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Voxtar DevelopersAPI Reference / v1
Biomarkersv1

Respiratory Panel

The respiratory panel reads breath support, airway turbulence, and phonatory efficiency from speech. It is most sensitive on a sustained vowel ("aaah") or a standard read passage, and is designed to surface drift in conditions like asthma, COPD, and lower-respiratory infection before a patient reports worsening symptoms.

Features

Each feature is returned raw under panels.respiratory.features and folded into the panel score.

FeatureMeaning
shimmerCycle-to-cycle amplitude variation. Rises with airway irritation and reduced breath support.
hnr_dbHarmonics-to-noise ratio (dB). Falls as breathiness and turbulence increase.
expiratory_ratioShare of the utterance spent on the outbreath. Shortens as expiratory effort drops.
cppCepstral peak prominence. A robust marker of dysphonia and vocal fold efficiency.
mpt_sMaximum phonation time on a sustained vowel (s). A direct proxy for respiratory reserve.

Best elicitation

Pass task: "sustained_vowel" for the cleanest respiratory signal, or task: "cough" when a forced expiratory sample is available. Aim for ≥5 seconds at 16kHz or higher in a quiet room.

Drift, not diagnosis

The panel reports how far a sample sits from the patient's own baseline — it is a screening and monitoring signal, not a diagnosis. See Interpreting Scores for how score, baseline_z, and drift relate.