Standing postural stability assessment and signal stationarity in children with cerebral palsy

Standing postural stability signals of 60 children and adolescents were examined. The ages ranged from 5 to 14 years with both males and females participating in the study. Twenty subjects were previously diagnosed with cerebral palsy (CP); the remaining 40 were categorized as normal. Seven sway parameters were computed and analyzed for sensitivity. The frequency content of the sway signals was examined including statistical assessment of signal stationarity. The seven sway parameters adequately discriminated between the normal and CP populations under eyes-open and eyes-closed test conditions. In the frequency analyses the 20 s test epochs were generally the most stationary, although sufficient nonstationarity was demonstrated in all test epochs to warrant the application of nonstationarity analysis methods