Does functional electrical stimulation for foot drop strengthen corticospinal connections?

Area of Science:

• Neuroscience
• Rehabilitation Medicine
• Biomedical Engineering

Background:

• Functional electrical stimulation (FES) applied to the common peroneal nerve for foot drop can improve walking performance even when the device is not in use.
• This sustained

Purpose of the Study:

• To investigate the impact of long-term FES use on residual corticospinal connections in individuals with central nervous system disorders.
• To correlate changes in electrophysiological measures with improvements in walking performance.

Main Methods:

• Ten participants with nonprogressive neurological disorders and 26 with progressive disorders used an FES foot drop stimulator for 3-12 months.
• Electrophysiological assessments included motor-evoked potentials (MEP), maximum voluntary contraction (MVC), and maximum motor wave (Mmax).
• Walking performance was evaluated with and without the FES device.

Main Results:

• Significant increases in MEP and MVC were observed in both nonprogressive (50% and 48%) and progressive (27% and 17%) groups, with a positive correlation between MEP and MVC changes.
• Walking speed improved by 24% (nonprogressive) and 7% (progressive) when the stimulator was off, indicating a therapeutic effect.
• Changes in Mmax were minimal and not correlated with MEP changes.

Conclusions:

• Regular FES use for foot drop strengthens motor cortical activation and descending corticospinal pathways.
• These neuroplastic changes likely underpin the observed therapeutic benefits in walking speed.
• FES offers a promising approach for enhancing motor function in individuals with central nervous system disorders.