Optimizing Neuromuscular Electrical Stimulation Pulse Width and Amplitude to Promote Central Activation in Individuals With Severe Spinal Cord Injury

Neuromuscular electrical stimulation (NMES) is a treatment for muscle changes after spinal cord injury (SCI). It can activate muscles through both direct and indirect mechanisms. This study looks at how to best use NMES to activate the central nervous system in people with SCI, by testing different pulse widths and amplitudes. The study found that a wider pulse width (1,000 μs) NMES was more effective at promoting central activation compared to a narrower pulse width (500 μs).

• 1
  The higher pulse width (1,000 μs) NMES demonstrated a greater effect on central activation, as quantified by more frequent occurrences of post-NMES EMG activity.
• 2
  Post-NMES EMG amplitude promoted by 1,000 μs pulse width was significantly larger than that elicited by 500 μs pulse width, indicating greater central activation when muscle torque output was matched.
• 3
  The interplay among central activation, stimulation amplitude, and muscle torque output differs across SCI individuals, possibly due to individual-specific characteristics of the cord lesion.