Clinical gait and balance scale (GABS): validation and utilization
Gait and Balance Scale (GABS) consists of historical information and examination of 14 different gait and balance parameters designed to assess the severity of these functional domains. Thirty-five patients with Parkinson's disease (PD), Hoehn and Yahr stages 1-3, were tested during their "off" period. GABS items were compared to quantitative data from two computerized gait analysis instruments, GAITRite and Pro Balance Master. Intra-class correlation coefficients were calculated to establish reliability. Intra-rater test-retest reliability was determined using Cohen's Kappa statistic. Concurrent validity was derived using the Spearman's rho test with the items from GABS, GAITRite and Balance Master. Intra-rater reliability was high with k>0.41 (k=kappa statistic) for 17 items, 6 had k>0.61. When performing validity measurements, a number of items on the GABS had a correlation coefficient significant at p<0.01 (2-tailed). Posture, pull test, balance during stance, single limb stance, tandem stance, turning, toe walking and functional reach had significant correlation with Balance Master data (R=0.46-1). Gait, arm swing, gait speed, steps/5 m, 'up-and-go test', modified performance oriented assessment of gait scale and provocative testing had significant correlation with the GAITRite items (R=0.51-0.83). GABS is an easy-to-use comprehensive clinical scale with high intra-rater and internal item reliability. We have shown concurrent validity with two computerized gait analysis instruments. We expect GABS to have a particular utility in clinical trials designed to modify functional impairment associated with abnormalities in gait and balance.