Onset and offset phonation threshold flow in excised canine larynges

Area of Science:

• Laryngology and Voice Science
• Biophysics of Phonation
• Aerodynamics of Speech

Background:

• Understanding phonation requires knowledge of airflow dynamics.
• The phonation threshold flow (PTF) is a key parameter, with distinct onset and offset values.
• Previous research has not fully elucidated the relationship between onset and offset PTF.

Purpose of the Study:

• To test if onset PTF is greater than offset PTF.
• To determine if the ratio of offset PTF to onset PTF falls within the range of 0.707 to 1.0.
• To explore the diagnostic potential of PTF values in voice assessment.

Main Methods:

• A methodology study using 10 excised canine larynges.
• Measuring onset and offset phonation threshold flow (PTF) and phonation threshold pressure (PTP).
• Analyzing the ratio of offset PTF to onset PTF in normal and pathologic-like larynges.

Main Results:

• Offset PTF was consistently lower than onset PTF (P << .0001).
• 80% of the observed onset-offset PTF ratios were within the predicted range of [0.707, 1.0].
• Hypotheses regarding PTF values were supported by the experimental data.

Conclusions:

• Onset and offset PTF values show potential as diagnostic parameters for voice disorders.
• Combining PTF with PTP can help characterize laryngeal resistance and aerodynamic power.
• Further research into PTF relationships can improve clinical voice diagnostics and phonation theories.