Change of speech fundamental frequency explains the satisfaction with voice in response to testosterone therapy in female-to-male gender dysphoric individuals.

Previous studies demonstrated that there is a significant change in speaking fundamental frequency after testosterone therapy in female-to-male gender dysphoric individuals. It is yet an open question how the satisfaction with voice alteration can be predicted because until now it is not clear whether a testosterone therapy is sufficiently effective. The aim of the current study was not only to measure satisfaction with voice, but additionally to detect factors that predict or explain satisfaction with voice after testosterone therapy. Therefore, nine female-to-male gender dysphoric individuals were examined during the first year of testosterone treatment at different points of time. The patients underwent several voice analyses within 1 year and had to fill out several questionnaires concerning their voice, depressive symptoms, quality of life and voice handicap index. Multiple regression analyses were performed to find the factors that explained satisfaction with altered voice after 1 year. The difference of voice frequency in semitones before the treatment and after 1 year is the only significant predictor for satisfaction after 1 year (B = 0.442; SE = 0.049) and more important than the absolute fundamental frequency.