What is the optimal dose of botulinum toxin A in the treatment of cervical dystonia? Results of a double blind, placebo controlled, dose ranging study using Dysport. German Dystonia Study Group

Dysphagia and Muscle Weakness Secondary to Botulinum Toxin Type A Treatment of Cervical Dystonia: A Drug Class Analysis of Prescribing Information

The first-line management of cervical dystonia (CD) symptoms is intramuscular injection of botulinum toxin type A (BoNTA). However, a comparison of safety among BoNTAs is difficult because, per regulatory authorities, units of BoNTA activity are not interchangeable. Dysphagia and muscle weakness are widely considered two key adverse events to monitor closely in the treatment of CD. This integrated analysis compared the safety of BoNTAs approved for CD in the US by evaluating relationships between the incidence of dysphagia and muscle weakness in prescribing information and the core neurotoxin content. Coefficients The coefficients of determination (R2) and trendlines were estimated via regression-based lines of best fit. Adverse drug reaction (ADR) rates were strongly correlated with core neurotoxin amounts for conventional BoNTAs (slope coefficients: dysphagia = 0.048, R2 = 0.74; muscle weakness = 0.096, R2 = 0.82). The published ADR rates at approved doses for conventional BoNTAs were higher compared with DaxibotulinumtoxinA (DAXI; DAXXIFY®, Revance Therapeutics, Inc., Nashville, TN, USA) by core neurotoxin content. The use of a core neurotoxin amount was found to be an effective method for comparing the safety of BoNTA products. Current clinical trials suggest that DAXI, a novel BoNTA formulation, provides a potentially wider safety margin compared with other approved BoNTAs for CD. The lower amount of core neurotoxin administered at approved doses compared with conventional BoNTAs may explain low on-target ADRs like muscle weakness, whereas reduced diffusion from the injection site is thought to be responsible for low off-target ADRs like dysphagia.

Update on Non-Interchangeability of Botulinum Neurotoxin Products

The growing use of botulinum neurotoxins (BoNTs) for medical and aesthetic purposes has led to the development and marketing of an increasing number of BoNT products. Given that BoNTs are biological medications, their characteristics are heavily influenced by their manufacturing methods, leading to unique products with distinct clinical characteristics. The manufacturing and formulation processes for each BoNT are proprietary, including the potency determination of reference standards and other features of the assays used to measure unit potency. As a result of these differences, units of BoNT products are not interchangeable or convertible using dose ratios. The intrinsic, product-level differences among BoNTs are compounded by differences in the injected tissues, which are innervated by different nerve fiber types (e.g., motor, sensory, and/or autonomic nerves) and require unique dosing and injection sites that are particularly evident when treating complex therapeutic and aesthetic conditions. It is also difficult to compare across studies due to inherent differences in patient populations and trial methods, necessitating attention to study details underlying each outcome reported. Ultimately, each BoNT possesses a unique clinical profile for which unit doses and injection paradigms must be determined individually for each indication. This practice will help minimize unexpected adverse events and maximize efficacy, duration, and patient satisfaction. With this approach, BoNT is poised to continue as a unique tool for achieving individual goals for an increasing number of medical and aesthetic indications.

Is There a Standard Rehabilitation Procedure in Cervical Dystonia?

Introduction: Idiopathic cervical dystonia, also known as spasmodic torticollis, is the most common form of focal dystonia in adults. Cervical dystonia usually appears between the ages of 30 and 50, twice as often in women, and is characterised by uncontrollable painful contractions of the sternocleidomastoid muscle, which results in misalignment of the head and shoulder. Over time, the disease becomes very burdensome for the patient and reduces his/her independence and quality of life; falls happen.Aim: The aim of the article is to present the current state of knowledge on comprehensive rehabilitation in cervical dystonia. Data on the prevalence, symptoms, diagnosis, clinical assessment, pharmacological treatment (including the most commonly used botulinum toxin), neurosurgical treatment and comprehensive rehabilitation are presented.Methods: The applied methods was a narrative critical review of scientific reports.Results: Out of several hundred publications, works worthy of particular attention were selected. In them, are described of conducting exercises, the main goal of which is to stretch and relax the dystonic muscles while strengthening the antagonistic muscles and correcting the position of the head. The selected authors used manual therapy, exercises at the patient's home, EMG biofeedback, magnetic stimulation of the cerebellum, vibration of the neck muscles, functional electrostimulation (FES) of antagonistic muscles, mobilisation of the cervical spine, postural exercises, isometric exercises, muscle relaxation, the PNF method, relaxation training, balance exercises, coordination, corrective exercises, massage, relaxation exercises, stretching and kinesiotaping.Conclusions: The variety of disease forms (10 head positioning patterns are described) and different severity of symptoms make it impossible to draw up a scheme of rehabilitation. In each case, rehabilitation must be tailored individually, and the physiotherapist taking care of the patient should have extensive experience. Physiotherapy can alleviate the disability caused by dystonia, however, due to the many non-motor symptoms, a holistic approach to the patient should also be kept in mind.

Botulinum toxin for motor disorders

Botulinum neurotoxins are a group of biological toxins produced by the gram-negative bacteria Clostridium botulinum. After intramuscular injection, they produce dose-related muscle relaxation, which has proven useful in the treatment of a large number of motor and movement disorders. In this chapter, we discuss the utility of botulinum toxin treatment in three major and common medical conditions related to the dysfunction of the motor system, namely dystonia, tremor, and spasticity. A summary of the existing literature is provided along with different techniques of injection including those recommended by the authors.

Lasting Peripheral and Central Effects of Botulinum Toxin Type A on Experimental Muscle Hypertonia in Rats

Recent animal experiments suggested that centrally transported botulinum toxin type A (BoNT-A) might reduce an abnormal muscle tone, though with an unknown contribution to the dominant peripheral muscular effect observed clinically. Herein, we examined if late BoNT-A antispastic actions persist due to possible central toxin actions in rats. The early effect of intramuscular (i.m.) BoNT-A (5, 2 and 1 U/kg) on a reversible tetanus toxin (TeNT)-induced calf muscle spasm was examined 7 d post-TeNT and later during recovery from flaccid paralysis (TeNT reinjected on day 49 post-BoNT-A). Lumbar intrathecal (i.t.) BoNT-A-neutralizing antiserum was used to discriminate the transcytosis-dependent central toxin action of 5 U/kg BoNT-A. BoNT-A-truncated synaptosomal-associated protein 25 immunoreactivity was examined in the muscles and spinal cord at day 71 post-BoNT-A. All doses (5, 2 and 1 U/kg) induced similar antispastic actions in the early period (days 1-14) post-BoNT-A. After repeated TeNT, only the higher two doses prevented the muscle spasm and associated locomotor deficit. Central trans-synaptic activity contributed to the late antispastic effect of 5 U/kg BoNT-A. Ongoing BoNT-A enzymatic activity was present in both injected muscle and the spinal cord. These observations suggest that the treatment duration in sustained or intermittent muscular hyperactivity might be maintained by higher doses and combined peripheral and central BoNT-A action.

KinesioTaping after botulinum toxin type A for cervical dystonia in adult patients

INTRODUCTION

Studies explored physiotherapeutic approaches in cervical dystonia (CD) patients with or without botulinum toxin (BoNT) injections, however the results are varying. There are no clinical trials investigating the effects of kinesiology taping in CD patients. The objective of this study is to investigate the efficacy of kinesiology taping as an adjunct to the BoNT injections in patients with CD.

METHODS

Twenty-five patients were enrolled to the study. Patients were randomly assigned to the experimental 1 (BoNT + KinesioTaping), experimental 2 (BoNT + ShamTaping) or control (BoNT) treatment. After 12 weeks they were moved to the next experimental group and finally every patient received all 3 proposed treatment options. The severity of CD was quantified with the Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS) including Torticollis severity, Disability, and Pain scales. Quality of life was evaluated using Craniocervical dystonia questionnaire (CDQ4).

