When the hand cannot move after stroke, many caregivers wonder whether buying an electrotherapy machine to stimulate it would speed up recovery. Electrical stimulation does have a place in stroke rehabilitation, but expectations in the community tend to go to two extremes. Some treat it as a miracle that restores function from electricity alone, and others dismiss it entirely as an ordinary massager. The reality lies between the two: the evidence supports electrical stimulation as a support in stroke rehabilitation, but it is only a tool and is not meant to do the work for the patient.
This article takes up the following key questions one by one: the difference between NMES and FES, what evidence supports each for the arm and for foot drop, when to use them for them to work, and how the consumer electrotherapy devices people buy themselves differ in essence from the clinical equipment used in hospital. Questions of purchase, such as which device to buy and what to look for, are covered on the page on home rehabilitation equipment. This article concentrates on whether electrical stimulation works and how to apply it so that it does.
Basic concepts of NMES and FES and how they differ
These two names are often mixed up in the community, but their actual uses are different. They share the same technology, using a low-frequency current to stimulate motor nerves and make muscle contract, and the real differences are the purpose of the stimulation and the timing of the intervention. An authoritative review divides the use of electrical stimulation for limb rehabilitation after stroke into two directions, therapeutic and neuroprosthetic, and analyses in detail the mechanisms of action of the two at the peripheral and central nervous system levels (Knutson, Fu, Sheffler & Chae 2015).
In short: NMES is mainly used to exercise the muscle and lay the groundwork, and FES gives help at the moment the patient makes a movement. In actual treatment, the therapist usually alternates or combines the two modes according to the rehabilitation goal, and there is no need to choose one or the other.
One more common misunderstanding needs to be cleared up: using electrical stimulation to drive movement and using it to stabilise a joint have quite different treatment intentions. The NMES and FES discussed on this page aim to produce functional movements, such as grasping and opening the hand, or ankle dorsiflexion during walking so that the foot does not drag, that is, helping the muscle to move again so that a specific functional movement can be completed. When the same technique is applied to shoulder subluxation after stroke, however, the aim is the opposite. The point is not to make the shoulder move. It is to stimulate the supraspinatus and the posterior deltoid to pull the displaced head of the humerus back into place and so stabilise the loosened joint. The two can complement each other but are separate matters: one seeks movement and the other seeks stability. Repositioning and stabilising a shoulder that drops, with an obvious gap felt on touch, is a different treatment goal and is not covered here. This page concentrates on driving movement and restoring function.
The principle of electrical stimulation as a support
This is the most central idea in the article. Whether electrical stimulation turns into real functional recovery depends not on how strong the current is but on whether the patient actively tries to move during treatment. The best illustration is a clinical study that compared contralateral controlled functional electrical stimulation (CCFES), triggered by the movement intention of the affected side, directly with purely passive NMES.
Loh and colleagues (2022) analysed 6 RCTs with 267 stroke patients and found that CCFES triggered by the patient’s movement intention was significantly better than passive NMES on the upper limb Fugl-Meyer motor score (SMD 0.42, 95% CI 0.07 to 0.76), and was also better across the board on the Box-and-Blocks test, active range of joint movement and the Barthel Index. In other words, among electrical stimulation treatments, when the current is combined in step with the patient’s intention to move, rehabilitation is clearly better. This confirms that the real value of electrical stimulation is in strengthening active training and not in replacing it.
Never treat the electrotherapy machine as a machine that moves the patient’s limbs for the patient. If during treatment the patient makes no attempt to use effort and the muscle only twitches passively under the current, the rehabilitation effect is greatly reduced, and the patient may even form the wrong habit of borrowing force. The correct approach is for the patient to try to make the movement actively, with electrical stimulation assisting at the right moment, and for the therapist to adjust when the current is timed to match.
