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Frame-by-Frame Video Analysis of Idiosyncratic Reach-to-Grasp Movements in Humans
Published on: January 15, 2018
How do flanking objects affect reaching and grasping behavior in participants with macular disorders?
Shahina Pardhan1, Carmen Gonzalez-Alvarez, Ahalya Subramanian
1Vision and Eye Research Unit, Postgraduate Medical Institute, Anglia Ruskin University, Cambridge, United Kingdom. shahina.pardhan@anglia.ac.uk
Investigative Ophthalmology & Visual Science
|August 25, 2012
Summary
Visually impaired (VI) individuals with macular disorders exhibit compromised reaching and grasping. Object crowding significantly impacts movement duration and grip aperture in both VI and normal subjects, with closer flankers causing greater disruption.
Area of Science:
- Neuroscience
- Ophthalmology
- Biomechanics
Background:
- Macular disorders cause visual impairment, affecting daily activities.
- Understanding the impact of visual deficits on motor control is crucial.
Purpose of the Study:
- To examine how flanking objects influence reaching and grasping in visually impaired (VI) individuals with macular disorders.
- To compare the motor behavior of VI subjects with age-matched normal controls.
Main Methods:
- Subjects performed reaching and grasping tasks with a target, alone and with flankers at varying distances.
- A 3D motion analysis system (Vicon 460) captured kinematic data of hand and finger movements.
- Key metrics included movement duration, grip aperture, and velocity.
Main Results:
- Visually impaired subjects showed longer movement durations and completion times compared to controls.
- Object crowding significantly affected movement duration, time after maximum velocity, and grip aperture in VI subjects.
- Closer flankers (high crowding) had a greater negative impact on performance than those farther away.
Conclusions:
- Reaching and grasping are impaired in individuals with VI due to macular disorders.
- Object crowding negatively affects motor performance in both normal and visually impaired individuals.
- The degree of impairment due to crowding depends on the proximity of flanking objects.
