| Summary: | Purpose: Rapid reach-to-grasp balance-recovery reactions play a critical role in preventing falls. Recent young-adult studies suggest these reactions may be guided using stored visuo-spatial information from the central field, and that peripheral vision may also play an important role. This study used gaze recordings to examine the visual control of reach-to-grasp reactions in older adults.
Methods: A motion platform was configured to simulate a “real-life” environment that included a handrail. Subjects performed an activity that required walking to the end of the platform, which was triggered to move suddenly and unexpectedly as they approached the handrail. Twelve healthy older adults (64-79 years old) were tested and compared to 12 healthy young adults (22-30 years old) tested as part of another study.
Results: Older adults were more than twice as likely as young adults to react to the platform perturbation by grasping the handrail (10/12 versus 4/12), despite being much less likely to visually fixate the handrail after entering the new environment. Grasping errors were remarkably common (5/10 older, 2/4 young), but there was no consistent relationship to the preceding gaze behavior.
Conclusion: Older adults were highly dependent on using a handrail to recover balance, but commonly failed to direct overt visual attention to the rail after entering the unfamiliar environment. The failure to fixate the rail required the reaching movement to be guided using peripheral vision. Further research is needed to determine whether grasping errors can be prevented via interventions that either attract overt attention to the handrail or improve processing of peripheral-field information.
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