Short-term acoustic effects of speech therapy in transgender women : a randomized controlled trial

Purpose: This study measured and compared the acoustic short-term effects of pitch elevation training (PET) and articulation-resonance training (ART) and the combination of both programs, in transgender women.Method: A randomized controlled study with cross-over design was used. Thirty transgender women were included and received 14 weeks of speech training. All participants started with 4 weeks of sham training; after which they were randomly assigned to one of two groups: One group continued with PET (5 weeks), followed by ART (5 weeks); the second group received both trainings in opposite order. Participants were recorded 4 times, in between the training blocks: pre, post 1 (after sham), post 2 (after training 1), and post 3 (after train-ing 2). Speech samples included a sustained vowel, continuous speech during reading, and spontaneous speech and were analyzed using Praat software. Fundamental frequency (fo), intensity, voice range profile, vowel formant fre-quencies (F1-2-3-4-5 of /a/-/i/-/u/), formant contrasts, vowel space, and vocal quality (Acoustic Voice Quality Index) were determined.Results and Conclusions: Fundamental frequencies increased after both the PET and ART program, with a higher increase after PET. The combination of both interventions showed a mean increase of the fo of 49 Hz during a sus-tained vowel, 49 Hz during reading, and 29 Hz during spontaneous speech. However, the lower limit (percentile 5) of the fo during spontaneous speech did not change. Higher values were detected for F1-2 of /a/, F3 of /u/, and vowel space after PET and ART separately. F1-2-3 of /a/, F1-3-4 of /u/, vowel space, and formant contrasts increased after the combination of PET and ART; hence, the combination induced more increases in formant frequencies. Intensity and voice quality measurements did not change. No order effect was detected; that is, starting with PET or ART did not change the outcome