Quasi-output-cost-ratio, perceived voice quality, and subjective evaluation in female kindergarten teachers.

This study estimated vocal economy and investigated its relation to perceived voice quality and self-reported symptoms of vocal fatigue in kindergarten teachers. Quasi-output-cost ratio (QOCR) was calculated for sustained vowel [a:] at habitual loudness and at sound pressure level (SPL) of 90 dB(6cm). QOCR was calculated as (SPL/CQ(EGG)) × T/T(0), where CQ(EGG) is the contact quotient measured from the electroglottogram, T is the period length, and T(0) is arbitrarily set mean period length (0.005 s in females). QOCR correlated negatively with perceived firmness at standard SPL and with the evaluation of too high pitch for the subject at both SPLs. QOCR did not predict self-reported vocal fatigue. Further studies with connected speech and objectively stated loading symptoms are warranted.