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[S/z ratio in glottic closure defects]
F J Gamboa1, A Nieto, A J del Palacio
1Servicio de ORL, Hospital Príncipe de Asturias, Insalud, Universidad de Alcalá de Hénares.
Acta Otorrinolaringologica Espanola
|January 1, 1995
Summary
The s/z ratio, comparing /s/ and vowel sound duration, helps detect laryngeal pathology. A ratio over 1.4 indicates a glottic closure defect, aiding in diagnosing vocal cord issues.
Area of Science:
- Laryngology
- Speech-Language Pathology
- Bioacoustics
Background:
- The s/z ratio quantifies expiratory airflow resistance.
- It differentiates between glottic and supraglottic airflow resistance.
- This ratio minimizes respiratory influence on phonation time measurements.
Purpose of the Study:
- To assess the s/z ratio's clinical utility for identifying laryngeal pathology.
- To correlate s/z ratio values with the severity of glottic closure defects.
Main Methods:
- Measured the s/z ratio in 72 patients with organic vocal cord pathology.
- Assessed glottic closure using videolaryngostroboscopy.
- Measured the s/z ratio in 22 healthy subjects for comparison.
Main Results:
- Normal-speaking subjects exhibited an s/z ratio near 1.0.
- Patients with glottic closure defects showed an s/z ratio exceeding 1.4.
- Organic lesions impairing glottic closure reduced airflow resistance, shortening vowel phonation time.
Conclusions:
- The s/z ratio is a valuable clinical indicator for laryngeal pathology.
- An s/z ratio > 1.4 suggests impaired glottic closure.
- This non-invasive measure aids in diagnosing vocal cord dysfunction.