Echoic Sensory Substitution Information in a Single Obstacle Circumvention Task.

Accurate motor control is required when walking around obstacles in order to avoid collisions. When vision is unavailable, sensory substitution can be used to improve locomotion through the environment. Tactile sensory substitution devices (SSDs) are electronic travel aids, some of which indicate the distance of an obstacle using the rate of vibration of a transducer on the skin. We investigated how accurately such an SSD guided navigation in an obstacle circumvention task. Using an SSD, 12 blindfolded participants navigated around a single flat 0.6 x 2 m obstacle. A 3-dimensional Vicon motion capture system was used to quantify various kinematic indices of human movement. Navigation performance under full vision was used as a baseline for comparison. The obstacle position was varied from trial to trial relative to the participant, being placed at two distances 25 cm to the left, right or directly ahead. Under SSD guidance, participants navigated without collision in 93% of trials. No collisions occurred under visual guidance. Buffer space (clearance between the obstacle and shoulder) was larger by a factor of 2.1 with SSD guidance than with visual guidance, movement times were longer by a factor of 9.4, and numbers of velocity corrections were larger by a factor of 5 (all p<0.05). Participants passed the obstacle on the side affording the most space in the majority of trials for both SSD and visual guidance conditions. The results are consistent with the idea that SSD information can be used to generate a protective envelope during locomotion in order to avoid collisions when navigating around obstacles, and to pass on the side of the obstacle affording the most space in the majority of trials.Vision and Eye Research Unit, Postgraduate Medical Institute at Anglia Ruskin University; Medical Research Council (Grant ID: G0701870)This is the final version of the article. It first appeared from the Public Library of Science via http://dx.doi.org/10.1371/journal.pone.016087

L'utilisation des sons spatialisés horizontalement en tant qu'aide à la navigation chez des aveugles précoces et tardifs

La vision est le sens privilégié pour intéragir avec notre environnement. C’est pourquoi le système visuel prend plus d’un tiers du cortex cérébral. Lorsqu’un individu perd sa vision, ce système est dépourvu de sa source première de stimuli. Il subit donc une réorganisation neuronale massive et devient un espace intermodal. Pour ce faire, il recrute des afférences des autres modalités afin que celles-ci prennent en charge les fonctions qui sont normalement soutenues par la vision. Ce phénomène, appelé plasticité cérébrale, est stimulé par la durée de la cécité et par l’entraînement des sens fonctionnels. Ceci fait en sorte que les aveugles développent des supra-capacités dans les modalités fonctionnelles. La substitution sensorielle est un principe qui exploite ce phénomène. Celle-ci permet de substituer un sens déficient par un autre sens. Pour ce faire, des appareils de substitution sensorielle sont développés pour acheminer des informations visuelles via le toucher ou l’audition. Bien que le but de ces appareils est d’offrir une vision fonctionnelle aux aveugles, la problématique principale demeure l’indépendance de navigation des aveugles. Cependant, ces appareils sont très peu appréciés par les aveugles parce qu’ils sont inaccessibles et qu’ils fournissent un signal complexe qui demande un entraînement intense et une charge cognitive trop élevée. Dans ce projet, nous avons évalué le potentiel d’un nouvel appareil de substitution sensorielle qui fournit des informations strictement pertinentes à la navigation spatiale sous la forme de sons spatialisés horizontalement. Pour ce faire, des participants aveugles précoces, aveugles tardifs et des voyants aux yeux bandés ont été testé pour leurs habiletés à détecter et éviter des obstacles à l’aide de l’appareil dans des conditions expérimentales de détection et d’évitement d’obstacles. L’étude a démontré qu’il est possible d’utiliser cet appareil en tant qu’aide à la navigation et que ce système est utilisé plus efficacement par les groupes d’aveugles.Vision is the preferred sense for interacting with our environment. This is why the visual system takes up more than a third of the cerebral cortex. When an individual loses his vision, this system misses its primary source of stimuli. It therefore undergoes a massive neuronal reorganization and becomes an intermodal space. To do so, it recruits afferents from other modalities so that they take over the functions that are normally mediated by vision. This phenomenon, known as cerebral plasticity, is stimulated by the experience of blindness as well as by the training of the functional senses. This causes the blind to develop supra-abilities in their functional modalities. Sensory substitution is a principle that exploits this phenomenon. It makes it possible to substitute a deficient modality with another modality. To help the blind, sensory substitution devices are being developed to convey visual information via touch or hearing. Although these devices attempt to provide functional vision for the blind, the main issue they try to address is the improvement of the navigational independency of the blind. However, these devices are very little appreciated by the blind since they are inaccessible and provide a complex signal that requires intense training and too high of a cognitive load. Therefore, in this project, we evaluated the potential of a new sensory substitution device that provides information strictly relevant to spatial navigation in the form of horizontally spatialized sounds. To do so, early blind , late blind and sighted blindfolded individuals were tested for their ability to detect and avoid obstacles using the device under experimental conditions. The study showed that it is possible to use this device as a navigation aid and that this system is used more effectively by the blind

