Patients with functional dysphonia will be recruited from a treatment-seeking population consulting at the voice clinic of Ghent University Hospital. Inclusion criteria are all genders, all ethnicities, aged 18 - 60 years (to exclude voice-related changes due to puberty/mutation or aging/presbyphonia), diagnosed with FD by an experienced otorhinolaryngologist and SLP (defined by a voice disorder in the absence of organic or structural mucosal disease and/or neuropathology sufficient to explain the voice disturbance (Roy et al., 2003), as determined with strobovideolaryngoscopy and a multidimensional voice assessment). Exclusion criteria include: being diagnosed with an organic voice disorder, current participation in voice therapy, practice of breathing exercises including mediation and yoga, current participation in psychotherapy or physical rehabilitation, pharmacological treatment (i.e. antidepressants, antipsychotics, heart medication, antihypertensives, inhalers), previous phonosurgical interventions, lung diseases, endocrinologic diseases, metabolic diseases, cardiovascular diseases, neurologic diseases, nasal or ear diseases, pregnancy, asthma, smoking or drug consumption.

For the vocally healthy controls, inclusion criteria are all genders, all ethnicities, aged 18 - 60 years, and matched with the FD groups by age and gender. The same exclusion criteria as above apply, with the addition of: 'diagnosed with FD'.