NORMAL VALUES AND PREDICTIVE EQUATIONS FOR AERODYNAMIC FUNCTION IN BRITISH CAUCASIAN SUBJECTS

Many useful objective measurements of air volume and flow may be made with a high degree of validity and reliability using present-day respi rometers within a speech clinic. We have studied measures of aerodynam ic function in 76 British Caucasian subjects and derived reference equ ations for mean flow rate (MFR), phonation quotient (PQ), vocal veloci ty index (VVI), phonation time and the phonation volume/vital capacity ratio. Measures from resting breathing patterns have also been invest igated. Age was found to be an important determinant in the reference equations. MFR, PQ and VVI were all greater than previously reported. The equations derived in this study should provide a more appropriate assessment of aerodynamic function than the previously reported normal ranges.