Related Experiment Video
Updated: Mar 27, 2026
A Protocol for Comprehensive Assessment of Bulbar Dysfunction in Amyotrophic Lateral Sclerosis ALS
Published on: February 21, 2011
Measurement Reliability of Phonation Quotient Derived From Three Aerodynamic Instruments
Ashwini Joshi1, Christopher R Watts2
1University of Houston, Houston, Texas.
Objective:
The purpose of this study was to examine parallel forms reliability between two hand-held spirometers and a pneumotachograph-based system for vital capacity and derived phonation quotient measurements.
Study Design:
This is a prospective, repeated measures design.
Methods:
A total of 20 adult males were tested using three aerodynamic instruments-Baseline windmill-type spirometer, Contec SP10 digital spirometer and the Pentax Medical Phonatory Aerodynamic System (PAS), Model 6600 for measures of vital capacity. Phonation quotient was calculated using vital capacity from each instrument along with maximum phonation time. Repeated measures analyses of covariance (ANCOVAs) were performed to test for main effects of the instruments on vital capacity and phonation quotient, with age as a covariate. Pearson Product Moment correlation was performed to assess measurement reliability between the instruments.
Results:
Statistically significant differences on ANCOVA were seen in vital capacity measures for the digital spirometer compared with the windmill spirometer and PAS. No differences were found between any of the instruments for phonation quotient. Large and positive correlations were present between all three instruments for both vital capacity and phonation quotient measurements.
Conclusions:
Strong parallel forms reliability in measures of vital capacity and derived phonation quotient was seen among the three instrument systems, although measurement precision was different when comparing the digital spirometer to two other instrument types.
Related Concept Videos
01:31Respiratory System Abnormal Finding II: Palpation and Auscultation
Palpation Findings
During a respiratory assessment, palpation can reveal several vital abnormalities:
01:28Physical Assessment of the Respiratory Tract IV: Auscultation
Breath Sounds
Breath sounds are categorized into vesicular, bronchovesicular, and bronchial.
01:29Assessment of Ventilation II: Respiratory Depth and Rhythm
Respiratory depth measures the volume of air inhaled or exhaled during a breath. It can vary from shallow to deep and typically remains consistent when a person is at rest or asleep. Occasionally, individuals will automatically inhale deeply, known as sighing, which inflates the lungs with more air than normal breathing.
To assess respiratory depth, observe the degree of chest excursion or movement:
01:29Physical Assessment of the Respiratory Tract III: Percussion
Percussion in Respiratory Assessment
Percussion evaluates underlying tissue composition with audible and tactile vibrations,...