Auditory-perceptual evaluation of disordered voice quality: pros, cons and future directions

Auditory-perceptual evaluation is the most commonly used clinical voice assessment method, and is often considered a gold standard for documentation of voice disorders. This view has arisen for many reasons, including the fact that voice quality is perceptual in nature and that the perceptual characteristics of voice have greater intuitive meaning and shared reality among listeners than do many instrumental measures. Other factors include limitations in the validity and reliability of instrumental methods and lack of agreement as to the most sensitive and specific instrumental measures of voice quality. Perceptual evaluation has, however, been heavily criticised because it is subjective. As a result, listener reliability is not always adequate and auditory-perceptual ratings can be confounded by factors such as the listener's shifting internal standards, listener experience, type of rating scale used and the voice sample being evaluated. This paper discusses these pros and cons of perceptual evaluation, and outlines clinical strategies and research approaches that may lead to improvements in the assessment of voice quality. In particular, clinicians are advised to use multiple methods of voice quality evaluation, and to include both subjective and objective evaluation tools.