RESULTS

In all treatment groups, there was a significant improvement in dystonia symptoms measured with TWSTRS (total score) after BoNT injection regardless of the allocation to the experimental treatment (p < .05). ANOVA analysis revealed no differences in any of the TWSTRS variables after the intervention. Quality of life was significantly improved after application of taping (p < .05, p = .03).

CONCLUSIONS

Application of KinesioTaping after BoNT injection provided no additional effect on the severity of dystonia, although the quality of life was improved in patients with CD. Further research investigating the effect of KinesioTaping prior to BoNT injection is required.

Time to onset and duration of botulinum toxin efficacy in movement disorders

Background

Botulinum toxin (BoNT) is a valuable treatment in movement disorders; however, time to onset and duration of efficacy may widely differ among patients. We aimed to clarify the impact of main demographic and clinical features on time to onset and duration of BoNT efficacy.

Methods

We analyzed time-to-onset and duration of BoNT efficacy in 186 consecutive patients treated with BoNT for blepharospasm, cervical dystonia, facial hemispasm, oromandibular dystonia, limb dystonia, and sialorrhea due to Parkinsonism. The following factors were considered as potential efficacy predictors: doses and types of toxin, sex, age, years of treatment, and clinical condition. Kruskall–Wallis, Spearman correlation, and multivariate linear regression were used for statistical analysis.

Results

The average time to onset was 6.7 ± 5 days and duration of BONT efficacy 78.5 ± 28.4 days. Both time to onset and duration of efficacy were correlated with BoNT doses (p: 0.007 and p: 0.02). The multiple regression analysis showed that sex, age, years of BoNT treatment, doses, type of toxin, and clinical condition significantly predicted time to onset (F(11, 171) = 2.146, p: 0.020) with age being the strongest predictor (p: 0.004).

The same model explained 20.1% of the variance of duration of BoNT efficacy, showing a significant prediction of the outcome (F(11, 164) = 3.754, p < 0.001), with doses (p < 0.001), type of toxin (p: 0.017), and clinical condition (p < 0.001) being the strongest predictors.

Conclusion

Our findings suggest that age, type of toxin, clinical condition and especially doses may account for the variability of BoNT efficacy in terms of time to onset and duration.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00415-022-10995-2.

Pain in cervical dystonia: mechanisms, assessment and treatment

INTRODUCTION

In patients with cervical dystonia (CD), pain is a major contributor to disability and social isolation and is often the main reason patients seek treatment. Surveys evaluating patient perceptions of their CD symptoms consistently highlight pain as a troublesome and disabling feature of their condition with significant impact on daily life and work.

AREAS COVERED

In this article, the authors review the epidemiology, assessment, possible mechanisms and treatment of pain in CD, including a meta-analysis of randomized controlled trial data with abobotulinumtoxinA.

EXPERT OPINION

Mechanisms of pain in CD may be muscle-based and non-muscle based. Accumulating evidence suggests that non-muscle-based mechanisms (such as abnormal transmission and processing of nociceptive stimuli, dysfunction of descending pain inhibitory pathways as well as structural and network changes in the basal ganglia, cortex and other areas) may also contribute to pain in CD alongside prolonged muscle contraction. Chemodenervation with botulinum toxin is considered the first-line treatment for CD. Treatment with botulinum toxin is usually effective, but optimization of the injection parameters should include consideration of pain as a core symptom in addition to the motor problems.

Botulinum Toxin in Movement Disorders: An Update

Since its initial approval in 1989 by the US Food and Drug Administration for the treatment of blepharospasm and other facial spasms, botulinum toxin (BoNT) has evolved into a therapeutic modality for a variety of neurological and non-neurological disorders. With respect to neurologic movement disorders, BoNT has been reported to be effective for the treatment of dystonia, bruxism, tremors, tics, myoclonus, restless legs syndrome, tardive dyskinesia, and a variety of symptoms associated with Parkinson's disease. More recently, research with BoNT has expanded beyond its use as a powerful muscle relaxant and a peripherally active drug to its potential central nervous system applications in the treatment of neurodegenerative disorders. Although BoNT is the most potent biologic toxin, when it is administered by knowledgeable and experienced clinicians, it is one of the safest therapeutic agents in clinical use. The primary aim of this article is to provide an update on recent advances in BoNT research with a focus on novel applications in the treatment of movement disorders. This comprehensive review of the literature provides a critical review of evidence-based clinical trials and highlights recent innovative pilot studies.

Improvement in Quality of Life with OnabotulinumtoxinA for Cervical Dystonia: POSTURe

Introduction:

Symptoms of cervical dystonia (CD) can vary in severity and cause significant pain. OnabotulinumtoxinA is an approved treatment for CD. This study assessed health-related quality of life (HRQoL) in patients with CD who received multiple onabotulinumtoxinA treatments.

Methods:

This prospective, observational standard-of-care study was conducted at multiple neurology centers in Québec, Canada. Patients reported the health impact of CD using the Cervical Dystonia Impact Profile (CDIP)-58, before and after up to eight onabotulinumtoxinA treatments. Other measures included the Cervical Dystonia Severity Rating Scale by physician, employment status using the Work Productivity Questionnaire and pain using the Pain Numeric Rating Scale (PNRS). Adverse events (AEs) were recorded.

Results:

Sixty-two patients were enrolled (safety population, n = 61; modified efficacy population, n = 58). Participants were mostly females who were employed; most (79.3%) had torticollis. In all, 21/62 patients (33.9%) discontinued the study. At the final visit, there was a statistically significant (p < 0.001) improvement in all eight CDIP-58 subscales, particularly head and neck symptoms (−31.0) and psychosocial functioning (−28.2). Employment increased from baseline (55%) to the end of the study (64%), and there was improvement in work productivity. There was a significant (p < 0.0001) reduction in pain measured by the PNRS, from −0.5 post-treatment 1 to −2.4 at end of study. AEs (neck pain, muscular weakness, dysphagia, nausea) were consistent with onabotulinumtoxinA use.

Conclusion:

These real-world data indicate that after repeated, long-term use, onabotulinumtoxinA continues to be a safe and effective treatment for CD, improving HRQoL and work productivity.

Botulinum toxin type A therapy for cervical dystonia

BACKGROUND

This is an update of a Cochrane Review first published in 2005. Cervical dystonia is the most common form of focal dystonia, and is a highly disabling movement disorder, characterised by involuntary, usually painful, head posturing. Currently, botulinum toxin type A (BtA) is considered the first line therapy for this condition.

OBJECTIVES

To compare the efficacy, safety, and tolerability of BtA versus placebo, in people with cervical dystonia.

SEARCH METHODS

We searched Cochrane Movement Disorders' Trials Register, CENTRAL, MEDLINE, Embase, reference lists of articles, and conference proceedings in July 2020. All elements of the search, with no language restrictions, were last run in July 2020.

SELECTION CRITERIA

Double-blind, parallel, randomised, placebo-controlled trials (RCTs) of BtA versus placebo in adults with cervical dystonia.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed records, selected included studies, extracted data using a paper pro forma, and evaluated the risk of bias. We resolved disagreements by consensus or by consulting a third review author. We performed meta-analyses using a random-effects model, for the comparison of BtA versus placebo, to estimate pooled effects and corresponding 95% confidence intervals (95% CI). We performed preplanned subgroup analyses according to BtA dose used, the BtA formulation used, and the use (or not) of guidance for BtA injections. The primary efficacy outcome was improvement in cervical dystonia-specific impairment. The primary safety outcome was the proportion of participants with any adverse event.

