[Digital analysis of the acoustic signal in vocal pathology diagnosis. Sensitivity and specificity of shimmer and jitter measurements].

OBJECTIVE

The aim of this study was to calculate the sensitivity and specificity of shimmer (APQ) and jitter (RAP) in the diagnosis of vocal pathology.

PATIENTS AND METHODS

Digital audio tape (DAT) recorded voices of 64 hoarse patients (20 men and 44 women) and 64 persons without hoarseness (20 men and 44 women), all professional teachers, were analyzed acoustically. The vowel /a/ was analyzed physically using Sound Scope software. Eight parameters were examined using Sound Scope 1.0: amplitude of the perturbation quotient (APQ), harmonics-to-noise ratio (HNR), breathiness (BR), relative average perturbation (RAP), fundamental frequency (F0) and the standard deviation (SD) of F0, and intensity and its SD.

RESULTS

Taking 5.5% as a normal APQ value for this algorithm, the sensitivity was 0.75 and the specificity was 0.64. Seventy percent of the normal teachers had a RAP below 0.40% in women and below 0.32% in men, and 85% of hoarse teachers had higher values than those reported by us. As for BR, taking 17.5 dB as a normal reference, this algorithm had a sensitivity of 0.73 and a specificity of 0.41.

CONCLUSIONS

Individual study of these tests is interesting because each one measures a different aspect of vocal function. They are most useful when studied together.