Pain Relief in Cervical Dystonia with Botulinum Toxin Treatment

Does botulinum toxin affect psycho-social aspects in dystonia?

Dystonia is a movement disorder in which sustained muscle contractions give rise to abnormal postures or involuntary movements. It is a disabling and disfiguring disorder that affects activities of daily living and gives people a bizarre appearance often associated with psychological morbidity, embarrassment and social avoidance. Intramuscular injection of botulinum toxin (BoNT) is the most effective treatment for motor symptoms in focal dystonia, but little is known about its impact on the psycho-social dimension. The main aim of this study was to evaluate psycho-social changes in patients with focal dystonia after starting BoNT treatment using self-reported scales. The Beck Depression Inventory (BDI-II), the 36-Item Short Form Health Survey (SF-36), the Body Uneasiness Test (BUT), the State-Trait Anxiety Inventory (STAI) and the Visual Analogue Scale (VAS) assessing body self-image, satisfaction with physical aspects, social avoidance, self-reported depression, and self-distress were completed by 11 patients with dystonia and 9 patients with hyperhidrosis as a control group before BoNT (T0). VAS was then performed after four weeks (T1) to assess whether BoNT induced changes in the psychosocial dimension. Our results showed that only depressive symptoms and rumination about body defects improved in patients with dystonia after BoNT treatment, while improvement in self-distress and satisfaction with physical aspects was also found in hyperhidrosis. Individuals with hyperhidrosis experience poorer psychological well-being and suffer from higher levels of distress compared to dystonic patients. This suggests that individuals with this disabling condition are more vulnerable to social impact than dystonic patients.

Exploring the Central Mechanisms of Botulinum Toxin in Parkinson's Disease: A Systematic Review from Animal Models to Human Evidence

Botulinum toxin (BoNT) is an effective and safe therapy for the symptomatic treatment of several neurological disturbances. An important line of research has provided numerous pieces of evidence about the mechanisms of action of BoNT in the central nervous system, especially in the context of dystonia and spasticity. However, only a few studies focused on the possible central effects of BoNT in Parkinson's disease (PD). We performed a systematic review to describe and discuss the evidence from studies focused on possible central effects of BoNT in PD animal models and PD patients. To this aim, a literature search in PubMed and SCOPUS was performed in May 2023. The records were screened according to title and abstract by two independent reviewers and relevant articles were selected for full-text review. Most of the papers highlighted by our review report that the intrastriatal administration of BoNT, through local anticholinergic action and the remodulation of striatal compensatory mechanisms secondary to dopaminergic denervation, induces an improvement in motor and non-motor symptoms in the absence of neuronal loss in animal models of PD. In human subjects, the data are scarce: a single neurophysiological study in tremulous PD patients found that the change in tremor severity after peripheral BoNT administration was associated with improved sensory-motor integration and intracortical inhibition measures. Further clinical, neurophysiological, and neuroimaging studies are necessary to clarify the possible central effects of BoNT in PD.

How does botulinum toxin really work?

Over the past 30 years, Botulinum toxin (BoNT) has emerged as an effective and safe therapeutic tool for a number of neurological conditions, including dystonia. To date, the exact mechanism of action of BoNT in dystonia is not fully understood. Although it is well known that BoNT mainly acts on the neuromuscular junction, a growing body of evidence suggests that the therapeutic effect of BoNT in dystonia may also depend on its ability to modulate peripheral sensory feedback from muscle spindles. Animal models also suggest a retrograde and anterograde BoNT transportation from the site of injection to central nervous system structures. In humans, however, BoNT central effects seem to depend on the modulation of afferent input rather than on BoNT transportation. In this chapter, we aimed to report and discuss research evidence providing information on the possible mechanisms of action of BoNT in relation to treatment of dystonia.