MAIN RESULTS

We included nine RCTs, with moderate, overall risk of bias, that included 1144 participants with cervical dystonia. Seven studies excluded participants with poorer responses to BtA treatment, therefore, including an enriched population with a higher probability of benefiting from this therapy. Only one trial was independently funded. All RCTs evaluated the effect of a single BtA treatment session, using doses from 150 U to 500 U of onabotulinumtoxinA (Botox), 120 U to 240 U of incobotulinumtoxinA (Xeomin), and 250 U to 1000 U of abobotulinumtoxinA (Dysport). BtA resulted in a moderate to large improvement from the participant's baseline clinical status, assessed by the investigators, with a mean reduction of 8.09 points in the Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS total score) at week four after injection (95% CI 6.22 to 9.96; I² = 0%) compared to placebo. This corresponded, on average, to a 18.4% improvement from baseline. The mean difference (MD) in TWSTRS pain subscore at week four was 2.11 (95% CI 1.38 to 2.83; I² = 0%) compared to placebo. Overall, both participants and clinicians reported an improvement of subjective clinical status. It was unclear if dropouts due to adverse events differed (risk ratio (RR) 2.51; 95% CI 0.42 to 14.94; I² = 0%) However, BtA treatment increased the risk of experiencing an adverse event (R) 1.23; 95% CI 1.05 to 1.43; I² = 28%). Neck weakness (14%; RR 3.40; 95% CI 1.19 to 9.71; I² = 15%), dysphagia (11%; RR 3.19; 95% CI 1.79 to 5.70; I² = 0%), and diffuse weakness or tiredness (8%; RR 1.80; 95% CI 1.10 to 2.95; I² = 0%) were the most common treatment-related adverse events. Treatment with BtA resulted in a decreased risk of dropouts. We have moderate certainty in the evidence across all of the aforementioned outcomes, with the exception of subjective assessment and tolerability, in which we have high confidence in the evidence. We found no evidence supporting the existence of a clear dose-response relationship between BtA and improvement in cervical dystonia-specific impairment, a destinction between BtA formulations, or a variation with use of EMG-guided injection for efficacy outcomes. Due to clinical heterogeneity, we did not pool health-related quality of life data, duration of clinical effect, or the development of secondary non-responsiveness.

AUTHORS' CONCLUSIONS

We are moderately certain in the evidence that a single BtA treatment session resulted in a clinically relevant reduction of cervical dystonia-specific impairment, and pain, and highly certain that it is well tolerated, compared with placebo. There is moderate-certainty evidence that people treated with BtA are at an increased risk of developing adverse events, most notably, dysphagia, neckweakness and diffuse weakness or tiredness. There are no data from RCTs evaluating the effectiveness and safety of repeated BtA injection cycles. There is no evidence from RCTs to allow us to draw definitive conclusions on the optimal treatment intervals and doses, the usefulness of guidance techniques for injection, the impact on quality of life, or the duration of treatment effect.

Pain incidence in cervical dystonia is determined by the disease phenotype

BACKGROUND

Cervical dystonia (CD) is a movement disorder caused by prolonged contractions of the head and neck muscles resulting in abnormal postures and repetitive movements. Depending on the direction of the head and neck deviation, CD phenotypes are divided into torti-, latero-, antero-, and retro- impairments assessed in commonly used TWSTRS classification, or -caput and -collis according to the novel Col-Cap concept. Cervical pain, which pathophysiology has not been fully elucidated, affects more than 60% of CD patients. To date, none of the studies have investigated the risk of pain associated with the particular disease phenotype.

METHODS

In this observational study data collection was based on the survey completion by the participants, analysis of the medical records, and physical examination with the use of proper scales (TWSTRS, Col-Cap, Tsui). Extended pain profile questionnaire included detailed questions about pain localization, character, and intensity.

RESULTS

We examined 60 patients suffered from CD; 66,7% of them reported cervical pain. Latero- as the only TWSTRS phenotype was associated with increased risk of pain occurrence (OR = 3,95; p < 0,05). Interestingly, each of two Col-Cap phenotypes correlated with cervical pain: -caput positively (OR = 3,78; p < 0,05) and -collis negatively (OR = 0,29; p < 0,05).

CONCLUSIONS

The risk of dystonic pain was highly differentiated within the particular CD phenotypes. The enhanced risk of cervical pain was observed in latero- (TWSTRS) and -caput (Col-Cap) phenotypes; conversely, -collis type (Col-Cap) was characterized by the lowest risk of cervical pain.

Patient perspectives on the therapeutic profile of botulinum neurotoxin type A in cervical dystonia

BACKGROUND

Botulinum neurotoxin type A (BoNT-A) is an effective pharmacological treatment for the management of cervical dystonia (CD) that requires repeated administration at variable intervals. We explored patient perceptions of the impact of CD and the waning of BoNT-A therapeutic effects.

METHODS

An internet-based survey was conducted through Carenity, a global online patient community, from May to September 2019. Eligible respondents were adults with CD who had ≥ 2 previous BoNT-A injections.

RESULTS

209 respondents (81% females; mean age of 49.7 years) met the screening criteria. The mean BoNT-A injection frequency was 3.9 injections/year. The mean reported onset of BoNT-A therapeutic effect was 11.7 days and the time to peak effect was 4.5 weeks. Symptom re-emergence between injections was common (88%); the time from injection to symptom re-emergence was 73.6 days (~ 10.5 weeks). Treatment was not reported to completely abolish symptoms, even at peak effect. However, symptom severity was rated (0 = no symptoms; 10 = very strong symptoms) as lowest at the peak of treatment effects (mean scores ~ 3/10), increasing as the effects of treatment start waning (~ 5.5/10) and was strongest one day before the next session (~ 7-8/10). The impact of CD on quality of life followed the same 'rollercoaster' pattern.

CONCLUSIONS

This survey highlights the burden of CD symptoms, even in patients undergoing regular treatment. Symptom re-emergence is common and has significant impact on daily activities and quality of life. Greater awareness of the therapeutic profile of BoNT-A treatment should lead to better informed therapeutic discussions and planning.

Use of AbobotulinumtoxinA in Adults with Cervical Dystonia: A Systematic Literature Review

Cervical dystonia (CD) is a neurological movement disorder characterized by sustained involuntary muscle contractions. First-line therapy for CD is intramuscular injections of botulinum neurotoxin (e.g., abobotulinumtoxinA) into the affected muscles. The objective of this systematic literature review is to assess the clinical evidence regarding the effects of abobotulinumtoxinA for treatment of CD in studies of safety, efficacy, patient-reported outcomes, and economic outcomes. Using comprehensive electronic medical literature databases, a search strategy was developed using a combination of Medical Subject Heading terms and keywords. Results were reviewed by two independent reviewers who rated the level of evidence. The search yielded 263 publications, of which 232 were excluded for being duplicate publications, not meeting the selection criteria, or failing to meet predefined eligibility criteria, leaving a total of 31 articles. Clinical efficacy, patient-reported outcomes, and safety data were in 6 placebo-controlled trials (8 articles), 6 active-controlled trials, and 16 observational studies (17 articles). Data on health economic outcomes were provided in one of the clinical trials, in two of the observational studies, and in one specific cost-analysis publication. This review demonstrated that the routine use of abobotulinumtoxinA in CD is well-established, effective, and generally well-tolerated, with a relatively low cost of treatment.

