Maps as Ability Amplifiers: Using Graphical Tactile Displays to Enhance Spatial Skills in People Who Are Visually Impaired

Leo, Fabrizio; Cocchi, Elena; Ferrari, Elisabetta; Brayda, Luca

doi:10.1007/978-3-030-34230-2_3

Cited by 5 publications

(3 citation statements)

References 80 publications

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“…Importantly, our findings do not seem to be due to differences in spatial memory in the groups of participants. There is evidence that congenitally blind subjects may have difficulties in specific spatial memory tasks, particularly when they have to memorize and recall two separate haptic spatial configurations (Vecchi et al, 2004;Leo et al, 2018Leo et al, , 2020 or sequences of semantic sounds. However, in our study the congenitally blind showed a similar recalling accuracy than the other groups.…”

Section: Discussionmentioning

confidence: 99%

Early blindness modulates haptic object recognition

Leo

Gori²,

Sciutti³

2022

Front. Hum. Neurosci.

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Haptic object recognition is usually an efficient process although slower and less accurate than its visual counterpart. The early loss of vision imposes a greater reliance on haptic perception for recognition compared to the sighted. Therefore, we may expect that congenitally blind persons could recognize objects through touch more quickly and accurately than late blind or sighted people. However, the literature provided mixed results. Furthermore, most of the studies on haptic object recognition focused on performance, devoting little attention to the exploration procedures that conducted to that performance. In this study, we used iCube, an instrumented cube recording its orientation in space as well as the location of the points of contact on its faces. Three groups of congenitally blind, late blind and age and gender-matched blindfolded sighted participants were asked to explore the cube faces where little pins were positioned in varying number. Participants were required to explore the cube twice, reporting whether the cube was the same or it differed in pins disposition. Results showed that recognition accuracy was not modulated by the level of visual ability. However, congenitally blind touched more cells simultaneously while exploring the faces and changed more the pattern of touched cells from one recording sample to the next than late blind and sighted. Furthermore, the number of simultaneously touched cells negatively correlated with exploration duration. These findings indicate that early blindness shapes haptic exploration of objects that can be held in hands.

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Section: Discussionmentioning

confidence: 99%

Early blindness modulates haptic object recognition

Leo

Gori²,

Sciutti³

2022

Front. Hum. Neurosci.

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“…Spatial representations related to mobility and spatial navigation can be supported by information of auditory, visual and tactile nature 7 , and are thus arguably multisensory 38 . Despite mostly depending on visual mediation 39,40 , spatial relations can successfully be conveyed by information from other senses 4,7,12,41 , such as tactile 3,17,[42][43][44][45] or auditory information [46][47][48][49] . For example, the shape of an object is encoded in the spatial pattern of activation evoked in mechanoreceptive bers, much like for vision the shape of an object is encoded in the spatial pattern of activation of photoreceptors in the retina 50 .…”

Section: Discussionmentioning

confidence: 99%

Learning and Navigating Digitally-Rendered Haptic Spatial Layouts

Murray

Tivadar

Franceschiello

et al. 2022

Preprint

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Learning spatial layouts and navigating through them rely not simply on sight, but rather on multisensory processes, including touch. Digital haptics are effective for creating and manipulating mental images of individual objects in sighted and visually impaired participants. Here, we tested if this extends to scenes and navigation within them. Using only digital haptics, sighted blindfolded participants first learned the basic layout of an apartment and then one of two pathways through it. While still blindfolded, participants successfully reconstructed the haptically learned 2D spaces and also navigated these spaces. Digital haptics were thus an effective means to learn and translate 2D images into 3D reconstructions of layouts and actions within real spaces. Digital haptics are thus an alternative learning tool for complex scenes as well as for successful navigation in previously unfamiliar layouts, which can likely be further applied in rehabilitation of spatial functions and mitigation of visual impairments.

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“…Traditionally, many of these technologies have employed visual feedback because of its intrinsic resolution and high-information bandwidth (e.g., Hinterberger et al 2004). However, visual feedback may not be adequate when the visual channel is already highly loaded by a complex task (Cincotti et al 2007), in the case of visually impaired users (Loomis et al 2012;Stronks et al 2016;Leo et al 2019), or whenever there is a need to restore missing Communicated by Francesco Lacquaniti. somatosensory information, e.g., following traumatic injuries or neurological diseases, such as amputation or stroke (Antfolk et al 2013b;Kita et al 2013;Tzorakoleftherakis et al 2015;Stephens-Fripp et al 2018;Sensinger and Dosen 2020).…”

Section: Introductionmentioning

confidence: 99%

Combined spatial and frequency encoding for electrotactile feedback of myoelectric signals

et al. 2022

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Electrotactile stimulation has been commonly used in human–machine interfaces to provide feedback to the user, thereby closing the control loop and improving performance. The encoding approach, which defines the mapping of the feedback information into stimulation profiles, is a critical component of an electrotactile interface. Ideally, the encoding will provide a high-fidelity representation of the feedback variable while being easy to perceive and interpret by the subject. In the present study, we performed a closed-loop experiment wherein discrete and continuous coding schemes are combined to exploit the benefits of both techniques. Subjects performed a muscle activation-matching task relying solely on electrotactile feedback representing the generated myoelectric signal (EMG). In particular, we investigated the performance of two different coding schemes (spatial and spatial combined with frequency) at two feedback resolutions (low: 3 and high: 5 intervals). In both schemes, the stimulation electrodes were placed circumferentially around the upper arm. The magnitude of the normalized EMG was divided into intervals, and each electrode was associated with one interval. When the generated EMG entered one of the intervals, the associated electrode started stimulating. In the combined encoding, the additional frequency modulation of the active electrode also indicated the momentary magnitude of the signal within the interval. The results showed that combined coding decreased the undershooting rate, variability and absolute deviation when the resolution was low but not when the resolution was high, where it actually worsened the performance. This demonstrates that combined coding can improve the effectiveness of EMG feedback, but that this effect is limited by the intrinsic variability of myoelectric control. Our findings, therefore, provide important insights as well as elucidate limitations of the information encoding methods when using electrotactile stimulation to convey a feedback signal characterized by high variability (EMG biofeedback).

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Maps as Ability Amplifiers: Using Graphical Tactile Displays to Enhance Spatial Skills in People Who Are Visually Impaired

Cited by 5 publications

References 80 publications

Early blindness modulates haptic object recognition

Early blindness modulates haptic object recognition

Learning and Navigating Digitally-Rendered Haptic Spatial Layouts

Combined spatial and frequency encoding for electrotactile feedback of myoelectric signals

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