Vital capacity & airflow measurement for voice evaluation: A vortex whistle system

PROJECT SUMMARY/ABSTRACT Comprehensive voice evaluation requires assessment of the essential subsystems, including the respiratory subsystem. However, surveys of assessment and treatment practices by speech-language pathologists (SLPs) both in and outside of the United States indicate that respiratory and aerodynamic measures are rarely used in the assessment of voice disorders, mainly due to lack of access to expensive equipment. The proposed series of studies seeks to overcome this serious deficiency in the voice assessment practice of SLPs by combining concepts and techniques from clinical voice science, acoustics, statistical methods, and aerodynamic engineering. The result will provide accurate, low-cost measures of respiratory capacity and phonatory airflow via the development and validation of a uniquely designed vortex whistle and accompanying signal analysis software. A vortex whistle is a non-mechanical, non-electronic device that provides a whistle frequency that varies proportional to the inlet airflow rate. When frequency is mapped to the inlet airflow rate, the area under the frequency-flow curve obtained from the vortex whistle can be used as an estimate of volume. Rather than a replacement for spirometry and other pneumotachometer-based aerodynamic instrumentation, our vortex whistle design is optimized to obtain accurate measures of vital capacity (VC) and mean phonatory airflow (PA) in sustained voicing that have important application to the assessment of respiratory and laryngeal function essential for effective voice production. The vortex whistle can be manufactured for a tiny fraction of the cost of pneumotachometer-based or other aerodynamic instrumentation. In addition, the platform-independent analysis software can be used with low-cost computers and can be easily translated to mobile platforms. The specific goals of this project are to: (1) develop a more complete understanding of the acoustic- aerodynamic capabilities of the vortex whistle via computational aeroacoustic (CAA) modeling, (2) assess hardware and software analysis modifications that can optimize the ability to provide accurate VC and PA estimates from the vortex whistle via physical aeroacoustic (PAA) modeling that incorporates an actuated syringe methodology for the production of highly controlled and repeatable airflows and volumes, (3) compare and correlate measures of VC and PA obtained via the vortex whistle system (VWS) with high-quality pneumotachometer-based aerodynamic instrumentation including the Koko SX 1000 spirometer and the Phonatory Aerodynamic System (PAS), (4) correlate voicing onset frequency-flow characteristics with underlying driving pressure (Psub), and (5) demonstrate the VWS as a noninferior alternative to “gold” standard pneumotachometer-based instrumentation for measures of VC and PA in groups of nondysphonic subjects across the lifespan and as a treatment outcome measure in a group of unilateral vocal fold paralysis (UVFP) patients pre- and post-surgical medialization.