Biofeedback and ETS in rehabilitation – what can and cannot they do?
In this article, I explain the two main areas of application of biofeedback: stroke rehabilitation and urinary incontinence. I presented electrical treatments in the article on electrotherapy methods; I describe the individual areas of application in more detail in the related articles on NMES in rehabilitation and practical treatment of incontinence.
Key point
Biofeedback and ETS are not standalone treatments – they are part of complex rehabilitation. In post-stroke shoulder–arm pain, a recent literature review [1] found that combining EMG biofeedback with physiotherapy is the most effective physical treatment for improving pain and function. In upper-limb stroke rehabilitation, a recent synthesis [2] found that biofeedback alone is not always better than conventional rehabilitation. In urinary incontinence, EMG biofeedback provided no meaningful additional benefit over conventional pelvic floor muscle training [4][5], but pressure-based biofeedback [6] significantly improved symptoms – particularly in women after childbirth. The choice of method and the parameters are indication-specific – consultation with a specialist or physiotherapist is necessary.
Main types of biofeedback
Three main types of biofeedback are used in clinical practice, with different areas of application:
EMG biofeedback measures the electrical activity generated during muscle contraction using skin electrodes. The user receives visual or acoustic feedback about their muscle activity and can therefore learn to activate or relax a specific muscle in a targeted way. ETS (EMG-Triggered Stimulation) takes this one step further: when the patient reaches a minimum threshold of muscle activity through their own voluntary effort, the device automatically starts electrical stimulation, which completes or strengthens the muscle contraction. This is particularly important for weak muscles after stroke [1][3] – the patient “relearns” the connection between intention and muscle movement.
Pressure biofeedback measures the pressure generated by the muscles using a probe inserted into the vagina or rectum, and displays the level of muscle activity visually in real time. It is particularly useful during pelvic floor muscle training, when the patient may otherwise find it difficult to sense the muscle activity. According to a recent clinical trial [6], combining pressure biofeedback with pelvic floor muscle training produced a significantly better recovery rate than exercise alone in women with postpartum stress incontinence. Important: EMG biofeedback did not show a meaningful benefit for the same indication [4][5] – the clinical value of the two types of biofeedback may differ in incontinence.
Other members of the biofeedback family include heart rate variability (HRV) biofeedback (autonomic balance and stress management), EEG biofeedback (neurofeedback) (modulation of brain activity patterns; areas under investigation include ADHD and anxiety), temperature biofeedback (Raynaud's syndrome and peripheral circulation) and breathing biofeedback (relaxation and adjunctive treatment for asthma). These types are generally most effective when used in a multidisciplinary team (physiotherapist, psychologist and neurologist); home devices are available only to a limited extent.
What conditions is biofeedback used for?
Recent clinical evidence shows a measurable contribution in the following areas. In each case, it is used as an adjunctive modality, as part of a multidisciplinary programme:
A large, multi-author literature review [1] found that the combination of EMG biofeedback and physiotherapy is the most effective physical treatment for post-stroke shoulder–arm syndrome – both for upper-limb motor function (range of motion and muscle strength) and for reducing pain, outperforming other physical methods. Another clinical trial [3] in people with chronic stroke achieved significant improvement in recovery of upper-limb movement using the combination of functional electrical stimulation + mirror therapy + EMG-triggered biofeedback. Important: stroke rehabilitation is the responsibility of a multidisciplinary team (neurologist, physiotherapist and occupational therapist).
The recent evidence is mixed: a large British trial [4] found that EMG biofeedback and pelvic floor muscle training were not meaningfully better than exercise alone for stress or mixed urinary incontinence. The full professional report [5] confirmed this. However, a newer clinical trial [6] found a significantly better recovery rate when pressure biofeedback was combined with pelvic floor muscle training in women after childbirth. Clinical lesson: the type of biofeedback (EMG vs pressure) and the population treated (general incontinence vs postpartum) may affect effectiveness. Careful device selection is necessary. Details: practical treatment of incontinence.
A literature review [2] found that surface EMG-guided rehabilitation interventions produced mixed results in improving upper-limb function – most studies showed measurable improvement compared with baseline, but biofeedback was not clearly better than conventional rehabilitation. Lesson: biofeedback is a promising “movement-learning” tool, but it does not provide an additional benefit on its own, without physiotherapy. Further, larger studies are needed to clarify the areas that remain uncertain.
