The validity of the GaitRite and the Functional Ambulation Performance scoring system in the analysis of Parkinson gait1

Abstract

The purpose of this study was (1) to determine the validity of the GaitRite System in detecting footfall patterns and selected gait characteristics of person with early stage Parkinson's disease (PD) and (2) to investigate whether the Functional Ambulation Performance (FAP) scoring system is a valid tool to distinguish between selected gait characteristics of patients with early stage Parkinson's disease and similar age of non-impaired individuals. The FAP score is a quantitative means of assessing gait based on specific spatial and temporal gait parameters. 11 volunteers with idiopathic Parkinson's disease, (mean age = 74.3), and 11 age matched volunteers, (mean age = 70.3), with no history of neurological disorder participated in the study. The non-impaired control group were not matched in age and sex but of similar age and males and females were represented in the control group. Temporal and spatial parameters of gait were analyzed for both preferred- speed and fast-speed walking using the computerized GaitRite system. The system integrates specific components of locomotion to provide a single, numerical representation of gait, the Functional Ambulation Performance Score (FAP) score. The most powerful and discriminating variable between Parkinson's and non-impaired groups for both walking speeds was the mean normalized velocity (MNV). Which is velocity divided by leg length. The MNV was 0.83 for PD at preferred walking speed and 1.14 at fast speed, the non-impaired group preferred-speed group walking was 1.33, while fast-speed walking MNV was 1.70. Note the fast walking of PD was slower than the preferred velocity of the non-impaired group. For preferred-speed walking, all gait variables analyzed in the study were different between the two groups beyond the p < 0.05 level of confidence with the single exception of right stance percentage. For fast-speed walking, three of the entered variables did not discriminate between the two groups: the fast walking FAP score, left fast-walking cadence, and right fast-walking single support percentage. Our results indicate that persons with Parkinson's disease (PD) attain a significantly lower FAP score when ambulating at their preferred rate and demonstrate shorter step length and a longer step time than the age matched non-impaired group during both preferred and fast velocities of walking. Stance duration and double support duration were increased for the Parkinson's population, whereas single support duration, mean cadence, and heel-to-heel base of support were markedly reduced for both walking speeds. The FAP score was significantly different from the non-impaired control group for preferred-speed walking. These results indicate that the GaitRite system can be useful in detecting footfall patterns and selected time and distance measurements of persons with early stage Parkinson's disease and the FAP score discriminates between the PD population and the non-impaired controls when walking at preferred rate but not at fast walking.