In most cases the cause of spasmodic dysphonia is unknown. 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 :
of spasmodic dysphonia differ, depending on the type of the disorder.
The following are characteristics of the two different types:
is characterized by nonspecific hoarseness , with associated “vocal catches”-pitch and phonation breaks that eventually
evolve into complete laryngospasms
with advanced form may present with strained, squeezed staccato phonation
phonatory effort results in little acoustic output
symptoms are most noticeable when attempting to communicate
singing, non-communicative vocalizations and sometimes shouting are often unaffected
intermittent- rarely goes away completely once it begins
may report a good voice for brief periods upon awakening, and when they are extremely relaxed, as when drinking alcohol
wide spaced vertical striations,
well preserved formants
Non-vocal symptoms - these symptoms may be observed as the patient struggles to speak
pain in the upper chest
chest and abdominal wall contractions
bulging veins in the neck
2. Abductor Type
A. Vocal Symptoms
moments of aphonia and breathiness
of voiced/voiceless phoneme distinctions
from a voiceless consonant to a vowel in a stressed syllable is most difficult
unable to initiate laryngeal valving following the voiceless consonant
abductor type laryngospasm
Non -Vocal Symptoms
is the primary non-vocal symptom
Audio-links : http://www.dysphonia.org/