RoMAT: Robot for Multisensory Analysis and Testing of visual-tactile perceptual functions (original) (raw)
Related papers
Sensors, 2013
Information obtained from multiple sensory modalities, such as vision and touch, is integrated to yield a holistic percept. As a haptic approach usually involves cross-modal sensory experiences, it is necessary to develop an apparatus that can characterize how a biological system integrates visual-tactile sensory information as well as how a robotic device infers object information emanating from both vision and touch. In the present study, we develop a novel visual-tactile cross-modal integration stimulator that consists of an LED panel to present visual stimuli and a tactile stimulator with three degrees of freedom that can present tactile motion stimuli with arbitrary motion direction, speed, and indentation depth in the skin. The apparatus can present cross-modal stimuli in which the spatial locations of visual and tactile stimulations are perfectly aligned. We presented visual-tactile stimuli in which the visual and tactile directions were either congruent or incongruent, and human observers reported the perceived visual direction of motion. Results showed that perceived direction of visual motion can be biased by the
A Novel Tactile Function Assessment Using a Miniature Tactile Stimulator
Sensors
Several methods for the measurement of tactile acuity have been devised previously, but unexpected nonspatial cues and intensive manual skill requirements compromise measurement accuracy. Therefore, we must urgently develop an automated, accurate, and noninvasive method for assessing tactile acuity. The present study develops a novel method applying a robotic tactile stimulator to automatically measure tactile acuity that comprises eye-opened, eye-closed training, and testing sessions. Healthy participants judge the orientation of a rotating grating ball presented on their index fingerpads in a two-alternative forced-choice task. A variable rotation speed of 5, 10, 40, or 160 mm/s was used for the tactile measurement at a variety of difficulties. All participants met the passing criteria for the training experiment. Performance in orientation identification, quantified by the proportion of trials with correct answers, differed across scanning directions, with the highest rotation sp...
Remapping motion across modalities: tactile rotations influence visual motion judgments
Experimental Brain Research, 2010
have shown that shapes, such as letters of the alphabet, when drawn on the skin, are differently perceived dependent upon which body part is stimulated and on how the stimulated body part, such as the hand, is positioned. Another line of research within this area has investigated multisensory interactions. Tactile perceptions, for example, have the potential to disambiguate visually perceived information. While the former studies focused on explicit reports about tactile perception, the latter studies relied on fully aligned multisensory stimulus dimensions. In the present study, we investigated to what extent rotating tactile stimulations on the hand affect directional visual motion judgments implicitly and without any spatial stimulus alignment. We show that directional tactile cues and ambiguous visual motion cues are integrated, thus biasing the judgment of visually perceived motion. We further show that the direction of the tactile influence depends on the position and orientation of the stimulated part of the hand relative to a headcentered frame of reference. Finally, we also show that the time course of the cue integration is very versatile. Overall, the results imply immediate directional cue integration within a headcentered frame of reference.
Advances in Science, Technology and Engineering Systems Journal
Tactile displays are widely used in the rehabilitation and education of blind persons, as it is one of the media of communication amongst them. Tactile display performance is measured in terms of accuracy in presenting pattern, accuracy in identification, recognition and reading time of presented pattern. However, it has had meager attention from researchers. This paper presents a novel 3 x 2 solenoid actuators pin array tactile display and evaluates its effectiveness in presenting alphabets to blind and normal subjects as well as compute facilitation and discrimination value. The proposed actuator requires 75 % of the current and 90 % of the power in comparison with presently available actuators. This is achieved due to the incorporation of conical spring. Two psychological experiments were conducted to evaluate system performance, also to measure perception (reading) and key pressing sense (writing) accuracy for the first time. The low-cost developed system achieved an average reading time of about 15.7 s, recognition time of 39 s and prediction accuracy to be 93 % using a confusion matrix. The developed prototype model has resulted in 94% facilitation value and 11 % discrimination index during psychological experiments for intended users.
Design of a robotic device for assessment and rehabilitation of hand sensory function
IEEE ... International Conference on Rehabilitation Robotics : [proceedings], 2011
This paper presents the design and implementation of the Robotic Sensory Trainer, a robotic interface for assessment and therapy of hand sensory function. The device can provide three types of well controlled stimuli: (i) angular displacement at the metacarpophalangeal (MCP) joint using a remote-center-of-motion double-parallelogram structure, (ii) vibration stimuli at the fingertip, proximal phalange and palm, and (iii) pressure at the fingertip, while recording position, interaction force and feedback from the user over a touch screen. These stimuli offer a novel platform to investigate sensory perception in healthy subjects and patients with sensory impairments, with the potential to assess deficits and actively train detection of specific sensory cues in a standardized manner. A preliminary study with eight healthy subjects demonstrates the feasibility of using the Robotic Sensory Trainer to assess the sensory perception threshold in MCP angular position. An average just noticea...
Combined contribution of tactile and proprioceptive feedback to hand movement perception
Here we investigated how the tactile modality is used along with muscle proprioception in hand movement perception, whether these two sensory inputs are centrally integrated and whether they work complementarily or concurrently. The illusory right hand rotations induced in eleven volunteers by a textured disk scrolling under their hand in two directions at three velocities and/or by mechanical vibration applied to their wrist muscles at three frequencies were compared. The kinesthetic illusions were copied by the subjects on-line with their left hand. Results: 1) in all the subjects, tactile stimulation alone induced an illusory hand rotation in the opposite direction to that of the disk, and the velocity of the illusion increased non-linearly with the disk velocity: the highest gain (the illusion velocity to disk velocity ratio) occurred at the slowest disk rotation; 2) adding a consistent roprioceptive stimulus increased the perceptual effects, whereas adding a conflicting proprioceptive stimulus of increasing frequency gradually decreased the tactile illusions and reversed their initial direction; 3) under both consistent and conflicting conditions, only strong proprioceptive stimulation significantly affected the gain of the resulting illusions, whereas the largest gain always occurred at low tactile stimulation levels when the illusory movements were in the same direction as the tactile-induced illusion. Tactile information may equal or even override muscle proprioceptive information in the perception of relatively small, slow hand movements. These two somatosensory inputs may be integrated complementarily, depending on their respective relevance to the task of accurately perceiving one's own hand movements.
British Journal of Visual Impairment, 2005
A new psychological test battery was designed to provide a much-needed comprehensive tool for assessing the perceptual and cognitive abilities of visually handicapped children in using active touch. The test materials consist of raised-line, raised-dot, raised-surface shapes and displays, and familiar and novel 3-D objects. The research used 20 sub-tests, ranging from tactual discrimination, systematic scanning and shape coding to short-term and longer-term memory tasks. The research sample consisted of 119 participants. Fifty-nine were blind and visually impaired schoolchildren, aged from 3 to 16 years (the total visually handicapped population of the region), and 60 sighted school children, matched to them on age, gender and social class, living in the Madrid region (capital and province). The dual aim here is to report the reliability, validity and relation to age and visual status of the subtests, and to use the data to refine and shorten the test battery further for more general use.
Integration of visual and tactile modalities
Scandinavian audiology. Supplementum, 1997
Experiments have been carried out in which subjects were required to discriminate time-varying visual and tactile stimuli presented simultaneously via a 2D array of light-emitting diodes and a vibrator on the fingertip. Contrary to expectations, no problems in parallel visual and tactile perception were apparent. Similar results were obtained in a second experiment in which subjects were require to lipread from a video image and simultaneously identify speech-derived tactile stimuli. The generally poor performance of tactile aids to lipreading has been attributed to problems of parallel perception, but such problems are clearly not present in all circumstances.