May 6, 2022

Dystonia Research Update

We are delighted to present this new page in our newsletter. Here we will share the most recent publications in the field of dystonia research together with a summary in lay language.

Ledda C, Artusi CA, Tribolo A et al. Time to onset and duration of botulinum toxin efficacy in movement disorders. J Neurol. 2022 Feb 3. doi: 10.1007/s00415-022-10995-2.

This study looked at factors that could influence botulinum toxin treatment benefit for people living with movement disorders.

The study found that the total dose of botulinum toxin injected may influence the time to start of treatment benefit and length of treatment benefit (a higher dose may reduce the time to start of benefit and increase the length of treatment benefit) experienced by patients.  The length of treatment benefit also appeared to be related to the type of dystonia. For example, patients living with blepharospasm experienced a shorter length of treatment benefit than patients living with cervical dystonia and focal limb dystonia; Patients living with cervical dystonia experienced a treatment benefit that lasted longer than patients living with hemifacial spasm and sialorrhea; hemifacial spasm a shorter length of treatment benefit than focal limb dystonia; focal limb dystonia a longer length of treatment benefit than sialorrhea. Age was a strong predictor of an earlier start of treatment effect, with older patients showing an earlier effect.

This study found new potential predictors of length of botulinum toxin treatment effectiveness worthy of being assessed in future studies and during clinical practice.

Hefter H, Ürer B, Brauns R et al. Significant Long-Lasting Improvement after Switch to Incobotulinum Toxin in Cervical Dystonia Patients with Secondary Treatment Failure. Toxins (Basel). 2022 Jan 6;14(1):44.

Treatment failures (where the treatment stops working) may occur in patients with long-term botulinum toxin treatment. Repetitive injections may activate the immune system with the risk of producing antibodies that reduce the effect of therapy. While the induction of such neutralizing antibodies is often related to reduced response to treatment, it does not prevent a clinical response.

This study evaluated the effectiveness of switching to a different botulinum toxin brand (in this case the name of the botulinum toxin was incobotulinumtoxinA) in  patients experiencing treatment failure with their current treatment (abobotuliumtoxinA or ona-botulinumtoxinA). Patients improved after the switch to the different brand of botulinum toxin but did not reach the improvement level obtained before the treatment failure developed.

In this study, a long-lasting improvement was shown in patients with treatment failure when switching to a different botulinum toxin brand.

Comella C, Hauser RA, Isaacson SH et al. Efficacy and safety of two incobotulinumtoxinA injection intervals in cervical dystonia patients with inadequate benefit from standard injection intervals of botulinum toxin: Phase 4, open-label, randomized, noninferiority study. Clin Park Relat Disord. 2022 Mar 14;6:100142.

Some patients with cervical dystonia who are responsive to treatment and receive botulinum toxin injections at standard treatment intervals (12 weeks) report a waning or reduction of clinical effect and reemergence of  symptoms before their next injection.

The authors of this study aimed to evaluate whether patients experienced benefit from shorter injection intervals and whether there were any side effects caused by shorter re-injection intervals. Patients were divided into two groups; the first group were reinjected at intervals of <10 weeks (short intervals) and the second group were re-injected at the standard 12 week interval (long intervals). Patients were followed for 8 injection cycles. Improvements in dystonia severity,  activities of daily life and pain were shown in both group of patients. Patient satisfaction with treatment improved over time in the short treatment interval. This was not shown in the long interval group. There were no new or unexpected safety findings with either treatment interval, and the number of participants with side effects was similar in both groups.

This study shows that patients living with cervical dystonia who experience early waning or “wearing off” of botulinum toxin effect can benefit from shorter injection cycles of incobotulinumtoxinA without increased risk and illustrates the advantages of adapting botulinum toxin treatment schedules to meet individual patient needs.

Chueluecha C and Moore AP. LIVECHART Patient-Reported Outcome Tool for Botulinum Toxin Treatment in Cervical Dystonia. Mov Disord Clin Pract. 2022 Jan 19;9(2):198-205.

The Liverpool botulinum toxin effects chart (LIVECHART) is a short questionnaire for patients which has been used for over 25 years in the botulinum toxin injection clinic at the Walton Centre in Liverpool. The LIVECHART allows patients to monitor how well their treatment is working between injections and to rate how well the treatment is working overall. This scale has not been formally tested so that it can be used in clinical trials.  The aim of this study was to understand how well the LIVECHART captures the self reported effects of  botulinum toxin treatment for patients with cervical dystonia.

The authors concluded that the LIVECHART adequately reflects the depth of treatment benefit, duration and overall benefit of botulinum toxin treatment, and is worth further formal evaluation to determine its validity and reliability.