In patients with functional voice disorders, no organic lesions can be seen on the vocal folds during laryngoscopy and stroboscopy. In those cases, voice changes are caused by technical (functional) limitations of voice use. Mostly, falsely learned (behavioural) muscular misuse / overuse and breathing problems are major components of functional voice disorders.
As a result, the closing and vibrating behavior of the vocal folds during vocalization are disturbed.
The cause is thought to be multifactorial. Possible causes include constitutional factors (for example, in the form of a larynx that is not as strong and powerful by design or a restriction of the overall physical constitution) and habitual factors (the conscious or unconscious habituation of an unfavorable vocal technique, an inappropriate speaking voice pitch, the unconscious imitation of other unfavorable voice models and voice-damaging habits such as clearing the throat) or an overload of the voice by speaking too long or too loudly. A voice disorder can also occur in the case of a severe general illness due to poor general health, without a cause being present in the larynx.
Of course there is always a potential possibility of psychological influence within voice use which in extreme cases may lead to patial or total voice loss (dysphonia or aphonia). Therapeutically, in patients with functional voice disorders, having access to the entire armamentarium of voice treatment techniques we have a good chance to improve the patient’s voice.
In functional voice disorders, a distinction is made between “too much” and “too little”. There are forms in which there is too much tension of the vocal folds and laryngeal muscles (so-called hyperfunctional dysphonia) and forms with too little tension (so-called hypofunctional dysphonia). Often there is a mixed symptomatology.