A Preliminary Comparison of Laryngeal Manipulation and Postural Treatment on Voice Quality in a Prospective Randomized Crossover Study.

Background: This crossover study compared the effects of two osteopathic treatments specific laryngeal manipulation (SLM) and postural manual therapy (PMT) on voice quality and pitch.

Methods: Twelve asymptomatic singers were measured acoustically immediately before and immediately after each intervention using a laryngograph. Fundamental frequency and the glottal closing quotient were used to determine any differences between groups before and after.

Results: Fundamental frequency showed a statistically significant change following both interventions (combined [P = 0.007] and PMT and SLM individually (P = 0.0143, P = 0.018, respectively). Although the benefit demonstrated using SLM was greater than that with PMT (2.4, 2.02, respectively), following Bonferroni correction there was no statistical significance demonstrated between the two groups. There was no statistically significant change with glottal closing time for any intervention or at any time (P = 0.52).

Conclusion: This pilot study provides evidence of the benefit for both SLM and PMT in singers. A significant difference was found in the voice quality of the participants involved in both PMT and SLM. These results set the way for further larger scale studies to evaluate group interactions and potential benefits in symptomatic patients.