Phonation Threshold Pressure (PTP or Pth) is defined as the minimum level of lung pressure required to sustain phonation at a given pitch.

• A. The maximum alveolar pressure during phonation.
• B. The minimum lung pressure needed to initiate and maintain phonation.
• C. The average subglottal pressure during sustained phonation.
• D. The peak airflow rate through the glottis.

Answer: (B)

PTP is the minimum pressure from the lungs that must be present beneath the vocal folds to start and keep them vibrating at a given pitch. It reflects the driving force needed to overcome the glottal resistance and tissue damping so phonation can begin and be sustained. This is a threshold concept, not about the most or average pressure or about airflow rate. Therefore, the statement that identifies the minimum lung pressure needed to initiate and maintain phonation best captures what phonation threshold pressure represents.