A randomized controlled trial of the effects of flow phonation voice treatment for primary muscle tension dysphonia.

Seventeen participants is a small sample, and the authors state their target enrollment was not met, so the study was underpowered to detect anything but large effects. Baseline aerodynamic and perceptual values varied widely across participants, which the authors note would have been better handled with stratified recruitment. Both groups received vocal hygiene education for the full six weeks, so the effect of the flow phonation exercises specifically cannot be separated from the effect of the education. The stroboscopic visual-perceptual rating was a forced binary choice (which video looks better), which limits how much can be said about specific laryngeal closure changes. The acoustic measures used (jitter, shimmer) are perturbation measures that the authors acknowledge are less standard in current voice research than cepstral or spectral measures. There was no no-treatment or no-therapy control group; the comparison was between two different sequences of the same two interventions.

The authors declare no conflicts of interest. The study was supported by NIH extramural funding.

Do not take the Discussion's claim that flow phonation improves aerodynamic power and balances laryngeal resistance as a confirmed result. The Results section reports that laryngeal resistance, aerodynamic power, and aerodynamic efficiency did not show a clear change, and the stroboscopic ratings were similar across all three time points. The significant improvements were in perceptual voice quality and voice-related quality of life, and both groups received vocal hygiene education throughout, so the specific contribution of the airflow exercises cannot be separated from it.