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A Protocol for Comprehensive Assessment of Bulbar Dysfunction in Amyotrophic Lateral Sclerosis ALS
Published on: February 21, 2011
An Oral Pressure Conversion Ratio as a Predictor of Vocal Efficiency
Ingo R Titze1, Lynn Maxfield2, Anil Palaparthi2
1National Center for Voice and Speech, The University of Utah, Salt Lake City, Utah; Department of Communication Sciences and Disorders, The University of Iowa, Iowa City, Iowa.
Abstract:
Voice production is an inefficient process in terms of energy expended versus acoustic energy produced. A traditional efficiency measure, glottal efficiency, relates acoustic power radiated from the mouth to aerodynamic power produced in the trachea. This efficiency ranges between 0.0001% and 1.0%. It involves lung pressure and hence would appear to be a useful effort measure for a given acoustic output. Difficulty in the combined measurement of lung pressure and tracheal airflow, however, has impeded clinical application of glottal efficiency. This article uses the large data base from Schutte (1980) and a few new measurements to validate a pressure conversion ratio (PCR) as a substitute for glottal efficiency. PCR has the potential for wide application because of low cost and ease of use in clinics and vocal studios.
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