The purpose of this research was to examine differences in gait symmetry between a group of children with autism and an age, height, and weight-matched control group. Using temporal-spatial data, six different symmetry indices were computed and analyzed using MANOVAs. The results of the statistical analysis showed no significant group differences (P > 0.05) for the six symmetry indices for cadence, stride length, swing time, stance time, double stance time, and swing/stance ratio. Further, no significant differences (P > 0.05) were observed between groups for the mean value of each temporal-spatial measure.
To date, most studies of gait symmetry in autism have focused on infants and toddlers. Several of these studies have reported gait asymmetries [2
]. However, little is known about the persistence of these deviations with development. Based on the results of this study, children with autism walk with a consistent interlimb pattern compared to age-matched controls. Due to a small sample size, further work is needed to validate these results.
Previous studies of gait symmetry in children with autism have typically used walking observation scales and video analysis. To our knowledge, no motion capture analyses of gait symmetry exist for this specific population. However, gait symmetry in adults with autism has been examined using similar techniques. Hallett et al. [10
] measured gait in 5 adults (aged 25–38 years) with autism versus a control group [10
]. No significant differences were found between limbs in the autism group for the kinematic and kinetic gait variables. As a result, the data for each limb was pooled prior to comparison with the control group. Only the ankle range of motion was found to be significantly different between the adults with autism and the control group, with the autism group showing a smaller range of motion.
The results of this study are specific to the age group, task, and gait parameters selected. In addition, the gait parameters used to compute the indices also play an important role in describing gait symmetry. The present study focused on temporal-spatial data; however, other kinematic (e.g., joint angles) and kinetic (e.g., joint moments) gait parameters may provide insight into gait symmetry in children with autism. Previous research [7
] suggests that ankle dorsiflexion angles and sagittal hip and ankle moments differ in children with autism versus age-matched controls. Therefore, gait symmetry should also be examined using these parameters.
As symmetry assessments are sometimes dependent on the specific symmetry index used, the present study computed several indices using temporal-spatial data. Similarly, Patterson et al. [21
] used four indices to examine gait asymmetry after stroke. Their results also showed that the indices were similar in discriminative ability, but differed in terms of interpretability. Therefore, symmetry indices, such as ratios, may be preferable for their ease of interpretation.
Symmetry measures can be a useful measure of interlimb coordination and help identify gait compensations. A limitation of indices is that the results do not provide an indication of abnormality. That is, the left and right limb could be equivalently abnormal and therefore symmetrical. However, results of tests for mean differences in temporal-spatial data between groups were not significant. Therefore, it would appear that children with autism have normative temporal-spatial data for the left and right legs.