The relation between ankle impairments and gait velocity and symmetry in people with stroke

Objective: To identify the most important factor among the ankle impairments on gait velocity and symmetry in stroke patients. Design: Cross-sectional, descriptive analysis of convenience sample. Setting: Patients from outpatient rehabilitation and neurovascular neurology departments in medical centers and municipal hospitals in Taiwan. Participants: Sixty-eight subjects with hemiparesis poststroke with the ability to walk independently. Interventions: Not applicable. Main Outcome Measures: Maximal isometric strength of plantarflexors and dorsiflexors were examined by a handheld dynamometer. Spasticity index, slope magnitudes between electromyographic activities, and muscle lengthening velocity of gastrocnemius during lengthening period of stance phases were measured to represent the dynamic spasticity. Passive stiffness of pantarflexors was indicated by degrees of dorsiflexion range that were less than normative values. Position error was measured by the degree of proprioceptive deficits of ankle joint by evaluating the joint position sense. Gait velocity, symmetry, and other gait parameters were measured by the GAITRite system. Results: Regression analyses revealed that the dorsiflexors strength was the most important factor for gait velocity and temporal symmetry (R²=.30 for gait velocity, P<.001; R²=.36 for temporal asymmetry, P<.001). Dynamic spasticity was the most important determinant for gait spatial symmetry (R²=.53, P<.001). Conclusions: Gait velocity and temporal asymmetry are mainly affected by the dorsiflexors strength, whereas dynamic spasticity of plantarflexors influenced the degree of spatial gait asymmetry in our patients who were able to walk outdoors. Treatment aiming to improve different aspects of gait performance should emphasize on different ankle impairments.