Over the last three years, a variety of oscillatory positive expiratory pressure (OPEP) devices have been commonly used by voice therapists and trainers (e.g., Acapella Choice, Shaker Deluxe, Shaker Medic Plus, New Shaker), even if they were not originally created for voice-treatment purposes. OPEP devices are intended to be used by physiotherapists to mobilize secretions from the lower airway when treating excessive sputum or secretion retention. The mechanism of oscillatory OPEP is based on a continuous and rapid shuttering of airflow, which in turn produces modulation of the oral and tracheal air pressure as patients blow into them. People diagnosed with cystic fibrosis and neurogenic diseases are usually recommended to use OPEP devices (Patterson et al., 2007; Saccente-Kennedy et al., 2020). OPEP devices are different from expiratory/inspiratory muscle strength training devices, which have no oscillatory mechanisms inside.

Different phonatory tasks such as sustained pitches, glissandos, accents, song melody, etc., can be performed when OPEP devices are used for voice purposes. Previous voice studies with OPEP devices have suggested that they can be useful (when they are used with phonation) to reduce sensations of muscle tension, vocal effort, and vocal fatigue (Saters et al., 2018; Guzman et al., 2022; Antonetti et al., 2022) in a similar way to what water bubbling does. Comparisons of the massage-like sensation effect between OPEP devices and water bubbling have been carried out. The same or greater positive effects in reducing throat discomfort have been reported for OPEP devices (Guzman et al., 2021).

Oral pressure (P_oral) oscillation has also been explored during phonation with OPEP devices. Acapella Choice produces a greater mean peak-to-peak amplitude of P_oral and higher regularity of P_oral modulation than water bubbling (Saccente-Kennedy et al., 2020). The higher regularity of P_oral modulation displayed by Acapella Choice can be explained by the more mechanistic shuttering of airflow offered by the magnetic system inside this device compared to water bubbles. A more intense massage-like sensation than water bubbling has also been reported for Acapella Choice (Saccente-Kennedy et al., 2020). When comparing phonation through the Shaker Deluxe device (another OPEP) with water bubbling, the amplitude of P_oral modulation was higher for the latter. This may imply that bubbles offer a stronger massage-like sensation than the Shaker Deluxe device. Moreover, it has been shown that the Shaker Deluxe upright had slightly higher flow resistance than a resonance tube 10 cm in water, while the Shaker held horizontally had half of that (5 cm) (Laukkanen et al., 2021).

Accelerometers have been used to explore neck, face, and chest tissue mobilization during phonation with OPEP devices. Data show that Acapella Choice produces the highest amplitude, the lowest frequency, and the greatest regularity of tissue oscillation when compared to double-source-of-vibration semi-occluded vocal tract exercises (e.g., water bubbles, lip trills, tongue trills) (Guzman et al., 2021). Control of these variables could be relevant to obtain the best massage-like sensation, which in turn may positively impact the reduction of perceived muscle tension, vocal effort, and vocal fatigue felt by patients.

Only a couple of studies have assessed the efficacy of long-term voice therapy using OPEP devices in subjects with voice complaints, despite evidence of the presence of a massage-like sensation, P_oral oscillation, and tissue oscillation during phonation with different OPEP devices (Guzman et al., 2022). Authors have compared the efficacy of Acapella Choice and Shaker Medic Plus against water bubbling in participants diagnosed with vocal fatigue. Improvements in self-reported variables when comparing pre- and post-treatment measures have been reported for OPEP devices, but no significant differences have been found when comparing these devices with water bubbles (Guzman et al., 2022). It seems that both water bubbles and OPEP devices are equally effective in reducing voice discomfort in people with vocal fatigue after several sessions of voice therapy.

Even though OPEP devices are expected to be a higher-cost option compared to water bubbles, they might prove beneficial for increasing adherence to vocal exercise practice for those who do not feel comfortable using a bottle filled with water in certain circumstances. OPEP devices could constitute a more practical option compared to water bubbles.

References

Antonetti, A. E. D. S., Ribeiro, V. V., Brasolotto, A. G., & Silverio, K. C. A. (2022). Effects of performance time of the voiced high-frequency oscillation and Lax Vox technique in vocally healthy subjects. Journal of Voice, 36(1), 140.e29–140.e37. https://doi.org/10.1016/j.jvoice.2020.04.008

Guzman, M., Acevedo, K., Castro, C., Moran, C., Espinoza, V., & Quezada, C. (2021). Tissue mobilization during double source of vibration semioccluded vocal tract exercises: A neck and face surface acceleration study. Journal of Speech, Language, and Hearing Research, 64(11), 4124–4137. https://doi.org/10.1044/2021_JSLHR-21-00033

Guzman, M., Ortega, A., Rocha, C., Salgado, L., & Quezada, C. (2022). Efficacy of voice therapy with Acapella Choice® device in subjects with vocal fatigue delivered via telepractice. Journal of Voice. Advance online publication. https://doi.org/10.1016/j.jvoice.2022.07.027

Laukkanen, A.-M., Horáček, J., & Radolf, V. (2021). Buzzer versus water resistance phonation used in voice therapy: Results obtained with physical modeling. Biomedical Signal Processing and Control, 66, 102417. https://doi.org/10.1016/j.bspc.2021.102417

Patterson, J. E., Hewitt, O., Kent, L., Bradbury, I., Elborn, J. S., & Bradley, J. M. (2007). Acapella versus “usual airway clearance” during acute exacerbation in bronchiectasis: A randomized crossover trial. Chronic Respiratory Disease, 4(2), 67–74. https://doi.org/10.1177/1479972306075483

Saccente-Kennedy, B., Amarante Andrade, P., & Epstein, R. (2020). A pilot study assessing the therapeutic potential of a vibratory positive expiratory pressure device (Acapella Choice) in the treatment of voice disorders. Journal of Voice, 34(3), 487.e21–487.e30. https://doi.org/10.1016/j.jvoice.2018.09.019

Saters, T. L., Ribeiro, V. V., Siqueira, L. T. D., Marotti, B. D., Brasolotto, A. G., & Silverio, K. C. A. (2018). The voiced oral high-frequency oscillation technique’s immediate effect on individuals with dysphonic and normal voices. Journal of Voice, 32(4), 449–458. https://doi.org/10.1016/j.jvoice.2017.06.018

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