Gait Deviation Index Correlates With Daily Step Activity in Children With Cerebral Palsy

• A moderate association was found between the Gait Deviation Index (GDI) and average daily step count and percentage of time spent in high activity (defined as >42steps/min for 1 individual leg).
• Weaker associations were found between the GDI and 6-minute walk test and walking speed.
• No association was found between the GDI and the percentage of time spent in low activity (<15steps/min for individual leg).

ObjectivesTo examine the association between the Gait Deviation Index (GDI), a multivariate measure of overall gait impairment, and measures of both community walking performance and walking capacity within the clinic setting in ambulatory children with cerebral palsy.DesignCross-sectional study.SettingGait analysis, 6-minute walk test (6MWT), and self-selected walking speed (WS) were conducted in laboratory and clinic settings. Activity monitoring was done in participants' community environment.ParticipantsChildren with cerebral palsy (N=55; age range, 6–18y) with Gross Motor Function Classification System levels I to III.InterventionsNot applicable.Main Outcome MeasuresThe GDI was derived from gait analysis data as a measure of overall gait impairment; an activity monitor was used to capture community walking performance, and the 6MWT and WS were the clinic-based measures of walking capacity.ResultsFifty-five children had a median GDI of 78.86 (range, 53.07–105.34). A moderate association was found between the GDI and daily step count (Spearman ρ=.58; 95% confidence interval [CI], .37–.74; P<.0001). Weaker associations were found between the GDI and 6MWT (Spearman ρ=.4718; 95% CI, .2283–.6597; P<.0003) and between the GDI and WS (Spearman ρ=.3949; 95% CI, .1368–.6028; P<.0028).ConclusionsThe GDI has a moderate association with daily step count, which suggests that interventions that positively change gait kinematics may also affect community walking performance. Although the GDI's deviation from the normal value provides valuable information, other measures are required to provide a complete picture of a child's walking capacity and performance.