Automatic application of neural stimulation during wheelchair propulsion after SCI enhances recovery of upright sitting from destabilizing events

Journal of NeuroEngineering and Rehabilitation, 2018 · DOI: https://doi.org/10.1186/s12984-018-0362-2 · Published: March 2, 2018

Spinal Cord Injury Assistive Technology Neurology

Simple Explanation

The study tested a system that automatically uses electrical stimulation to help manual wheelchair users with spinal cord injuries (SCI) stay stable while sitting. The system uses sensors to detect sudden stops and turns and then stimulates muscles to keep the user upright. The results showed the system could accurately detect these events and, in some cases, improve trunk stability.

Study Duration

Not specified

Participants

Three participants completed simulated collision events and four participants completed simulated rapid turns. Data were analyzed as a series of individual case studies with subjects acting as their own controls with and without the system active.

Evidence Level

Not specified

Key Findings

1
The controller achieved 93% accuracy in detecting collisions and right turns, and 100% accuracy in left turn detection.
2
Two of the three subjects who participated in collision testing with stimulation experienced significantly decreased maximum anterior-posterior trunk angles (p < 0.05).
3
The average detection delay across all four subjects during right and left turns was 342 ± 73 ms.

Research Summary

This study demonstrates the feasibility of a neural stimulation control system based on simple inertial measurements to improve trunk stability and overall safety of people with spinal cord injuries during manual wheelchair propulsion. The system accurately detected potentially destabilizing events and triggered activation of the paraspinal and hip muscles to improve stability and compensate for the disturbances. Two of the three subjects who received stimulation to the hip and trunk extensor muscles during the collision events experienced increased trunk stability manifested by decreased forward lean and more rapid restoration of erect posture from a flexed position.

Practical Implications

Improved Safety

The system has the potential to reduce the risk of falls and injuries for manual wheelchair users with SCI by improving trunk stability during destabilizing events.

Increased Independence

By providing automatic trunk stabilization, the system may reduce the need for restrictive straps or supports, allowing users greater freedom of movement and increased independence.

Wider Applicability

The system was tested with both implanted and surface stimulation, suggesting its potential applicability for a wider population beyond implant recipients.

Study Limitations

1
Further studies are required to determine clinical utility in real world situations and generalizability to the broader SCI or other population of manual or powered wheelchair users.
2
The accelerometers utilized in this experiment were limited to a range of ±4 g.
3
Larger delays in detection for turns based on angular velocity negatively affected the ability of the controller to return the trunk to erect from a lateral bend

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