Functional voice disorders: Clinical presentations and differential diagnosis.

In this chapter, an overview of the heterogeneous group of functional voice disorders is given, including the psychogenic voice disorder (PVD) and hyperfunctional or muscle tension voice disorder (MTVD) subgroups. Reference is made to prevalence and demographic data, with empiric evidence for psychosocial factors commonly associated with the onset and maintenance of these disorders. Clinical features that distinguish between the different presentations of PVD and MTVD are described. While there are some shared characteristics, key differences between these two subgroups indicate that PVD more closely resembles the psychogenic movement disorders and a range of other functional neurologic disorders. Assessment procedures and auditory-perceptual features of the voice that distinguish these disorders from the neurologically based voice disorders are discussed, with case examples highlighting ambiguous features that may influence differential diagnosis. The clinical profiles of PVD and MTVD affirm approaches to clinical management by speech-language pathologists that integrate symptomatic behavioral voice therapy with "top-down" models of counseling or psychotherapy. They also support the proposition that PVD may be construed as a subtype of functional neurologic disorders.