Applying Concurrent Auditory Feedback on Swing Phase Kinematics in Hemiparetic Gait Training

Objective: Our goal was to develop and test a novel method to provide concurrent auditory feedback on limb angular velocity during the swing phase of walking in the context of hemiparetic gait rehabilitation.
Design: The feedback stimulus was the sound of wading through water - a real-life situation where the swing phase generates sound. We achieved this using thigh and shank angular velocity signals to control pre-recorded flowing water sounds, and evaluated it in a feasibility test involving patients and physiotherapists. The feedback was applied as an add-on to conventional gait therapy in a case-by-case manner determined by the physiotherapists.
Setting: Patients performed overground walking training in a 20 m hospital corridor using their preferred assistive devices.
Participants: Nine hemiparetic stroke patients (5M, 4F, aged 55.44 ± 16.08 y/o) along with seven physiotherapists (13 ± 10.5 years of clinical experience).
Interventions: Three feedback variants were tested in a user-adjustable format:
Plain wading sound - A direct translation of their movements to a wading sound.
Negative reinforcement - A urinating sound if the forward limb rotation was not fast enough.
Positive reinforcement - A splash if a target forward rotation velocity was achieved.
https://drive.google.com/drive/folders/1LWHEXB1K9ZZsX9zDFKkhVOesTqoP1Gg2?usp=share_link
Main Outcome Measure(s): Kinematic characterizations with and without feedback.
Results: The patients exhibited substantial variability in their response to the feedback but three of them exhibited immediately observable improvements in kinematic quality (cadence, step periodicity, knee extension control) and most reported positive subjective experiences. Most therapists expressed that the core idea had potential for everyday adoption, while some found the positive and negative feedback variants too complex for the users.
Conclusions: We believe that the clinical potential of this form of swing phase feedback is worthy of further investigation.