Effects of Performance Time of the Voiced High-Frequency Oscillation and Lax Vox Technique in Vocally Healthy Subjects.

OBJECTIVES The primary objective was to analyze and compare the effects of the voiced high-frequency oscillation (VHFO) and Lax Vox techniques in different performance times. The secondary objective was to determine if there were any differences between the exercises in men and women. METHODS Thirty volunteers (15 male, 15 female) without vocal complaints or any history of dysphonia participated in this study. The volunteers performed the VHFO and the Lax Vox techniques with a week washout, and the performance times were 1- and 3-minute long with a 15-minute interval. They answered two questionnaires on vocal and laryngopharyngeal symptoms intensity self-assessment and had acoustic measurements (cepstral peak prominence-smoothed - CPPs - , alpha ratio, and L1-L0) obtained, before 1 minute (M0), after 1 minute (M1), and after 3 minutes (M3). They had their sustained vowel /a/ and number counting 1-10 recorded. Data were analyzed by using the repeated measures ANOVA (P < 0.05) and the post hoc Tukey's test. RESULTS For vowel /a/, men had higher CPPs and lower alpha ratio values. For number counting, men had lower CPPs values, and for both genders there was an improvement after M1, which remained at M3. For the low-pitched voice symptom, men showed a decrease after M1, regardless of the exercise. Men had better results after VHFO, while women had better results after the Lax Vox technique for the tightness symptom. Regardless of exercise or gender, there was a decrease in tickling and irritated throat after M1, but at M3 their intensity tended to increase. The lump in the throat symptom decreased at M1 and remained at the same intensity at M3 regardless of exercise or gender. CONCLUSIONS It is important to be aware of the voice effects and the patient reports when requesting 3 minutes of both exercises. Thus, the conclusion is that the best performance time is 1 minute. For most outcomes, there was no difference between exercises and participants' genders. However, for the low-pitched voice symptom, men benefited more from both exercises, and for tightness, men benefited more from VHFO; in contrast, women benefited more from the Lax Vox technique. Therefore, such gender differences should be considered when choosing these exercises.