Biofeedback (EMG, HRV and temperature) has traditionally been used for chronic headache, temporomandibular joint syndrome (TMD), musculoskeletal tension and stress-related complaints. Its effectiveness can generally be measured as part of a psychotherapeutic programme (cognitive behavioural therapy and relaxation techniques). When used independently at home, without supervision by a physiotherapist or clinical psychologist, its effectiveness is limited; it is more effective when combined with professionally guided sessions.
In sports rehabilitation, EMG biofeedback primarily supports the process of movement learning – for example, during rehabilitation after an injury, the athlete learns how to activate the target muscle group selectively or how to avoid compensatory movement patterns. The evidence is more limited here (sport-specific and based on fewer studies), but its practical usefulness in a clinical setting under physiotherapist guidance is accepted. It is less effective when used independently, without practical supervision.
SineBravo vs. DuoBravo N – key difference
The Medimarket portfolio includes several types of biofeedback devices. SineBravo provides feedback only, while other devices, including DuoBravo, Perobravo, evostim E and evostim P, also provide active stimulation (ETS). They do not replace one another – they have different functions and clinical purposes:
| Feature | SineBravo | DuoBravo N |
|---|---|---|
| Main function | BIOFEEDBACK ONLY | stimulator + ETS (EMG-Triggered Stimulation) |
| Electrical stimulation? | ✗ NO | ✓ yes |
| ETS function? | ✗ NONE | ✓ yes (triggered by the patient's own intention) |
| Main indication | visualisation of own muscle activity, pelvic floor awareness and movement learning | central paralysis (stroke) and active rehabilitation |
| What does the patient learn? | targeted muscle activation / relaxation | linking voluntary intention with automatic stimulated completion |
| Number of channels | 2 | 2 |
| Home use | ✓ yes (simpler) | ✓ yes, but professional guidance is recommended |
The two devices do not replace one another
SineBravo is specifically intended for people who want to visualise and learn to control their own muscle activity (for example, to develop pelvic floor muscle awareness). DuoBravo N is a key device for active stroke rehabilitation: when the device detects the muscle signal generated by the patient's weak voluntary effort, it automatically starts muscle stimulation, which completes or strengthens the movement. This supports the brain's “neuroplastic” relearning – restoring the connection between intention and movement.
Medimarket biofeedback and ETS devices
The following biofeedback and related devices are available in the Medimarket portfolio:
- SineBravo – biofeedback ONLY device (does NOT stimulate), for visualising one's own muscle activity and developing pelvic floor awareness.
- DuoBravo N – muscle stimulator with ETS (EMG-Triggered Stimulation) function, specifically for active post-stroke rehabilitation.
- PeroBravo – selective electrical stimulation device for peripheral paralysis (denervated muscle).
- evostim E - EMG-based biofeedback device with ETS function, specialised for incontinence treatment
- evostim P - pressure-based biofeedback device with ETS function, specialised for incontinence treatment
Incontinence-specific probe-based biofeedback devices are available on the incontinence category page.
Typical biofeedback / ETS protocol parameters
The protocols used in recent clinical trials vary; the factory programmes of home devices are optimised. The following table is for information only:
| Parameter | Range | Note |
|---|---|---|
| Muscle activity threshold (ETS) | 5–20% | individual setting; lower for weaker patients |
| Stimulation parameters (ETS) | 30–50 Hz, 200–400 µs | muscle stimulation standard, depending on muscle type |
| Treatment time | 20–30 minutes/session | stroke rehabilitation: 30 minutes; incontinence: 20 minutes |
| Frequency | 3–5 sessions per week | most clinical trials: 3–5 times per week |
| Programme period | 4–16 weeks | stroke rehabilitation: 4 weeks; incontinence protocol: 12–24 weeks |
| Supervision | initially physiotherapist-led | home continuation only after practice |
| Feedback type | visual (bar, curve) and acoustic signal | patient-specific and motivating |
When is biofeedback / ETS not recommended?
The risk of purely biofeedback devices (sensor + visual feedback) is minimal. For ETS and associated stimulation devices, the general contraindications for electrotherapy apply (see: contraindications to electrical treatment and electrical treatment and implants):
- Pacemaker, ICD or implanted neurostimulator – only with permission from a cardiologist / arrhythmologist (for stimulation devices).
