Gait Asymmetry in Winters Group I Hemiplegic Children: Role of Tibialis Anterior

Hemiplegia is a neurological disorder that occurs quite often in children, affecting up to one child in one thousand. Typically, only one side of the body is affected by hemiplegia, while the other side is maintaining an apparently normal behavior. Purpose of present analysis was assessing gait asymmetry in group I (W1) hemiplegic children according to Winters classification, where W1 is characterized by presence of drop foot in swing in the hemiplegic side. Asymmetry was quantified by differences between hemiplegic and non-hemiplegic side in terms of foot-floor contact and electromyographic (EMG) activity. Surface EMG from tibialis anterior (TA) and foot-floor contact data were acquired in ten hemiplegic W1 children during walking to fulfill this aim. An exceptional number of strides was analyzed to consider the data variability, expected in W1 (mean ± SD = 287 ± 62 strides for each child, more than 3000 in total). Statistical gait analysis, a recent methodology performing a statistical characterization of gait, was applied to process EMG data. The research was undertaken in compliance with ethical principles of Helsinki Declaration and approved by institutional expert committee. Results showed that asymmetries were detected in basographic data: W1 children showed a significant decrease (p < 0.05) of strides with normal foot-floor contact (HFPS sequence: heel contact, flat-foot contact, push-off, swing) in hemiplegic side with respect to non-hemiplegic side. Also, TA recruitment presented asymmetries during walking, characterized by a curtailed, less frequent activity (p < 0.05) during terminal swing and a lack of activity at heel strike in hemiplegic side, with respect to non-hemiplegic side. In conclusion, present study suggested that walking in W1 children is characterized by asymmetries in both foot-floor contact patterns and TA recruitment.