Effects of Voice Therapy on Relative Fundamental Frequency During Voicing Offset and Onset in Patients With Vocal Hyperfunction

Abstract

Purpose The purpose of this study was to determine if the relative fundamental frequency (RFF) surrounding a voiceless consonant in patients with hyperfunctionally related voice disorders would normalize after a successful course of voice therapy. Method Pre- and post-therapy measurements of RFF were compared in 16 subjects undergoing voice therapy for voice disorders associated with vocal hyperfunction. Results A two-way ANOVA showed a statistically significant effect of both cycle of vibration near the consonant and therapy phase (PRE vs. POST), with p < .001. A post hoc paired Student’s t-test showed that post-therapy RFF measurements were significantly higher (more normal; p < .0001) than pre-therapy measurements. Conclusions Prior to therapy, participants exhibited lowered RFF values, similar to those found previously. After successful completion of voice therapy, RFF values increased toward patterns seen previously in individuals with healthy normal voice. The goal of voice therapy in these patients was to reduce laryngeal muscle tension; therefore the increase of RFF towards more typical values may be indicative of decreased baseline laryngeal muscle tension resulting from therapy. Results are discussed further in terms of necessary research to incorporate RFF as a clinical measure of vocal hyperfunction.

Individual Monitoring of Vocal Effort With Relative Fundamental Frequency: Relationships With Aerodynamics and Listener Perception

“…This corroborates previous findings that have suggested that while offset RFF may be well-suited to detection of mild changes in vocal effort, onset RFF is more sensitive to differences in the level of vocal effort (Eadie & Stepp, 2013; Stepp et al, 2012). A simple model has been proposed to explain the physiological mechanisms behind RFF (Stepp et al, 2011; Watson, 1998). The model involves a combination of vocal fold kinematics, aerodynamics, and tension, incorporating the observation that the activity of the cricothyroid muscle tends to be high immediately preceding, during, and following the voiceless consonant (Löfqvist, Baer, McGarr, & Story, 1989).…”

“…In contrast, in individuals with vocal hyperfunction, both offset and onset RFF tend to be lower in comparison to individuals with healthy voices. The RFF of individuals with vocal hyperfunction normalizes after successful voice therapy (Stepp, Merchant, Heaton, & Hillman, 2011), but has been found not to significantly change following surgery (Stepp et al, 2010). These results suggest that the measure is sensitive to the functional nature of vocal hyperfunction, which may or may not be accompanied by organic pathologies (Hillman et al, 1989).…”

Relative Fundamental Frequency Distinguishes Between Phonotraumatic and Non-Phonotraumatic Vocal Hyperfunction

“…Individuals with VH and healthy controls have been shown to have differences in RFF values Stepp, Hillman, et al, 2010a;Stepp et al, 2012). Stepp, Merchant, et al (2011) have previously proposed a model incorporating a simple summation of vocal fold tension, aerodynamic factors, and abductory factors to explain these differences. The authors proposed that the lowered RFF noted in individuals with VH could be accounted for by a simple reduction in the effects of tension, presumably due to higher baseline laryngeal tension in individuals with VH.…”

“…Previous work examining differences in RFF values demonstrated that these values remain unchanged in individuals who have received surgery to remove vocal nodules or vocal polyps (e.g., structural change; Stepp, Hillman, et al, 2010a). RFF values were, however, shown to increase in individuals with VH after a successful course of voice therapy (i.e., functional change; Stepp, Merchant, Heaton, & Hillman, 2011), suggesting that these changes in RFF values may be due to functional differences in voice use rather than representative of structural differences. These results support the use of RFF to examine the potential functional differences between these two subtypes of VH.…”

“…On the basis of previous work (Stepp, Hillman, et al, 2010a;Stepp, Merchant, et al, 2011;Stepp et al, 2012) and results of the post hoc testing indicating that Offset Cycle 10 was statistically different among all three groups, additional analyses were conducted on Offset Cycle 10 RFF values. RFF values in the PVH group for Offset Cycle 10 (M = −1.76 ST) were significantly lower than in the NPVH group (M = −1.35 ST), and both groups were significantly lower than the control group (M = −0.82 ST).…”