Vocal Function Exercises Research Explained

Singers and SLPs listen up! If you have ever heard of Vocal Function Exercises (a staple in our field since Joe Stemple and team introduced the early concept in 1994) you may have someone recommend them to you. But have you wondered if you could modify them and still get a good warm up effect on your vocal cords? What if you wanted to do less SOVT? Would changing it to /a/ be harmful by causing hyperfunction of the voice box?

Joe Stemple, Richard Andreatta, Dan Croake, Vrushali Angadi, Megan Brown and Maria Bane for a 2019 study, rounded up some folks with no voice disorders and set out to answer these questions. 

Original Vocal Function Exercises were completed as you see here:

Eeeeee, oooooo, ooooooo, oooooox5 starting on middle C for females and an octave below for males


Why the weird mouth postures? Well, semi occluded vocal tract modifications actually occlude the vocal tract partially and keep the cords slightly separated due to the build up of positive intraoral pressure. Parallel vocal cords lessen the physical effort and improve vocal economy. 

What happened when they looked at modifications to the SOVT component? They had the people practice VFE’s twice daily for 6 weeks. One group did traditional VFE’s, the second modified them to include no nasality and a less occluded /o/ and the third again did no nasality and a less occluded /a/. 


What is the magic bullet for VFE’s, or the thing that makes them so special? The Mechanism of change? It is semi occlusion and active ingredient of the VFE’s, so you should know this if you’re trying to improve voice box efficiency and economy for yourself or your patients.  

The /a/ phoneme? Caused no swelling, lesions or redness. SWEET! It also resulted in the greatest maximum phonation time (or ability to hold out a single /a/ note) so if your patient’s goal is this, consider this modification with no fear for any hyperfunction. 

What happens after you stop the regimen? The modified groups improved how long they could hold out a sound. And after they stopped the practice for 6 weeks, all groups declined in the ability to hold the sound out as long. If you don’t use it, you lose it. 

What if people have trouble with SOVT /o/? Modified /o/ can be easier for people to complete, and might be the difference in confidence for them to complete the exercises at all. (singers versus non singers, introverts vs extroverts) 


Remember, this study looked at people with non-disordered voices, so be careful when drawing general conclusions for the disordered population based on what they found. Researchers are awesome humans and we rely on them in the trenches of real life clinical practice. 

If you want more reading on this study, here is the reference:

Bane, M., Brown, M., Angadi, V., Croake, D. J., Andreatta, R. D., & Stemple, J. C. (2019). Vocal function exercises for normal voice: With and without semi-occlusion. International journal of speech-language pathology, 21(2), 175–181. https://doi.org/10.1080/17549507.2017.1416176

Kristie Knickerbocker, MS, CCC-SLP, is a speech-language pathologist and singing voice specialist in Fort Worth, Texas. She rehabilitates voice and swallowing at her private practice, a tempo Voice Center, and lectures on voice science nationally. She is part of the Professional Development Committee for ASHA Special Interest Group 3, Voice and Upper Airway Disorders, and a member of the National Association of Teachers of Singing and the Pan-American Vocology Association. Knickerbocker blogs on her website at  www.atempovoicecenter.com. She has developed a line of kid and adult-friendly therapy materials specifically for voice on TPT or her website. Follow her on Pinterest, on Instagram or like her on Facebook. Also check out what she and her partners are building at www.confidentclinician.com.


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