How does FES work?
Author: SCIRE Community Team | Reviewer: Shannon Sproule | Published: 10 October 2017 | Updated: ~
Our bodies naturally use electrical signals as part of the nervous system. When we move, the brain generates and sends electrical impulses along the spinal cord and nerves to tell the muscles to move.
Spinal cord injury can interrupt this pathway, preventing electrical impulses from passing through the spinal cord to reach the muscles. However, if the nerves and muscles below the injury are not damaged, they can still respond to electrical signals.
FES electrodes are placed over nerves or over electrically-sensitive parts of the muscles below the SCI. The specific type of electrical stimulation used with FES can trigger the nerve cells of movement (motor neurons) to send signals that cause muscle movement. An intact peripheral nerve and healthy muscle tissue are required to enable the external source of electricity to facilitate muscle contraction.
FES does not work for nerve injuries outside the spinal cord
FES can only be used for muscle weakness or paralysis caused by injuries to the spinal cord, but not injuries to the conus medullaris, cauda equina, or the nerves outside of the spinal cord. The nerve cells in these structures (called lower motor neurons) must to be intact for FES to work.
Like exercise, regular treatment with FES is usually needed to maintain the effects of the treatment. For people with complete injuries, when FES treatments are stopped, the treatment effects will usually go away over time. For people with incomplete injuries, the goal is for some carryover of strength and movement be retained after the treatment is stopped.