Electrical Stimulation after Stroke
With so much information at our fingertips, it's hard to know what to believe. Electrical stimulation is an appealing treatment option for many patients because it looks like might do the work for them, but is it too good to be true?
Here are the answers to your e-stim questions:
- What is electrical stimulation?
- Does treatment for stroke include electrical stimulation?
- What other devices can be used?
- Will e-stim help me recover from stroke?
What is electrical stimulation?
Electrical stimulation is a type of therapeutic treatment that can be performed by an occupational or physical therapist, or a trained home user with the correct equipment. There are 3 devices lumped into the category of e-stim that look similar but have different functions. All of the devices consist of electrode pads that stick to the skin and a machine that you can use to adjust the parameters.
True electrocutaneous muscle stimulation (EMT or e-stim) sends an electric impulses to the belly of the muscle to make it contract. It has a limited affect on the muscle, meaning that activating it with an electrical signal alone won't build strength. In order to build strength and neuroplasticity the signal for the muscle contraction has to come from your brain.
Remember that fad where they sold e-stim for you stomach muscles that were supposed to give you a 6 pack without the work of doing sit-ups? People quickly learned this was just not true. You have to put the work in to gain strength.
Does treatment for stroke include electrical stimulation?
When a stroke occurs, there is a blood clot and lack of blood supply to the brain tissue (ischemic stroke) or bleeding in the brain (subarachnoid hemorrhage), resulting in brain damage.
For stroke rehabilitation, electrical stimulation is used with people that don't have full active movement of a muscle. The e-stim can give it an extra boost of muscle contraction. So, the patient is actively sending signals to the muscle, but the machine gives the muscle a little extra force.
This helps in several ways:
- It's more motivating to see more muscle activation
- You'll be more successful in an activity with more muscle movement
- It increases sensory feedback to your brain to help your body process the muscle activation
Electrocutaneous muscle stimulation can also be used to reduce edema, also known as swelling, which is one of the symptoms of stroke. The frequency of the signal is set so that the muscle actually becomes a pump, pushing excess fluid out of the area.
E-stim is also sometimes used for the management of pain, but this is not specific to stroke rehabilitation.
What other devices can be used?
Transcutaneous electrical nerve stimulation or TENS is a device that often gets mistaken for EMT. A TENS unit is a more superficial electrical signal sent to the nerve at the level of the skin. (whereas the EMT signal is sent to the muscle). The most common use of a TENS unit is for pain, which again is not a stroke specific intervention. A TENS unit can make a muscle contract with a strong enough signal, but it would be better to use an EMT unit for muscle activation.
The other device that often gets mistaken for an EMT unit is an electromyography biofeedback device, also known as an EMG. An EMG device has the same type of electrodes, but instead of sending a signal to the muscle it receives the signal and creates visual or auditory feedback to motivate the person to activate the muscle. The simplest type is one that has a light that activates when the muscle reaches a certain threshold. EMG biofeedback does have evidence to support its use with people after stroke. There are also combo E-stim/biofeedback devices that send a signal to the muscle to activate and receive a signal from the muscle to create a feedback loop.
Will electrical stimulation help me recover from stroke?
Answer: Sometimes. I know everyone's favorite answer to a yes or no question is: "It depends", but really it does. Electrical stimulation or e-stim may be used after stroke to reduce swelling or to stimulate muscle activation with stroke survivors that do not have full muscle activation.
E-stim is frequently used after stroke to work on foot drop, wrist extension, finger extension, shoulder subluxation, and elbow extension.
If you don't have swelling or if you have full active range of motion after stroke, there is no evidence that e-stim is beneficial.
Not all therapists are trained electrical stimulation, so you might need to ask your therapist if it's a good fit for you and if there is someone that is trained in providing it.
Bottom line: electrical stimulation can be beneficial for stroke recovery... if you have edema or you have partial but not full muscle activation. You should work with a specialist trained in the delivery of these devices to optimize your recovery. E-stim won't help you gain strength where movement does not exist, so if you're severely affected it might not help.
Functional Electrical Stimulation. Stroke Engine, Canadian Partnership for Stroke Recovery, 2020, www.strokengine.ca/en/patient-info/functional-electrical-stimulation-upper-extremity-info/.Faghri PD. The effects of neuromuscular stimulation-induced muscle contraction versus elevation on hand edema in CVA patients. J Hand Ther. 1997;10(1):29‐34. doi:10.1016/s0894-1130(97)80008-7