Pain Reduction in Cervical Dystonia Following Treatment with IncobotulinumtoxinA: A Pooled Analysis

This analysis pooled pain severity data from four phase 3 and 4 studies of incobotulinumtoxinA (incoBoNT-A) for the treatment of cervical dystonia (CD) in adults. CD-related pain severity was assessed at baseline, each injection visit, and 4 weeks after each injection of incoBoNT-A using the Toronto Western Spasmodic Torticollis Rating Scale pain severity subscale or a pain visual analog scale. Both were analyzed using a score range of 0-10 and pain was categorized as mild, moderate, or severe. Data for 678 patients with pain at baseline were assessed and sensitivity analyses evaluated pain responses in the subgroup not taking concomitant pain medication (n = 384 at baseline). At Week 4 after the first injection, there was a mean change of -1.25 (standard deviation 2.04) points from baseline pain severity (p < 0.0001), with 48.1% showing ≥ 30% pain reduction from baseline, 34.4% showing ≥50% pain reduction from baseline, and 10.3% becoming pain free. Pain responses were sustained over five injection cycles with a trend to incremental improvements with each successive cycle. Pain responses in the subgroup not taking concomitant pain medication demonstrated the lack of confounding effects of pain medications. These results confirmed the pain relief benefits of long-term treatment with incoBoNT-A.

OnabotulinumtoxinA Dosing, Disease Severity, and Treatment Benefit in Patients With Cervical Dystonia: A Cohort Analysis From CD PROBE

Introduction

The Cervical Dystonia Patient Registry for Observation of OnabotulinumtoxinA Efficacy (CD PROBE) study (ClinicalTrials.gov identifier: NCT00836017), a multicenter, prospective, observational registry, was designed to identify real-world practices and outcomes for patients with cervical dystonia (CD) treated with onabotulinumtoxinA (onabotA). This secondary analysis from CD PROBE aims to determine the impact of presentation subtype on onabotA utilization and CD severity.

Materials and Methods

The study cohort includes those who completed all 3 treatments, 4 office visits, and had data recorded for all assessments. Patient outcomes were assessed with the Cervical Dystonia Impact Profile (CDIP-58), Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS), and determination of CD severity. Treatment interval, dose, and adverse events (AEs) were also recorded. Data were stratified according to prior exposure to botulinum toxins (BoNTs) and analyzed with descriptive statistics.

Results

Torticollis was the most common presentation subtype in the study cohort (N = 350); the proportion of patients with torticollis was highest in those with severe disease. At each treatment, between 40.7 and 65.2% of those categorized as severe shifted to moderate or mild severity after treatment. Sustained improvements in CDIP-58 and TWSTRS were observed regardless of prior exposure to BoNTs. Dosing of onabotA generally increased from injection 1 to injection 3 and tended to be lower for patients naïve to BoNT. Median time interval between injections for the study cohort was 94.0 to 97.5 days. The most common AEs (dysphagia, muscular weakness) and injection intervals were similar between naïve vs. non-naïve patients; there were no serious treatment-related AEs.

Conclusions

This secondary cohort analysis from CD PROBE demonstrates that three repeat treatments with onabotA at intervals consistent with labeling attenuated disease severity and neck pain, resulting in sustained improvements in physician- and patient-reported outcomes. No new safety signals were identified.

Treatment of occipital neuralgia using onabotulinum toxin A

OBJECTIVES

To determine the effectiveness of botulinum toxin in a sample of patients diagnosed with greater occipital nerve neuralgia.

MATERIAL AND METHODS

Twenty-nine patients (28 females, 1 male) were treated for greater occipital nerve neuralgia with onabotulinum toxin type A; the Visual Analog Pain Scale was used to determine pain severity at treatment and again 12 weeks after application.

RESULTS

Average doses of onabotulinum toxin type A of 18.66±6.44 U per nerve and 35.96±12.89 U per patient were utilized. Average pain severity among the sample was 9.81±0.89 prior to botulinum toxin application and 3.68±2.31 points (p<0.0001) twelve weeks after application. Pain frequency decreased from 29.93±0.37 to 12.17±11.05 days with pain per month (p<0.0001). Six patients reported absence of pain after application (p=0.023). Dose did not correlate with the degree of clinical response observed, and no side effects were reported.

CONCLUSION

Our findings suggest onabotulinum toxin type A is a safe and effective treatment alternative for patients suffering from refractory greater occipital nerve neuralgia.

