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Cause :
In most cases the cause of
spasmodic dysphonia is glottis2.gifunknown. Most Medical personnel believe that Spasmodic Dysphonia is a central nervous
system disorder and a focal form of dystonia.

Dystonia disorders are thought to be due to abnormal functioning in the area of the brain called the basal ganglia.The basal ganglia are structures situated deep in the brain.

The onset is usually gradual with no obvious explanation. Researchers are investigating possible reasons why individuals suffer from Spasmodic Dysphonia including familial factors, inflammation, and/or injury that may potentially lead to central nervous system changes in laryngeal motor control, but none of these factors have been confirmed as a cause. 

Spasmodic Dysphonia may occur with other dystonias such as blepharospasm, oromandibular dystonia, or cervical dystonia. 

Symptoms of Spasmodic Dysphonia :

Symptoms of spasmodic dysphonia differ, depending on the type of the disorder. 


The following are characteristics of the two different types:


1.       Adductor Type 

       A.   Vocal symptoms


         onset is characterized by nonspecific hoarseness , with associated “vocal catches”-pitch and phonation breaks that eventually evolve into complete laryngospasms

         patients with advanced form may present with strained, squeezed staccato phonation

         extreme phonatory effort results in little acoustic output

         vocal symptoms are most noticeable when attempting to communicate

         laughing, singing, non-communicative vocalizations and sometimes shouting are often unaffected

         abrupt voice breaks

         not intermittent- rarely goes away completely once it begins

         patients may report a good voice for brief periods upon awakening, and when they are extremely relaxed, as when drinking alcohol

         spectral analysis

         abrupt voice breaks,

         irregular wide spaced vertical striations,

         some high-frequency noise

         distinct well preserved formants


B.      Non-vocal symptoms - these symptoms may be observed as the patient struggles to speak



         difficulty breathing

         muscle pain in the upper chest

         synkinetic eye blinking

         exaggerated chest and abdominal wall contractions

         bulging neck muscles

         bulging veins in the neck


2.    Abductor Type


    A.     Vocal Symptoms

         abrupt voice breaks

         intermittent moments of aphonia and breathiness

         impairment of voiced/voiceless phoneme distinctions

         transitions from a voiceless consonant to a vowel in a stressed syllable is most difficult

         frequently unable to initiate laryngeal valving following the voiceless consonant

         glottal-widening, abductor type laryngospasm


B.      Non -Vocal Symptoms

         Breathiness is the primary non-vocal symptom


Audio-links :

Team contact for Voice 508 :
Karen Nix