What You Will Learn
- The key findings from the RISE programme and other research
- How muscle mass, tissue quality, and function improved with treatment
- Why starting early produces the best results, though it is rarely too late
- What the evidence does not yet tell us
1. Does It Work?
For anyone considering electrical stimulation for denervated muscle, the fundamental question is straightforward: Does it work? The answer, based on the evidence, is yes, with important nuances.
The most comprehensive evidence comes from the EU RISE programme, led by Helmut Kern and colleagues. This programme enrolled patients with complete lower motor neuron lesions (permanent denervation with no prospect of nerve regrowth) and demonstrated measurable improvements across multiple outcomes. What made the evidence particularly compelling was that it went beyond simply measuring whether muscles got bigger. The researchers took muscle biopsies and used advanced imaging to see exactly what was happening inside the tissue.
2. What the RISE Programme Found
Electrical stimulation rescued muscle bulk and tissue quality.
Muscle mass
The headline finding was a 35 per cent increase in quadriceps (thigh muscle) cross-sectional area after two years of home-based electrical stimulation, measured by CT scanning. In muscles permanently disconnected from their nerve supply, this represented a substantial reversal of the wasting process.
Tissue structure
The biopsy evidence was, in many ways, even more compelling than the imaging. After treatment, muscle biopsies showed that the density of contractile protein (the machinery that produces force) increased from approximately 45 per cent to 82 per cent of normal values. The internal structures required for contraction, including the coupling system between the electrical signal and calcium release, as described in Chapter 1, were rebuilt. This was not cosmetic swelling; it was genuine structural restoration.
An unexpected bonus was that muscles not directly targeted also improved. Stimulation aimed at the quadriceps produced a 15 per cent increase in hamstring size, likely because the electrical field spreads to neighbouring muscles. The skin overlying stimulated muscles showed a 27 per cent increase in thickness and restoration of its blood supply, a benefit that is particularly important for people at risk of pressure injuries.
Force and function
Muscle force output improved dramatically, with some patients achieving enough strength to support FES-assisted standing. Twenty-five per cent of patients in the study achieved this milestone after two years of training, a genuine functional achievement for people with complete lower motor neuron lesions.
Independent confirmation
Encouragingly, these findings are not limited to a single research group. The Swiss Paraplegic Centre and the Richmond VA Medical Centre in the United States have both reported positive results using similar approaches, with no connection to the Vienna group. This independent replication strengthens confidence in the findings.
3. When to Start: The Evidence on Timing
One of the most important findings from the research concerns timing. As we revealed in Part 1, Earlier intervention consistently produces better outcomes, but it is rarely too late to start.
Patients who began treatment within the first year after injury achieved the best results: approximately 24 per cent gain in muscle size per year, compared with 7 per cent per year in those who started later. The biological reasons are clear: in the early months, the muscle retains much of its internal architecture, stem cell reserves are still strong, and the tissue is most responsive to stimulation.
In the chronic phase, for patients starting two or more years after injury, outcomes were reduced but still meaningful. Even after prolonged denervation, skin quality improves, blood supply is restored, and measurable gains in muscle mass are observed. In our experience, we have seen meaningful progress in people who started years after their injury. It simply takes longer and requires more patience.
The key message: start as early as possible, but do not assume the door is closed if you are learning about this for the first time, years after your injury.
4. Evidence Beyond Spinal Cord Injury
While the RISE programme focused on spinal cord injury, the principles apply wherever denervation occurs.
For brachial plexus injuries, the evidence includes high-quality clinical trials demonstrating that electrical stimulation can both preserve muscle and support nerve regrowth. Independent studies have confirmed improvements in muscle properties using modest currents over 12 weeks.
For facial palsy, recent evidence shows that electrical stimulation reduces the rate of incomplete recovery by 35 per cent compared to standard treatment alone. This is covered in detail in Chapter 12.
5. How Progress Is Measured
If you undergo this treatment, your clinician will use several methods to track your progress.
A strength-duration test is the most specific measure. Your clinician places an electrode on the muscle and delivers pulses of varying durations. This test shows exactly how your muscle responds and whether its electrical properties are improving over time. As treatment progresses, the muscle should respond to progressively shorter pulses, a direct sign that the tissue is recovering.
Limb girth measurements using a tape measure are the simplest way to track changes in muscle size. Measuring the circumference of your thigh or arm at consistent points over time shows whether the muscle is growing. In our experience, people who see their measurements increasing are significantly more committed to continuing their programme.
Tissue quality is assessed by feel. A denervated muscle that is responding to treatment develops a firmer, more defined quality compared to the soft, flaccid feel of untreated tissue.
Photographs taken at regular intervals provide a visual record that complements the measurements. People often do not notice gradual changes in their own bodies; comparison photographs taken months apart can reveal significant and motivating changes.
6. What the Evidence Does Not Yet Tell Us
The evidence has genuine limitations that deserve acknowledgement.
Most of the evidence comes from a single research network (the Vienna group), though independent replication is now emerging. There is no large randomised controlled trial in the specific population (chronic, permanent denervation) where the evidence is strongest. Long-term follow-up data beyond the RISE study period are limited. We do not yet know definitively whether people maintain their gains if they reduce their treatment intensity, or exactly how long treatment needs to continue.
These are real limitations, but they are the kind that characterise many areas of rehabilitation medicine, where populations of affected individuals are relatively small, treatments are complex, and timelines are long. They are reasons for continued research, not for withholding a treatment that has demonstrated clear benefit.
Chapter Summary
The RISE programme demonstrated clinically meaningful improvements in muscle mass (35 per cent increase), tissue structure (contractile protein density nearly doubling), force production, and functional capacity in people with permanent denervation. These findings are confirmed by biopsy and imaging data and are being independently replicated. Earlier intervention produces the best results, but later intervention still produces measurable benefits. The evidence extends beyond spinal cord injury to brachial plexus injuries and facial palsy. The evidence has genuine limitations, including the absence of large randomised trials and limited long-term follow-up, but these are reasons for further research, not for withholding treatment.