Spasmodic dysphonia (referred to in the older literature as “spastic dysphonia” or “stuttering”) is a severe vocal disorder of still largely unexplained origin. It is classed as a neurological form of dystonia and called focal dystonia of the larynx. The severity of the disease ranges from mild forms which manifest themselves as the voice “getting stuck” and thus break the flow of speech to the most severe forms which make vocal communication impossible. The consequences are not uncommonly social isolation and occupational invalidity.
Spasmodic dysphonia comes from the Greek and means a spasmodic disorder of the voice. The disease was first described in 1871 by Prof. Traube as a “spastic form of nervous trachyphonia”. Two different types of the disease were described in 1973 by Prof. Aronson. This classification is still valid today: the adductor form and the much rarer abductor form (the names refer to the muscle groups affected in each case). The adductors (from the Latin: adducere = to draw towards) are the group of muscles in the larynx which cause the vocal folds to draw together and to close the vocal folds. The abductor muscles (from the Latin: abducere = to draw or lead away) draw the vocal folds apart and allow air to pass through the windpipe (respiration).
With the adductor form, spasms over which the patient has no voluntary control occur in the inner laryngeal muscles during vocalization. The voice is very tense and groaning, and sounds strained and laborious; with more severe spasms it is characterized by the voice breaking up. In the most severe cases the voice fails completely. Accordingly, the patient has great difficulty speaking.
With the abductor form, these spasms occur with the vocal folds adbucted, i.e. opened. This gives the voice a breathy, more whispering sound.
One peculiarity of both forms of spasmodic dysphonia is that the voice can be completely normal when laughing and crying. The voice is usually much better when singing and reciting verse, but the symptoms may be intensified under stress and in particular when on the telephone.
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Stand: 18.10.2007, 11:51 Uhr
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