Development and testing of the Gait Assessment and Intervention Tool (G.A.I.T.): A measure of coordinated gait components

Abstract

Recent neuroscience methods have provided the basis upon which to develop effective gait training methods for recovery of the coordinated components of gait after neural injury. We determined that there was not an existing observational measure that was, at once, adequately comprehensive, scored in an objectively-based manner, and capable of assessing incremental improvements in the coordinated components of gait. Therefore, the purpose of this work was to use content valid procedures in order to develop a relatively inexpensive, more comprehensive measure, scored with an objectively-based system, capable of incrementally scoring improvements in given items, and that was both reliable and capable of discriminating treatment response for those who had a stroke.

Eight neurorehabilitation specialists developed criteria for the gait measure, item content, and scoring method. In subjects following stroke (>12 months), the new measure was tested for intra- and inter-rater reliability using the Intraclass Correlation Coefficient; capability to detect treatment response using Wilcoxon Signed Ranks Test; and discrimination between treatment groups, using the Plum Ordinal Regression.

The Gait Assessment and Intervention Tool (G.A.I.T.) is a 31-item measure of the coordinated movement components of gait and associated gait deficits. It exhibited the following advantages: comprehensive, objective-based scoring method, incremental measurement of improvement within given items. The G.A.I.T. had good intra- and inter-rater reliability (ICC = .98, p = .0001, 95% CI = .95, .99; ICC = .83, p = .007, 95% CI = .32, .96, respectively. The inexperienced clinician who had training, had an inter-rater reliability with an experienced rater of ICC = .99 (p = .0001, CI = .97, .999). The G.A.I.T. detected improvement in response to gait training for two types of interventions: comprehensive gait training (z = −2.93, p = .003); and comprehensive gait training plus functional electrical stimulation (FES; z = −3.3, p = .001). The G.A.I.T. was capable of discriminating between two gait training interventions, showing an additive advantage of FES to otherwise comparable comprehensive gait training (parameter estimate = 1.72, p = .021; CI, .25, 3.1).

Introduction

In recent years, neuroscience studies have provided the basis upon which to construct gait recovery interventions for those who have persistent gait dyscoordination after stroke (Daly and Ruff, 2007a). The research evidence of activity-dependent central nervous system (CNS) plasticity (Nudo, 2006, Ziemann et al., 2004, Chu and Jones, 2000, Jones et al., 1999, Biernaskie and Corbett, 2001, Liepert et al., 2001) and the associated principles of motor learning (Plautz et al., 2000, Butefisch et al., 1995, Dean and Shepherd, 1997, Elbert et al., 1995, Pascual-Leone and Torres, 1993, Singer et al., 1993) provide an evidence basis upon which to develop potentially efficacious gait training protocols. Recent work, with patients after stroke, has shown that a gait training protocol, which utilized this CNS plasticity evidence basis and motor learning principles, was able to produce significant gains in gait coordination (Daly and Ruff, 2007a, Daly et al., 2007b). With the recent success of the recovery of the coordinated components of gait, it is important to develop credible and useful measures with which to evaluate the response to new, more successful gait training protocols.

One important type of gait assessment is the observational gait assessment, which does not require an expensive motion capture system or special walkway with sensors. There are some existing observational measures of coordinated gait components. Although each existing observational measure has its advantages, each observational measure has its shortcomings for assessing response to intervention according to the coordinated gait components that compose normal walking. Shortcomings of existing observational measures include heterogeneity (e.g., a mix of items measuring temporal/distance gait characteristics, compensatory strategies, and coordinated gait components (Tinetti Gait Scale (TGS (Tinetti, 1986)), Wisconsin Gait Scale (WGS (Rodriquez et al., 1996, Turani et al., 2004)); lack of comprehensiveness (TGS, WGS, Modified Gait Assessment Rating Scale (mGARS (VanSwearingen et al., 1996)), Rivermeade Visual Gait Index (RVGA (Lord et al., 1998)); subjective scoring method (RVGA); and inability to document incremental gains in response to gait training (Rancho Observational Gait Analysis (OGA; Rancho Los Amigos, 2001)).

In assessing response to intervention, it is critical to utilize an objectively-based, accurate, comprehensive measure that is capable of discriminating restoration of volitional control of the coordinated movement components of gait. Without this capability, we forfeit the ability to both credit efficacious rehabilitation methods and justify the financial support of providing effective gait training interventions.

Therefore, it was our purpose to conduct a content validity study in order to develop, test, and provide for use, a new observational measure of coordinated gait components that would be comprehensive, scored in an objectively-based manner, reliable, provide for scoring of incremental gains within given items, and also sensitively quantify response to gait training interventions for those who have had a stroke.