Multi-dimensional study on neuromotor control characteristics and functional mobility capability in stroke patients

The purpose of this study was to explore whether we could provide supportive laboratory evidence for clinical observations that stroke patient has loss functional mobility/locomotion capability based on dynamic balance responses (COP sway patterns) and motor control activities (EMG patterns) during motor task of sit-to-stand. A computerized controlled dynamic postural control assessment system was developed and used in this study. Various dynamic balance indices were introduced and derived from COP sway patterns expressed in four domains (i.e. space, time, force, and frequency). Motor control was assessed by multi-channel surface electromyography of the both side of lower limb during same motor task. The functional mobility capability was evaluated using traditional FIM method. Fourteen stroke patients with right hemiplegia and nine healthy elderly were recorded both quadriceps hamstrings, anterior tibialis and triceps surae muscles and used for analysis. Center of Pressure (COP) sway patterns and ground reaction forces were registered. All signals were synchronized at seat-off. Surface electromyographic patterns of activities recorded during sit-to-stand and dynamic balance indices computed from COP sway patterns were categorized and compared with the functional mobility scores. The results show that both the motor control patterns and dynamic balance indices correlated well to the extend of mobility impairment evaluated using traditional FIM method. An important conclusion for rehabilitation medicine is that the functional mobility capability of stroke patients may be quantified analytical using dynamic balance indices and visible graphically through EMG motor patterns.