Standing after Spinal Cord Injury with Four-contact Nerve-Cuff Electrodes for Quadriceps Stimulation

IEEE Trans Neural Syst Rehabil Eng, 2008 · DOI: 10.1109/TNSRE.2008.2003390 · Published: October 1, 2008

Simple Explanation

This study explores the use of a 16-channel implanted neuroprosthesis with nerve-cuff electrodes to help individuals with spinal cord injury (SCI) stand and transfer. The new system, IST-16, utilizes four-contact nerve-cuff electrodes stimulating the femoral nerve to improve knee extension and standing ability compared to an older system (IRS-8) that used muscle-based electrodes. The results showed that the nerve-cuff electrodes were stable, and the subject was able to stand for longer periods and support more of their body weight on their legs compared to when using the older system.

Study Duration

72 Weeks

Participants

1 male volunteer (age 53, 7 years post-injury) with motor-complete SCI (T6 level, ASIA A)

Evidence Level

Case Study

Key Findings

1
Responses of the nerve-cuffs were stable and standing times increased by 600% over time-matched values with a similar 8-channel neuroprosthesis.
2
The IST-16 system outperformed the IRS-8 system at every time interval.
3
Stimulated responses with nerve-cuff electrodes can be selective and produce greater joint moments than muscle-based electrodes.

Research Summary

This report describes the performance of a 16-channel implanted neuroprosthesis for standing and transfers after spinal cord injury including four-contact nerve-cuff electrodes stimulating the femoral nerve for knee extension. Responses of the nerve-cuffs were stable and standing times increased by 600% over time-matched values with a similar 8-channel neuroprosthesis utilizing muscle-based electrodes on vastus lateralis for knee extension. Data for this subject suggest that nerve-cuff electrodes provide a stable means of generating strong knee extension moments to allow for considerably longer standing times than epimysial electrodes.

Practical Implications

Improved Standing Times

Nerve-cuff electrodes can significantly increase standing times for individuals with SCI compared to traditional muscle-based electrodes.

Enhanced Knee Extension

Nerve-cuff stimulation can produce greater knee extension moments, crucial for standing and transfers.

Selective Muscle Activation

Nerve-cuff electrodes offer the potential for selective activation of different muscle populations, reducing fatigue and improving performance.

Study Limitations

1
Single-subject case study limits generalizability.
2
Subject’s prior experience with the IRS-8 system may have influenced the outcome with the IST-16 system.
3
Subject’s body weight was not controlled during the study, potentially confounding the results.

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