DDK Acoustic Analysis and Swallowing Indicators

Classification of swallowing function based on the Repetitive Saliva Swallowing Test (RSST). Participants will be classified as having normal RSST performance if they complete greater than or equal to 3 swallows in 30 seconds, and abnormal RSST performance if they complete fewer than 3 swallows in 30 seconds.

Total score on the Eating Assessment Tool-10 (EAT-10), a 10-item self-report questionnaire used to assess swallowing-related symptoms. The total score ranges from 0 to 40, where higher scores indicate worse swallowing-related symptoms. A score of 3 or higher suggests possible swallowing difficulty.

Rate of repeated diadochokinetic speech productions of /pa/, /ta/, and /ka/. The rate will be reported as syllables per second.

Fundamental frequency (F0) extracted from repeated diadochokinetic (DDK) speech recordings of /pa/, /ta/, and /ka/. Fundamental frequency will be reported in Hertz (Hz).

First formant frequency (F1) extracted from repeated diadochokinetic (DDK) speech recordings of /pa/, /ta/, and /ka/. F1 reflects the first resonance frequency of the vocal tract and will be reported in Hertz (Hz).

Second formant frequency (F2) extracted from repeated diadochokinetic (DDK) speech recordings of /pa/, /ta/, and /ka/. F2 reflects the second resonance frequency of the vocal tract and will be reported in Hertz (Hz).

Jitter extracted from repeated diadochokinetic (DDK) speech recordings of /pa/, /ta/, and /ka/. Jitter reflects short-term cycle-to-cycle variability in fundamental frequency and will be reported as a percentage.

Shimmer extracted from repeated diadochokinetic (DDK) speech recordings of /pa/, /ta/, and /ka/. Shimmer reflects short-term variability in voice amplitude and will be reported in decibels (dB).

Harmonics-to-noise ratio (HNR) extracted from repeated diadochokinetic (DDK) speech recordings of /pa/, /ta/, and /ka/. HNR reflects the ratio of periodic harmonic energy to noise energy in the voice signal and will be reported in decibels (dB).

Root mean square (RMS) amplitude extracted from repeated diadochokinetic (DDK) speech recordings of /pa/, /ta/, and /ka/. RMS amplitude reflects the average acoustic energy of the speech signal and will be reported in normalized amplitude units.

Zero-crossing rate (ZCR) extracted from repeated diadochokinetic (DDK) speech recordings of /pa/, /ta/, and /ka/. ZCR reflects the rate at which the speech signal changes sign over time and will be reported as the number of zero crossings per second.

Age of participants collected at baseline, reported in years.

Sex of participants collected on Day 1, reported as male or female according to the study case report form.

Highest level of education completed by participants collected at baseline, categorized as primary school or below, junior high school, senior high school, or college or above.

Body mass index (BMI) calculated from measured height and weight at baseline. Height will be measured in meters and weight in kilograms; BMI will be reported in kg/m².

Dentition status of participants collected at day 1, categorized as natural dentition, partial denture, full denture, or other.

Self-reported frequency of dry mouth symptoms collected at day 1, categorized as never, occasionally, frequently, or always.

Self-reported smoking history collected at baseline, categorized as never smoker, former smoker, or current smoker.

Self-reported medical history collected at day 1 and categorized as none, hypertension, hyperglycemia, hyperlipidemia, or gastrointestinal disease (such as gastroesophageal reflux disease).