- Pregnancy – avoid use over the abdomen and lumbar region.
- Active malignant tumour in the treatment area.
- Active venous thrombosis (DVT) in the treatment area.
- Recent skin wound, eczema or infection in the electrode area.
- Poorly controlled epilepsy – individual specialist assessment (for stimulation devices).
- Metal implant in the stimulation area – risk of electrical heating.
- Carotid sinus, front of the neck and placement over the heart on the chest – avoid.
- Acute vaginal / rectal inflammation when using probe-based biofeedback.
- Recent vaginal tissue injury or within 6 weeks after childbirth – gynaecologist's approval is required.
For a new, worsening or unexplained complaint, medical or physiotherapy consultation is always necessary before starting biofeedback treatment independently.
Frequently asked questions about biofeedback and ETS
SineBravo is a biofeedback ONLY device – it measures with a sensor and provides visual feedback on muscle activity, but it does NOT provide electrical stimulation. DuoBravo N is a combined device: muscle stimulator + ETS (EMG-Triggered Stimulation) function. ETS means that when the patient reaches a muscle activity threshold through their own voluntary effort, the device automatically stimulates the muscle, completing or strengthening the movement. DuoBravo N is a key device in post-stroke rehabilitation; for general biofeedback training (for example, pelvic floor muscle awareness), SineBravo is sufficient.
Most clinical trials examined 4–16 weeks of regular use. In stroke rehabilitation, changes can be measured within 4 weeks; pelvic floor muscle training programmes typically last 12–24 weeks. Results vary from person to person. Patience and regularity are key – a meaningful change cannot be expected after one or two sessions.
It cannot replace it. Recent clinical studies [1][2][4] all show that biofeedback is most effective when combined with conventional rehabilitation (physiotherapy, movement therapy and manual therapy). Used alone, without physiotherapy, it provides no additional benefit – but when used alongside it (such as ETS in stroke), it may provide an additional clinical benefit.
The evidence is mixed. A large British trial [4] found that EMG biofeedback provided no additional benefit compared with conventional pelvic floor muscle training in stress and mixed urinary incontinence. However, a newer clinical trial [6] found a significant benefit from pressure biofeedback in women after childbirth. The two types of biofeedback measure through different mechanisms, and the patient group (general vs postpartum) may also affect the result. Before choosing a device, it is worth consulting a gynaecologist, urogynecologist or pelvic floor physiotherapist.
Yes, especially during the initial stage. Clinical trials generally use a physiotherapist-led introduction, followed by home continuation. In stroke rehabilitation, correct electrode placement, muscle activity threshold settings and stimulation parameters require the knowledge of a physiotherapist. In an incontinence protocol, a pelvic floor physiotherapist first teaches the correct muscle activation. Home use is appropriate only after the correct technique has been practised.
Purely biofeedback devices (such as SineBravo), which only measure and do not provide electrical stimulation, generally do not interfere with pacemakers – but it is advisable to seek approval from a cardiologist before use. Devices that also provide stimulation (DuoBravo N ETS, evoStim) must not be used with a pacemaker without permission from a cardiologist / arrhythmologist. Details are provided in the article on electrical treatment and implants.
Summary – biofeedback and ETS in brief
What everyone interested should know
- Biofeedback is real-time biological feedback (muscle activity, pressure, heart rate, brain waves and so on) that helps people learn self-regulation.
- ETS (EMG-Triggered Stimulation) automatically starts stimulation in response to the patient's own voluntary effort – it is key in stroke rehabilitation.
- Strong evidence: post-stroke shoulder–arm syndrome – the combination of EMG biofeedback and physiotherapy has been shown to be the most effective physical treatment [1].
- Mixed evidence: stress and mixed urinary incontinence – EMG biofeedback provides no additional benefit [4][5], but pressure biofeedback produces significant improvement in women after childbirth [6].
- Products: SineBravo (biofeedback ONLY, does NOT stimulate), DuoBravo N (stimulator + ETS, key for stroke), MyoBravo (EMS biofeedback) and PeroBravo (selective, denervated muscle).