Neuroplasticity in dystonia: Motor symptoms and beyond

This chapter first focuses on the role of altered neuroplasticity mechanisms and their regulation in the genesis of motor symptoms in the various forms of dystonia. In particular, a review of the available literature about focal dystonia suggests that use-dependent plasticity may become detrimental and produce dystonia when practice and repetition are excessive and predisposing conditions are present. Interestingly, recent evidence also shows that functional or psychogenic dystonia, despite the normal plasticity in the sensorimotor system, is characterized by plasticity-related dysfunction within limbic regions. Finally, this chapter reviews the non-motor symptoms that often accompany the motor features of dystonia, including depression and anxiety as well as obsessive-compulsive disorders, pain, and cognitive dysfunctions. Based on the current understanding of these symptoms, we discuss the evidence of their possible relationship to maladaptive plasticity in non-motor basal ganglia circuits involved in their genesis.

Immunogenicity of botulinum toxin

Botulinum toxin treatment is the most common non-surgical cosmetic treatment. Although there are many available treatments using botulinum toxin, their effects are temporary and repeated injections are required. These frequent injections can trigger an immunological response. In addition, botulinum toxin acts as an antigen in the body; thus, its effect disappears progressively due to this immunological reaction, which may cause treatment failure. Active botulinum toxin consists of a core neurotoxin and complexing proteins, the exact effects of which remain unclear. However, the complexing proteins are closely related to the immune response and the formation of neutralizing antibodies. Since neutralizing antibodies can lead to treatment failure, their formation should be prevented. Furthermore, various methods of detecting neutralizing antibodies have been used to predict treatment failure.

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.

Efficacy of single-photon emission computed tomography aided botulinum toxin injection in cervical dystonia: A double-blind, randomized study

BACKGROUND

Although single-photon emission computed tomography (SPECT/CT) could help to predetermine dystonic muscles in patients with cervical dystonia (CD), its efficacy in aiding botulinum toxin injection is undetermined. This randomized, double-blinded study aimed to assess the efficacy of SPECT/CT aided botulinum toxin injection in CD.

METHODS

Patients were randomized into study group (candidate muscles selected by SPECT/CT and clinical evaluation) or control group (clinical evaluation). Follow-ups were done at two weeks (T1), one (T2), three (T3) and six months (T4). The primary outcomes included symptom improvement assessed using Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS) and Tsui score at T2.

RESULTS

A total of 122 patients were enrolled and 108 patients accomplished the study. For primary outcomes, the study group had significantly better symptom improvement at T2 (TWSTRS: β, -4.86 [95%CI -9.40 to -0.32; P = 0.036]; Tsui: β, -1.65 [95%CI -2.77 to -0.54; P = 0.004]). For secondary outcomes, the study group also showed better outcomes at T1 (TWSTRS: β, -6.33 [95%CI -10.17 to -2.49; P = 0.001]; Tsui: β, -1.42 [95%CI -2.48 to -0.37; P = 0.008]) and T3 (TWSTRS: β, -6.05 [95%CI -11.09 to -1.01; P = 0.019]; Tsui: β, -1.24 [95%CI -2.40 to -0.08; P = 0.037]). The interval of re-injection was significantly longer in the study group than the control group (159.1 ± 28.6 versus 141.8 ± 51.0 days, P = 0.032).

CONCLUSIONS

SPECT/CT could improve the efficacy of botulinum toxin in CD. It could become a useful tool to aid botulinum toxin injection.

Effect of Botulinum Toxin on Non-Motor Symptoms in Cervical Dystonia

Patients with cervical dystonia (CD) may display non-motor symptoms, including psychiatric disturbances, pain, and sleep disorders. Intramuscular injection of botulinum toxin type A (BoNT-A) is the most efficacious treatment for motor symptoms in CD, but little is known about its effects on non-motor manifestations. The aim of the present study was to longitudinally assess BoNT-A’s effects on CD non-motor symptoms and to investigate the relationship between BoNT-A-induced motor and non-motor changes. Forty-five patients with CD participated in the study. Patients underwent a clinical assessment that included the administration of standardized clinical scales assessing dystonic symptoms, psychiatric disturbances, pain, sleep disturbances, and disability. Clinical assessment was performed before and one and three months after BoNT-A injection. BoNT-A induced a significant improvement in dystonic symptoms, as well as in psychiatric disturbances, pain, and disability. Conversely, sleep disorders were unaffected by BoNT-A treatment. Motor and non-motor BoNT-A-induced changes showed a similar time course, but motor improvement did not correlate with non-motor changes after BoNT-A. Non-motor symptom changes after BoNT-A treatment are a complex phenomenon and are at least partially independent from motor symptom improvement.

