J.M. Belda-Lois

Rehabilitation Robotics: a Wearable Exo-Skeleton for Tremor Assessment and Suppression

There is a need for wearable powered upper limb exoskeletons able to apply forces to the upper limb for use by people with disabilities and/or limb weakness or injury. The robotic exoskeleton called WOTAS (Wearable Orthosis for Tremor Assessment and Suppression) presented in this paper will provide a means of testing non-grounded control strategies in order to help these people. For instance, biomechanical loading, in particular, viscous loading of the upper limb has been proposed in the literature as a means for suppressing pathologic tremor. This article describes in detail the general concept for WOTAS, outlining the special features of the design and selection of system components.

Multimodal BCI-mediated FES suppression of pathological tremor

Tremor constitutes the most common movement disorder; in fact 14.5% of population between 50 to 89 years old suffers from it. Moreover, 65% of patients with upper limb tremor report disability when performing their activities of daily living (ADL). Unfortunately, 25% of patients do not respond to drugs or neurosurgery. In this regard, TREMOR project proposes functional compensation of upper limb tremors with a soft wearable robot that applies biomechanical loads through functional electrical stimulation (FES) of muscles. This wearable robot is driven by a Brain Neural Computer Interface (BNCI). This paper presents a multimodal BCI to assess generation, transmission and execution of both volitional and tremorous movements based on electroencephalography (EEG), electromyography (EMG) and inertial sensors (IMUs). These signals are combined to obtain: 1) the intention to perform a voluntary movement from cortical activity (EEG), 2) tremor onset, and an estimation of tremor frequency from muscle activation (EMG), and 3) instantaneous tremor amplitude and frequency from kinematic measurements (IMUs). Integration of this information will provide control signals to drive the FES-based wearable robot.

On the use of an active wearable exoskeleton for tremor suppression via biomechanical loading

Biomechanical loading, in particular, viscous loading of the upper limb has been proposed in the literature as a means for suppressing pathologic tremor. It is expected that an improvement on manipulative function can be obtained by reducing the tremorous motion associated to some neurological disorders. This article presents two non-grounded control strategies to suppress tremor by means of a orthotic (wearable) exoskeleton. These two strategies are based on biomechanical loading and notch filtering of tremor via internal forces. Both controls strategies are evaluated and validated on the robotic exoskeleton called WOTAS (wearable orthosis for tremor assessment and suppression). At the end, results obtained in the pre-clinical trials and conclusions of this study are presented

A soft wearable robot for tremor assessment and suppression

Tremor constitutes the most common motor disorder, and poses a functional problem to a large number of patients. Despite of the considerable experience in tremor management, current treatment based on drugs or surgery does not attain an effective attenuation in 25 % of patients, motivating the need for research in new therapeutic alternatives. In this context, this paper presents the concept design, development, and preliminary validation of a soft wearable robot for tremor assessment and suppression. The TREMOR neurorobot comprises a Brain Neural Computer Interface that monitors the whole neuromusculoskeletal system, aiming at characterizing both voluntary movement and tremor, and a Functional Electrical Stimulation system that compensates for tremulous movements without impeding the user perform functional tasks. First results demonstrate the performance of the TREMOR neurorobot as a novel means of assessing and attenuating pathological tremors.

CPWalker: Robotic platform for gait rehabilitation in patients with Cerebral Palsy

Cerebral Palsy (CP) is a disorder of posture and movement due to an imperfection or lesion in the immature brain. CP is often associated to sensory deficits, cognition impairments, communication and motor disabilities, behaviour issues, seizure disorder, pain and secondary musculoskeletal problems. New strategies are needed to help to promote, maintain, and rehabilitate the functional capacity, and thereby diminish the dedication and assistance required and the economical demands that this condition represents for the patient, the caregivers and the whole society. This paper describes the conceptualization and development of the integrated CPWalker robotic platform to support novel therapies for CP rehabilitation. This platform (Smart Walker + exoskeleton) is controlled by a multimodal interface to establish the interaction of CP children with robot-based therapies. The objective of these therapies is to improve the physical skills of children with CP and similar disorders. CPWalker concept will promote the earlier incorporation of CP patients to the rehabilitation therapy and increase the level of intensity and frequency of the exercises according to the task, which will enable the maintenance of therapeutic methods in daily basis, with the intention to lead to significant improvements in the treatment outcome.

