Instrumental Assessment of Voice Disorders

Instrumental assessment is a key component to understanding phonatory function and vocal output. Instrumental voice assessments can also contribute significant information to enable differential diagnosis and inform management decisions for disordered voices. Some instrumental assessment tools can also be used as voice outcome measures, that is, to measure change over time. Almost all instrumental voice assessment tools require interpretation and are therefore not strictly objective. Careful administration of procedures and interpretation are required to maximize validity and protect against possible sources of bias and unreliability.

Phonation may be described as the integration of four main subsystems: vocal fold vibration, pulmonary egressive airflow, vocal tract resonance, and sound signal output from the mouth. Interestingly, only three of these subsystems of phonation have well-developed assessment instrumentation. The first ...