Stride length regulation in Parkinson's disease: the use of extrinsic, visual cues

Abstract

It has been well documented that marked improvements in the hypokinetic gait pattern of Parkinson's disease patients are possible with the use of appropriate visual cues. This project served to evaluate Parkinson's disease gait performance as well as residual processing capacity while using fixed or gait-regulated visual cues. Three-dimensional kinematic, kinetic and electromyographic gait analysis was carried out on 14 patients and 14 matched controls in baseline conditions and with two types of visual cues: taped step length (SL) markers and an individualized subject-mounted light device (SMLD). A probe reaction time paradigm was invoked to assess residual processing capacity. Ratings of perceived task load were also made using the NASA-Task Load Index. Stride length and gait velocity were reduced in patients in baseline conditions. Both of these parameters increased to control levels with the use of visual cues. These alterations were generally accompanied by modifications of lower limb kinematics and kinetics towards control subjects. Perceived task load was higher in all conditions and was further elevated by the use of the SMLD for both groups. Patients produced larger overall reaction times, although reaction time was not different between baseline and SL marker conditions. Reaction time was increased in both groups when using the SMLD. The overarching finding is that stride length can be regulated in Parkinson's disease using stationary visual cues without increased central processing capacity or perceived effort. This may occur via utilization of visual feedback, reducing the patients' reliance on kinaesthetic feedback for the regulation of movement amplitude.

Quantitative Gait Analysis in Parkinson’s Disease: Comparison With a Healthy Control Group

“…This finding is in agreement with other studies that have reported reduced ankle joint angular excursions of subjects with PD. 9,10 Most important, plantarflexion (but not dorsiflexion) was decreased in the PD group and consisted of a reduction in ROM during push-off and a reduction in plantarflexion at toe-off.…”

“…Lewis 10 observed marked variability in subjects with PD. The fairly small sample size would have contributed to this variability.…”

“…2,10,[18][19][20] These studies also documented a tendency of longer duration in the double-support phase of the gait cycle and a normal cadence. In other studies, 21,22 a reduction of cadence values was reported.…”

“…Factors other than ankle power generation alone (push-off power) may therefore be responsible for the reduced step length. In the study of Lewis et al, 10 the question was raised whether patients with PD specify a normal stride length but fail to generate the required stride amplitude, or whether they specify a shortened stride length and regulate their movement around a smaller scale. It appears from the correlation analysis that no linear relation exists between stride length and peripherally reduced ankle power generation.…”

“…4 The reduction of stride length is considered the most prominent feature of PD gait and is often accompanied by lower walking speed and the tendency toward a longer duration in the double-support phase. 2,5,6 Other studies [7][8][9][10] have indicated that patients with PD are able to improve gait components, such as stride length and speed, if appropriate influences, like cues, are used.…”