1. What is the S/Z Ratio?

Definition: The S/Z ratio is a measurement comparing the duration of sustained /s/ and /z/ sounds in speech.

Purpose: It's used in speech pathology and voice assessment to evaluate laryngeal function and vocal fold vibration.

2. How Does the S/Z Ratio Work?

The calculator uses the formula:

Where:

• \( \text{S/Z} \) — S/Z ratio (dimensionless)
• \( S_{\text{duration}} \) — Duration of sustained /s/ sound (seconds)
• \( Z_{\text{duration}} \) — Duration of sustained /z/ sound (seconds)

Explanation: The ratio compares how long a person can sustain the voiceless /s/ sound versus the voiced /z/ sound.

3. Importance of S/Z Ratio

Details: A normal S/Z ratio is approximately 1.0. Higher ratios may indicate vocal fold pathology, as the /z/ sound requires vocal fold vibration which may be impaired.

4. Using the Calculator

Tips: Measure the maximum duration a person can sustain the /s/ and /z/ sounds separately, then enter these values in seconds.

5. Frequently Asked Questions (FAQ)

Q1: What does a high S/Z ratio indicate?
A: A ratio significantly greater than 1.0 (typically >1.4) may suggest vocal fold pathology or incomplete glottic closure.

Q2: How should the sounds be produced for testing?
A: The patient should sustain /s/ and /z/ at comfortable pitch and loudness, with maximum duration on a single breath.

Q3: What's considered a normal S/Z ratio?
A: Normally, the ratio is close to 1.0 (range 0.8-1.2). Values above 1.4 are considered abnormal.

Q4: Can this test diagnose specific voice disorders?
A: While it can indicate potential problems, it's not diagnostic by itself and should be used with other assessments.

Q5: How many trials should be conducted?
A: Typically 3 trials for each sound, with the longest durations used for calculation.