Designing sensory-substitution devices: Principles, pitfalls and potential1

An exciting possibility for compensating for loss of sensory function is to augment deficient senses by conveying missing information through an intact sense. Here we present an overview of techniques that have been developed for sensory substitution (SS) for the blind, through both touch and audition, with special emphasis on the importance of training for the use of such devices, while highlighting potential pitfalls in their design. One example of a pitfall is how conveying extra information about the environment risks sensory overload. Related to this, the limits of attentional capacity make it important to focus on key information and avoid redundancies. Also, differences in processing characteristics and bandwidth between sensory systems severely constrain the information that can be conveyed. Furthermore, perception is a continuous process and does not involve a snapshot of the environment. Design of sensory substitution devices therefore requires assessment of the nature of spatiotemporal continuity for the different senses. Basic psychophysical and neuroscientific research into representations of the environment and the most effective ways of conveying information should lead to better design of sensory substitution systems. Sensory substitution devices should emphasize usability, and should not interfere with other inter- or intramodal perceptual function. Devices should be task-focused since in many cases it may be impractical to convey too many aspects of the environment. Evidence for multisensory integration in the representation of the environment suggests that researchers should not limit themselves to a single modality in their design. Finally, we recommend active training on devices, especially since it allows for externalization, where proximal sensory stimulation is attributed to a distinct exterior object.This work was supported by the European Union’s Horizon 2020 Research and Innovative Programme under grant agreement no. 643636, “Sound of Vision”.Peer Reviewe

Blindness enhances auditory obstacle circumvention: Assessing echolocation, sensory substitution, and visual-based navigation

Performance for an obstacle circumvention task was assessed under conditions of visual, auditory only (using echolocation) and tactile (using a sensory substitution device, SSD) guidance. A Vicon motion capture system was used to measure human movement kinematics objectively. Ten normally sighted participants, 8 blind non-echolocators, and 1 blind expert echolocator navigated around a 0.6 x 2 m obstacle that was varied in position across trials, at the midline of the participant or 25 cm to the right or left. Although visual guidance was the most effective, participants successfully circumvented the obstacle in the majority of trials under auditory or SSD guidance. Using audition, blind non-echolocators navigated more effectively than blindfolded sighted individuals with fewer collisions, lower movement times, fewer velocity corrections and greater obstacle detection ranges. The blind expert echolocator displayed performance similar to or better than that for the other groups using audition, but was comparable to that for the other groups using the SSD. The generally better performance of blind than of sighted participants is consistent with the perceptual enhancement hypothesis that individuals with severe visual deficits develop improved auditory abilities to compensate for visual loss, here shown by faster, more fluid, and more accurate navigation around obstacles using sound.This research was supported by the Vision and Eye Research Unit, Postgraduate Medical Institute at Anglia Ruskin University (awarded to SP), and the Medical Research Council (awarded to BCJM, Grant number G0701870)

Aplicación dos produtos de apoio de alta tecnoloxía no desempeño ocupacional das persoas con discapacidade visual: scoping review

