What You Will Learn
- Why standard devices will not work for denervated muscle
- What the specialist devices can do
- What the different electrode types are for
- How to evaluate whether a device is appropriate
1. Why the Right Device Matters
If you work in rehabilitation long enough, you learn that people with disabilities often accumulate specialist equipment over time, and some of it ends up unused. Standing frames become clothes horses. Exercise machines gather dust in spare rooms. This happens when there is a mismatch between what the equipment does and what the person actually needs.
Assessment, as described in Chapter 7, determines what you need. This chapter helps match that need to the right device.
2. What Your Assessment Tells Us About the Device You Need
If your strength-duration test shows that your muscle responds only at very long pulse durations (above 10 milliseconds), you need a device capable of delivering pulses of 100 milliseconds or more. If the denervation is severe or long-standing, pulses of 150 to 200 milliseconds may be needed initially.
If some muscles are denervated while others retain their nerve supply (a mixed presentation, common in brachial plexus injuries), you may need a device capable of delivering both long-pulse denervation programmes and standard stimulation.
In short, the assessment determines the device specification, not the other way around.
3. The Specialist Devices
The vast majority of commercially available electrical stimulation devices are unsuitable for denervated muscle. TENS units, consumer muscle stimulators, "ab toner" devices, and standard FES cycling systems are all designed for muscles with an intact nerve supply.
The devices we use at Anatomical Concepts have established track records for denervated muscle:
The RISE Stimulator has a direct lineage from the European RISE study. It offers two independent channels (so both legs can be treated simultaneously), pulse lengths up to 200 milliseconds, current output up to 250 mA, and the ability to perform strength-duration testing. Pre-programmed settings map directly to the Vienna protocol phases, and a Home User mode restricts settings to prevent accidental changes during daily use.
The Stimulette Edition 5 is a versatile device from the same manufacturer, supporting both denervation programmes and standard stimulation. It is particularly useful for brachial plexus injuries and other situations where denervated muscles sit alongside innervated ones, because it can deliver both rectangular and triangular waveforms. It also features a Home User mode.
The KT-Motion supports denervated muscle protocols and offers EMG-triggered stimulation, which detects any residual voluntary muscle activity and supplements it with electrical stimulation. This is useful for incomplete injuries where some voluntary control exists.
Which device is right for you depends on your assessment findings. A person with bilateral lower limb denervation from a conus/cauda equina injury usually needs the RISE Stimulator. A person with a brachial plexus injury may be better served by Edition 5. A person with an incomplete injury and residual voluntary activity may benefit from the KT-Motion.
4. Electrodes: Getting Them Right
Electrodes receive less attention than the device itself, but getting them wrong can have serious safety consequences.
Standard gel electrodes are unsuitable for denervated muscle. Their typical size (25 to 45 cm²) is too small, and at the higher currents needed for denervated muscle, the current concentration at the skin could cause burns.
Appropriate electrodes include:
- Wet sponge with carbon rubber backing. These are the most commonly used. The sponge is wetted before each session and provides excellent current distribution over a large area (100 to 180 cm²). They are reusable, which matters when treatment is five to six days per week.
- Safety electrodes with conductive gel. These provide an alternative with consistent conductivity and are designed for the higher current levels used in denervation treatment.
Your clinician will show you exactly how to prepare and position your electrodes during training. Chapter 9 provides the step-by-step details.
5. Red Flags: What to Watch Out For
If you are considering purchasing equipment, or if someone is recommending a device to you, watch for these warning signs:
- Claims of miraculous outcomes or guaranteed results
- High-pressure sales without a proper assessment
- Devices marketed as suitable for "all types of muscle stimulation" without specific denervation specifications
- No medical device certification (CE marking in Europe, FDA clearance in the US)
- No pathway for clinical assessment before or after purchase
No device should be purchased without a professional assessment confirming your denervation status and identifying which muscles need treatment.
Chapter Summary
The vast majority of commercially available stimulation devices are unsuitable for denervated muscle because they cannot deliver the long pulse durations required. A small number of specialist devices exist, each serving different clinical scenarios. Device selection flows from assessment, not from marketing. Electrodes are as important as the device: standard gel pads are dangerous at denervation-level currents, and large wet sponge and rubber electrodes or safety electrodes are essential. No device should be purchased without a prior professional assessment.