Rafael Raya

A Robust Kalman Algorithm to Facilitate Human-Computer Interaction for People with Cerebral Palsy, Using a New Interface Based on Inertial Sensors

This work aims to create an advanced human-computer interface called ENLAZA for people with cerebral palsy (CP). Although there are computer-access solutions for disabled people in general, there are few evidences from motor disabled community (e.g., CP) using these alternative interfaces. The proposed interface is based on inertial sensors in order to characterize involuntary motion in terms of time, frequency and range of motion. This characterization is used to design a filtering technique that reduces the effect of involuntary motion on person-computer interaction. This paper presents a robust Kalman filter (RKF) design to facilitate fine motor control based on the previous characterization. The filter increases mouse pointer directivity and the target acquisition time is reduced by a factor of ten. The interface is validated with CP users who were unable to control the computer using other interfaces. The interface ENLAZA and the RKF enabled them to use the computer.

Robotic Therapies for Children with Cerebral Palsy: A Systematic Review

Title: This paper presents a systematic review of robotic devices and therapies for cerebral palsy (CP), trying to shed some light on the present literature on robot-based CP rehabilitation. Background: Recent publications have demonstrated that robot-assisted therapies may constitute an effective tool for the compensation and rehabilitation of the functional skills of people with CP. The most important robotic devices for lower and upper limb rehabilitation were selected, specifying the assisted therapies, experiments done with them, and their results in children with CP. Methods: Scientific articles were obtained by means of an extensive search in electronic databases, primarily PubMed and Scopus. Papers published from the year 2000 to 2015 were considered for inclusion. The search was performed by using the following keywords in combination: robot, Cerebral Palsy, children, and therapies. Moreover, some web pages about CP organizations were used to complete the review. Conclusions: There is still a lack of randomized clinical trials with a representative number of subjects, which makes it difficult to evaluate the impact of robot-based therapy, especially the long-term effects. The inclusion of cognitive aspects into the therapies and the design of virtual scenarios in combination with robotic devices provide promising results.

Characterizing head motor disorders to create novel interfaces for people with cerebral palsy: Creating an alternative communication channel by head motion

This paper aims to validate a head mounted inertial interface to characterize disorder movements in people with cerebral palsy (CP). The kinematic patterns extracted from this study will be used to design an alternative communication channel (using head motion) adapted to users capabilities and limitations. Four people with CP participated (GMFCS level V) and three healthy subjects as reference group. The main outcome measures were divided into 1) Time-domain, 2) Frequency-domain and 3) Spatial domain. Results showed that the inertial interface succeeds assessing the pathological motion. Firstly, the system differentiates between voluntary and involuntary motion in terms of motor control, frequency and range of motion. Secondly some motion disorders such as hypertonia, hypotonia can be identified. These results suggest that people with motor disorders could benefit from the developed inertial system in three fields: 1) diagnosis of motor disorder by means of an objective quantification, 2) physical and cognitive rehabilitation by means of proprioceptive enhancement through visual-motor feedback and 3) functional compensation by means of an inertial person-machine interface for controlling computer and assistive devices (e.g. wheelchairs or walkers).

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.

Assistive Robots for Physical and Cognitive Rehabilitation in Cerebral Palsy

Cerebral palsy (CP) is one of the most severe disabilities in childhood and makes heavy demands on health, educational, and social services as well as on families and children themselves. The most frequently cited definition of CP is a disorder of posture and movement due to a defect or lesion in the immature brain, [1].

