Laryngeal Dystonia, Dystonic Tremor and Vocal Tremor: Three Different Entities

João Viana Pinto; Susana Santiago Pérez; Isabel Garcia-Lopez

doi:10.1016/j.jvoice.2023.11.017

Laryngeal Dystonia, Dystonic Tremor and Vocal Tremor: Three Different Entities

J Voice. 2023 Dec 27:S0892-1997(23)00378-8. doi: 10.1016/j.jvoice.2023.11.017. Online ahead of print.

Authors

João Viana Pinto¹, Susana Santiago Pérez², Isabel Garcia-Lopez³

Affiliations

¹ Department of Otolaryngology Head & Neck Surgery, La Paz University Hospital, Madrid, Spain. Electronic address: joaopvfpinto@gmail.com.
² Department of Clinical Neurophysiology, La Paz University Hospital, Madrid, Spain.
³ Department of Otolaryngology Head & Neck Surgery, La Paz University Hospital, Madrid, Spain.

PMID: 38155056
DOI: 10.1016/j.jvoice.2023.11.017

Abstract

Objective: The main objective of this study was to compare the demographic and clinical characteristics of patients with laryngeal dystonia (LD), dystonic tremor (DT), and vocal tremor (VT).

Study design: This was a retrospective longitudinal study.

Methods: Data analysis from every patient diagnosed with LD, DT, or VT from January 1, 2010, to September 30, 2022, at a tertiary hospital center. Differential diagnosis between these entities was clinical (clinical history, voice assessment, and endoscopy) and confirmed by laryngeal electromyography.

Results: A total of 87 patients were included in this study: 50 patients with LD, 23 with DT, and 14 with VT. Age at diagnosis was significantly lower in patients with LD, with a mean age of 56.2 years when compared to DT (67.6 years; P = 0.002) and VT (70.5 years; P = 0.009). Furthermore, VT had a higher female prevalence (92.9%) when compared with LD (52%; P = 0.011). LD was mainly adductor, with only two patients diagnosed with abductor LD, and DT was adductor in every case. Tremor direction in patients with VT was horizontal in 50% and mixed (horizontal + vertical) in 50%, while in DT was mixed in 65.2% and horizontal in 34.8%. LD was more commonly an isolated laryngeal movement disorder (78%) when compared to DT (47.8%; P = 0.015) or VT (28.5%; P < 0.001), which were more often secondary to generalized neurological disorders. There were no differences between groups on Voice Handicap Index-10, self-reported grade of dysphonia on a visual analogic scale (0-10), maximum phonation time, and G, R, B, A, and I in the GRBAS-I scale at diagnosis (P > 0.05). S was significantly higher in LD when compared to VT (P < 0.001) and nonsignificantly higher than in DT (P = 0.075).

Conclusions: LD, DT, and VT seem to be different entities with different demographics and clinical characteristics.

Keywords: Laryngeal dystonia; Laryngeal dystonic tremor; Movement disorders of the larynx; Vocal tremor.