Feasibility of Real-Time Autonomous Functional Electrical Stimulation for Freezing of Gait

Freezing of gait is a debilitating walking disturbance that can severely worsen quality of life for people with Parkinson's disease. However, current Parkinson's disease treatments do not effectively address freezing of gait, leading researchers to explore cueing to mitigate the symptom. Somatosensory stimulation is an emerging cueing strategy that could be discreet and practical to mitigate freezing of gait duration. Twenty-six participants (seven females) attempted walking trials in a freeze-inducing path while wearing a functional electrical stimulation cueing device. Functional electrical stimulation cueing was activated autonomously in real time. Constrained random sampling was used to designate each trial as cueing system on or off, providing a control for within-participant analysis. A total of 576 freezing episodes were recorded with the device on. Of those, 492 were successfully stimulated. To assess cueing performance, freezing of gait time per trial in the on and off device states was calculated for each participant. On average, freezing of gait time per trial decreased from 5.84 to 5.69 s (2.44%). Freezing of gait time per trial increased for half the participants and the other half experienced a decrease. There were no statistically significant group-level effects, though electrical stimulation cueing elicits a wide range of responses from different participants, with the technology mitigating freezing of gait for some individuals. Because functional electrical stimulation has numerous modifiable parameters that influence sensation and nervous system response, personalizing these parameters could enhance the effectiveness of freezing of gait mitigation and provide deeper insights into freezing of gait.