s/z ratio
Pronunciation: S over Z ratio
Clinical screening tool comparing voiceless /s/ to voiced /z/ sustained production times to detect potential voice disorders.
Full Definition
The s/z ratio is calculated by dividing the maximum sustained duration of the voiceless fricative /s/ by the maximum sustained duration of the voiced fricative /z/. Normal ratios are typically 1.0 or slightly less, as both sounds require similar articulatory and respiratory demands but differ in laryngeal involvement. Ratios exceeding 1.4 may suggest vocal fold pathology, as voice disorders often reduce the ability to sustain voiced sounds more than voiceless ones. This quick screening measure helps identify patients requiring comprehensive voice evaluation.
Usage
Usage note: Express as a numerical ratio (e.g., 1.4:1 or simply 1.4); ratios above 1.4 are considered abnormal.
In Context
- "The s/z ratio of 1.8 exceeded normal limits, warranting further voice evaluation." — Screening assessment report
- "Post-treatment s/z ratio normalized from 2.1 to 1.1, indicating improved vocal fold function." — Treatment outcome documentation