Comparing vocal fold contact criteria derived from audio and electroglottographic signals

• Collision threshold pressure (CTP), i.e., the lowest subglottal pressure producing vocal fold contact during phonation, is a parameter likely to reflect relevant vocal fold properties. The amplitude of an electroglottographic (EGG) signal or the amplitude of its first derivative (dEGG) has been used as the criterion of such contact. Manual measurement of CTP is time-consuming, making the development of a simpler, alternative method desirable. In this investigation we compare CTP values automatically derived from the dEGG signal to values measured manually, and to values derived from a set of alternative parameters, some obtained from audio and some from EGG signals. One of the parameters was the novel EGG wavegram, which visualizes sequences of EGG or dEGG cycles, normalized with respect to period and amplitude. Raters with and without previous acquaintance with EGG analysis marked the disappearance of vocal fold contact in dEGG and in wavegram displays of /pa:/-sequences produced with continuously decreasing vocal loudness by seven singer subjects. Vocal fold contact was equally accurately identified in displays of dEGG amplitude as of wavegram. Automatically derived CTP values showed high correlation with those measured manually, and with those derived from the ratings of the visual displays. Seven other parameters were tested as criteria of such contact. Mainly due to noise in the EGG signal, most of them yielded CTP values differing considerably from those derived from the manual and the automatic methods, while the EGG spectrum slope showed a high correlation. The possibility of measuring CTP automatically seems promising for future investigations.

Ämnesord

NATURVETENSKAP  -- Data- och informationsvetenskap -- Datavetenskap (hsv//swe)

NATURAL SCIENCES  -- Computer and Information Sciences -- Computer Sciences (hsv//eng)

NATURVETENSKAP  -- Data- och informationsvetenskap -- Språkteknologi (hsv//swe)

NATURAL SCIENCES  -- Computer and Information Sciences -- Language Technology (hsv//eng)

Nyckelord

Collision threshold pressure

vocal fold contact

wavegram

alpha

signal-to-noise ratio

EGG derivative

EGG spectrum slope

relative contact rise time

normalized amplitude quotient

relative dEGG amplitude

Publikations- och innehållstyp

ref (ämneskategori)

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