You may have heard the term biofeedback mentioned to you by your clinician or you may have come across it on this very site. Some of you may have even received swallowing therapy with the help of biofeedback. But what is it actually and why do speech-language pathologists use it?
Biofeedback offers important advantages when coupled with swallowing exercise. In this article, you will learn what biofeedback is and how this technology can be used to support swallowing therapy. You will also be introduced to an example mobile biofeedback system (Mobili-T®) that allows you use this technology from home.
- What is biofeedback?
- What is sEMG?
- Why is sEMG biofeedback important to swallowing therapy?
- What sEMG does not do
- How do I know if sEMG is right for me?
- Has sEMG been used before with swallowing exercises?
- Other biofeedback devices
- Example: Mobili-T® – A system that lets you use biofeedback from home
What is biofeedback?
Biofeedback is a way to show you what your body is doing, especially when it comes to functions that are not easy to observe, such as swallowing. Biofeedback can be feedback that you see (visual), that you feel (tactile), that you hear (auditory) or a combination of these. This information about what your body is doing can be detected with low-tech approaches such as a mirror or a finger on your throat, but with more advanced types of technologies as well. This article focuses on visual biofeedback created by sEMG sensors (you may hear sEMG sensors referred to as electrodes elsewhere).
What is sEMG biofeedback?
sEMG stands for surface electromyography. It is one way to provide visual biofeedback (feedback that you can see) about what your muscles are doing. It has been used extensively by physical therapists, occupational therapists and speech-language pathologists because it’s non-invasive, easy to apply, and requires minimal training.
- surface means that the information is collected at the surface of the skin. This makes sEMG simple and safe to use.
- electro and myo refer to the collection of the electrical activity (electro) of your muscles (myo) as they contract.
- graphy refers to the recording of information, and in this case refers directly to the graph used to show you information about your muscles.
Taken together, surface electromyography (sEMG for short) means a graph of what your muscles are doing as you exercise.
Fig 1. Typical sEMG biofeedback seen in clinic using the KayPENTAX Inc. Swallowing Signals Lab (no longer available). Patient users can see the line go up when they swallow. This type of biofeedback has been used by clinicians during swallowing exercise.
Why is sEMG biofeedback important to swallowing therapy?
When it comes to the swallowing muscles, it’s hard to feel the activity of the muscles, let alone the progress that you’re making. Biofeedback brings these actions into conscious awareness by providing real-time representations of the muscle activity.
sEMG biofeedback lets you “see” how hard your muscles are working and for how long. Said simply, when the line goes up on the graph your muscles are contracting; when the line goes down your muscles are relaxed. The higher the line goes up, the more intense the contraction. The longer the line stays up, the longer your muscles remain contracted.
sEMG biofeedback is a nice enhancement to swallowing exercise because it offers a means to engage with your exercises and challenge yourself a bit more than if you were to just sit in front of a mirror, or follow exercise that are written on a piece of paper.
Fig 2. Typical sEMG biofeedback seen with the Mendelsohn maneuver swallowing exercise. Biofeedback can assist patients in understanding how to perform the exercise and in creating tangible goals (e.g., make the line stay up for 2 seconds).
What sEMG biofeedback does not do
sEMG biofeedback is not a magical cure for dysphagia, nor is it a blanket solution for every type of swallowing difficulty. sEMG biofeedback on its own cannot improve your swallow. It is the exercises completed with the assistance of biofeedback that improve the swallow. These exercises need to be completed regularly, under the guidance of your healthcare team, and with intensity, for notable improvements to take place.
How do I know if sEMG is for me?
The best way to answer this question is to consult a speech-language pathologist. He or she will let you know the root cause of your swallowing disorder and determine if you would benefit from swallowing exercises. If these exercises need to be completed for longer than a couple of days and at home, then you may wish to consider using biofeedback as a means to motivate yourself and track how you’re doing.
Has sEMG been used before with swallowing exercises?
