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- Creators: Artemiadis, Panagiotis
A knee exoskeleton and ankle assistive device (Robotic Shoe) are developed and used to provide walking assistance. The knee exoskeleton provides personalized knee joint assistive torque during the stance phase. The robotic shoe is a light-weighted mechanism that can store the potential energy at heel strike and release it by using an active locking mechanism at the terminal stance phase to provide push-up ankle torque and assist the toe-off. Lower-limb Kinematic time series data are collected for subjects wearing these devices in the passive and active mode. The changes of kinematics with and without these devices on lower-limb motion are first studied. Orbital stability, as one of the commonly used measure to quantify gait stability through calculating Floquet Multipliers (FM), is employed to asses the effects of these wearable devices on gait stability. It is shown that wearing the passive knee exoskeleton causes less orbitally stable gait for users, while the knee joint active assistance improves the orbital stability compared to passive mode. The robotic shoe only affects the targeted joint (right ankle) kinematics, and wearing the passive mechanism significantly increases the ankle joint FM values, which indicates less walking orbital stability. More analysis is done on a mechanically perturbed walking public data set, to show that orbital stability can quantify the effects of external mechanical perturbation on gait dynamic stability. This method can further be used as a control design tool to ensure gait stability for users of lower-limb assistive devices.
Down syndrome (DS) is caused by either an extra copy of chromosome 21 or by extra material on chromosome 21. This causes various levels of intellectual disability and issues with gross motor skill development which can prevent these individuals from participating in activities of daily living (ADL) such as getting dressed, self-care, or grocery shopping. People with DS have a decreased ability to balance, an abnormal and slower gait pattern, difficulty adapting to new environments, and a lack of improvement in these areas with growth and development when compared to their neurotypical peers. The objective of this study was to determine the immediate effects of resistance training (RT) and assisted cycle therapy (ACT) on adults with DS’s balance ability and gait speed. Each participant completed one session of RT, ACT (stationary cycling with the assistance of a motor to maintain a cadence of at least 35% greater than their voluntary cycling speed), and no training in a randomly selected order. Balance and gait speed were measured by a Clinical Test of Sensory Interaction on Balance (CTSIB) (i.e., eyes open firm surface, eyes closed firm surface, eyes open foam surface, eyes closed foam surface) on a Balance Tracking System Board (Btracks board) and by a Timed Up and Go (TUG) test. A total of ten participants’ data was used for analysis. The measures of total path length (cm), anterior-posterior (AP) excursion, and medial-lateral (ML) excursion were used to analyze the CTSIB. The average time was used to analyze the TUG test. The results showed that the eyes closed foam surface balance task was the most challenging balance task for every participant in every intervention. Furthermore, the most improvement was evident in the eyes closed foam surface balance task from pre to post intervention in all of the interventions. Post hoc tests also indicated statistically significant improvements of path length from pre to post in the RT intervention with the eyes closed foam surface balance task as well as with AP excursion in the ACT intervention with the eyes closed foam surface balance task. Possible explanations for improvements from pre to post in the eyes closed foam balance task across all interventions will be discussed with respect to the length of the intervention, and the effect of strength, social and learned factors on balance in adults with DS.