- Biofeedback / ETS is an adjunctive modality – it does not replace conventional rehabilitation, physiotherapy or specialist treatment.
- Physiotherapist-led introduction is essential; home use should begin only after practice.
- Contraindications (pacemaker, pregnancy, tumour, recent skin wound and acute fever) must be strictly observed.
Scientific sources (2020+)
The reference numbers [1]–[6] in the article refer to the following studies (number = order in the list):
-
Feng S, Tang M, Huang G, Wang J, He S, Liu D, Gu L.
EMG biofeedback combined with rehabilitation training may be the best physical therapy for improving upper limb motor function and relieving pain in patients with the post-stroke shoulder-hand syndrome: A Bayesian network meta-analysis.
Frontiers in Neurology.
2023;13:1056156.
PMID: 36703623.
Brief summary: Bayesian network meta-analysis of 45 randomised controlled trials (3379 post-stroke patients in total); the combination of EMG biofeedback + rehabilitation was the most effective physical treatment, with a SUCRA of 96.8%. -
Munoz-Novoa M, Kristoffersen MB, Sunnerhagen KS, Naber A, Alt Murphy M, Ortiz-Catalan M.
Upper Limb Stroke Rehabilitation Using Surface Electromyography: A Systematic Review and Meta-Analysis.
Frontiers in Human Neuroscience.
2022;16:897870.
PMID: 35669202.
Brief summary: Systematic review and meta-analysis of 24 randomised trials (808 patients with stroke); sEMG-guided intervention showed no clear advantage over conventional rehabilitation in improving upper-limb function. -
Kim YS, Song JY, Park SH, Lee MM.
Effect of functional electrical stimulation-based mirror therapy using gesture recognition biofeedback on upper extremity function in patients with chronic stroke: A randomized controlled trial.
Medicine (Baltimore).
2023;102(52):e36546.
PMID: 38206692.
Brief summary: Randomised trial of 26 patients with chronic stroke; the combination of functional electrical stimulation + mirror therapy + EMG biofeedback significantly improved upper-limb motor function (Fugl-Meyer, MFT and range of motion) after the 4-week treatment. -
Hagen S, Elders A, Stratton S, Sergenson N, Bugge C, Dean S, et al.
Effectiveness of pelvic floor muscle training with and without electromyographic biofeedback for urinary incontinence in women: multicentre randomised controlled trial.
BMJ.
2020;371:m3719.
PMID: 33055247.
Brief summary: Multicentre British randomised trial of 600 women with stress/mixed urinary incontinence; EMG biofeedback + pelvic floor muscle training was NOT meaningfully better (ICIQ-UI SF 8.2 vs 8.5; p=0.84) than exercise alone at 24-month follow-up. -
Hagen S, Bugge C, Dean SG, Elders A, Hay-Smith J, et al.
Basic versus biofeedback-mediated intensive pelvic floor muscle training for women with urinary incontinence: the OPAL RCT.
Health Technology Assessment.
2020;24(70):1-144.
PMID: 33289476.
Brief summary: The full British health technology assessment (HTA) report of the OPAL trial – it confirms the findings of the BMJ publication above: EMG biofeedback provides no meaningful additional benefit over pelvic floor muscle training and is not cost-effective. -
Wang X, Qiu J, Li D, Wang Z, Yang Y, Fan G, et al.
Pressure-Mediated Biofeedback With Pelvic Floor Muscle Training for Urinary Incontinence: A Randomized Clinical Trial.
JAMA Network Open.
2024;7(11):e2442925.
PMID: 39499517.
Brief summary: Multicentre Chinese randomised trial of 452 women with postpartum stress incontinence; pressure biofeedback + pelvic floor muscle training showed a significantly better recovery rate (20.2% vs 8.7%; p=0.001) than exercise alone after 3 months.
This article is for general information only and does not replace a personal medical consultation. Biofeedback and ETS devices are CE-certified medical devices; the clinical trials cited used different devices and protocols, and results may vary from person to person. The method is an adjunctive modality; it does not replace conventional rehabilitation, prescribed medication or a specialist diagnosis. Before purchasing a stroke, incontinence or other rehabilitation device, it is advisable to consult a specialist or physiotherapist about choosing the appropriate device. Contraindications (pacemaker, pregnancy, tumour and recent skin wound) must be strictly observed.
