Saccade to stepping delays in elders at high risk for falling.
OBJECTIVE
Visually guided stepping is an essential function in many normal activities of daily living requiring the coordination of eye movements with precise foot placement. The objective of this investigation was to compare the saccade-footlift latency in community dwelling elderly identified as high-risk for falling with elderly who are at a low-risk of falling during a walking task that requires precise foot placement.


METHODS
A non-randomized between-group repeated measures design was employed using independently living elderly volunteers from the Minneapolis, MN community. Thirty older adults volunteered to participate in the study; fifteen who had a history of a fall in the previous 12 months or a prolonged score on a fall risk screening instrument (Timed Up and Go test), and fifteen elders who had not fallen and had a negative score on the screening instrument. Subjects were required to walk along a pathway of 4 irregularly spaced stepping targets. The time between horizontal saccadic eye movement to the initiation of footlift (saccade-footlift latency) was the primary dependent measure.


RESULTS
The mean saccade- footlift latency between high-risk (H-R) elderly and low-risk (L-R) elderly was statistically different (mean H-R 940 ms, L-R 825 ms; F1,3=7.45, p=0.006). The H-R elderly also performed more slowly on the cognitive test - Trail Making Test Part B (mean H-R 195 s, L-R 129 s; F1,2=7.21, p=0.01). The results suggest that there is an association between horizontal saccades, stepping and cognition for elderly at risk for falling.


CONCLUSIONS
The timing of saccades and precise foot placement in older persons living in the community are associated with fall risk status and cognitive status. The prolonged time for saccade-footlift in H-R elderly may be attributed to greater central nervous system processing time necessary to plan precise foot placements or volitional processing delays in postural control due to fall risk status. In addition, age related changes in cognitive functions appear to be associated with saccade stepping interaction when performing a visually guided stepping pattern and may influence the ability to coordinate precise lower extremity movements.
Greany
John F
JF
Department of Health Professions, Physical Therapy Program, University of Wisconsin - La Crosse, La Crosse, WI 54601, USA. greany.john@uwlax.edu
Di Fabio
Richard P
RP
D000058:Accidental Falls; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D005403:Fixation, Ocular; D006801:Humans; D008297:Male; D012307:Risk Factors; D012438:Saccades; D016138:Walking