Dysphagia in cervical dystonia patients receiving optimised botulinum toxin therapy: a single-center retrospective cohort study

To explore the correlations of botulinum toxin (BT) therapy with dysphagia, we wanted to study a group of cervical dystonia (CD) patients with optimised BT therapy during a prolonged period of time to record their dysphagia frequency, severity and duration, to study potential risk factors and try to avoid it by BT application with ultrasound guidance. BT therapy of 75 CD patients (23 males, 52 females, age 60 ± 12 years, BT total dose 303.5 ± 101.5 uMU) was retrospectively analysed for 1 year. BT therapy was optimised prior to the observation period. Dysphagia was noticed by one fifth of the patients. In those patients, it only occurred in about one third of the injection series. It was never associated with a functional deficit and lasted several days to 2 weeks. It was not related to patient age or gender, BT total dose, BT dose in the sternocleidomastoid muscle, BT dose in the sternocleidomastoid and scalenii muscles, by BT therapy with bilateral sternocleidomastoid muscle injections or BT therapy with abobotulinumtoxinA. Ultrasound guidance was not able to prevent it. Further prospective studies will be necessary to study underlying dystonia associated swallowing abnormalities as a potentially predisposing factor.

Impact of abobotulinumtoxinA on the clinical features of cervical dystonia in routine practice

INTRODUCTION

The efficacy and safety of abobotulinumtoxinA in the management of cervical dystonia has been established in randomized, controlled trials that use a selected trial population. In this meta-analysis of observational data, we evaluated the real-life effectiveness of abobotulinumtoxinA as delivered in routine clinical practice.

METHODS

Meta-analysis of patient-level data for adult patients with cervical dystonia treated with abobotulinumtoxinA from three prospective, multicenter, observational studies (NCT01314365, NCT00833196 and NCT01753349).

RESULTS

We report data for patients treated with abobotulinumtoxinA over one injection cycle at 181 neurology centers in 35 countries. CD clinical features as assessed by Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS) Total scores (N = 920) significantly reduced by a mean [95%CI] of -12.9 [-13.9, -11.8] points at Week 4 (N = 449) and -3.2 [-3.8, -2.7] points at the end of the injection cycle (N = 890). All three TWSTRS domains (symptom severity, disability and pain) contributed to the overall improvement. Patients were generally content with symptom control at peak effect of the treatment cycle, with 86% reporting overall satisfaction.

CONCLUSION

Findings from this meta-analysis of observational studies confirm the effectiveness of abobotulinumtoxinA in routine practice. Despite inclusion of a broader population sample, the magnitude of improvements observed is consistent with that seen in the pivotal, randomized controlled trials.

Frequency and risk factors of antibody-induced secondary failure of botulinum neurotoxin therapy

Objective

To investigate the risk factors of neutralizing antibody (NAB)–induced complete secondary treatment failure (cSTF) during long-term botulinum neurotoxin (BoNT) treatment in various neurologic indications.

Methods

This monocenter retrospective cohort study analyzed the data of 471 patients started on BoNT therapy between 1995 and 2015. Blood samples of 173 patients were investigated for NABs using the mouse hemidiaphragm test (93 with suspected therapy failure, 80 prospective study participants). The frequency of NAB-cSTF was assessed for various indications: hemifacial spasm, blepharospasm, cervical dystonia, other dystonia, and spasticity. A priori defined potential risk factors for NAB-cSTF were evaluated, and a stepwise binary logistic regression analysis was performed to identify independent risk factors.

Results

Treatment duration was 9.8 ± 6.2 years (range, 0.5–30 years; adherence, 70.6%) and number of treatment cycles 31.2 ± 22.5 (3–112). Twenty-eight of 471 patients (5.9%) had NAB-cSTF at earliest after 3 and at latest after 103 treatment cycles. None of the 49 patients treated exclusively with incobotulinumtoxinA over 8.4 ± 4.2 (1–14) years developed NAB-cSTF. Independent risk factors for NAB-cSTF were high BoNT dose per treatment, switching between onabotulinumtoxinA and other BoNT formulations (except for switching to incobotulinumtoxinA), and treatment of neck muscles.

Conclusions

We present a follow-up study with the longest duration to date on the incidence of NAB-cSTF in patients treated with various BoNT formulations, including incobotulinumtoxinA. Whereas the overall risk of NAB-cSTF is low across indications and BoNT formulations, our findings underpin the recommendations to use the lowest possible dose particularly in cervical dystonia, and to avoid unnecessary switching between different formulations.

Economic evaluation of AbobotulinumtoxinA vs OnabotulinumtoxinA in real-life clinical management of cervical dystonia

Background

Botulinum neurotoxins type A (BoNT-As) are commonly used treatments for cervical dystonia (CD). Clinical trials have demonstrated the benefits of them in these patients, but data from real-life clinical practice as well as comparative data on the cost and outcome of different BoNT-A formulations are limited. The aim of this study was to compare abobotulinumtoxinA (aboBoNT-A) and onabotulinumtoxinA (onaBoNT-A) on their clinical outcomes and drug costs in real-life clinical practice.

Methods

This analysis included 356 adult patients with idiopathic CD treated with aboBoNT-A (n = 253) or onaBoNT-A (n = 103) from 38 centres across Europe and Australia (NCT00833196). The clinical outcome measures were treatment responses, changes in TWSTRS scores and changes in health utility scores from baseline to study visit 2 and 3. Health utility score was mapped from the TWSTRS total scale, using a previous publication. Costs included drug cost for France.

Results

The aboBoNT-A treated group had 2.06 (95% CI: 1.15 to 3.69) times higher odds of achieving treatment response than the onaBoNT-A treated group. The adjusted mean change in TWSTRS total score from baseline to visit 3 were - 6.42 (95% CI: - 7.52 to - 5.33) for aboBoNT-A and - 3.94 (95% CI: - 5.68 to - 2.2) for onaBoNT-A, with a difference of - 2.48 (95% CI: - 4.57 to - 0.39). The corresponding difference in the adjusted mean change for health utility score was 0.008 (95% CI: 0.001 to 0.014). Mean treatment costs for aboBoNT-A and onaBoNT-A were 314.1 (95% CI: 299.1 to 329.0) and 346.6 (95% CI: 322.9 to 370.4) Euros, respectively.

Conclusions

This comparative analysis indicated that treatment with aboBoNT-A may be less costly and lead to improved clinical outcomes when compared with onaBoNT-A, from a French healthcare system perspective. Additional comparative clinical data from larger patient cohorts, as well as more information about cost consequences of an improvement in clinical outcome would be of value to further confirm the findings.

The Prevalence of Dystonic Tremor and Tremor Associated with Dystonia in Patients with Cervical Dystonia

The link between dystonia and tremor has been known for decades, but the question of whether they are two separate illnesses or just different manifestations of one disease with the same pathophysiological background remains unanswered. We distinguish two types of tremor in dystonia: dystonic tremor (DT), which appears on the body part affected by dystonia, and tremor associated with dystonia (TAWD), which appears in locations where the dystonia does not occur. In this study, the frequency of occurrence of different forms of tremor was determined by clinical examination in a group of adult-onset isolated cervical dystonia (CD) patients treated with regular local injections of botulinum toxin A in our department. In total, 120 patients were included in the study, of which 70 (58.3%) had DT of the head. TAWD was, in all 14 cases (11.7%), observed on the upper limbs, in the form of static or intentional tremor. The aim of this study was to point out the presence of TAWD as one of the clinical signs of CD. DT occurred in more than half of the patients and appears to be a relatively common part of the clinical picture in patients with CD.

Injection into the Longus Colli Muscle via the Thyroid Gland

Background

Anterior forms of cervical dystonia are considered to be the most difficult to treat because of the deep cervical muscles that can be involved.

Case Report

We report the case of a woman with cervical dystonia who presented with anterior sagittal shift, which required injections through the longus colli muscle to obtain a satisfactory outcome. The approach via the thyroid gland was chosen.

Discussion

The longus colli muscle can be injected under electromyography (EMG), computed tomography (CT), ultrasonography (US), or endoscopy guidance. We recommend using both ultrasonography and electromyography guidance as excellent complementary techniques for injection at the C5-C6 level.

