Background. Although psychological factors have been implicated in patients with functional dysphonia (FD), conventional voice therapy (CVT) typically targets the aberrant voice symptoms exclusively. Yet, CVT is not always successful, and in view of the significant adverse quality of life impact combined with the financial burden on the healthcare system, research is needed to elucidate the underlying psychophysiology of FD and improve treatment outcomes.

Objectives. The first objective of this pilot study was to investigate the occurrence and frequency of symptoms and/or disorders related to autonomic nervous system (ANS) dysfunction in patients with FD. The second objective was to investigate the effects of a therapy based on ANS regulation, i.e. heart rate variability (HRV) biofeedback, in this population.

Methods. Six patients with FD (5 ciswomen, 1 cismen, mean age: 36 years) were included in this pilot study. Autonomic (dys)function was investigated using both physiological measures (e.g. HRV) and psychological patient-reported outcome measures (e.g. Depression Anxiety and Stress Scale). Patients received 1 month of HRV biofeedback training with 20min of daily practice. Both the autonomic assessment and the voice assessment were performed pre- and posttherapy.

Results. Each case reported at least 2 disorders related to ANS dysfunction. 83.3% (n = 5/6) scored high on anxiety and stress (Roy et al., 2000). HRV was significantly lower than the mean norm with 83.3% (n = 5/6) of the cases scoring below that norm. A positive evolution in both autonomic function (HRV and skin conductance level) and voice function (Dysphonia Severity Index and Voice Handicap Index) was found for most cases after the HRV biofeedback intervention.

Conclusion. ANS dysfunction seems to be associated with the investigated cases with FD. This pilot study showed promising preliminary results on voice after HRV biofeedback, an ANS intervention with no phonation involved. In a later stage of the project, autonomic dysfunction in FD will be compared with gender- and age-matched vocally healthy controls, using a case-control study. Second, the effects of the ANS regulation therapy in FD will be compared with CVT alone or in combination with ANS regulation therapy, using a randomized controlled trial.

Note: Data recruitment is currently ongoing. More results will be available at the moment of the symposium.