Clinical evidence for electrical stimulation in upper limb and hand function
For the upper limb, electrical stimulation is most often used to assist wrist extension and finger extension, movements that are hard to rebuild by the patient’s will alone. A systematic review and pooled analysis (Kristensen et al. 2022) combined data from 20 studies and 428 participants and confirmed that NMES significantly improves the ability to carry out daily activities (ADL) after stroke (SMD 0.41, 95% CI 0.14 to 0.67). Of particular note is how the benefit is distributed under different conditions:
These data strongly support the central point of the article: the supporting effect of electrical stimulation differs according to the stage of rehabilitation and the condition of the affected area. The benefit is greatest in patients in the subacute phase, when it is applied to the upper limb, and in patients with severe paralysis who need an outside force to trigger early movement. For how the overall treatment plan should be arranged for moderate upper limb paralysis, see moderate upper limb physiotherapy. Within such a treatment framework, electrical stimulation is only one of many means of intervention and must be built into a more complete rehabilitation plan.
Clinical evidence on foot drop: FES compared with an ankle-foot orthosis (AFO)
In the lower limb, the most representative use of electrical stimulation is to deal with foot drop. This is when weak ankle dorsiflexor muscles after stroke cause the toes to drag during walking, making it easy to trip. The traditional approach is for the patient to wear an ankle-foot orthosis (AFO), which supports the ankle mechanically. FES instead releases current in the swing phase of walking to trigger contraction of the ankle dorsiflexors. Which method is better?
In a pooled analysis of 5 RCTs and 815 stroke participants, Prenton, Hollands and Kenney (2016) found that FES and AFO are equally effective in improving the 10-metre walking speed of patients with foot drop, which means the orthotic effect of the two is the same. The two options are therefore not clearly better or worse than each other, and in practice each involves a trade-off:
- Actively makes the muscle contract and may give a therapeutic stimulus
- Improvement in walking speed equal to AFO (Prenton et al. 2016)
- Needs charging, placing electrodes and adjusting the timing, so it is more complicated to operate
- Skin problems, impaired sensation or a pacemaker need assessment
- Supports the ankle mechanically, ready to wear and needs no electricity
- Improvement in walking speed equal to FES (Prenton et al. 2016)
- Simple and reliable, but passive in nature and does not trigger the muscle
- Long-term dependence may reduce chances of active effort
Although the two improve walking speed to a similar degree, this does not mean any choice is equally good for every patient. In clinical practice, the therapist tends to choose one of them according to the patient’s individual situation. The directions below are the usual clinical considerations (this is a practice-consensus framework and not a hard rule, and the final plan must be assessed professionally by the physiotherapist according to the patient’s gait, skin condition and living needs):
| FES is usually considered when | FES may be considered when the muscles of the lower leg that lift the foot (the ankle dorsiflexors) still respond to electrical stimulation and can contract; when the aim is to stimulate the muscle to work while the foot is lifted, so that the muscle is not left passive for a long time; when the skin at the electrode sites is intact, there is no serious sensory loss, and no contraindication such as a cardiac pacemaker; and when the patient or caregiver can manage the daily charging, placing of electrodes and regular adjustment, and is willing to take part in active gait training. |
| An AFO (ankle-foot orthosis) is usually considered when | An ankle-foot orthosis (AFO) may be considered when a ready-to-wear, simple and reliable aid is wanted; when real support from a brace is needed because of muscle spasticity or an unstable ankle joint; when the skin has impaired sensation, there is a contraindication to electrical stimulation, or daily electrode placement and charging are hard to manage; or when the caregiver prefers a tool that is easier to look after. |
| Neither is a once-and-for-all fix | Whichever tool is finally chosen, it is only a support and must be combined with active strength training and gait practice to be of most use. Also note that wearing an ankle-foot orthosis (AFO) does not by itself lower the risk of falls, and the correct way to use it has to be learned to keep walking safe. |
For the immediate and long-term clinical evidence on AFOs, the criteria for choosing between rigid and hinged orthoses, and why wearing an AFO does not mean the patient will not fall, see ankle-foot orthoses (AFO) and walking after stroke. This page concentrates on the use of electrical stimulation (FES).
