Does the Acoustic Voice Quality Index (AVQI) Correlate with Perceived Creak and Strain in Normophonic Young Adult Finnish Females?

BACKGROUND

The Acoustic Voice Quality Index (AVQI) is a correlate of dysphonia. It has been found to differentiate between dysphonic and normophonic speakers and to indicate the effects of voice therapy. This study investigates how the AVQI reacts towards creak and strain, which are common in normophonic speakers.

METHODS

The material was obtained from an earlier study on 104 Finnish female university students (mean age 24.3 years, SD 6.3 years) with no known pathology of voice or hearing and a perceptually normal voice (G = 0 in GRBAS), who were recorded while reading aloud a standard text and sustaining the vowel [a:]. Perceptual analysis for the amount of creak and strain was carried out by 2 expert listeners. In this study, the AVQI v03.01 was analyzed and correlated with perceptual evaluations. Samples with low and high amounts of creak and strain were compared with t tests.

RESULTS

On average, the AVQI was below the threshold value of dysphonia in the Finnish population. The AVQI (ρ = 0.35, p = 0.000) and its subparameters, smoothed cepstral peak prominence (CPPS; ρ = -0.35, p = 0.000) and harmonics-to-noise ratio (HNR; ρ = -0.30, p = 0.002) showed low but significant correlations with creak. Strain had low but significant correlations with spectral Slope (ρ = 0.38, p = 0.000) and Tilt (ρ = -0.40, p = 0.009). The AVQI was lower (better) in samples that were evaluated as having a high amount of strain, but the difference was not significant. Only CPPS differentiated significantly between low and high amounts of creak.

CONCLUSION

The AVQI does not seem to differentiate between high and low amounts of creak and strain in normophonic speakers.

Feature Maps of the Acoustic Spectrum of the Voice

The change in the spectrum of sustained /a/ vowels was mapped over the voice range from low to high fundamental frequency and low to high sound pressure level (SPL), in the form of the so-called voice range profile (VRP). In each interval of one semitone and one decibel, narrowband spectra were averaged both within and across subjects. The subjects were groups of 7 male and 12 female singing students, as well as a group of 16 untrained female voices. For each individual and also for each group, pairs of VRP recordings were made, with stringent separation of the modal/chest and falsetto/head registers. Maps are presented of eight scalar metrics, each of which was chosen to quantify a particular feature of the voice spectrum, over fundamental frequency and SPL. Metrics 1 and 2 chart the role of the fundamental in relation to the rest of the spectrum. Metrics 3 and 4 are used to explore the role of resonances in relation to SPL. Metrics 5 and 6 address the distribution of high frequency energy, while metrics 7 and 8 seek to describe the distribution of energy at the low end of the voice spectrum. Several examples are observed of phenomena that are difficult to predict from linear source-filter theory, and of the voice source being less uniform over the voice range than is conventionally assumed. These include a high-frequency band-limiting at high SPL and an unexpected persistence of the second harmonic at low SPL. The two voice registers give rise to clearly different maps. Only a few effects of training were observed, in the low frequency end below 2 kHz. The results are of potential interest in voice analysis, voice synthesis and for new insights into the voice production mechanism.

Diagnosis and staging of caries using spectral factors derived from the blue laser-induced autofluorescence spectrum

OBJECTIVE

The aim of this study was to identify the factors derived from the 405nm laser-induced autofluorescence (AF) spectra that could be used to diagnose and stage caries.

MATERIALS AND METHODS

Teeth (20 teeth per stage) were classified as sound, stage II, III, and IV based on a visual and tactile inspection. The specimens were re-examined and reclassified based on micro-CT analysis. From the teeth, the AF was obtained using a 405nm laser. Three spectral factors (spectral slope at 550-600nm, area under the curve at 500-590nm, and two-peak ratio between 625 and 667nm) were derived from the AF spectra. Using these factors, the diagnosis and staging of caries were tested, and the results were compared with those of DIAGNOdent.

RESULTS

After micro-CT analysis, only 13, 11, and 13 teeth were reclassified as stages II, III, and IV, respectively. The reclassified groups showed less data overlap between the stages, and the spectral slope was 40.1-74.6, 27.5-39.6, 11.1-27.4, and 1.0-9.7 for sound, stage II, III, and IV, respectively. The differentiation of stages III and IV using DIAGNOdent appeared to be difficult due to the considerable data overlap.

CONCLUSION

Among the factors tested, the spectral slope at 550-600nm showed the best match with the caries specimens, in which their stage had been identified precisely.

CLINICAL SIGNIFICANCE

The 405nm laser-induced AF spectra can be applied to the diagnosis and staging of caries alone or in conjunction with conventional methods, such as visual, tactile, and X-ray inspection.