Grasping Deficits and Adaptations in Adults with Stereo Vision Losses

Melmoth, Dean R.; Finlay, Alison L.; Morgan, M.; Grant, Simon

doi:10.1167/iovs.08-3229

Cited by 101 publications

(119 citation statements)

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“…In line with evidence that binocular disparity processing has special significance for controlling the grasp (e.g., Bradshaw et al 2004;Melmoth et al 2007Melmoth et al , 2009, these additional problems were manifest by selective increases in grip closure times and in late adjustments to the digit positions, compared to all other task conditions. We note that all of the above effects were also relatively subtle, even with a real wine glass as the flanker, and involved some movement parameters and/or a behind obstacle location not examined in otherwise similar previous Watt and Bradshaw 2002) or contemporaneous (Gnanaseelan et al 2014) work that found little or no difference in binocular compared to monocular avoidance of less salient non-target objects.…”

Section: Does the Additional 3d Information Provided By Binocular Vissupporting

confidence: 68%

“…Moreover, adults with binocular dysfunctions due to these conditions exhibit similar deficits when reaching to grasp isolated objects (e.g., Grant et al 2007;Melmoth et al 2009;Pardhan et al 2011) to those of normal subjects forced to perform equivalent actions using one eye alone. This raises final questions as to whether sub-optimal gaze strategies are adopted when binocular vision is reduced or absent and whether this contributes to poorer hand action control.…”

Section: [Figure 1 Near Here]mentioning

confidence: 99%

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Gaze–grasp coordination in obstacle avoidance: differences between binocular and monocular viewing

Grant

2015

Exp Brain Res

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This is the accepted version of the paper.This version of the publication may differ from the final published version. Permanent repository link AbstractMost adults can skillfully avoid potential obstacles when acting in everyday cluttered scenes. We examined how gaze and hand movements are normally coordinated for obstacle avoidance and whether these are altered when binocular depth information is unavailable. Visual fixations and hand movement kinematics were simultaneously recorded while 13 right-handed subjects reached-toprecision grasp a cylindrical household object presented alone or with a potential obstacle (wine glass) located to its left (thumb's grasp-side), right or just behind it (both closer to the finger's grasp-side) using binocular or monocular vision. Gaze and hand movement strategies differed significantly by view and obstacle location. With binocular vision, initial fixations were near the target's centre of mass (COM) around the time of hand movement onset, but usually shifted to end just above the thumb's grasp-site at initial object contact, this mainly be made by the thumb, consistent with selecting this digit for guiding the grasp. This strategy was associated with faster binocular hand movements and improved end-point grip precision across all trials than with monocular viewing, during which subjects usually continued to fixate the target closer to its COM despite a similar prevalence of thumb-first contacts. While subjects looked directly at the obstacle at each location on a minority of trials and their overall fixations on the target were somewhat biased towards the grasp-side nearest to it, these gaze behaviours were particularly marked on monocular vision-obstacle behind trials which also commonly ended in finger-first contact. Subjects avoided colliding with the wine glass under both views when on the right (finger-side) of the workspace by producing slower and straighter reaches, with this and the behind obstacle location also resulting in 'safer' (i.e., narrower) peak grip apertures and longer deceleration times than when the goal-object was alone or the obstacle was on its thumb-side. But monocular reach paths were more variable and deceleration times were selectively prolonged on finger-side and behind obstacle trials, with this latter condition further resulting in selectively increased grip closure times and corrections. Binocular vision thus provided added advantages for collision avoidance, known to require intact dorsal cortical stream processing mechanisms, particularly when the target of the grasp and potential obstacle to it were fairly closely separated in depth. Different accounts of the altered monocular gaze behaviour converged on the conclusion that additional perceptual and/or attentional resources are likely engaged compared to when continuous binocular depth information is available. Implications for people lacking binocular stereopsis are briefly considered.