Non-motor phenotypic subgroups in adult-onset idiopathic, isolated, focal cervical dystonia

BACKGROUND

Non-motor symptoms are well established phenotypic components of adult-onset idiopathic, isolated, focal cervical dystonia (AOIFCD). However, improved understanding of their clinical heterogeneity is needed to better target therapeutic intervention. Here, we examine non-motor phenotypic features to identify possible AOIFCD subgroups.

METHODS

Participants diagnosed with AOIFCD were recruited via specialist neurology clinics (dystonia wales: n = 114, dystonia coalition: n = 183). Non-motor assessment included psychiatric symptoms, pain, sleep disturbance, and quality of life, assessed using self-completed questionnaires or face-to-face assessment. Both cohorts were analyzed independently using Cluster, and Bayesian multiple mixed model phenotype analyses to investigate the relationship between non-motor symptoms and determine evidence of phenotypic subgroups.

RESULTS

Independent cluster analysis of the two cohorts suggests two predominant phenotypic subgroups, one consisting of approximately a third of participants in both cohorts, experiencing increased levels of depression, anxiety, sleep impairment, and pain catastrophizing, as well as, decreased quality of life. The Bayesian approach reinforced this with the primary axis, which explained the majority of the variance, in each cohort being associated with psychiatric symptomology, and also sleep impairment and pain catastrophizing in the Dystonia Wales cohort.

CONCLUSIONS

Non-motor symptoms accompanying AOIFCD parse into two predominant phenotypic sub-groups, with differences in psychiatric symptoms, pain catastrophizing, sleep quality, and quality of life. Improved understanding of these symptom groups will enable better targeted pathophysiological investigation and future therapeutic intervention.

Real-World Dosing of OnabotulinumtoxinA and IncobotulinumtoxinA for Cervical Dystonia and Blepharospasm: Results from TRUDOSE and TRUDOSE II

The real-world use of onabotulinumtoxinA and incobotulinumtoxinA for cervical dystonia and blepharospasm treatment was assessed in two separate retrospective studies using identical protocols (TRUDOSE and TRUDOSE II). The studies were conducted in Mexico, Norway, and United Kingdom and designed to evaluate dose utilization of the two botulinum toxins in clinical practice. Eighty-three patients treated with both onabotulinumtoxinA and incobotulinumtoxinA for ≥2 years for each botulinum toxin were included, (52, cervical dystonia; 31, blepharospasm). All patients switched from onabotulinumtoxinA to incobotulinumtoxinA for administrative/financial reasons. A range of dose ratios (incobotulinumtoxinA to onabotulinumtoxinA) was reported; with the majority of dose ratios being >1. The mean dose ratio was >1 regardless of the study site or underlying clinical condition. The inter-injection interval was significantly longer for onabotulinumtoxinA versus incobotulinumtoxinA when assessed for all patients (15.5 vs. 14.3 weeks; p = 0.006), resulting in fewer onabotulinumtoxinA treatments over the study time period. Consistent with product labeling, no single fixed-dose ratio exists between incobotulinumtoxinA and onabotulinumtoxinA. The dosage of each should be individualized based on patient needs and used as per product labeling. These real-world utilization data may have pharmacoeconomic implications.

Non-aesthetic uses of botulinum toxin in the head and neck

INTRODUCTION

The use of botulinum toxin in the specialty of aesthetic surgery in the head and neck is well known. However, it has also been used for other conditions affecting the head and neck, and in recent years its use, as well as the number of relevant applications, has expanded enormously.

REVIEW

This article presents a summary of the current range of uses in the laryngeal, pharyngeal, cervical, oromandibular and facial muscles and salivary glands. We highlight particular conditions focusing on dystonia (laryngeal, craniocervical, oromandibular and cervical), multiple system atrophy, migraines, facial nerve palsy, post-laryngectomy, cricopharyngeal dysphagia, Zenker's diverticulum, retrograde cricopharyngeal dysfunction disorder, sialorrhea and gustatory sweating (Frey's syndrome).

