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Article Excerpt
This study reports the case of a 61-year-old female participant with severe, intractable muscle tension dysphonia and ventricular phonation treated with botulinum toxin-A (Botox) and subsequent voice therapy. Following bilateral injections of Botox, the participant received 6 months of regular voice therapy aimed at reducing laryngeal constriction. Perceptual ratings of vocal quality, acoustic analyses of voice (fundamental frequency, relative average perturbation, shimmer, noise-to-harmonic ratio, voice turbulence index), and videolaryngoscopic evaluations of laryngeal function were conducted pre- and post-Botox injections at regular intervals over a 7-month period. In addition, the participant completed the Voice Handicap Index during each assessment. Results revealed gradual improvements in perceptual and acoustic parameters of vocal quality over the treatment period. Supraglottic constriction reduced after the initial Botox treatment. This improvement was maintained for the duration of the study. The Voice Handicap Index ratings indicated the participant perceived quality of life improvements following Botox and voice therapy. It was concluded that the combination of Botox and voice therapy was effective.
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Muscle tension dysphonia (MTD) is a hyperfunctional voice disorder in which excessive activity of the intrinsic and extrinsic laryngeal muscles affects voice production (Roy, Ford, & Bless, 1996). The disorder is associated with a range of perceptual characteristics, including hoarseness, hard glottal attack, low/high modal pitch, pitch breaks, aphonic periods, and vocal fatigue (Dworkin, Meleca, & Abkarian, 2000; Mathieson, 2001), together with somatic symptoms such as pain or the sensation of a lump in the throat, effortful phonation, and unproductive throat clearing (Maryn, De Bodt, & Van Cauwenberge, 2003; Mathieson, 2001; Von Doersten, Izdebski, Ross, & Cruz, 1992). Koufman and Blalock (1991) have classified various types of MTD: a glottic subtype characterized by an open posterior commissure; and three supraglottic subtypes in which patients present with either approximation of the false vocal folds, partial antero-posterior contraction of the supraglottis, or complete (sphincteric) closure of the larynx, respectively.
The traditional treatment of MTD involves programs of vocal hygiene and vocal re-education (Boone & McFarlane, 2000; Dworkin, Meleca, & Abkarian, 2000; Mathieson, 2001). Voice facilitating techniques that have been found to be effective in the treatment of MTD include manual circumlaryngeal massage, easy-onset phonation, yawn-sigh vocalizations, the chewing technique, forward resonance and projection, breath control, and relaxation techniques (Boone & McFarlane, 2000; Dworkin, Meleca, & Abkarian, 2000; Mathieson, 2001; Roy et al., 1996; Roy, Bless, Heisey, & Ford, 1997). Inhalation phonation may also be used to treat the supraglottic subtypes (Dworkin, Meleca, & Abkarian, 2000). Psychotherapy may be necessary when emotional or stress-related factors are noted to contribute significantly to the voice disorder (Dworkin, Meleca, & Abkarian, 2000; Mathieson, 2001). However, there are some patients with MTD who fail to respond to prolonged and intensive voice therapy or psychotherapy regimens (Dworkin, Meleca, & Abkarian, 2000; Von Doersten et al., 1992). In such cases, alternative treatments such as surgical excision of the false vocal folds (Feinstein, Hilger, Szachowicz, & Stimson, 1987), topical anaesthesia (lidocaine) (Dworkin, Meleca, Simpson, & Garfield, 2000), or botulinum toxin-A (Botox) (Kendall & Leonard, 1997; Rosen & Murry, 1999) may need to be considered.
Botox that results in transient and reversible muscular paralysis has been found to be a valuable agent in the treatment of neuromuscular disorders including spasmodic dysphonia (Rosen & Murry, 1999; Simpson, 1992). Since the supraglottic subtypes of MTD are considered to be the result of hyperfunction of laryngeal musculature (Roy et al., 1996), injecting Botox into the false vocal folds and supraglottic structures should result in an improvement in physiological function that is more amenable to voice therapy intervention, and normal voice production (Kendall & Leonard, 1997; Rosen & Murry, 1999; Simpson, 1992).
Kendall and Leonard (1997) reported on the use of Botox and voice therapy to treat seven participants with ventricular dysphonia. Each participant underwent bilateral injections of Botox (10 units/side) to the false vocal fold/aryepiglottic fold junction (Kendall & Leonard, 1997). Laryngeal visualization indicated supraglottic relaxation in all seven participants postinjection. Perceptually, five of the seven participants were noted to achieve normal voicing after Botox injection and one session of voice therapy, while two participants demonstrated improvement of their dysphonia following Botox alone (Kendall & Leonard, 1997). The authors concluded that supraglottic injection of Botox was a potential adjunct to voice therapy in the treatment of ventricular dysphonia (Kendall & Leonard, 1997).
Rosen and Murry (1999) later reported a single case of severe hyperadduction of the false vocal folds in an individual for whom extensive voice therapy had been unsuccessful and who was subsequently treated with bilateral Botox injections to the false vocal folds. While the participant did not receive any post-Botox voice therapy, significant improvement in vocal quality was noted following Botox injection. Laryngoscopic and stroboscopic examinations at 9 months post-Botox revealed complete resolution of false vocal fold adduction during phonation, and normal vocal fold vibration and glottic closure pattern, while acoustic analysis revealed improved acoustic features (Rosen & Murry, 1999). Perceptual analysis of the participant's voice at 1 year post-Botox revealed a good voice quality. The effect of the voice disorder on the participant's life was significantly reduced following Botox injection (Rosen & Murry, 1999). Based on these results, the authors concluded that Botox could potentially be a treatment option for individuals with severe vocal fold hyperadduction and failure to respond to voice therapy (Rosen & Murry, 1999).
While the two previous studies have highlighted the potential of utilizing Botox either alone, or in combination with voice therapy, in the treatment of persons with severe laryngeal hyperfuction, further research is required to...
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