Botulinum toxin treatment for adductor spasmodic dysphonia with EMG and endoscopic guidance

Background & Objective: Spasmodic dysphonia is idiopathic focal dystonia characterized by irregular contractions or postural disorders of the laryngeal muscles, resulting in abnormal speech. Progress in laryngoscopy has resulted in development of a precise technique of botulinum toxin (BTX) injection into the thyroarytenoid muscle under visual control. Methods: We used EMG and endoscopic guidance for BTX injection in adductor spasmodic dysphonia (AdSD). Results: Thirty eight patients with AdSD were injected with BTX in 84 treatment sessions. The voice handicap index (VHI) level of the patients were: severe (73.8%), moderate (26.2%) and mild (none). The average VHI score was 74.6 points. After 8 weeks of BTX treatment, the VHI level was: Severe (3.6%), moderate (10.8%), and mild (85.7%). The average VHI score was 27.7 points. The average values of jitter, shimmer and harmonic to noice ratio (HNR) improved statistically (p < 0.05). The incidence of side effects were: breathiness (17.9%), choking (15.5%); hoarseness (8.5%), and dysphagia (4.7%). Conclusions: Injection of BTX under both EMG and laryngoscopy guidance for treatment of adductor spasmodic dysphonia is an effective and safe treatment.

Efficacy of Botulinum toxin A in treatment of primary hemifacial spasm

Objective: Evaluating the effects of toxin botulinum A in treatment of primary hemifacial spasm. Methods: A total of 48 patients with primary hemifacial spasm were treated by injections of botulinum toxin A (Dysport) in Tam Anh Hospital from 6/2020 to 5/ 2021. Methods: Prospective, descriptive study. Results: Forty-eight patients (8 male, 40 female) were included in the study, the ages were from 36 to 79 years with an average age of 57 ± 10,43 years, having mean Jankovic disability rating scale score of 3.25±0.55SD. MRI revealed vascular compression in all patients. The dose Dysport was 80-145UI; 91,7% reported improvement after 2 weeks - 1 month from the injected. Benefits begin in 2-7 days after the treatment and last for an average of 5,50 ± 0,97 months (3-8 months). Side effects such as ectropion (45,83%), ptosis (4,2%), and hematoma (12,5%) are transient and reversible after 1-3 weeks. No severe complication was noted. Conclusions: This finding show that local botulinum toxin treatment provides effective and safe relief of hemifacial spasm.

Smell and taste in idiopathic blepharospasm

The pathophysiology of blepharospasm is incompletely understood. Current concepts suggest that blepharospasm is a network disorder, involving basal ganglia, thalamus, cortex, and, possibly, the cerebellum. Tracing, imaging, and clinical studies revealed that these structures are also concerned with olfaction and taste. Because of this anatomical overlap, dysfunction of the chemical senses in blepharospasm is expected. Injections of botulinum toxin into the eyelid muscles are the first-line treatment of blepharospasm. Yet, the effects of botulinum toxin on the chemical senses have not been systematically assessed. To contribute to a better understanding of blepharospasm, olfactory and gustatory abilities were assessed in 17 subjects with blepharospasm and 17 age-/sex-matched healthy controls. Sniffin Sticks were used to assess odor threshold, odor discrimination, and odor identification. Results of these three Sniffin Sticks subtests were added to the composite olfactory score. The Taste Strips were applied to assess taste. In an adjacent study, we assessed the sense of smell and taste in eight subjects with blepharospasm before and 4 weeks after botulinum toxin treatment. Subjects with blepharospasm had significantly lower (= worse) scores for odor threshold and for the composite olfactory score than healthy controls, while odor discrimination, odor identification, and the composite taste score were not different between groups. The adjacent study revealed that botulinum toxin did not impact the chemical senses. In this study, subjects with blepharospasm had a lower (= worse) odor threshold than healthy controls. As olfaction is important in daily life, findings justify further research of olfaction in blepharospasm.

Nonlinear Changes in Botulinum Toxin Treatment of Task-Specific Dystonia during Long-Term Treatment

Botulinum toxin (BoTX) is the standard treatment for task-specific dystonias (TSDs) such as musician’s dystonia (MD). Our aim was to assess the long-term changes in BoTX treatment in a highly homogeneous and, to our knowledge, largest group of MD patients with respect to the following parameters: (1) absolute and (2) relative BoTX dosage, (3) number of treated muscles, and (4) inter-injection interval. We retrospectively assessed a treatment period of 20 years in 233 patients, who had received a cumulative dose of 68,540 MU of BoTX in 1819 treatment sessions, performed by two neurologists. Nonlinear correlation was used to analyze changes in the parameters over the course of repeated treatments. Post-hoc we applied a median-split to classify two subgroups (high-BoTX, low-BoTX) depending on the total amount of BoTX needed during treatment. Across all patients, we found a decrease of dosage for the first approximately 25 treatments with an increase afterwards. The number of muscles and inter-injection intervals increased with time with a discrete decrease of inter-injection intervals after about 35 treatments. Subgroup differences were observed in the amount of BoTX and inter-injection intervals, with continuously increasing inter-injection intervals and decreasing BoTX dosage in the low-BTX group. Both groups showed a continuously increasing number of injected muscles. In summary, we found nonlinear changes of BoTX dosage and inter-injection intervals and a continuously increasing number of injected muscles with treatment duration in TSD-patients. Furthermore, we, for the first time, identified two subgroups with distinct differences. Increasing inter-injection intervals and decreasing BoTX dosages in the low-BoTX group indicated improvement of symptoms with continued treatment. Continually increasing BoTX dosages with unchanged inter-injection intervals in the high-BoTX group indicated deterioration.

The Role of Ultrasound for the Personalized Botulinum Toxin Treatment of Cervical Dystonia

The visualization of the human body has frequently been groundbreaking in medicine. In the last few years, the use of ultrasound (US) imaging has become a well-established procedure for botulinum toxin therapy in people with cervical dystonia (CD). It is now undisputed among experts that some of the most relevant muscles in this indication can be safely injected under visual US guidance. This review will explore the method from basic technical considerations, current evidence to conceptual developments of the phenomenology of cervical dystonia. We will review the implications of introducing US to our understanding of muscle function and anatomy of common cervical dystonic patterns. We suggest a flow chart for the use of US to achieve a personalized treatment of people with CD. Thus, we hope to contribute a resource that is useful in clinical practice and that stimulates the ongoing development of this valuable technique.