Absolutely. In fact there are a studies comparing groups who received swallowing therapy combined with biofeedback (experimental group) to groups who received swallowing exercise without biofeedback (control groups). In their systematic review of such studies, Albuquerque and colleagues concluded that:
“In all studies, the experimental group underwent a significant improvement in relation to the control group or intervention group without electromyographic biofeedback (P < 0.01 and P < 0.05, respectively) in all outcome measures. The results suggest that a combination of conventional rehabilitation with adjunctive electromyographic biofeedback was more effective in improving dysphagia than exclusive conventional rehabilitation. No adverse effects were reported.” (p. 935).
Although the research points to the use of sEMG biofeedback being effective, not many clinicians have access to the equipment. Irrespective of how you do it, the importance of completing your rehabilitation exercises is paramount. This is why sticking to a regular exercise schedule that challenges your system is important.
Other biofeedback devices
Most devices listed under a previous article, Tongue Strengthening Devices for Dysphagia Rehabilitation, use biofeedback. Some of these systems come with apps (e.g., Tongueometer), while others have a light array (e.g., IOPI). These devices and systems focus on tongue strengthening, which is one type of exercise prescribed to some patients with dysphagia.
Other sEMG systems for swallow-specific exercises are currently only available for in-clinic use, such as the Synchrony (not portable) and the MyoTrac Infiniti (not dysphagia specific). Two other systems exist, but are either discontinued (KayPentax Inc. Swallowing Signals Laboratory), or not available in the USA (Rehaingest). These systems use wired sensors (i.e., potential for noisy signal and hence, poorer biofeedback) and range in price from $1,800 USD (MyoTrac) to $19,000 USD (Synchrony).
Example: Mobili-T® – swallowing exercise from home using biofeedback
Imagine if you could do your swallowing exercises using sEMG biofeedback right now. Right where you’re sitting. In the time it would normally take you to drive to the clinic and back, you would already be done today’s sets and maybe even have had a bit of fun while doing them.
Over the past six years, True Angle has designed and developed a mobile health system for swallowing exercise with biofeedback called Mobili-T®. This system allows patients to complete their swallowing exercises from the comfort of their home.
What is it? The Mobili-T system is made up of a device and an app. The device (the gray device in front of the blue case) sticks (with disposable adhesive) under your chin. The Mobili-T device uses sEMG sensors to detect the activity of the swallowing muscles under your chin. This information is sent via Bluetooth® to the Mobili-T smartphone app and is shown to you as biofeedback. The app sets targets for you and rewards you accordingly. The wireless aspect of Mobili-T means cleaner signal and better biofeedback.
What will it do for me? Mobili-T lets you see how hard your muscles are working and tracks your progress. If you want to, you can also connect to a clinician and have them monitor your adherence, which helps to keep patients accountable and modify their goals as appropriate.
The Mobili-Texercise program was designed in line with current best evidence for dysphagia exercise and principles of neuroplasticity. Furthermore, the information it can capture on exercise adherence offers an avenue for additional study on how behavioural and neural changes may relate to treatment dose.
If you have undiagnosed swallowing difficulties you should see a speech-language pathologist first. He or she will assess the root cause of your problem and let you know if exercise is a good option.
Mobili-T Research. The Mobili-T system was designed and developed by talking to patients and clinicians and pairing their needs with technology that is accessible and affordable right now. This work included formal, peer-reviewed research studies as well as iterative design and development work.
More recently, a feasibility study was conducted where 20 patients with a history of head and neck cancer were sent home with an earlier prototype of the Mobili-T for six weeks. We observed good adherence rates and improved patient reported outcomes. Some of these data were presented at the Dysphagia Research Society 2020.
If you would like to read the peer-reviewed work involving Mobili-T, you can find these articles here.
True Angle is interested in your feedback and welcomes your questions – you can connect with the developers of the device system by dropping them a line here.
About the author:
PhD, R.SLP, S-LP(C)
Gabi is an Adjunct Assistant Professor in the Department of Communication Sciences and Disorders at the University of Alberta. She is also the CPO for True Angle. Her doctoral work directly influenced the design and development of the Mobili-T, a mobile therapy system for swallowing exercise.