Use of botulinum toxin for movement disorders

The term movement disorders encompasses all disorders hypokinetic and hyperkinetic, which were previously known as extrapyramidal syndromes. With the definition of movement disorders and their diagnostic criteria and classifications, new studies for therapeutics could be performed. New drugs were launched, functional neurosurgery was developed, and the introduction of botulinum toxin (BoNT) for hyperkinesias was introduced. BoNT is an important therapy for dystonia, tics, myoclonus, and tremors. The aim of this review is to present the new and well-established uses of BoNT for movement disorders.

Modified Selective Neurectomy for the Treatment of Post-Facial Paralysis Synkinesis

BACKGROUND

To address functional and smile dysfunction associated with post-facial paralysis synkinesis, the senior author (B.A.) has offered "modified selective neurectomy" of the lower division of the facial nerve as a long-term solution. This article examines technical considerations and outcomes of this procedure.

METHODS

A retrospective review was conducted of patients who underwent modified selective neurectomy of buccal and cervical branches of the facial nerve performed by a single surgeon over a 4½-year period. House-Brackmann facial grading scores, electronic clinician-graded facial function scale, and onabotulinumtoxinA (botulinum toxin type A) dosages were examined before and after the procedure.

RESULTS

Sixty-three patients underwent modified selective neurectomy between June 20, 2013, and August 12, 2017. There were no serious complications. The revision rate was 17 percent. Temporary oral incompetence was reported in seven patients (11 percent) postoperatively. A statistically significant improvement was achieved in electronic clinician-graded facial function scale analysis of nasolabial fold depth at rest, oral commissure movement with smile, nasolabial fold orientation with smile, nasolabial depth with smile, depressor labii inferioris lower lip movement, midfacial synkinesis, mentalis synkinesis, platysmal synkinesis, static score, dynamic score, synkinesis score, periocular score, lower face and neck score, and midface and smile score. There was a significant decrease in botulinum toxin type A dosage and House-Brackmann score after surgery.

CONCLUSION

Modified selective neurectomy of the buccal and cervical divisions of the facial nerve is an effective long-term treatment for smile dysfunction in patients with post-facial paralysis synkinesis.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, IV.

Pain in cervical dystonia and the antinociceptive effects of botulinum toxin: what is currently known?

Pain is the most common and disabling non-motor symptom in cervical dystonia (CD). Up to 88.9% of patients report pain at some point in the course of the disease. It is still a matter of debate whether CD-related pain originates only from prolonged muscle contraction. Recent data suggest that the alterations of transmission and processing of nociceptive stimuli play a crucial role in pain development. Botulinum toxin (BT) is the first-line therapy for CD. Despite fully elucidated muscle relaxant action, the antinociceptive effect of BT remains unclear and probably exceeds a simple decompression of the nerve fibers due to the reduction in muscle tone. The proposed mechanisms of the antinociceptive action of BT include inhibition of pain mediator release, inhibition of membrane sodium channels, retrograde axonal transport and impact on the other pain pathways. This article summarizes the current knowledge about the antinociceptive properties of BT and the clinical analgesic efficacy in the treatment of CD patients.

The Use of Botulinum Toxin for Treatment of the Dystonias

Dystonias are characterized by involuntary muscle contractions, twisting movements, abnormal postures, and often tremor in various body regions. However, in the last decade several studies have demonstrated that dystonias are also characterized by sensory abnormalities. While botulinum toxin is the gold standard therapy for focal dystonia, exactly how it improves this disorder is not entirely understood. Neurophysiological studies in animals and humans have clearly demonstrated that botulinum toxin improves dystonic motor manifestations by inducing chemodenervation, therefore weakening the injected muscles. In addition, neurophysiological and neuroimaging evidence also suggests that botulinum toxin modulates the activity of various neural structures in the CNS distant from the injected site, particularly cortical motor and sensory areas. Concordantly, recent studies have shown that in patients with focal dystonias botulinum toxin ameliorates sensory disturbances, including reduced spatial discrimination acuity and pain. Overall, these observations suggest that in these patients botulinum toxin-induced effects encompass complex mechanisms beyond chemodenervation of the injected muscles.

Spectrum of practice in the routine management of cervical dystonia with abobotulinumtoxinA: findings from three prospective open-label observational studies

Background

Cervical dystonia is a heterogeneous disorder with several possible presentations, for which first-line therapy is often botulinum toxin (BoNT). In routine clinical practice the success of each BoNT injection is dependent on several variables, including individual presentation and injection technique. Large multicenter, observational studies provide important information on individualized administration strategies that cannot be otherwise ascertained from controlled clinical trials. In this meta-analysis of patient level data, we aimed to evaluate the clinical characteristics of patients with cervical dystonia undergoing routine treatment with botulinum toxin, specifically abobotulinumtoxinA. We also aimed to characterize current abobotulinumtoxinA injection techniques and parameters and to explore international differences in patient presentation and treatment.

Methods

This was a meta-analysis of baseline data from three prospective, international, multicenter, observational studies (NCT01314365, NCT00833196 and NCT01753349) of botulinum toxin treatment for the routine management of adult cervical dystonia.

Results

Data presented illustrate the significant heterogeneity of CD presentation in routine practice. Most subjects presented with a complex pattern of dystonic movements and the majority had additional components of shoulder elevation, tremor and/or jerk. Dosing was generally in accordance with that recommended in the abobotulinumtoxinA prescribing information, although the range of dosing also indicates that injections are tailored to individual presentation. Sub-group analyses at the country level revealed distinct differences in injection practice.

Conclusions

This meta-analysis is based on the largest dataset of subjects with cervical dystonia studied to date. The heterogeneity revealed in our baseline findings support the need to develop consistent, practical and comprehensive best practice guidelines.

Botulinum neurotoxin formulations: overcoming the confusion

Botulinum toxin A is produced by anaerobic spore-forming bacteria and is used for various therapeutic and cosmetic purposes. Botulinum toxin A injections are the most popular nonsurgical procedure worldwide. Despite an increased demand for botulinum toxin A injections, the clinical pharmacology and differences in formulation of commonly available products are poorly understood. The various products available in the market are unique and vary in terms of units, chemical properties, biological activities, and weight, and are therefore not interchangeable. For safe clinical practice and to achieve optimal results, the practitioners need to understand the clinical issues of potency, conversion ratio, and safety issues (toxin spread and immunogenicity). In this paper, the basic clinical pharmacology of botulinum toxin A and differences between onabotulinum toxin A, abobotulinum toxin A, and incobotulinum toxin A are discussed.

Pilot Study of a Device to Induce the Hanger Reflex in Patients with Cervical Dystonia

The hanger reflex (HR) is an involuntary head rotation that occurs in response to a clothes hanger encircling the head and compressing the unilateral fronto-temporal area. Here, we developed an elliptical device to induce the HR and examined its utility for the treatment of cervical dystonia (CD). The study included 19 patients with rotational-type CD. The device was applied to each subject’s head for at least 30 min/day for 3 months. Severity scores on part 1 of the Toronto Western Spasmodic Torticollis Rating Scale were evaluated at baseline and after the 3-month trial. Mean scores without and with the device were significantly different both at baseline (16.6 vs. 14.7, respectively; P < 0.05) and after the trial (14.9 vs. 13.6, respectively; P < 0.05). This preliminary trial suggests that our device can improve abnormal head rotation in patients with CD.

