Blurred vision impairs spatial cognition in fall-prone older adults

Aug 31 2011

Among older adults, falls are a common problem. About one-third of those over age 65 fall once each year. Visual information helps us to coordinate our movements so that we can successfully navigate our surroundings. In fall-prone older adults, however, the ability to collect visual information is compromised, and this group is not adequately compensating for this effect.

The current issue of the journal Insight: Research and Practice in Visual Impairment and Blindness reports on an experiment comparing three groups: older adults who had fallen at least once in the past 12 months, older adults who had not fallen, and younger adults.

The participants completed a walking course that consisted of an invisible equilateral triangle. One side of the triangle was a mat with sensors that recorded the gait of the participants. Researchers also tested the subjects' ability to navigate this unmarked course. After following the course under normal conditions, the participants then attempted to walk the course again wearing safety goggles wrapped with masking tape. The tape blurred the participants' vision but still allowed light in.

Blurred vision took its toll on the performance of all three groups, but especially the fall-prone older adults. When the vision of the other two groups was reduced, they reduced their walking speed. They were compensating for their impairment by proceeding more slowly. The fall-prone group, however, did not walk more slowly. They also made more errors in returning to the starting point of the course.

Performance in older adults has generally been found to be less than that of younger adults in tasks involving the use of spatial memory to guide movement. In this study, the fall-prone older adults displayed an overreliance on visual information for spatial cognition, but at the same time they did not adjust their behavior to compensate for their lack of visual information. The results of this research suggest that spatial cognition may be more greatly compromised among fall-prone older adults.