Comparison of labial and mechanical interruption for measurement of aerodynamic parameters.
OBJECTIVE
To directly compare the mechanical and labial interruption techniques of measuring subglottal pressure (P(s)), mean flow rate (MFR), and laryngeal resistance (R(L)).


METHODS
Thirty-four subjects performed 10 trials with both mechanical and labial interruption. P(s) and MFR were recorded, whereas R(L) was calculated by dividing P(s) by MFR. Coefficients of variation were calculated to compare intrasubject precision. A subset of 10 subjects performed the tasks twice with 30 minutes between sessions. Bland-Altman plots were used to determine intrasubject repeatability for each of the methods.


RESULTS
Mechanical interruption produced coefficients of variation for P(s), MFR, and R(L) of 0.0995, 0.127, and 0.129, respectively. Labial interruption produced coefficients of variation of 0.102, 0.147, and 0.169, respectively. P values were 0.824 for P(s), 0.159 for MFR, and 0.043 for R(L). The Bland-Altman plots revealed comparable repeatability between the two methods. The 95% confidence intervals of the Bland-Altman plots for mechanical interruption were (-0.050, 0.072), (-0.543, 1.832), and (-2.498, 10.528) for MFR, P(s), and R(L). Confidence intervals for labial interruption were (-0.018, 0.031), (0.057, 2.442), and (-3.267, 10.595) for MFR, P(s,) and R(L).


CONCLUSIONS
Mechanical interruption produced higher precision when measuring R(L) because of more reliable airflow measurements. Mechanical and labial interruption showed comparable repeatability. Further research into using mechanical interruption clinically is warranted.
Chapin
William J
WJ
Division of Otolaryngology-Head and Neck Surgery, Department of Surgery, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, USA.
Hoffman
Matthew R
MR
Rieves
Adam L
AL
Jiang
Jack J
JJ
D002404:Catheterization; D045268:Flowmeters; D006801:Humans; D007830:Larynx / Q000502:physiology*; D010036:Otolaryngology / Q000295:instrumentation / Q000379:methods*; D010699:Phonation; D011312:Pressure; D015203:Reproducibility of Results; D012212:Rheology; D013061:Speech Acoustics; D013997:Time Factors; D014831:Voice