Botulinum Toxin Treatment of Movement Disorders

Botulinum neurotoxins (BoNTs) are now among the most widely used therapeutic agents in clinical medicine with indications applied to the fields of movement disorders, pain disorders, and autonomic dysfunction. In this literature review, the efficacy and utility of BoNTs in the field of movement disorders are assessed using the criteria of the Guideline Development Subcommittee of the American Academy of Neurology. The literature supports a level A efficacy (established) for BoNT therapy in cervical dystonia and a level B efficacy (probably effective) for blepharospasm, hemifacial spasm, laryngeal dystonia (spasmodic dysphonia), task-specific dystonias, essential tremor, and Parkinson rest tremor. It is the view of movement disorder experts, however, that despite the level B efficacy, BoNTs should be considered treatment of first choice for blepharospasm, hemifacial spasm, laryngeal, and task-specific dystonias. The emerging data on motor and vocal tics of Tourette syndrome and oromandibular dystonias are encouraging but the current level of efficacy is U (undetermined) due to lack of published high-quality studies.

Ixcellence Network®: an international educational network to improve current practice in the management of cervical dystonia or spastic paresis by botulinum toxin injection

Botulinum toxin is a well-established treatment for a number of conditions involving muscle hyperactivity, such as focal dystonia and spastic paresis. However, current injection practice is not standardized and there is a clear need for structured training. An international group of experts in the management of patients with cervical dystonia (CD) and spastic paresis created a steering committee (SC). For each therapeutic area, the SC developed a core slide set on best practice, based on the literature. International sites of expertise were identified for training and courses were designed to include lectures and casebased learning. Where possible, courses received accreditation from the European Union of Medical Specialists (UEMS). Each course was peer reviewed by the SC, the UEMS accreditation board and the attendees themselves (through evaluation questionnaires). Attendees' feedback was shared with the SC and the trainers to tailor future training sessions. From the program launch in 2012 to December 2014, 328 physicians from 34 countries were trained in a total of 58 courses; 67% of the courses focused on spastic paresis and 33% on CD. Of the 225 (69%) physicians who completed feedback forms, 95% rated their course as 'above average/excellent' in meeting the preset learning objectives. Most (90%) physicians declared that attending a course would lead them to change their practice. The development of the 'Ixcellence Network' for continuous medical education in the fields of spastic paresis and CD has provided a novel and interactive way of training physicians with previous experience in botulinum toxin injection.

Towards flexible and tailored botulinum neurotoxin dosing regimens for focal dystonia and spasticity - Insights from recent studies

Botulinum neurotoxin (BoNT) is an effective, well-tolerated, and well-established option for the treatment of dystonic and spastic movement disorders. However, a single approach does not suit all patients, even within one disease indication. The degree of flexibility in treatment protocols is determined by individual product licenses, which often lag behind real-world clinical experience. A number of patient/practitioner surveys conducted recently have highlighted a desire for greater flexibility than that currently approved, both in BoNT doses and in the intervals between consecutive doses. New evidence arising from research conducted during the last few years has opened new avenues for tailoring BoNT treatment to patients' needs. Data suggest that escalating incobotulinumtoxinA doses enables treatment of a greater number of spasticity patterns than current dose limitations allow, without compromising safety or tolerability. Similarly, in patients with cervical dystonia (CD), repeated injections of incobotulinumtoxinA at intervals as early as 6 weeks after a previous treatment, based on individual patient need, were effective and well tolerated. Here, the BoNT doses and dosing intervals currently indicated in the USA and European Union are reviewed, together with the use of BoNT for the treatment of spasticity, CD, and blepharospasm. Opportunities for tailored BoNT therapy are also discussed.

Botulinum toxin type A therapy for cervical dystonia

BACKGROUND

This is an update of a Cochrane Review first published in 2005. Cervical dystonia is the most common form of focal dystonia and is a highly disabling movement disorder characterised by involuntary, usually painful, head posturing. Currently, botulinum toxin type A (BtA) is considered the first line therapy for this condition.

OBJECTIVES

To compare the efficacy, safety, and tolerability of botulinum toxin type A (BtA) versus placebo in people with cervical dystonia.

SEARCH METHODS

To identify studies for this review we searched Cochrane Movement Disorders' Trials Register, CENTRAL, MEDLINE, Embase, reference lists of articles and conference proceedings. All elements of the search, with no language restrictions, were run in October 2016.

SELECTION CRITERIA

Double-blind, parallel, randomised, placebo-controlled trials (RCTs) of BtA versus placebo in adults with cervical dystonia.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed records, selected included studies, extracted data using a paper pro forma, and evaluated the risk of bias. We resolved disagreements by consensus or by consulting a third review author. We performed meta-analyses using a random-effects model for the comparison of BtA versus placebo to estimate pooled effects and corresponding 95% confidence intervals (95% CI). In addition, we performed preplanned subgroup analyses according to BtA dose used, the BtA formulation used, and the use or not of guidance for BtA injection. The primary efficacy outcome was improvement in cervical dystonia-specific impairment. The primary safety outcome was the proportion of participants with any adverse event.

MAIN RESULTS

We included eight RCTs of moderate overall risk of bias, including 1010 participants with cervical dystonia. Six studies excluded participants with poorer responses to BtA treatment, therefore including an enriched population with a higher probability of benefiting from this therapy. Only one trial was independently funded. All RCTs evaluated the effect of a single BtA treatment session, using doses from 150 U to 236 U of onabotulinumtoxinA (Botox), 120 U to 240 U of incobotulinumtoxinA (Xeomin), and 250 U to 1000 U of abobotulinumtoxinA (Dysport).BtA was associated with a moderate-to-large improvement in the participant's baseline clinical status as assessed by investigators, with reduction of 8.06 points in the Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS total score) at week 4 after injection (95% CI 6.08 to 10.05; I2 = 0%) compared to placebo, corresponding on average to a 18.7% improvement from baseline. The mean difference (MD) in TWSTRS pain subscore at week 4 was 2.11 (95% CI 1.38 to 2.83; I2 = 0%). Overall, both participants and clinicians reported an improvement of subjective clinical status. There were no differences between groups regarding withdrawals due to adverse events. However, BtA treatment was associated with an increased risk of experiencing an adverse event (risk ratio (RR) 1.19; 95% CI 1.03 to 1.36; I2 = 16%). Dysphagia (9%) and diffuse weakness/tiredness (10%) were the most common treatment-related adverse events (dysphagia: RR 3.04; 95% CI 1.68 to 5.50; I2 = 0%; diffuse weakness/tiredness: RR 1.78; 95% CI 1.08 to 2.94; I2 = 0%). Treatment with BtA was associated with a decreased risk of participants withdrawing from trials. We have moderate certainty in the evidence across all of the aforementioned outcomes.We found no evidence supporting the existence of a clear dose-response relationship with BtA, nor a difference between BtA formulations, nor a difference with use of EMG-guided injection.Due to clinical heterogeneity, we did not pool data regarding health-related quality of life, duration of clinical effect, or the development of secondary non-responsiveness.

AUTHORS' CONCLUSIONS

We have moderate certainty in the evidence that a single BtA treatment session is associated with a significant and clinically relevant reduction of cervical dystonia-specific impairment, including severity, disability, and pain, and that it is well tolerated, when compared with placebo. There is also moderate certainty in the evidence that people treated with BtA are at an increased risk of developing adverse events, most notably dysphagia and diffuse weakness. There are no data from RCTs evaluating the effectiveness and safety of repeated BtA injection cycles. There is no evidence from RCTs to allow us to draw definitive conclusions on the optimal treatment intervals and doses, usefulness of guidance techniques for injection, the impact on quality of life, or the duration of treatment effect.

