Selective neural stimulation methods improve cycling exercise performance after spinal cord injury: a case series

J NeuroEngineering Rehabil, 2021 · DOI: https://doi.org/10.1186/s12984-021-00912-5 · Published: July 15, 2021

Spinal Cord Injury Neurology Neurorehabilitation

Simple Explanation

Exercise after paralysis is beneficial, but difficult to achieve at sufficient intensity due to loss of motor control. Electrical stimulation can help, but current systems cause rapid muscle fatigue. This study explores selective stimulation patterns using nerve cuff electrodes to improve exercise output by increasing work performed and power maintained. The study found that selective stimulation patterns can increase work performed and power sustained by paralyzed muscles before fatigue sets in, with increased stimulation efficiency.

Study Duration

Not specified

Participants

Three people with spinal cord injury and implanted stimulation systems

Evidence Level

Level 4: Case Series

Key Findings

1
Selective stimulation patterns significantly increased total work and end power compared to conventional stimulation in all participants.
2
Selective stimulation patterns reduced charge accumulation and increased stimulation efficiency compared to conventional methods.
3
Low duty cycle stimulation patterns can cause inconsistent power outputs, but this can be managed with optimized stimulation levels.

Research Summary

This study investigates the effects of selective stimulation patterns on cycling performance in individuals with spinal cord injury. The goal was to increase work performed and power maintained during exercise. The study compared conventional stimulation with selective patterns that reduced overlap of activated fibers and/or duty cycle. Outcomes included total work, end power, power fluctuation index, charge accumulation, and efficiency. The results showed that selective stimulation patterns can significantly improve work performed and power sustained compared to conventional methods, with increased stimulation efficiency. However, low duty cycle patterns can cause inconsistent power outputs.

Practical Implications

Improved Exercise Intensity

Selective stimulation paradigms like S-Low and C-Max 2c enabled a more intense workout within the same amount of time, potentially improving regimen satisfaction and adherence.

Enhanced Muscle Loading

The power fluctuation index results suggest the importance of balanced muscle loading for user comfort. S-Low stimulation reduces PFI and improves ride smoothness.

Increased Efficiency and Safety

Selective stimulation patterns inject less charge, prolonging battery life of stimulation control units and decreasing the risk of overstimulating and damaging neural tissue.

Study Limitations

1
No physiological or metabolic measures were recorded.
2
All cycling trials were performed on an indoor trainer.
3
No official subjective measures of participant preferences or standardized measures of changes in perceived effort were recorded.

Your Feedback

Was this summary helpful?

Back to Spinal Cord Injury