Gait Stability and Central Processing Capacity with Extrinsic Visual Cueing During Walking in Parkinsonís Disease


G. N. Lewis, W. D. Byblow, & S. Walt

Department of Sport & Exercise Science, University of Auckland,
Auckland, New Zealand

 

Kinesia paradoxa is a term that describes marked improvements in the hypokinetic gait pattern of individuals with Parkinsonís disease (Pd) that are possible with the use of appropriate visual cues. This project served to evaluate Pd gait performance as well as residual processing capacity while using fixed or gait-regulated visual cues. 3D kinematic, kinetic and electromyographic analyses were carried out on 16 patients and age-matched controls while walking normally and while walking with two types of visual cues: taped step length markers, and an individualised subject-mounted light device (SMLD). A probe reaction time paradigm was invoked to assess residual processing capacity in the different walking conditions. Ratings of perceived workload were also made using the NASA-Task Load scale. Stride length and gait velocity were both reduced in the Pd group in baseline conditions. In accordance with recent literature, stride length increased towards control levels with the use of visual cues. The increase in stride length was accompanied by an increased range of motion in the ankle, knee and hip joints as well as an increase in peak ankle joint moment. Cadence for the Pd group was relatively elevated in baseline conditions but was reduced with the introduction of visual cues. Perceived task load was higher in the patients in all conditions, and further elevated by the use of the SMLD for both Pd and control groups. Individuals with Pd responded with longer simple and probe reaction times. The overarching finding is that stride length can be regulated using stationary or gait-regulated extrinsic cues without elevated costs in terms of central processing capacity. However, with Pd cost is associated through perceived effort, a finding which has been observed in gait and non-gait related tasks.