Visualizations by acoustics of voice stress. Is there an optical mucosal wave correlate based on HSDI?
We present data on how stress is manifested in the human voice by analyzing acoustic and phonetic structure of live recordings from the Police 997 emergency call center number in Poland. From the data corpus comprising thousands of authentic Police 997 emergency phone calls, a few hundred were automatically selected according to their duration (calls shorter than 3-4 seconds were omitted), and finally from this corpus, voices of 45 speakers were chosen for acoustic analysis and were contrasted to neutral samples. Statistical measurements for stressed and neutral speech samples showed relevance of the arousal dimension in stress processing. The MDVP analysis confirmed statistical significance of the following parameters in voice stress detection: fundamental frequency, pitch variation, noise-to-harmonic-ratio, sub-harmonics, and voice irregularities. In highly stressful conditions, a systematic over-one-octave shift in pitch was observed. Linear Discriminant Analysis based on nine acoustic features showed that it is possible to categorize the following classes of male and female stressed and neutral characteristics.