The Dysphonia Severity Index

TLDR

The Dysphonia Severity Index (DSI) provides an objective, quantitative correlate of perceived vocal quality. The study derives the DSI from a multivariate analysis of 387 subjects to describe perceived voice quality using objective measures. The DSI is calculated as a weighted sum of highest frequency, lowest intensity, maximum phonation time, and jitter, using the formula DSI = 0.13 × MPT + 0.0053 × F(0)-High – 0.26 × I-Low – 1.18 × Jitter + 12.4. DSI scores range from +5 for normal voices to –5 for severely dysphonic voices, with more negative values indicating worse quality; the index correlates strongly with the Voice Handicap Index, making it useful for tracking therapeutic progress.

Abstract

The vocal quality of a patient is modeled by means of a Dysphonia Severity Index (DSI), which is designed to establish an objective and quantitative correlate of the perceived vocal quality. The DSI is based on the weighted combination of the following selected set of voice measurements: highest frequency (F(0)-High in Hz), lowest intensity (I-Low in dB), maximum phonation time (MPT in s), and jitter (%). The DSI is derived from a multivariate analysis of 387 subjects with the goal of describing, purely based on objective measures, the perceived voice quality. It is constructed as DSI = 0.13 x MPT + 0.0053 x F(0)-High - 0.26 x I-Low - 1.18 x Jitter (%) + 12.4. The DSI for perceptually normal voices equals +5 and for severely dysphonic voices -5. The more negative the patient's index, the worse is his or her vocal quality. As such, the DSI is especially useful to evaluate therapeutic evolution of dysphonic patients. Additionally, there is a high correlation between the DSI and the Voice Handicap Index score.