engleski

Early glottic cancer - vibratory and acoustical analysis

The retrospective 20 years analysis included patients with hoarseness caused by vocal fold cancer and risky vocal fold epithelial lesions. All the patients were preoperatively investigated by stroboscopical and acoustical methods and the data were correlated to histological findings obtained during laryngomicroscopical biopsy. Although the methods of stroboscopical and acoustical analysis have changed with time, correlation between stroboscopical and acoustical parameters was evident. In majority of patients with stiff and non-vibratory vocal fold acoustical analysis demonstrated the signs of fundamental tone instability and those results did not depend on the method of vibratory vs. acoustical analysis applied. In the past, stroboscopy was utilized in the technique of indirect laryngoscopy while nowadays we use digital endovideolaryngoscopy with simultaneous PC AV recording. This new method enabled us to observe glottic wave in detail (wave-like movement of the mucous membrane) and to correlate reduced or absent glottic wave with the acoustical pattern. We developed some other tests as well, like provoked Bernoulli phenomenon in forced inspiratory phonation to test elasticity of the vocal fold cover. Acoustical voice analysis can determine objective and comparable elements of acoustical voice signal. In our research we use the following parameters: duration of phonation, No. of voice breaks, jitter (local), shimmer (local), shimmer (local) dB, F0, periodicity to noise ratios of sounding frames (HNR) and intensity of voice in dB. We found the quick changes of the FO (jitter) were important in controlling the regularity of vocal fold movement. When comparing the acoustical analysis to subjective voice evaluation, we can follow – up the progress in therapy. Our results suggest that in cases of morphologically risky fold lesion, pathological acoustical finding (unstable fundamental tone or pathological jitter) could help us in decision to do an urgent vocal fold biopsy. Such conclusions are supported by high correlation in our investigation between pathological vibratory, pathological acoustical and histologically proved early vocal fold cancer.

hoarseness; vocal folds; laryngeal neoplasms; voice acoustics; laryngoscopy

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