Oscillatory Flow
Weekly Teaching Tip
by Dr. Curt Stock
I am reminded of the comments by Professor Ken Bozeman at last year’s IVTOM conference in Atlanta: “There is so much new science being discovered about the voice that we could have a voice conference every month and still not cover it.”
I don’t pretend to be an expert on the voice and only try to understand voice science adequately in order to direct my speech and voice patients toward healthy habits. In the voice clinic, we like to listen to the patient sing and measure vocal parameters to get an idea of how well they move through their bridges and to sense if they are pressing or too breathy, etc.
Then after about 30 minutes of talking and singing we do a strobe. I want to show a montage of a singer who never had complete closure and was 100% open, with 0% closed quotient, As we all know, the open phase to closed phase in one vocal cycle should be around 50/50 in the speaking voice. You will see in this montage on video strobe that there is some mucous on the right vocal fold posteriorly, mild edema posteriorly of the left vocal fold and some anterior posterior compression from the epiglottis petiole and the arytenoids. The arytenoids do come together and there is some bowing which is unusual for someone under 60 years old. All in all, this patient needed massage and voice therapy to include straw exercises to relax the muscles and maintain better balance of the airflow.
I talked with Dr. Ingo Titze about this case and airflow in general and the use of the straw. This was his response. “Aerodynamic power is the product of pressure and flow. Only oscillatory flow is acoustic and therefore relates to sound. You feel very little oscillatory flow. Steady flow which you can feel produces no sound. Hence, pedagogically, I am not a proponent regulating solely with airflow, but using a balanced approach.”
Anyhow, this is another opinion we should consider and ponder.
