Trial reportEuropean journal of neurology2021
Botulinum toxin injection into the intrinsic laryngeal muscles to treat spasmodic dysphonia: A multicenter, placebo-controlled, randomized, double-blinded, parallel-group comparison/open-label clinical trial.
Trial report in European journal of neurology, 2021. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 9 papers, 1 of them a synthesis that pooled it.
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The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
9 citing papers in PubMed, 1 synthesis or guideline pooled it, 18 citations in OpenAlex.
- Guidelines for the Use of Botulinum Toxin in Otolaryngology From the Korean Society of Laryngology, Phoniatrics and Logopedics Guideline Task Force.Clinical and experimental otorhinolaryngology · 2023Guideline
- Laryngeal mask airway improves hemodynamics and reduces pharyngeal discomfort in total joint arthroplasty.Scientific reports · 2025Trial
- Laryngeal Vibration to Treat Abductor-Type Laryngeal Dystonia: Effectiveness and Cortical Response.The Laryngoscope · 2026Article
- Trends and off-label use of botulinum toxin type A in Chinese neurological practice from 2016 to 2023: a real-world study.Frontiers in pharmacology · 2026Article
- Voice Outcomes in Patients With Laryngopharyngeal Reflux: A Systematic Review and Meta-Analysis.Cureus · 2025Review
- Article
- Review
- Botulinum Toxin Therapy: A Series of Clinical Studies on Patients with Spasmodic Dysphonia in Japan.Toxins · 2021Review
- Post-treatment clinical course following botulinum toxin injection therapy for adductor spasmodic dysphonia: Analysis of data from a placebo-controlled, randomized, double-blinded clinical trial in Japan.Laryngoscope investigative otolaryngology · 2021Article
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
15 authors at 11 institutions in 1 country.
Funding
No grant is acknowledged in the PubMed record.
Abstract
background and purposeBotulinum toxin (BT) injection into the laryngeal muscles has been a standard treatment for spasmodic dysphonia (SD). However, few high-quality clinical studies have appeared, and BT is used off-label in most countries.
methodsWe performed a multicenter, placebo-controlled, randomized, double-blinded, parallel-group comparison/open-label clinical trial to obtain approval for BT (Botox) therapy in Japan. Twenty-four patients (22 with adductor SD and two with abductor SD) were enrolled. The primary end point was the change in the number of aberrant morae (phonemes) at 4 weeks after drug injection. The secondary end points included the change in the number of aberrant morae, GRBAS scale, Voice Handicap Index (VHI), and visual analog scale (VAS) over the entire study period.
resultsIn the adductor SD group, the number of aberrant morae at 4 weeks after injection was reduced by 7.0 ± 2.30 (mean ± SE) in the BT group and 0.2 ± 0.46 in the placebo group (p = 0.0148). The improvement persisted for 12 weeks following BT injections. The strain element in GRBAS scale significantly reduced at 2 weeks after BT treatment. The VHI and VAS scores as subjective parameters also improved. In the abductor SD group, one patient responded to treatment. Adverse events included breathy hoarseness (77.3%) and aspiration when drinking (40.9%) but were mild and resolved in 4 weeks.
conclusionsBotulinum toxin injection was safe and efficacious for the treatment of SD. Based on these results, BT injection therapy was approved as an SD treatment in Japan.
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