Preliminary Result from a Multimodal Interface for Cerebral Palsy Users Based on Eye Tracking and Inertial Technology

Cerebral palsy (CP) is a disorder that arises in childhood and stays the rest of life. CP affects movement, posture and muscle tone. According ASPACE Confederation CP is a whole person disorder consisting of a permanent but not unchanging disorder of muscle tone, posture and movement due to a non-progressive lesion in the brain before the development and growth are complete”. CP generates constraints that affect motor control of traditional human-computer interfaces (HCI), reducing the opportunities for interaction. There are various solutions to access computer for people with disabilities. However, accessibility is compromised when the user suffers a severe motor impairment. This paper hypothesizes that the integration of HCI that use different technologies can facilitate access to the computer for people with severe neuro-motor limitations. Based on this hypothesis, we studied in a practical way, with people with CP, the features of two existing HCI: IRISCOM, an eye tracking interface and ENLAZA, a head motion tracking based on inertial technology. Several metrics will used to evaluate the usability of the IRISCOM system as input device for subjects with CP. The head posture will be analyzed using the ENLAZA interface in order to estimate its influence on the usability of the IRISCOM system.

A mobile robot controlled by an adaptive inertial interface for children with physical and cognitive disorders

This paper presents novel strategies for the interaction and mobility of infants with cerebral palsy (CP) and similar disorders. Initially, the design of a playful robotic vehicle is proposed. It aims to promote the physical and cognitive skills through mobility experiences. Despite the versatility of the vehicle, some children present severe motor limitations hindering the control of the driving console. In order to increase the accessibility of the vehicle, different driving modes are not enough. For people with CP, the human-machine interaction is a critical factor. For this reason, a novel human-machine head-mounted interface (HMI) is proposed to drive the vehicle. The HMI is based on inertial technology, which enables users to drive the vehicle by their movements and postures. The solutions and methods proposed in this paper have been validated experimentally with people with CP.

Positive and Negative Motor Signs of Head Motion in Cerebral Palsy: Assessment of Impairment and Task Performance

This paper analyzes the presence of positive and negative motor signs in people with cerebral palsy (CP). Positive motor signs are those that lead to involuntarily increased frequency or magnitude of muscle activity. Negative motor signs describe insufficient muscle activity or insufficient control of muscle activity. In this paper, a head-mounted alternative computer interface based on inertial technology was used to assess motor signs in seven users with CP. Task performance and control of posture was related to the impairment. There are no significant differences between users with CP and healthy control participants in the frequency domain of the head movement. Results suggest that this kind of motor disorders is not related to positive motor signs. Moreover, a control mode based on posture more than on movements is not optimum; an alternative control mode must be specially designed for users with poor postural control.

Coupled control of human-exoskeleton systems: An adaptative process

Robotic exoskeletons are wearable robots coupled to the human body, being the human an integral part of the human-robot system. Specifically, the control plays an important role, and stability must be guarantee. Both actors form a close loop with two control systems interacting dynamically. In this regard, a relevant issue is to understand how humans and robots could physically (kinesthetically) interact and communicate better. This paper deeps in the control of systems interacting dynamically and presents an analytical discussion on the controller design for exoskeletons and the coupled stability problem. Finally, a particular study is described in order to demonstrate the human cognitive system adapting under functional compensation of tremor.

Human-computer interaction for users with cerebral palsy based on head orientation. Can cursor’s movement be modeled by Fitts’s law?

Abstract This paper presents an experiment to validate a head-mounted inertial interface for human-computer interaction (HCI) developed for people with cerebral palsy (CP). The method is based on Fitts’s law, an empirical model of human motor performance for aimed movements. Head motion is recorded in a series of goal-crossing tasks and a regression model of the movement time ( MT ) is estimated for each user. Values of R 2 above 0.9 are indicators of a strong correlation of those motion patterns with the linear model proposed by Fitts. The analysis of MT confirmed that head movements of users without disability follow Fitts’s law and showed that 3 users with CP (MACS IV and V) had the same behavior. There was a weaker correlation ( R 2 =0.839) for one individual with cervical dystonia and ballistic movements and no correlation for two users with cervical hypotonia and dyskinetic CP. Results show the impact of ballistic movements and poor postural control in computer interaction. They also provide the foundation for new interaction techniques to develop a universal computer interface for motor impaired users.