Electrotherapy

Electrotherapy covers distinct modalities with distinct purposes and very different evidence. TENS delivers current through the skin to reduce pain. Neuromuscular electrical stimulation contracts a muscle directly, which is used where voluntary contraction is absent or very weak. Functional electrical stimulation times that contraction to a task, most commonly to lift the foot during walking.

Treating them as one thing is how the field acquired its mixed reputation. They should be judged separately.

Neuromuscular stimulation has the clearest role: maintaining muscle and re-establishing activation after surgery or neurological injury, particularly quadriceps activation after knee surgery, where voluntary contraction is inhibited and does not simply return with use.

Functional electrical stimulation for foot drop after stroke has good support and produces an immediate, visible improvement in walking. TENS provides short-term pain relief for some people: a review of 381 randomised trials found moderate-certainty evidence that pain is lower during or immediately after TENS than with placebo, without serious adverse events 1. It is cheap and self-administered, which makes it a reasonable thing to try.

Passive electrical treatment does not build strength the way exercise does, does not restore function on its own, and does not justify a long course of clinic appointments.

Where a patient can contract a muscle voluntarily, exercise beats stimulation. Stimulation is for where they cannot, or not yet.

Not used over the heart or over an implanted pacemaker or defibrillator, over the pregnant abdomen, over the carotid sinus, over active malignancy, over broken skin, or where sensation is impaired and the patient cannot report discomfort.

Skin irritation under electrodes is the common minor problem and is usually a placement or hygiene issue.

Electrical stimulation used to produce a functional movement — lifting a dropped foot during walking, activating a muscle that cannot yet contract voluntarily — is different from stimulation used passively for pain.

In neurological rehabilitation this is where the technique earns its place, and it is delivered as part of movement training rather than as a standalone modality.

Passive modalities are easy to deliver, easy to bill and produce short-term comfort. None of them build capacity, and a plan filled with them displaces the exercise that does.

We use them where they make the active work possible and we state that role rather than presenting them as treatment.

Not on current evidence. A review of 11 randomised trials with 1,135 participants after stroke found moderate-quality evidence that both an ankle-foot orthosis and functional electrical stimulation increase walking speed, with neither better than the other 2. A Cochrane review of peroneal nerve stimulators reached a similar conclusion and found low-certainty evidence that people using stimulation may be more likely to drop out during treatment 3.

So the choice is practical: whether the skin tolerates electrodes, whether the person can put the device on without help, and which of the two they are willing to wear every day. Walking training continues with whichever device is chosen, because neither replaces it.