Functional dysphonia is characterised by an abnormal quality of voice in the absence of an identifiable lesion. People in occupations where voice use is central, like teachers, are more at risk of developing functional dysphonia. The causes of voice disorders are still being debated. There is also no consensus on the best method of evaluating voice, although many consider auditory voice quality assessment as a gold standard measure. Because functional dysphonia is a non-organic voice disorder there is no indication for surgical or medical interventions, and it is treated with behavioural (i.e. voice) therapy. Voice therapy usually consists of a combination of direct and indirect treatment techniques. Direct techniques focus on the underlying physiological changes needed to improve an individual's technique in using the vocal system whereas indirect techniques concentrate on contributory and maintenance aspects of the voice disorder (such as lack of knowledge).
We conducted a systematic search of the literature on treating functional dysphonia in adults. We then appraised the quality of the studies found and combined their results.
A combination of direct and indirect voice therapy is effective in improving vocal functioning when compared to no intervention. The achieved results may still be apparent after a year.
Most of the studies are small and of low methodological quality and further research is warranted.