Prediction of laryngeal aspiration using voice analysis.

OBJECTIVE

To determine the diagnostic value of voice analysis to screen for patients with high risk of clinically significant aspiration.

DESIGN

A total of 93 patients referred for a videofluoroscopic swallowing study were included in the study. Voice analyses were performed before and after videofluoroscopic swallowing study, and five acoustic variables were measured, including average fundamental frequency, relative average perturbation, shimmer percentage, noise-to-harmonic ratio, and voice turbulence index. The patients were divided into two groups based on the results of the videofluoroscopic swallowing study: a high-risk group with patients who had the ingested materials on or below the vocal cords and a low-risk group with patients who did not have the ingested materials on or below the vocal cords. The changes of each acoustic variable before and after the videofluoroscopic swallowing study were compared between the two groups.

RESULTS

Relative average perturbation, shimmer percentage, noise-to-harmonic ratio, and voice turbulence index were significantly increased after videofluoroscopic swallowing study in the high-risk group as compared with the low-risk group (P < 0.05). The change of average fundamental frequency, however, was not significantly different between the two groups (P > 0.05). According to the receiver operating characteristics curve, the sensitivity of these acoustic variables in detecting aspiration or penetration ranged from 68.9% to 91.1% and specificity ranged from 68.8% to 97.9%. Relative average perturbation was the most accurate variable, with a sensitivity of 91.1% and a specificity of 97.9% in predicting aspiration or penetration. The combination of relative average perturbation and noise-to-harmonic ratio increased the sensitivity to 100% but reduced the specificity to 77.1%.

CONCLUSION

Voice analysis is a safe, noninvasive, and reliable screening tool for patients with dysphagia and can detect patients at high risk of clinically significant aspiration, thereby augmenting clinical bedside examination.