CONCLUSION

This article should aid the ear, nose and throat surgeon garner knowledge about the range of uses for botulinum toxin in the head and neck.

Intramuscular BoNT/A injections cause an inflammatory response in the muscle tissue of rats

Objectives

The purpose of the present study was to investigate whether intramuscular BoNT/A injections cause an systemic inflammatory response and a local inflammatory response in the muscle tissue.

Methods

Thirty-two male Sprague Dawley rats treated with BoNT/A (i.m., 1IU) were divided in four groups, depending on the time of BoNT/A injection (2 days before, 1, 2, and 4 weeks before the experiment). Bio-Plex Pro Rat Cytokine 23-plex Multiplex Assay (Bio-Rad, USA).

Results

Systemic inflammation: 17 cytokines (IL1-α ( p = 0.005), IL-1β ( p = 0.01), IL-2 ( p = 0.04), IL-4 ( p = 0.03), IL-6 ( p = 0.03), IL-10 ( p = 0.02), IL12(p70) ( p = 0.03), IL-13 ( p = 0.04), IL-17 ( p = 0.03), GM-CSF ( p = 0.03), INF-γ ( p = 0.03), MIP-1α ( p = 0.03), MIP-3α ( p = 0.04), RANTES ( p = 0.001), TNF-α ( p = 0.04), vascular endothelial growth factor ( p = 0.03), and MCP-1 ( p = 0.02)) showed significantly higher expression levels 2 days after intramuscular BoNT/A injections compared to other time points (1, 2, and 4 weeks). Local inflammation: 12 cytokines (IL-1β ( p = 0.02), IL-6 ( p = 0.002), IL-10 ( p = 0.02), IL-13 ( p = 0.04), IL-17 ( p = 0.02), TNF-α ( p = 0.001), GM-CSF ( p = 0.01), M-CSF ( p = 0.04), MIP-1α ( p = 0.04), MIP-3α ( p = 0.002), RANTES ( p = 0.02), and MCP-1( p = 0.004)) showed higher expression levels 2 and/or 4 weeks after intramuscular BoNT/A injections compared to the other time points (2 days and 1 week).

Conclusion

Intramuscular BoNT/A injections result in a rapid systemic inflammatory response that only lasts a couple of days. At the same time, intramuscular BoNT/A injections cause an inflammatory response locally in the muscle with significantly higher cytokine levels 2 and/or 4 weeks after injections.

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.

Targeting pain in the long-term treatment of cervical dystonia with botulinum toxin A

AIMS

Cervical pain is one of the most common non-motor symptoms of cervical dystonia (CD) and affects from 54.6% to 88.9% of patients. To date, minority of studies investigated the relevance of pain in a long-term botulinum toxin (BoNT) therapy of CD. The aim of the study was to define an impact of cervical pain on the disease severity and disability, as well as to assess antinociceptive BoNT efficacy in a long-term treatment of CD.

MATERIALS AND METHODS

In this case-control study, CD patients who received stable doses of BoNT for at least 3 years were assessed with the use of validated scales. Participants were divided into two groups depending on the occurrence of CD-related pain.

RESULTS

We examined 50 participants who received a mean of 24 injection cycles (6-51) of BoNT during a mean treatment period of 10.3 years (3.0-23.5). Participants with cervical pain (68.0%) were characterized by higher scores in all scales used in this study: TWSTRS severity (p = 0.030), disability (p < 0.001), total (p < 0.001) and TSUI score (p = 0.046). Pain reduction following BoNT injection lasted longer than muscle relaxation in 85.3% of patients. Pain improvement between first and last BoNT injection cycle was reported by 76.5% of patients with CD-related pain.

CONCLUSIONS

The presence of cervical pain in CD may increase the severity of muscular symptoms and disease-related disability. BoNT has a noticeable antinociceptive effect in the long-term treatment of CD.

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.