[Resumo] Introdución: As persoas con discapacidade visual poden experimentar dificultades na realización de diferentes ocupacións cotiás. A tecnoloxía de apoio (TA) debe actuar coma un facilitador na participación desta poboación en actividades desexadas. Obxectivo: Coñecer se os produtos de apoio de alta tecnoloxía dan resposta ás dificultades no desempeño ocupacional coas que se atopan máis frecuentemente as persoas con discapacidade visual no seu día a día. Metodoloxía: Seguiuse unha metodoloxía de revisión de alcance. A busca bibliográfica foi levada a cabo nas bases de datos CINAHL, PubMed, Scopus e Web of Science. As variables temáticas establecéronse seguindo os compoñentes propostos polo Modelo da Actividade Humana e da Tecnoloxía de Apoio. Para a súa análise empregouse un enfoque mixto. Resultados: Na mostra incluíronse un total de 44 estudos. En moitos casos, non se especificou certa información relativa ás persoas participantes. A TA analizada centrouse principalmente na detección e na evitación de obstáculos, facilitando a mobilidade funcional. Os dispositivos reciben a información mediante sistemas de cámaras para transmitirlla á persoa por son. A TA está deseñada para contextos tanto interiores coma exteriores da vida diaria, e foi testada maiormente en ambientes reais. Conclusión: Os produtos de apoio de alta tecnoloxía están dirixidos principalmente a facilitar a mobilidade funcional, a participación social, e a lectura das persoas con discapacidade visual. En menor medida, abordaron a educación, o deporte e as tarefas do fogar. Así, non se centraron noutras actividades relevantes como a condución ou o emprego.[Resumen] Introducción: Las personas con discapacidad visual pueden experimentan dificultades en la realización de diferentes ocupaciones cotidianas. La tecnología de apoyo (TA) debe actuar como un facilitador en la participación de esta población en actividades deseadas. Objetivo: Conocer si los productos de apoyo de alta tecnología dan respuesta a las dificultades en el desempeño ocupacional con las que se encuentran más frecuentemente las personas con discapacidad visual en su día a día. Metodología: Se siguió una metodología de revisión de alcance. La búsqueda bibliográfica se llevó a cabo en las bases de datos CINAHL, PubMed, Scopus y Web of Science. Las variables temáticas se establecieron siguiendo los componentes propuestos por el Modelo de la Actividad Humana y la Tecnología de Apoyo. Para su análisis se empleó un enfoque mixto. Resultados: En la muestra se incluyeron un total de 44 estudios. En muchos casos, no se especificó cierta información relativa a las personas participantes. La TA analizada se centró principalmente en la detección y evitación de obstáculos, facilitando la movilidad funcional. Los dispositivos reciben la información mediante sistemas de cámaras para transmitírsela a la persona por audio. La TA está diseñada para contextos tanto interiores como exteriores de la vida diaria, y fue testada mayormente en ambientes reales. Conclusión: Los productos de apoyo de alta tecnología están dirigidos principalmente a facilitar la movilidad funcional, la participación social, y la lectura de las personas con discapacidad visual. En menor medida, abordaron la educación, el deporte, o las tareas del hogar. Así, no se centraron en otras actividades relevantes como la conducción o el empleo.[Abstract] Background: People with visual impairment can have difficulties in performing different daily occupations. Assistive technology (AT) should be an enabler in the participation of these population’s desired activities. Aim: To know if high-tech assistive devices respond to difficulties in the occupational performance that people with visual impairment most frequently experiment in their day-to-day lives. Methodology: A methodology of Scoping Review was used. The bibliographic search was carried out in the databases CINAHL, PubMed, Scopus y Web of Science. Thematic variables were established following the components proposed by the Human Activity Assistive Technology Model. For their analyses, a mixed methods approach was used. Results: A total of 44 studies were included in the sample. In many cases, certain information regarding the participants was not specified. The analyzed AT focused mainly on the detection and avoidance of obstacles, facilitating functional mobility. The devices receive the information through camera systems to transmit it to the person by audio. The AT is designed for indoor and outdoor contexts of everyday life, and it was mostly tested in real-world environments. Conclusion: The high-tech assistive devices are primarily aimed at facilitating the functional mobility, social participation, and reading of people with visual impairment. To a lesser extent, they addressed education, sports, or housework. However, they did not focus on other relevant activities such as driving or working.Traballo fin de mestrado (UDC.FCS). Asistencia e investigación sanitaria. Especialidade en Reeducación Funcional, Autonomía Persoal e Calidade de Vida. Curso 2020-202

An ecological approach to sensory substitution

Tesis doctoral inédita leída en la Universidad Autónoma de Madrid, Facultad de Psicología, Departamento de Psicología Básica. Fecha de lectura: 15-09-2017Esta tesis tiene embargado el acceso al texto completo hasta el 15-03-201