Table 1
Total Unique References Reporting on EVT Populations for Review
| 1. Anand S, Shrivastav R, Wingate JM, Chheda NN. An acoustic-perceptual study of vocal tremor. J Voice 2012;26(6):811 e1–e7. http://dx.doi.org/10.1016/j.jvoice.2012.02.007 |
| 2. Aronson AE, Brown JR, Litin EM, Pearson JS. Spastic dysphonia. II. Comparison with essential (voice) tremor and other neurologic and psychogenic dysphonias. J Speech Hear Disord 1968;33(3):219–231. http://dx.doi.org/10.1044/jshd.3303.219 |
| 3. Aronson AE, Hartman DE. Adductor spastic dysphonia as a sign of essential (voice) tremor. J Speech Hear Disord 1981;46(1):52–58. http://dx.doi.org/10.1044/jshd.4601.52 |
| 4. Barkmeier-Kraemer J, Lato A, Wiley K. Development of a speech treatment program for a client with essential vocal tremor. Semin Speech Lang 2011;32(1):43–57. http://dx.doi.org/10.1055/s-0031-1271974 |
| 5. Brown JR, Simonson J. Organic voice tremor. A tremor of phonation. Neurology 1963;13:520–525. http://dx.doi.org/10.1212/WNL.13.6.520 |
| 6. Brown JR, Simonson J. Organic voice tremor. Trans Am Neurol Assoc 1962;87:179–180. |
| 7. Busenbark K, Ramig L, Dromey C, Koller WC. Methazolamide for essential voice tremor. Neurology 1996;47(5):1331–1332. http://dx.doi.org/10.1212/WNL.47.5.1331 |
| 8. Estes C, Sadoughi B, Coleman R, Sarva H, Mauer E, Sulica L. A prospective crossover trial of botulinum toxin chemodenervation versus injection augmentation for essential voice tremor. Laryngoscope 2018;128(2):437–446. http://dx.doi.org/10.1002/lary.26911 |
| 9. Gurey LE, Sinclair CF, Blitzer A. A new paradigm for the management of essential vocal tremor with botulinum toxin. Laryngoscope 2013;123(10):2497–2501. http://dx.doi.org/10.1002/lary.24073 |
| 10. Hachinski VC, Thomsen IV, Buch NH. The nature of primary vocal tremor. Can J Neurol Sci 1975;2(3):195–197. http://dx.doi.org/10.1017/S0317167100020254 |
| 11. Hartman DE, Overholt SL, Vishwanat B. A case of vocal cord nodules masking essential (voice) tremor. Arch Otolaryngol 1982;108(1):52–53. http://dx.doi.org/10.1001/archotol.1982.00790490054016 |
| 12. Hartman DE, Vishwanat B. Spastic dysphonia and essential (voice) tremor treated with primidone. Arch Otolaryngol 1984;110(6):394–397. http://dx.doi.org/10.1001/archotol.1984.00800320048011 |
| 13. Hemmerich AL, Finnegan EM, Hoffman HT. The distribution and severity of tremor in speech structures of persons with vocal tremor. J Voice 2016. http://dx.doi.org/10.1016/j.jvoice.2016.05.004 |
| 14. Hertegard S, Granqvist S, Lindestad PA. Botulinum toxin injections for essential voice tremor. Ann Otol Rhinol Laryngol 2000;109(2):204–209. http://dx.doi.org/10.1177/000348940010900216 |
| 15. Ho AL, Choudhri O, Sung CK, DiRenzo EE, Halpern CH. Deep brain stimulation for essential vocal tremor: a technical report. Cureus 2015;7(3):e256. |
| 16. Justicz N, Hapner ER, Josephs JS, Boone BC, Jinnah HA, Johns MM, 3rd. Comparative effectiveness of propranolol and botulinum for the treatment of essential voice tremor. Laryngoscope 2016;126(1):113–117. http://dx.doi.org/10.1002/lary.25485 |
| 17. Koller W, Graner D, Mlcoch A. Essential voice tremor: treatment with propranolol. Neurology 1985;35(1):106–108. http://dx.doi.org/10.1212/WNL.35.1.106 |
| 18. Lederle A, Barkmeier-Kraemer J, Finnegan E. Perception of vocal tremor during sustained phonation compared with sentence context. J Voice 2012;26(5):668 e1–e9. http://dx.doi.org/10.1016/j.jvoice.2011.11.001 |
| 19. Lester RA, Barkmeier-Kraemer J, Story BH. Physiologic and acoustic patterns of essential vocal tremor. J Voice 2013;27(4):422–432. http://dx.doi.org/10.1016/j.jvoice.2013.01.002 |
| 20. Lowell SY, Kelley RT, Monahan M, Hosbach-Cannon CJ, Colton RH, Mihaila D. The effect of octanoic acid on essential voice tremor: a double-blind, placebo-controlled study. Laryngoscope 2019;129(8):1882–1890. http://dx.doi.org/10.1002/lary.27695 |
| 21. Massey EW, Paulson GW. Essential vocal tremor: clinical characteristics and response to therapy. South Med J 1985;78(3):316–317. http://dx.doi.org/10.1097/00007611-198503000-00020 |
| 22. Nida A, Alston J, Schweinfurth J. Primidone therapy for essential vocal tremor. JAMA Otolaryngol Head Neck Surg 2016;142(2):117–121. http://dx.doi.org/10.1001/jamaoto.2015.2849 |
| 23. Orbelo DM, Duffy JR, Hughes Borst BJ, Ekbom D, Maragos NE. Differences in botulinum toxin dosing between patients with adductor spasmodic dysphonia and essential voice tremor. J Voice 2014;28(1):123–127. http://dx.doi.org/10.1016/j.jvoice.2013.05.008 |
