The treatment of essential voice tremor with botulinum toxin A: A longitudinal case report

Physiologic and Acoustic Patterns of Essential Vocal Tremor

“…Therefore, tremor is observed primarily during voluntary movement of the involved body parts or during postureholding. 4,12 Although the onset of ET is most commonly noted in the upper limbs, ET can also affect components of the speech mechanism including the respiratory system, [13][14][15] the larynx, [15][16][17][18][19][20][21] and the vocal tract. 6,14,[22][23][24][25] When ET causes involuntary, rhythmic activation of the musculature involved in speech production, the sound of the voice may be altered.…”

“…This research demonstrated that tremor affecting the structures within the speech mechanism resulted in nearly rhythmic modulation of the fundamental frequency (F 0 ) and the intensity of the voice. [18][19][20][21][22]28 The rate of modulation in the acoustic signal for individuals with essential vocal tremor (EVT) was found to range between 4 and 8 Hz. 22 Measurements of both the rate and the extent of F 0 and intensity modulation were found to vary when individuals with ET produced different pitches and loudness levels.…”

Perception of Vocal Tremor During Sustained Phonation Compared With Sentence Context

“…27,28 In contrast, a more localized application of pharmaceutical treatment via Botulinum toxin (ie, Botox Allergen, Inc., Irvine, CA) injection has been reported as beneficial in reducing symptoms in as many as 80% of individuals with vocal tremor involving the larynx. 3,22,[29][30][31][32][33] Although generally beneficial in reducing vocal tremor and effort levels during speaking, Botox injections have also been associated with excessive breathiness and impaired swallowing for up to 6 weeks following treatment in some individuals. 22,29,32,33 These individuals may consequently choose to discontinue Botox treatment.…”

An Acoustic-Perceptual Study of Vocal Tremor

“…Although a number of medications have been used to treat tremor in the past, BOTOX has been the primary choice of treatment. 5,[15][16][17] Extensive research has been carried out on the acoustic characteristics of vocal tremor. However, clinical judgments of voice disorders by patients and therapists rely heavily on the perception of tremor in voice.…”

“…BOTOX reduces the perceived effort to speak, and the rate and extent of tremor. [15][16][17] BOTOX provides symptomatic relief and can be useful only when the tremor is primarily linked to the vocal folds because it is commonly injected into the thyroarytenoid muscle. Warrick et al 5 showed that when tremor involved several anatomical sites, injections of BOTOX did not lead to uniform improvements on acoustic measures of voice.…”