Acoustic measurement of change in voice quality with treatment for chronic posterior laryngitis

Sixteen patients who had symptoms and signs of chronic posterior laryngitis were evaluated before, during, and after treatment with omeprazole and nocturnal antireflux precautions. Data were analyzed for patients who complained of some hoarseness, who had no smoking history, and who completed all of the voice recording protocol. The patients' voices were recorded before, during, and following treatment with omeprazole and nocturnal antireflux precautions. Voice quality was analyzed by perceptual analysis, and acoustic signal data were measured for jitter, shimmer, and signal-to-noise ratio. Measures of jitter, shimmer, and signal-to-noise ratio changed significantly with treatment of posterior laryngitis (p < .01 for change in each of the measures). Acoustic measures showed some trend of deterioration with cessation of treatment, although the overall improvement in acoustic measures of voice quality was still statistically significant after treatment with omeprazole was discontinued. Although perceived abnormality of voice increased and decreased with the magnitude of measured perturbation of the acoustic signal for some patients, the perceptual assessments were not highly correlated with acoustic measures for individual patients, and the perceptual analysis group data did not show a significant change with time during treatment, in contrast to the significance of change in acoustic measures. The data demonstrate that acoustic measures of jitter, shimmer, and signal-to-noise ratio improve significantly with antisecretory and antireflux treatment of chronic posterior laryngitis, and that for individual patients, these are changes that are detected by trained listeners, but not at statistically high levels of confidence.