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Section: Does the Additional 3d Information Provided By Binocular Vissupporting

confidence: 68%

Section: [Figure 1 Near Here]mentioning

confidence: 99%

Gaze–grasp coordination in obstacle avoidance: differences between binocular and monocular viewing

Grant

2015

Exp Brain Res

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“…Melmoth & Grant 2006;Melmoth et al 2007;Melmoth et al 2009 Firstly, in addition to the components identified by Proverbio et al (2011) we also investigated purely visual discrimination as associated with the posterior N1 ERP component (Hopf et al 2002;Mangun & Hillyard 1991;Thorpe et al 1996;Vogel & Luck 2000). We used this component to search for any differences in the visual brain response evoked by our stimuli, hoping to rule out such effects.…”

Section: Introductionmentioning

confidence: 99%

Objects rapidly prime the motor system when located near the dominant hand

Rowe

Haenschel

Kosilo

et al. 2017

Brain and Cognition

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This is the accepted version of the paper.This version of the publication may differ from the final published version. Permanent repository link AbstractObjects are said to automatically "afford" various actions depending upon the motor repertoire of the actor. Such affordances play a part in how we prepare to handle or manipulate tools and other objects. Evidence obtained through fMRI, EEG and TMS has proven that this is the case but, as yet, the temporal evolution of affordances has not been fully investigated. The aim here was to further explore the timing of evoked motor activity using visual stimuli tailored to drive the motor system. Therefore, we presented three kinds of stimuli in stereoscopic depth; whole hand grasp objects which afforded a power-grip, pinch-grip objects which afforded a thumb and forefinger precision-grip and an empty desk, affording no action. In order to vary functional motor priming while keeping visual stimulation identical, participants between the participants' posture and the object category they viewed. These results indicate strong affordance-related activity around 300ms after stimulus presentation, particularly when the dominant hand can easily reach an object.

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“…Traditionally, this has been interpreted as increased reliance on tactile feedback (Ernst and Banks, 2002; Melmoth et al, 2009). However, since the increase in grasping time correlates with the parameters used to quantify the amount of interaction with the support surface, we also attribute the increased grasping time to increased interaction with the environment.…”

Section: Discussionmentioning

confidence: 99%

“…Severely impairing normal vision of humans with lenses can lead to an almost threefold increase in failed grasps (Melmoth et al, 2009). It has also been shown that tactile impairments (fingertip anesthesia) can lead to ' 30% failed grasps even in the presence of a support surface (Gentilucci et al, 1997).…”

Section: Interactions Between Hand Object and Environmentmentioning

confidence: 99%

Exploitation of Environmental Constraints in Human and Robotic Grasping

Deimel¹,

Eppner²,

Álvarez-Ruiz³

et al. 2016

Springer Tracts in Advanced Robotics

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We investigate the premise that robust grasping performance is enabled by exploiting constraints present in the environment. These constraints, leveraged through motion in contact, counteract uncertainty in state variables relevant to grasp success. Given this premise, grasping becomes a process of successive exploitation of environmental constraints, until a successful grasp has been established. We present support for this view found through the analysis of human grasp behavior and by showing robust robotic grasping based on constraint-exploiting grasp strategies. Furthermore, we show that it is possible to design robotic hands with inherent capabilities for the exploitation of environmental constraints.

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Grasping Deficits and Adaptations in Adults with Stereo Vision Losses

Abstract: High-grade binocular stereo vision is essential for skilled precision grasping. Reduced disparity sensitivity results in inaccurate grasp-point selection and greater reliance on nonvisual (somesthetic) information from object contact to control grip stability.

Cited by 101 publications

References 48 publications

Gaze–grasp coordination in obstacle avoidance: differences between binocular and monocular viewing

Gaze–grasp coordination in obstacle avoidance: differences between binocular and monocular viewing

Objects rapidly prime the motor system when located near the dominant hand

Exploitation of Environmental Constraints in Human and Robotic Grasping

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