By Shannon Stocks, MS, CCC-SLP
Speech-Language Pathologist
LSVT LOUD Certified Clinician
PA South East 2

Just about as large as a kazoo, with a rainbow neck and plastic finish, an expiratory muscle strength trainer (EMST) may not seem like much at first glance. Yet this hand-held device has become a clinical staple in the toolbox of many medically-based clinicians. 

This pressure-threshold device was originally developed in the 1990s at the University of Florida, as a result of collaboration between neurologists, physiologists, engineers, professors, and Speech-Language Pathologists (SLPs). 

The device, paired with specific training techniques, is used as a behavioral treatment program to support individuals with respiratory muscle weakness.

Clinical EMST Uses

Over the years, researchers have found EMST to be efficacious for improving maximum expiratory pressure, cough function, and even swallowing safety. Patient populations who may benefit include individuals with pulmonary conditions such as COPD as well as those with peripheral or central nervous system conditions including stroke, MS, PD, and ALS. 

By breathing into the device, a patient encounters the calibrated pressure relief valve, creating an isometric load for the respiratory muscles. A user of EMST would be instructed to adhere to a strict routine of 5-5-5-5. In other words, to complete five sets of five breaths, five days a week for five weeks. Over time, the resistive load is increased and this routine effort would strengthen expiratory and supralaryngeal muscles. 

How to Introduce an EMST to Your Patients

When introducing the device to a patient, first familiarize the patient with each part of the device. There is a round blue or white comfort mouthpiece, an adjustable knob, a one-way valve, pressure settings from 30 to 150 cmH2O, and a silver screw that marks the current pressure setting. 

Establish the Patient’s Baseline

Once the patient is up to speed with the device parts, establish the patient’s baseline. Turn the adjustable knob clockwise until it stops on the lowest setting. Then, instruct the patient to blow out “hard and fast.” If exhaling into the device is easy, turn the nozzle counterclockwise by a quarter turn and instruct the patient to blow again. 

Keep moving the piece by a quarter turn until the patient is unable to blow through the device. This setting is considered the threshold. Then turn the cap back a quarter turn to the previous setting, and this is their starting point. 

Continue Using the EMST

Have the patient follow the 5-5-5-5 routine. As soon as the starting point is no longer challenging, turn the cap a quarter-turn counterclockwise to increase the amount of pressure your patient must push through to achieve the same results. 

Addressing Potential Roadblocks With EMST Devices

Some problem areas may arise during the introduction to the EMST device. If patient fatigue becomes an obstacle, increase break time between sets. These breaks ultimately do not affect the patient’s outcome. 

Should the patient struggle with identifying how hard to blow into the device, try saying “it’s like blowing out a birthday candle.” You can also practice diaphragmatic breathing techniques without the device. 

In the case of difficulty with adequate lip seal, encourage the patient to hold both cheeks while blowing into the device. And if air is escaping through the nose upon exhale, introduce the nose clip included in the EMST package.

EMST in the Field

I was first introduced to EMST in graduate school while interning at a hospital in Brooklyn. I was working with a woman in her early 80’s — let’s call her Penelope.

Although Penelope had been diagnosed with Parkinson’s Disease years ago, the progression of the disease had only just begun to impact her speech intelligibility and swallowing function. She was mostly unaware of her deficits until her daughters would say, “Ma, no one can hear what you’re saying,” or she would cough her way through a Sunday family dinner.

Penelope was typically transported to and from sessions by her adult children, and she at first seemed to participate in speech therapy to appease them. Then, EMST was introduced. The concept was simple, and she was able to adhere to the training schedule with a little help from some external memory aids and her family’s continued support. It was incredible to see this woman pushing past her thresholds, monitoring her own progress, and feeling accomplished doing it. 

While EMST has been found to provide specific advancements in the areas of respiration and deglutition, introducing and educating on this type of device is up to each clinician. And, with a positive patient-clinician relationship and caregiver involvement, you can motivate a patient to participate consistently in this program and achieve clinically meaningful gains.