| 24. Paige C, Hopewell BL, Gamsarian V, Myers B, Patel P, Garrett CG, et al. Characterizing the normative voice tremor frequency in essential vocal tremor. JAMA Otolaryngol Head Neck Surg 2018. http://dx.doi.org/10.1001/jamaoto.2018.2566 |
| 25. Patel A, Frucht SJ. Isolated vocal tremor as a focal phenotype of essential tremor: a retrospective case review. J Clin Mov Disord 2015;2:1–5. http://dx.doi.org/10.1186/s40734-015-0016-5 |
| 26. Parker LA, Kunduk M, Fink DS, McWhorter A. Reliability of high-speed videoendoscopic ratings of essential voice tremor and adductor spasmodic dysphonia. J Voice 2019;33(1):16–26. http://dx.doi.org/10.1016/j.jvoice.2017.10.009 |
| 27. Ravikumar VK, Ho AL, Parker JJ, Erickson-DiRenzo E, Halpern CH. Vocal tremor: novel therapeutic target for deep brain stimulation. Brain Sci 2016;6(4). http://dx.doi.org/10.3390/brainsci6040048 |
| 28. Sulica L, Louis ED. Clinical characteristics of essential voice tremor: a study of 34 cases. Laryngoscope 2010;120(3):516–528. http://dx.doi.org/10.1002/lary.20702 |
| 29. Van Doren M, Faudoa E, Carroll TL. Treatment of patients with vocal fold atrophy and comorbid essential voice tremor: long-term injection augmentation outcomes after successful diagnostic vocal fold injection augmentation. J Voice 2018. http://dx.doi.org/10.1016/j.jvoice.2018.11.004 |
| 30. Warrick P, Dromey C, Irish J, Durkin L. The treatment of essential voice tremor with botulinum toxin A: a longitudinal case report. J Voice 2000;14(3):410–421. http://dx.doi.org/10.1016/S0892-1997(00)80086-7 |
Table 2
Literature Describing Clinical Characteristics of those with EVT, or Isolated Voice Tremor
| Reference | Population Size | Family History | Duration of Vocal Tremor | Age of Onset | Male and Female Representation | Body Distribution | Activation Condition (Rest vs. Action) | Rate | Alcohol Responsiveness | Other Associated Neurologic Disorders |
|---|---|---|---|---|---|---|---|---|---|---|
| Patel and Frucht39 | 19 | 8 (42%) with family h/o ET and 5 (26%) with vocal tremor specifically | 6 years (+/- 4 years) | 64 years (+/- 8 years) | 89% female | Larynx, palatal, and pharyngeal musculature during sustained phonation (no mention of respiratory observations); Head tremor (N = 6), N = 3 had slight action tremor of upper extremities; N = 2 had both head and limb tremor | Action (based on presence during phonation) | 4–8 Hz via acoustic measures | 100% of those who consumed alcohol (N = 11) | “Patients were subsequently followed for as little as 6 months and as long as 10 years without the development of dystonia or parkinsonism.” (p 2) |
| Sulica and Louis40 | 34 | 38.2% had a familial history and 58.8% did not | 12.7 years (+/-13.4 years) Range of 0.5–20 years | 62.9 years (+/- 15 years) Range of 19–84 years | 92.6% female | 68% experienced onset of vocal tremor prior to upper limb involvement; 74% exhibited laryngeal oscillation during respiration, palate, pharyngeal wall in majority, with 24% exhibiting base of tongue oscillation | Action, Kinetic and postural (based on presence during phonation and quiet breathing) | 4–10 Hz via laryngeal Electromyography (EMG) | 42.9% of those who consumed alcohol | essential tremor |
| Massey and Paulson41 | 4 of 131 | Of the four patients with isolated vocal tremor, all reported a family history for tremor (one exhibited family history only of vocal tremor) | 0.67–6 years | not reported, although the age range was 37 –59 years at time of evaluation | 75% female | respiratory; indirect laryngeal examination only was conducted, making body distribution difficult to determine | Action (based on presence during phonation) | 4–10 Hz via acoustic measures | 100% (N = 4) | 26 of 131 exhibited vocal tremor with 4 of these as the initial sign; all others met inclusion criteria for essential tremor. From the 26 with vocal tremor, 2 exhibited head, hands, and voice; 5 exhibited head and voice; 14 exhibited hands and voice; 1 exhibited head, voice, and chin |
[i] Abbreviations: EVT, Essential Vocal Tremor; ET, Essential Tremor.
Figure 1
Total Number of References Identified during the PubMed Search Using Each of the Specific Search Phrases. References specific to EVT and those providing adequate clinical phenotype information to meet inclusion criteria for final descriptive analysis are indicated. A total of 30 unique references addressing EVT were evaluated for clinical phenotype characteristics and three references provided the target clinical phenotype information for descriptive analyses.