generate strong pelvis-dropping forces.

Performance of three electromyogram decomposition algorithms as a function of signal to noise ratio: Assessment with experimental and simulated data

Abstract: We have previously published a full report [25] comparing the performance of three automated electromyogram (EMG) decomposition algorithms In our prior report, the primary measure of decomposition difficulty/challenge for each data record was the “Decomposability Index” of Florestal et al [3] This conference paper is intended to augment our prior work by providing companion results when the measure of difficulty is the motor unit signal-to-noise ratio (SNR MU ) — a measure that is commonly used in the literature Thus, we analyzed experimental and simulated data to assess the agreement and accuracy, as a function of SNR MU , of three publicly available decomposition algorithms-EMGlab[1] (single channel data only), Fuzzy Expert [2] and Montreal [3] Data consisted of quadrifilar needle EMGs from the tibialis anterior of 12 subjects at 10%, 20% and 50% maximum voluntary contraction (MVC); single channel needle EMGs from the biceps brachii of 10 control subjects during contractions just above threshold; and matched simulated data Performance vs SNR MU was assessed via agreement between pairs of algorithms for experimental data and accuracy with respect to the known decomposition for simulated data For experimental data, RMS errors between the achieved agreement and those predicted by an exponential model as a function of SNR MU ranged from 84% to 192% For the simulations, RMS errors between achieved accuracy and those predicted by the SNR MU exponential model ranged from 37% to 147% Agreement/accuracy was strongly related to SNR MU •

Challenges of Clinical Research in Physical Medicine & Rehabilitation: Considerations from a Working Group from Brazil, USA and Canada

Abstract: Lauren Richardson, Marta Imamura, Magdalena Sarah Volz,, Moises Lima, Marcos Renato de Assis, Paolo Bonato, Christina May Moran de Brito, Hsin Fen Chien, Andrea Dompieri Furlan, Alexandra Passos Gaspar,, Wu Tu Hsing, Hermano Igo Krebs, Henry Lew, Eduardo Carvalho Rocha Mello, André Silva Pedroso, Marcelo Riberto, Isabel Salles Chateaubriand, Maria Matilde de Mello Sposito, Linamara Rizzo Battistella, Ross Zafonte and Felipe Fregni.