Influence of vowel selection on determination of phonation threshold pressure

Phonation threshold pressure values reported in the literature have largely been determined with use of one of three consonant-vowel sequences, /pi/, /pae/, and /pa/; however, it is not currently known if vowel choice influences phonation threshold pressure values. Based on the evidence that describes velopharyngeal closure variations between vowels, this research effort hypothesized that phonation threshold pressure values measured from the consonant-vowel sequence /pi/ would be significantly lower than the /pae/ and /pa/ sequences.

Twelve female participants aged between 20 and 27 years produced five-syllable trains of /pi/, /pae/, and /pa/ at low, modal, and high pitches.

A within-subject repeated measures approach was conducted to compare phonation threshold pressure value differences between the three consonant-vowel sequences for three different pitches while controlling for other task elicitation variables that may also influence phonation threshold pressure values.

Repeated measures analysis of the data indicated that there was no significant difference (P<0.05) in phonation threshold pressure values between the three consonant-vowel sequences at any frequency assessed. Further, for all three consonant-vowel sequences measured, significant differences of phonation threshold pressure magnitude were observed when comparing the high frequency versus the low and modal frequencies, a finding consistent with previous publications.

The vowel selected for task elicitation for phonation threshold pressure determination does not appear to significantly affect phonation threshold values, indicating flexibility of the vowel aspect of this measure for clinical use of phonation threshold pressure.