Development and evaluation of a novel robotic platform for gait rehabilitation in patients with Cerebral Palsy

The term Cerebral Palsy (CP) is a set of neurological disorders that appear in infancy or early childhood and permanently affect body movement and muscle coordination. The prevalence of CP is twothree per 1000 births. Emerging rehabilitation therapies through new strategies are needed to diminish the assistance required for these patients, promoting their functional capability. This paper presents a new robotic platform called CPWalker for gait rehabilitation in patients with CP, which allows them to start experiencing autonomous locomotion through novel robot-based therapies. The platform (smart walker +exoskeleton) is controlled by a multimodal interface that gives high versatility. The therapeutic approach, as well as the details of the interactions may be defined through this interface. CPWalker concept aims to promote the earlier incorporation of patients with CP to the rehabilitation treatment and increases the level of intensity and frequency of the exercises. This will enable the maintenance of therapeutic methods on a daily basis, with the intention of leading to significant improvements in the treatment outcomes. Rehabilitation with free displacement and not restricted to a treadmill.Integration of central nervous system into therapies.Postural control and partial body weight support for individuals with more severe disorders.Assist as needed approach.Locomotion strategy based on laser sensor.

Usability Model Based on Traditional Metrics and Physiological and Eye Tracking Variables Depending on User Profile

Usability recommendations need to be checked with users, combining subjective methodologies with objective and quantitative approaches. The use of physiological response and eye tracking variables allowed detecting better the effect of usability recommendations and user profile. Moreover, some usability recommendations seems to have low effect on improving usability and even can difficult the interaction for users without functional limitaions. Finally, a model to assess the usability has been defined, which related web design parameters with objective variables and user perception, where task outcomes are key indicators for users without functional limitations while variables related with emotional response or behaviour are more important for users with motor disorders.

A new methodology for Functional Principal Component Analysis from scarce data. Application to stroke rehabilitation

Functional Principal Component Analysis (FPCA) is an increasingly used methodology for analysis of biomedical data. This methodology aims to obtain Functional Principal Components (FPCs) from Functional Data (time dependent functions). However, in biomedical data, the most common scenario of this analysis is from discrete time values. Standard procedures for FPCA require obtaining the functional data from these discrete values before extracting the FPCs. The problem appears when there are missing values in a non-negligible sample of subjects, especially at the beginning or the end of the study, because this approach can compromise the analysis due to the need to extrapolate or dismiss subjects with missing values. In this paper, we present an alternative methodology extracting the FPCs directly from the sampled data, avoiding the need to have functional data before extracting them. We demonstrate the feasibility of our approach from real data obtained from the analysis of balance recovery after stroke. Finally, we demonstrate that FPCA can obtain differences between groups when these differences are more related to the dynamics of the process than data values at given points.

Influence of Emotions on Web Usability for Users with Motor Disorders

Emotions are related with many key cognitive processes during human computer interaction (HCI). The aim of this study was to validate usability recommendations depending on user profile, to check the effect of the emotional state on HCI and to compare physiological response analysis and questionnaires. 10 control users and 10 users with upper limb disorders were involved. An orthogonal design with seven usability parameters were used to generate 16 websites with different styles but with the same content. Galvanic skin response and facial electromyography on the corrugator supercilii and zygomaticus major muscles were used to assess emotional response, which are related to arousal and valence respectively; and user opinion was collected using a questionnaire. The results showed significant correlations between questionnaires and physiological signals, which are more sensitive to web parameters effect; and most of usability recommendations improve usability but only have a significant influence on users with motor disorders.

Assistive Robotics as Alternative Treatment for Tremor

Tremor is the most common movement disorder and strongly increases in incidence and prevalence with ageing. Although not life threatening, upper limb tremors hamper independent life of 65% of those suffering from them, greatly impacting on their quality of life. Current treatments of tremor include drugs and surgery. However, tremor is not effectively managed in 25% of patients. Therefore, further research and new therapeutic options are required for an effective management of pathological tremor. This paper introduces some rehabilitation robots developed for tremor suppression based on biomechanical loading, their evaluation and the identification of their limitations. At the end, authors aim to provide a view of the potential of this novel approach for tremor management and the plans for commercialization.