AbobotulinumtoxinA: A 25-Year History

During the late 1960s and early 1970s, Alan Scott showed that intramuscular injections of botulinum toxin (BoNT) corrected nonaccommodative strabismus without resorting to surgery. The UK doctors who trained with Scott soon realized the significant potential offered by BoNT type A as a therapeutic option for several difficult-to-treat diseases. This led to a collaboration between these pioneering clinicians and the Centre for Applied Microbiology and Research at Porton Down, United Kingdom, and, in turn, to the development and commercialization of abobotulinumtoxinA as Dysport (Dystonia/Porton Down; Ipsen Biopharm Ltd., Wrexham, UK). Dysport was approved in Europe for the treatment of specific dystonias in December 1990 and now has marketing authorizations in 75 countries. Since then, the use of BoNT in therapeutic and aesthetic indications has grown year-on-year, and continues to expand well beyond Scott's initial aim. For example, ongoing trials are assessing potential new indications for BoNT-A, including acne and psoriasis. Furthermore, a growing number of other BoNT products, often termed "biosimilars," together with innovative formulations of well-established BoNT types, are likely to reach the market over the next few years. This review focuses on the history of Dysport to mark the 25th anniversary of its first launch in the United Kingdom.

Clinical Practice: Evidence-Based Recommendations for the Treatment of Cervical Dystonia with Botulinum Toxin

Cervical dystonia (CD) is the most frequent form of focal dystonia. Symptoms often result in pain and functional disability. Local injections of botulinum neurotoxin are currently the treatment of choice for CD. Although this treatment has proven effective and is widely applied worldwide, many issues still remain open in the clinical practice. We performed a systematic review of the literature on botulinum toxin treatment for CD based on a question-oriented approach, with the aim to provide practical recommendations for the treating clinicians. Key questions from the clinical practice were explored. Results suggest that while the beneficial effect of botulinum toxin treatment on different aspects of CD is well established, robust evidence is still missing concerning some practical aspects, such as dose equivalence between different formulations, optimal treatment intervals, treatment approaches, and the use of supportive techniques including electromyography or ultrasounds. Established strategies to prevent or manage common side effects (including excessive muscle weakness, pain at injection site, dysphagia) and potential contraindications to this treatment (pregnancy and lactation, use of anticoagulants, neurological comorbidities) should also be further explored.

Occurrence of Dysphagia Following Botulinum Toxin Injection in Parkinsonism-related Cervical Dystonia: A Retrospective Study

Background

The aim was to compare the occurrence of post-injection dysphagia in parkinsonism-related cervical dystonia (PRCD) versus cervical dystonia (CD) of other etiologies (non-PRCD). A secondary objective was to explore potential clinical differences between PRCD and non-PRCD and their respective responses to botulinum toxin (BoNT).

Methods

A cross-sectional chart review was carried out of patients treated for CD with Onabotulinumtoxin A at the University of Florida. We collected demographic information, dose of BoNT injected, patient-reported presence of dysphagia as a side effect, patient-perceived duration of benefit and efficacy according to the Clinical Global Impression Scale (CGIS).

Results

Of the 144 patients included, 24 patients were diagnosed with PRCD and 120 were diagnosed as non-PRCD. Data analysis showed no significant differences in number of weeks of benefit from BoNT (PRCD 9.1±3.7 versus non-PRCD 9.4±3.7 weeks, p = 0.830), BoNT dosage (PRCD 235.0±95.6 versus non-PRCD 263.7±101.3 units, p = 0.181), median CGIS score (median = 2 or “much improved” for both groups, p = 0.88), or the presence of dysphagia after BoNT (PRCD 17% versus non-PRCD 19 %, p = 0.753, n = 132). In a subgroup analysis of the non-PRCD group, patients who experienced dysphagia were older than those who did not (63.9±8.9 years versus 58.1±14.4 years, p = 0.02).

Discussion

Despite an increased baseline risk of dysphagia in patients with PRCD, BoNT appears to be equally safe and equally beneficial in PRCD and non-PRCD patients.

Unmet Needs in the Management of Cervical Dystonia

Cervical dystonia (CD) is a movement disorder which affects daily living of many patients. In clinical practice, several unmet treatment needs remain open. This article focuses on the four main aspects of treatment. We describe existing and emerging treatment approaches for CD, including botulinum toxin injections, surgical therapy, management of non-motor symptoms, and rehabilitation strategies. The unsolved issues regarding each of these treatments are identified and discussed, and possible future approaches and research lines are proposed.

Factors Associated With Attrition in Randomized Controlled Trials of Vocal Rehabilitation: Systematic Review and Meta-Analysis

OBJECTIVES/HYPOTHESIS

This study aimed to determine the dropout rates and the reasons for dropout in randomized clinical trials of vocal rehabilitation.

STUDY DESIGN

This study used systematic review and meta-analysis (CRD42013003807).

METHODS

We included randomized controlled trials for voice disorders. In June 2015, we searched the following databases: MEDLINE, EMBASE, Cochrane, Clinical Trials, and AJSLP. The titles and abstracts or full texts of articles were independently analyzed by two reviewers. Study quality was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) scale. Our initial research base included more than 8491 articles.

RESULTS

A total of 51 articles were obtained using our eligibility criteria. The low-quality studies evaluated had higher dropout rates (odds ratio: 3.3, 95% confidence interval: 1.04-12.9). Studies with healthy patients (45%) or vocal training versus no training (25%) also had higher dropout rates. Methodological issues seemed to have a greater influence on the dropout rates of the studies included in the co-occurrence matrix.

CONCLUSIONS

Dropout rates of approximately 15% occur in randomized clinical trials of speech therapy when assessed by the Grading of Recommendations Assessment, Development and Evaluation. Studies with lower methodological quality had higher patient loss rates. Methodological and clinical reasons accounted for the highest dropout rates in the studies included in this meta-analysis.

Botulinum toxin type A with or without needle electromyographic guidance in patients with cervical dystonia

Aim

To investigate the efficacy and safety of electromyography (EMG)- and palpation-guided botulinum toxin type A injection in cervical dystonia (CD) patients.

Methods

In this randomized, controlled trial, 68 CD patients were randomly allocated to two groups, receiving botulinum toxin type A injections guided by either palpation (Group A) or EMG (Group B). The primary endpoint is defined as the difference in the Tsui score between groups at 16 weeks. The secondary endpoints were the visual analog scale (VAS) and Hospital Anxiety and Depression Scale (HADS) scores and Clinical and Patient Global Impression of Change (CGIC and PGIC).

Results

Sixty-five patients completed the study. No significant difference was observed in the Tsui score between groups A and B at 4, 8, and 12 weeks after treatment (p > 0.05). However, 16 weeks after treatment, the Tsui score of group A was significantly higher than that of group B. For both groups, the degree of pain at each time point during follow-up significantly reduced after treatment. However, no significant difference was observed in VAS scores between the two groups. Interestingly, the patient HADS score decreased without statistical significance 8 weeks following treatment. No significant difference in HADS scores was observed between the two groups. Additionally, there was no significant difference in PGIC and CGIC between the two groups. However, CGIC was significantly higher than PGIC. No significant difference in adverse reactions was observed between groups. CD patients treated with EMG guidance experienced a significantly more pain at the injection site but a significantly lower adverse event occurrence rate of dysphagia when compared to CD patients treated with palpation guidance only.

Conclusions

CD patients treated with EMG guidance experienced a prolonged benefit as measured by the Tsui scale when compared to CD patients treated with palpation guidance alone. EMG-guided injection resulted in a lower incidence of dysphagia and higher incidence of discomfort at the injection site than palpation-guided injection.

A Comparison of Botox 100 U/mL and Dysport 100 U/mL Using Dose Conversion Ratio 1: 3 and 1: 1.7 in the Treatment of Cervical Dystonia: A Double-Blind, Randomized, Crossover Trial

OBJECTIVES

Intramuscular injections of botulinum toxin (BTX) are used as symptomatic treatment for cervical dystonia. Botox and Dysport are commercial products containing BTX; however, dosage and concentration of the prepared solution vary considerably among studies. The concentration of BTX in the prepared solution affects clinical outcome. This double-blind, randomized crossover trial compares Botox and Dysport in 2 different dose conversion ratios (1:3 and 1:1.7) when diluted to the same concentration (100 U/mL).

