Laboratory investigation of the abnormal voice.

The patient with an abnormal voice has variously been investigated by laryngologists and speech pathologists, the diagnosis being based on visualization of the larynx and the sound of the voice. With the advent of phoniatric surgery, for example augmentation of the vocal cord and recurrent nerve section for spastic dysphonia, more objective means of quantifying abnormalities and results became pressing. Investigation of dysphonia where obvious lesions of the vocal cords were absent required further laboratory methods. The advent of microprocessors and fiberoptic endoscopy allows research methods to be applied clinically with better ability to diagnose and document patients with voice disorders. This paper outlines the experience of a voice laboratory and tries to assess the relevance of laboratory tests to clinical practice.