Voiced High-Frequency Oscillation or Lax Vox Technique? Immediate Effects in Dysphonic Individuals

Abstract

To analyze the immediate effects of voiced high-frequency oscillation (VHFO) and Lax Vox technique on vocal quality and self-reported intensity of vocal and laryngeal symptoms in individuals with behavioral dysphonia. This experimental, prospective, randomized cross-over study, investigated thirty adults (15 women and 15 men) with behavioral dysphonia (vocal complaints, altered voice on auditory-perceptual evaluation, vocal nodules or mucosal thickening, and incomplete glottic closure). The outcome variables analyzed were auditory-perceptual analysis, acoustic analysis (voice quality characteristics), and self-reported intensities of vocal and laryngeal symptoms. Each participant performed two exercises-VHFO and Lax Vox technique-in a random sequence for 3 minutes. A 7-day washout period was provided between the exercises. The data were analyzed using the paired t-test and Wilcoxon test (P < 0.05). After VHFO, no significant difference was observed on auditory-perceptual evaluation in all participants, whereas the Lax Vox technique worsened breathiness among women (P=0.027). VHFO significantly increased the fundamental frequency (P=0.014) and decreased the noise harmonic ratios for women (P=0.026). Among men, there was a decrease in shimmer parameter (P=0.035). Moreover, symptoms such as "lump in the throat" (P=0.005), "voice loss" (P=0.017), and "high-pitched voice" (P=0.023) decreased in women after VHFO, whereas in men, "itchiness" and "hoarseness" (P < 0.001) decreased after VHFO. The Lax Vox technique decreased "hoarseness" (P=0.003) in women, without any effect in men. The VHFO exercise provided more positive immediate effects results than the Lax Vox technique regarding vocal quality and self-reported symptom intensity in participants with behavioral dysphonia.