Timing of intervention is equally important. A network meta-analysis published in 2025 shows that, for improving ankle dorsiflexion angle and lower limb function in stroke patients with foot drop, electrical stimulation works clearly better in the recovery phase (1 to 6 months) than in the acute phase (1 month or less) and the chronic phase (6 months or more), and has no significant effect in the chronic phase. This finding agrees with the idea of the critical window in stroke rehabilitation: the best benefit comes from using the treatment window of the subacute phase and building electrical stimulation into active training. Dealing with foot drop is also only one part of the overall lower limb rehabilitation plan. Depending on the patient’s walking ability, see moderate lower limb physiotherapy for a fuller training arrangement. For general balance and falls prevention training, see balance and falls prevention.
Consumer home electrotherapy devices compared with clinical NMES and FES
Many families ask a very practical question: is a home electrotherapy device (EMS or TENS) sold online for a few hundred dollars the same as the equipment used in a hospital physiotherapy department? The answer is that the two are essentially different. Consumer devices are not useless (TENS, for example, does help to ease pain), but anyone who expects such a product alone to achieve the functional recovery of clinical NMES and FES will often be disappointed. The differences lie mainly in three areas:
Current parameters
- Clinical equipment can adjust pulse width, frequency and current intensity carefully for the target muscle and the treatment need
- Most consumer devices on the market offer only fixed or rather rough preset modes
- If the current parameters are unsuitable, it is hard to make the muscle contract effectively
Electrode placement
- In the clinic, the therapist finds the motor point of the muscle and places the electrode accurately
- If placed carelessly by oneself, the wrong muscle is easily stimulated, which can even produce abnormal compensatory movement
- A small error in electrode position can make a large difference to the effect of treatment
Timing with movement
- Clinical FES and CCFES can release current in step with the moment the patient intends to move
- Ordinary home devices cannot match the point at which the patient actively makes a movement
- If the current cannot match the timing of the movement, it loses its role of supporting active training
This echoes the earlier point: the rehabilitation benefit of electrical stimulation depends heavily on the precision of electrode placement and the matching of timing to movement, and these are exactly the weakest parts of consumer devices and the parts that most need professional clinical assessment. If a family buys and uses one blindly, at best the effect is poor and the effort wasted, and at worst the patient practises a wrong compensatory pattern of movement.
Safety note: electrical stimulation must be used with care or avoided in the following situations. If the patient has a cardiac pacemaker or other implanted electronic device in the body, if there is a wound or infection where the electrodes would be placed, or if sensation in that area is seriously impaired, these are high-risk situations. Before electrical stimulation is used, a registered physiotherapist must first assess the suitable placement and current intensity, and it must not be tried alone.
The role of electrical stimulation in the overall rehabilitation plan
Putting these points together, the position of electrical stimulation in stroke rehabilitation is quite clear. It is one of many rehabilitation tools and must be built into an overall plan that includes active exercise, strength training and task-based training, and it is not a course that can be relied on alone. In the clinical division of work, the physiotherapist (PT) promotes the recovery of movement and applies the electrical stimulation technique, and the occupational therapist (OT) helps the patient turn the recovered movement into real daily living skills (such as eating and dressing).
- Treat electrical stimulation as a supporting tool. The patient must try actively to use effort during treatment and must not rely on the device alone
- For the upper limb, use the subacute phase and focus on assisting movements such as lifting the wrist and straightening the fingers
- For foot drop, the therapist can assess whether to use FES or an ankle-foot orthosis (AFO) according to the patient’s gait and daily needs
- Use the treatment window of the recovery phase after stroke (1 to 6 months). In the chronic phase, electrical stimulation alone has a more limited effect
- Do not expect a home electrotherapy device from the market to give the effect of clinical treatment, because electrode position and the timing of current with movement need professional adjustment
- Do not use electrical stimulation alone if the patient has a cardiac pacemaker, or over areas with a wound or impaired sensation
To see how the improvement in movement from electrical stimulation carries over to daily function, see occupational therapy after stroke. For the place of electrical stimulation devices among the many kinds of home rehabilitation tools and the points to look for in buying one, go back to the page on home rehabilitation equipment.