Is RMST Right for Me?
RMST, or respiratory muscle strength training, is a treatment modality becoming widely used in the field of speech-language pathology for patients with impairments in speech, voice, ventilation, cough, and swallowing. RMST involves using resistance or pressure threshold devices to strengthen either the muscles of inspiration (breathing in) or expiration (breathing out). The muscles involved in inspiration include the diaphragm and the external intercostal muscles. The diaphragm pushes down on the abdomen and stomach contents to make room for the rib cage to expand while the external intercostals elevate the ribs and expand the rib cage. The abdominal muscles and the internal intercostals are the primary muscles for expiration. The abdominal muscles increase the pressure moving the diaphragm upwards and the internal intercostals lower the rib cage.
Inspiratory muscle strength training (IMST) is most appropriate when a person experiences difficulty filling the lungs with air. Expiratory muscle strength training (EMST) is most beneficial in cases where there is a weak or inefficient cough, reduced breath support to sustain voicing, and reduced vocal loudness. In some cases, a combined approach including IMST and EMST is appropriate. Some patient populations that may benefit from RMST include; professional voice users or athletes, sedentary older adults, Parkinson’s disease, amyotrophic lateral sclerosis (ALS), spinal cord injury, multiple sclerosis (MS), chronic obstructive pulmonary disease (COPD), head and neck cancer, congestive heart failure (CHF), vocal cord dysfunction, myotonic dystrophy, diaphragm paresis or paralysis, dysarthria and dysphonia, Huntington’s disease, progressive supranuclear palsy (PSP), cardiopulmonary disease, and those requiring mechanical ventilation. RMST is not recommended for patients with untreated hypertension or GERD, a perforated eardrum, or any medical condition which would contraindicate a Valsalva maneuver (Sapienza & Troche, 2012). If in doubt, it is recommended to seek guidance from your physician.
A typical assessment for RMST will include measuring your maximum inspiratory and/or maximum expiratory pressure. This can be completed with a digital manometer or a peak flow meter. Alternately, the SLP completing your evaluation may use the devices used in treatment to measure your one repetition max or the maximum intensity you can reach completing only one repetition. Depending on your particular diagnosis or reason for pursuing this type of treatment, your starting treatment level will be set at a certain percentage of your maximum inspiratory or expiratory pressure.
Treatment devices are divided into resistance and pressure threshold devices. Resistance devices are often used in cases where a person may not have enough strength or respiratory driving force to use a pressure threshold device. Pressure threshold devices are most frequently used in research to assess the effectiveness of RMST. I most commonly use the EMST 150, Threshold PEP, and Threshold IMT with my patients. Your SLP will be able to help you select the most appropriate device and training level.
I’ve successfully used RMST with my patients since 2018. I also developed an RMST program at a skilled nursing facility and authored three peer-reviewed articles for a speech pathology resource website. If you feel that RMST may be appropriate for you, I’d love to talk with you more!
References:
Sapienza, C. & Troche, M. (2012). Respiratory Muscle Strength Training Theory and Practice. San Diego, CA: Plural Publishing Inc.
