Cepstral Peak Prominence Values for Clinical Voice Evaluation.
Olivia Murton, Robert Hillman, Daryush Mehta
PMID 32658592WHAT IT FOUND
Cepstral peak prominence values below 11.46 dB for sustained /a/ vowels and 6.11 dB for the Rainbow Passage indicate a voice disorder in ADSV.
Praat thresholds are 14.45 dB and 9.33 dB. These cutoffs help screen for dysphonia in English speakers using these common software tools.
Key findings
01ADSV-based CPP values below 11.46 dB for sustained vowels and below 6.11 dB for continuous speech are indicative of a voice disorder in English speakers.
02Praat-based CPPS values below 14.45 dB for sustained vowels or below 9.33 dB for continuous speech indicate a high probability of the presence of a voice disorder.
03CPP values vary significantly by speech task due to unvoiced segments, so comparisons must use the same sentences or passages.
STILL TO COME
How it was doneWhat they foundWhat it means for SLPs
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What it does not show
The MEEI database used for Experiment 1 had a wide age range for patients (13-93 years) but a narrower range for controls (22-59 years), potentially affecting generalizability for older adults. Experiment 2 had a small sample size (32 speakers), leading to wide prediction intervals for severity estimates. CPP values are influenced by loudness and vowel quality, which were not controlled for in the comparisons. The study did not establish upper cutoff thresholds, so some disorders associated with abnormally high CPP (e.g., certain vocal hyperfunctions) might be missed.
Declared interests
Funding was provided by the National Institute on Deafness and Other Communication Disorders and the National Heart, Lung, and Blood Institute. No commercial conflicts of interest were reported by the authors.
The easy way to misread this
Do not assume these cutoffs apply to all speech tasks or software versions. CPP values change significantly based on the specific sentence read due to unvoiced segments, so comparing a Rainbow Passage score to a CAPE-V sentence score is invalid. Additionally, values near the cutoffs require clinical judgment, as the accuracy drops when applied to independent data.