Article

Vision is of paramount importance in regulating adaptive gait. Using
three-dimensional motion analysis, the current study investigated how central
visual field loss (CFL) affects step ascent. Ten patients with chronic CFL (77
+/- 10 years) and 13 visual normal participants (72 +/- 6 years) walked up to and
ascended a single step (of varying height). Movement kinematics assessed the
period immediately prior to and during step ascent. Compared to visual normal
participants, patients with CFL exhibited a lower lead foot horizontal crossing
velocity, increased lead limb swing time and increased head flexion (looking down
at more immediate areas of the ground/step). They also took longer to initiate
the step up, transfer weight to the lead foot upon landing on the upper level and
increased trail limb swing time when negotiating the medium and high step height.
Increased variability was also shown in a number of dependent measures. Data
indicate that during step ascent, patients with CFL exhibit a cautious stepping
strategy when compared to visual normal participants. This cautious strategy
becomes increasingly evident when negotiating higher step heights, as shown by an
increased planning time prior to entering the relatively unstable period of
single support during the step up. The increased variability among CFL patients
increases their likelihood of experiencing dynamic instability and falling during
step ascent.
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Langue : ANGLAIS