The Characteristics Of The Center Of Pressure During Gait Among Hemiplegic Stroke Survivors

ObjectivesTo explore the characteristics and asymmetry of the related parameters of center of pressure (COP), and their correlations with velocity and the asymmetry of single support time during gait among hemiplegic stroke survivors.MethodsThirty hemiplegic stroke survivors who could walk at least 10 meters were recruited as the experimental group and thirty healthy elderly persons as the control group. All participants were asked to walk across a walkway with embedded pressure sensitive mat. Outcome measures include the following parameters:single support time, double support time, anterior-posterior(AP) COP displacement during single-support phase(AP-COPDS), AP-COP velocity during single-support phase(AP-COPVS), AP-COPD during double-support phase(AP-COPDD), AP-COPV during double-support phase(AP-COPVD), symmetry ratios of COP related parameters. Student’s t test was used to compare the parameters above between two groups or limbs. Pearson correlation coefficients were performed to determine COP related parameters’ correlations with velocity and single-support-time symmetry ratio, and the correlations between symmetry ratios of COP related parameters and velocity.Results1. Compared with the control group, the experimental group had shorter single support time for the paretic limb, prolonged single support time for the non-paretic limb, prolonged double support time, smaller AP-COPDS and AP-COPDD, slower AP-COPVS and AP-COPVD for both the paretic and non-paretic limb. The difference was significant(P<0.05).2. Compared with the non-paretic limb, the paretic limb had shorter single support time, smaller AP-COPDS and larger AP-COPDD. The difference was significant(P <0.05).3. All the COP related parameters were positively correlated to velocity(r=0.765～ 0.967, P<0.05) and single-support-time symmetry ratio(r=0.505～0.764, P<0.05).4. Compared with the control group, the experimental group had smaller symmetry ratio of single support time, AP-COPDS and AP-COPVS, but larger symmetry ratio of AP-COPDD. The difference was significant(P<0.05).5. Velocity was positively correlated with the symmetry ratios of single support time, AP-COPDS and AP-COPVS(r=0.442-0.76, P<0.05), there was a trend that velocity was negatively correlated with AP-COPVD symmetry ratio(r=-0.363, P=0.053).Conclusion1. The displacement and velocity of COP in sagittal plane is decreased and the ability of loading transferring in anterior-posterior direction is impaired during gait among hemiplegic stroke survivors.2. The asymmetry of COP related parameters increases during gait among hemiplegic stroke survivors.3. COP related parameters and their symmetry ratios are correlated to velocity and single-support-time symmetry ratio during gait among hemiplegic stroke survivors.