Neurological Concomitants in Spasmodic Dysphonia
By Lyn Dee Harrelson

Differential Diagnosis

Duffy (1995) suggests that the etiology can be neurogenic, psychogenic, and idiopathic, while Higgins, Chait, and Schulte (1999) argue this by stating "Although there has been some reference to psychogenic cases of AdSD that do respond to voice therapy, Sapir (1995) has argued that such disorders must be clearly distinguished as nonorganic entities that merely share some of the symptoms of AdSD." Other similar disorders are musculoskeletal tension dysphonia and psychogenic dysphonia.

SD is as common in women as it is in men. In the past few years there has been an increase in the number of identified cases of SD. There are some reports of a relation of SD to a familial history of the disorder.

diagnosis of SD is very difficult. In most cases, SD is not identified usually until a year post onset. It can be triggered by a number of incidences such as a cold or flu, and is sometimes associated with a life event or trauma, while others reported that their voice disorder began with mild symptoms and developed into spasmodic dysphonia. Here are some differentiating characteristics of SD along with some similar voice disorders.

Case History

MTD (Musculoskeletal Tension Dystonia)
  • generally reports stressful events during the onset of symptoms
PD (Psychogenic Dystonia)
  • generally reveals a traumatic life event or stress
SD (Spasmodic Dysphonia)
  • generally reports an increase in stress since the onset of symptoms

Voice Symptoms

MTD voice symptoms are consistent and are not influenced by phonemic context
somewhat predictable episodes of vocal tension
tension visible during direct examination
persons respond well to voice therapy
PD voice problems may vary but show variability within phonemic contexts
unique voice characteristics present with no developing patterns
possible reports of the voice returning for hours, days, weeks, or months at a time
symptoms are not present during reflexive phonation acts
respond well to voice therapy
SD voice has limited variability with consistencies in various phonemic contexts
return of normal voice characteristics as with PD
symptoms reflect the nature of the underlying etiology (spastic)
do not respond well to therapy

Spasmodic Dysphonia Neurological Concomitants Differential Diagnosis Treatment Links