# Acute suppression of lower limb spasm by sacral afferent stimulation for people with spinal cord injury: A pilot study

## TL;DR

This pilot study explores using sacral afferent stimulation to reduce lower limb spasm in people with spinal cord injuries, offering a safe and low-cost alternative to medication.

## Contribution

The study introduces sacral afferent stimulation as a novel method to acutely suppress spasm in spinal cord injury patients.

## Key findings

- Sacral afferent stimulation significantly reduced acute provoked spasms in participants with spinal cord injury.
- Both conditional and unconditional stimulation methods were effective in suppressing spasms.
- SAS showed a statistically significant reduction in electromyography activity during spasm episodes.

## Abstract

Lower limb spasm and spasticity may develop following spinal cord injury (SCI), causing hyper-excitability and increased tone, which can impact function and quality of life. Pharmaceutical interventions for spasticity may cause unwanted side effects such as drowsiness and weakness. Invasive and non-invasive electrical stimulation has been shown to reduce spasticity without these side effects. The aim of this study was to investigate the effect of sacral afferent stimulation (SAS), through surface electrical stimulation of the dorsal genital nerve (N = 7), and through implanted electrodes on the sacral afferent nerve roots, on lower limb spasm and spasticity (N = 2). Provoked spasms were interrupted with conditional SAS, where stimulation commenced following a provoked spasm, or unconditional stimulation, which was applied continuously. Conditionally and unconditionally applied SAS was shown to suppress acute provoked spasms in people with SCI. There was a statistically significant reduction in area under the curve of quadriceps electromyography during acute spasm with SAS compared to a control spasm. These results show that SAS may provide a safe, low-cost method of reducing acute spasm and spasticity in people living with SCI. SAS through implanted electrodes may also provide an additional function to sacral nerve stimulation devices.