Breath Training Devices For Parkinson's
Let me start out by saying that any device that is used for respiratory training is only as good as it's purpose. It is overwhelming the number of devices, techniques, and practices that are available to address the needs of the body to breathe. It can be difficult to know where to start! I have provided a summary of a few devices available on the market that can be helpful for those with Parkinson's who want to improve their breathing. Discussion about breathing techniques and practices is beyond the scope of this topic. Having said that, the best advice I can give on breath training is to establish a daily breath practice where the goal is curiosity not outcome. That process may or may not involve external devices. However, for those with Parkinson's who are interested in strengthening the respiratory system, I have listed a few devices to narrow the field.
There is strong research that indicates expiratory muscle strengthening is advantageous for people with Parkinson's. This type of training can aid in better volume with voice and speech. It has also been shown to improve pressure force for cough and respiratory toileting. Cough strengths plays an important role in keeping the lungs clear of food and liquid from entering the airway.
Inspiratory muscle strength training has not been shown to facilitate the same degree of improvements in the areas of voice, swallowing, and cough for individuals with Parkinson's. That is not to say inspiratory muscle strength training is unhelpful and invalid. In fact, inspiratory muscle strength training has been shown to lower blood pressure, improve diaphragm muscle mass for respiratory function, decrease the perception of shortness of breath in people with COPD and asthma, and improve exercise capacity in people with heart failure. Beyond strength training with devices, there is an entire world of discussion about the improvements in respiratory abilities with pranayama yoga, tai chi, and generalized breathwork practices. All this to say, breath training is a huge landscape and everyone has unique needs.
Devices With Spring Valve
pressure threshold
There are two main categories of devices that provide resistance or "weight" to the breath. One group includes things that have a mouth piece with a spring inside. These devices are referred to pressure-threshold devices. The spring inside the device operates to keep the passage way closed until enough breath force has been applied to overcome the threshold and open the passage. Once this threshold has been overcome, the spring-loaded valve opens and there is no more "weight" or resistance added to the airflow. The valve setting can be changed according to the lower and upper range capabilities of each device.
EMST 150

EMST 150 is an expiratory-only device. Airflow is applied upon exhale through the mouthpiece. The level of difficulty is set by turning the cylinder which has a spring valve inside. The recommended start point is 75% of maximum expiratory capacity. The manufacturer provides instructions on how to determine this set point. The basic training protocol is to complete 5 repetitions x 5 sets, 5 days of week for 8 weeks. Maintenance continues at 3-5 days per week after training is completed.
EMST is an abbreviation for Expiratory Muscle Strength Training. EMST 150 allows the spring to be set at a maximum threshold of up to 150 cm H20 (water pressure). Hence the name, EMST 150. It does have a minimum threshold of 30 cm H20. This means that very weak individuals may find it difficult to overcome the lower level minimal threshold that must be overcome to use this device. The manufacture of this device recognized this shortcoming and developed the EMST lite (described below). A large portion of the research validating expiratory muscle training in people with Parkinson's has used this specific device.
EMST lite

EMST lite is also an expiratory-only device. It is a step down in difficulty from the EMST 150. EMST lite has a minimum threshold of 0cm H20 and a maximum threshold of 75cm H20. This device can be useful for those who are very weak and recently needing mechanical ventilation for an extended period of time. It may also be useful for individuals who are weak to the point that they need assistance to move their body.
The start point, training protocol, and maintenance protocol are the same for EMST lite. Some individuals may progress from EMST lite to EMST 150 as their respiratory strength improves.
Devices Without A Spring
resistive
The other main category of devices that provide "weight' to the breath, like a dumbbell would provide an arm, are referred to as resistive devices. These types of devices typically have several small holes that are closed or opened to provide more or less resistance or "weight" to the breath as it is applied through a mouthpiece. With these types of devices, the resistance is applied to the entire breath cycle, in comparison to threshold devices that apply resistance only to the point that the threshold is overcome.
The Breather

The Breather operates differently than the pressure- threshold devices listed above. There is a dial on each side of the device. There is one dial for the inhale and a separate dial for the exhale. These dials cover small holes. Airflow that is applied through the mouthpiece is manipulated by these holes that are more or less open, depending on the dial setting. The level of difficulty is set by increasing the dial settings. The recommended start point setting is based on a perceived level of effort scale ranging between 1-10. The work level needs to feel in the 5 - 6 - 7 effort range when completing a set of 10 repetitions. The manufacturer has educational videos explaining how to determine "in the zone effort."
The exhale has a minimum resistance of 5cm H20 (water pressure) at setting 1 up to 31cm H20 at setting 5. The inhale has a minimum resistance of -10cm H20 at setting 1 and up to -52 cm H20 at setting 6. The Breather has 5 settings for the exhale and 6 settings for the inhale.
A frequent criticism of resistive devices, such as The Breather, is that a person can use a slowed rate of airflow to "cheat". This effectively lessens the work load and modifies how exercise effects can be measured across trials. In other words, you can't guarantee that each repetition is completed with the exact same degree of force if a person can slow the airflow to cheat the process. Thus each repetition may not be apples to apples. Each repetition should be applied with maximum effort and force to receive maximum resistance of the device setting. This criticism is important to the discussion of respiratory muscle training as it relates to Parkinson's and the faulty feedback loop that is part of the disease. Faulty feedback can negatively impact awareness of effort.
There is major advantage of resistive devices that is often overlooked. Because the resistance is applied to the entire breath cycle, it effectively places the breath in slow motion. This allows perception and sensation of the breath pattern that is not afforded by spring loaded devices which require fast movement. Breath pattern dysfunction is a significant factor in most people with respiratory muscle weakness. Hence, resistive devices have a role to play in breath training.
Common Household Items
cheap options
There are a few common household items that can be used to exercise the exhale portion of the breath. These items are a nice entry point into experimenting with respiratory muscle training and breath awareness.
Balloons

Expiratory muscle training can be done by exhaling fast and forcefully into a balloon. The exhale should continue until the resistance of the balloon prevents further airflow. Keep in mind that depending upon a person's respiratory fitness, a balloon may provide too much resistance. If straining to blow a balloon creates too great of pressure in the head, consider blowing bubbles (see below), EMST lite or The Breather. This is a precaution to prevent increased blood pressure associated serious vascular events.
Balloons can be purchased in the party section of any store. The amount of latex and resistance that a balloon will provide varies according the count per package and manufacturer. Each time a balloon is inflated it become less stiff and easier to expand. It is helpful to keep this in mind because the goal is to maximize exercise with the resistance of a balloon.
Blowing Bubbles

Expiratory muscle training can also be done by blowing though a straw into a cup filled with a small amount of water. This is a great entry point for those who find balloon resistance too difficult. Resistance can be increased or decreased by the diameter of the straw, length of the straw, and amount of liquid the straw is placed. I do not advise using coffee straws. These are simply too small to be useful when blowing bubbles. It can be fun to play with these variables and experiment to find your threshold max. Water is actually quite heavy. Once you start blowing bubbles, you find this out very quickly!
Choosing Where To Start
suggestions
If you want a very inexpensive starting point, my suggestion is to start with balloons or blowing bubbles with a straw. I show how to use straws and balloons and other breathwork practices in my class, The Breath Chamber on my channel TeeBombshell. If you want something that has a more structured way to train the respiratory muscles, my suggestion is to start with the EMST 150 or EMST lite. If you want something to help you explore the sensation of your breathing or think you would benefit from inspiratory resistance, my suggestion is to start with The Breather.
There is no perfect place to start. The most important part is that you pick a place and begin and then modify from there.
I hope this helps get you started.