METHODS

Forty-six patients with cervical dystonia received 3 different treatments, Botox in 2 different doses and Dysport as control treatment. The efficacy was evaluated 4 and 12 weeks after treatment using 5 instruments, including Toronto Western Spasmodic Torticollis Rating Scale.

RESULTS AND CONCLUSION

The primary outcome was the estimated median Toronto Western Spasmodic Torticollis Rating Scale total score, which was 1.96 points higher for Botox (1:3) compared with Dysport at week 4, but the difference was not statistically significant (confidence interval, -0.88-4.61; P = 0.0799). No significant differences were seen between Botox (1:1.7) and Dysport. At week 12, a statistically significant difference in effect between Botox (1:3) and Dysport was observed, suggesting a shorter duration of effect for Botox when this ratio (low dose) was used. Furthermore, the patients' assessments showed that the ratio 1:3 resulted in suboptimal efficacy of Botox. These secondary outcome observations indicate that the dose conversion ratio between Dysport 100 U/mL and Botox 100 U/mL may be lower than 1:3, but this must be further validated in a larger patient material.

Selective peripheral denervation for cervical dystonia: long-term follow-up

OBJECTIVE

61 procedures with selective peripheral denervation for cervical dystonia were retrospectively analysed concerning surgical results, pain, quality of life (QoL) and recurrences.

METHODS

The patients were assessed with the Tsui torticollis scale, Visual Analogue Scale (VAS) for pain and Fugl-Meyer scale for QoL. Evaluations were performed preoperatively, early postoperatively, at 6 months, then at a mean of 42 (13-165) months. All patients underwent electromyogram at baseline, which was repeated in cases who presented with recurrence of symptoms after surgery.

RESULTS

Six months of follow-up was available for 55 (90%) of the procedures and late follow-up for 34 (56%). The mean score of the Tsui scale was 10 preoperatively. It improved to 4.5 (p<0.001) at 6 months, and 5.3 (p<0.001) at late follow-up. VAS for pain improved from 6.5 preoperatively to 4.2 (p<0.001) at 6 months and 4 (p<0.01) at late follow-up. The Fugl-Meyer score for QoL improved from 43.3 to 46.6 (p<0.05) at 6 months, and to 51.1 (p<0.05) at late follow-up. Major reinnervation and/or change in the dystonic pattern occurred following 29% of the procedures, and led in 26% of patients to reoperation with either additional denervation or pallidal stimulation.

CONCLUSIONS

Selective peripheral denervation remains a surgical option in the treatment of cervical dystonia when conservative measures fail. Although the majority of patients experience a significant relief of symptoms, there is a substantial risk of reinnervation and/or change in the pattern of the cervical dystonia.

Botulinum neurotoxins for the treatment of focal dystonias: Review of rating tools used in clinical trials

Botulinum neurotoxins (BoNTs) are used to achieve therapeutic benefit in focal dystonia. An expert panel recently reviewed published evidence on the efficacy of BoNTs for the treatment of focal dystonias and produced recommendations for clinical practice. Another panel reviewed the clinimetric properties of rating scales for dystonia and produced recommendations for current usage and future directions. Considering that the strength of evidence derives not only from the quality of the study design, but also from usage of validated outcome measures, we combined the information provided by these two recent reviews and assessed the appropriateness of the rating instruments used in clinical trials on BoNT treatment in focal dystonia. Data sources included all the publications on BoNT treatment for focal dystonias reviewed by the recent evidence-based analysis. We reviewed all rating instruments used to assess primary and secondary outcome following BoNT treatment. The publications were allocated into five topics according to the focal dystonia type reviewed in the meta-analysis: blepharospasm, oromandibular dystonia, cervical dystonia, upper limb dystonia, and laryngeal dystonia. For each topic, papers were divided, according to the terminology used in the meta-analysis, into placebo-controlled, active comparator and methodological or uncontrolled. For each topic we identified the rating tools used in each study class and annotated which were the mostly used in each focal dystonia type. Outcome measures included tools related to motor and non-motor features, such as pain and depression, and functional as well as health-related quality of life features. Patient- and investigator-reported outcomes were also included. Rating instruments were classified as recommended, suggested, listed or not included, based on recommendations produced by the rating scale task force. Both primary and secondary outcome measures were assessed. As a final step we compared current practice, as summarized by the meta-analysis, with the recommendations of the rating scales panel. For blepharospasm, three placebo-controlled trials used suggested scales, one active-comparator study used a recommended scale and three active-comparator studies used suggested scales. For oromandibular dystonia, one placebo-controlled study used a suggested scale. For cervical dystonia, six placebo-controlled trials used a recommended scale, four active-comparator trials used a recommended scale and one active-comparator study used a suggested scale. For upper limb and laryngeal dystonia, no trial used validated instruments. Appropriately designed studies should be based on recommended rating instruments. Therapeutic trials not using clinimetrically tested rating measures do not provide sufficient information on efficacy of BoNT treatment, even if the study design is robust. Further research is needed to develop and validate new tools to assess all types of focal dystonia and to apply them in prospective placebo-controlled clinical trials.

Rate of Hanger Reflex Occurrence: Unexpected Head Rotation on Fronto-temporal Head Compression

When the head is encircled with a wire clothes hanger and the unilateral fronto-temporal region is compressed, the head rotates unexpectedly. As the mechanism is unclear, however, we have temporarily named this phenomenon as the "hanger reflex." We previously reported a case wherein this phenomenon was applied to treat cervical dystonia. Because little is known about this phenomenon, we determined how often this phenomenon is observed in healthy subjects. Study participants were 120 healthy Japanese adults (60 men and 60 women) aged 19-65 years. A wire clothes hanger was applied to each subject's head. The longer side of the hanger was attached over the volunteer's fronto-temporal regions on both sides of the head in succession (i.e., two applications per volunteer). We evaluated whether the subjects felt the sensation of head rotation by using a questionnaire. The sensation of head rotation was observed in 95.8% of subjects. There were five non-responders (4.2%). In 85.4% of the trials, head rotation was observed in the direction that coincided with the side compressed by the hanger. There were no differences in responses between genders. The incident rate of the hanger reflex was remarkably high and most likely represents a prevalent phenomenon in humans. The mechanism underlying the reflex remains unknown. Further research should be performed to elucidate the underlying causes of the hanger reflex, which represents a potential treatment for cervical dystonia.

Pain Relief in Cervical Dystonia with Botulinum Toxin Treatment

Dystonia is a neurological disorder characterized by intermittent or sustained muscle contractions that cause abnormal, usually repetitive, movements and postures. Dystonic movements can be tremulous and twisting and often follow a pattern. They are frequently associated with overflow muscle activation and may be triggered or worsened by voluntary action. Most voluntary muscles can be affected and, in the case of the neck muscles, the condition is referred to as cervical dystonia (CD), the most common form of dystonia. The high incidence of pain distinguishes CD from other focal dystonias and contributes significantly to patient disability and low quality of life. Different degrees of pain in the cervical region are reported by more than 60% of patients, and pain intensity is directly related to disease severity. Botulinum toxin (BoNT) is currently considered the treatment of choice for CD and can lead to an improvement in pain and dystonic symptoms in up to 90% of patients. The results for BoNT/A and BoNT/B are similar. The complex relationship between pain and dystonia has resulted in a large number of studies and more comprehensive assessments of dystonic patients. When planning the application of BoNT, pain should be a key factor in the choice of muscles and doses. In conclusion, BoNT is highly effective in controlling pain, and its analgesic effect is sustained for a long time in most CD patients.

WITHDRAWN: Botulinum toxin for subacute/chronic neck pain

Withdrawn due to non‐compliance with The Cochrane Collaboration’s Commercial Sponsorship Policy

The editorial group responsible for this previously published document have withdrawn it from publication.