Long-term efficacy and safety of a new botulinum toxin type A preparation in mouse gastrocnemius muscle

A new type A botulinum toxin (BoNT/A) preparation, JTM201 (NCBI chromosomal DNA ID: CP046450), has been developed, which comprises 900-kDa complexed toxin purified from Clostridium botulinum (strain: NCTC13319), but its safety and efficacy have not yet been evaluated. The purpose of this study was to evaluate the long-term efficacy and safety of JTM201 at different concentrations in comparison to another commercially available BoNT/A product, Botox® (onabotulinumtoxin A, ONA), using a mouse model. The LD₅₀ of JTM201 was similar to that of ONA, but the intrinsic activity of JTM201 was higher than that of ONA. Functional recovery of the nerves and muscles in SKH-1 mice after administration of the two BoNT/A preparations (JTM201 and ONA) to the right gastrocnemius muscle was observed over 24 weeks. In addition, JTM201 did not induce any skin or muscle inflammatory response in 24 weeks. Paralysis induced by neurotransmitter blockade after JTM201 administration was comparable to that of ONA treatment. Both muscle weight and volume decreased in a concentration-dependent manner following JTM201 or ONA toxin injection until week 4. Reduced muscle fiber size due to atrophy and consequent fibrosis were detected following injection of JTM201 or ONA. Moreover, we assessed the extent of diffusion of JTM201 or ONA to the tibialis anterior and quadriceps femoris muscles, demonstrating limited diffusion to off-target muscles. In conclusion, JTM201 demonstrated long-term efficacy and safety equivalent to those of ONA based on compound muscle action potential, muscle volume, and histology analyses. These data suggest that JTM201 is a new BoNT/A formulation with safety and efficacy comparable to those of ONA.

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.

Comparison study of the response with botulinum toxin muscle injection in the ICR mice from three different sources

Botulinum-toxin A (BoNT/A) is a widely used not only for cosmetics but also for various experimental purposes including muscle-related research. In this study, we applied BoNT/A to mouse muscle of three different sources to compare and evaluate the biological and pathological response. The three different mouse sources consist of Korl:ICR (Korea FDA source), A:ICR (USA source) and B:ICR (Japan source) which were purchased from each different vendors. To compare the responses of ICR mice with BoNT/A muscle injection, we examined the body weight, hematological and serum biochemistry analysis. Also, we evaluated the muscle change by histopathological analysis and gene expression patterns of muscle-related target by qPCR. The body weight gain was decreased in the BoNT/A-treated group compared with the control group. In clinical pathologic analysis and gene expression patterns, the data showed that the responses in the BoNT/A-treated group were similar compared with the control group. Decreased muscle fiber was observed in BoNT/A-treated group compared with control group, while Korl:ICR showed a little low response with the other mouse sources. In conclusion, our results suggest that three different sources ICR mice (Korl:ICR, A:ICR and B:ICR) have a similar biological and pathological responses in BoNT/A muscle injection.

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.

Comorbidity and retirement in cervical dystonia

BACKGROUND

Cervical dystonia (CD) is the most common form of dystonia. The onset of CD is usually before 60 years of age and it may cause severe functional and psychosocial impairment in everyday life. Recently non-motor symptoms have been reported to occur in CD substantially affecting the quality of life.

METHODS/PATIENTS

We studied comorbidities of patients with primary focal CD in Finland based on ICD-10 codes obtained from the care registry and patient records of 937 confirmed adult isolated focal CD patients between the years 2007-2016. The retirement months and diagnosis of retirement were calculated from pension registry information. The results were compared with 3746 age and gender-matched controls.

RESULTS

Most prominent comorbidities with primary focal CD were depression (14%), anxiety (7%), and back pain (11%). The retirement age was significantly younger in CD patients compared to control group controls (59.0 years, 95% CI 58.5-59.5 vs. 61.7 years, 95% CI 61.6-61.9) years, p < 0.001). For dystonia patients the most common diagnoses for retirement due to sickness were dystonia (51%), depression (14%), and anxiety (8%). Patients with anxiety and depression retired earlier than other dystonia patients.

DISCUSSION

Cervical dystonia considerably reduces working ability and leads to earlier retirement. Anxiety and depression are most notable comorbidities and their co-occurrence further reduces working ability. Our results suggest that more health care resources should be administered in treatment of CD to longer maintain working ability of CD patients. Further, psychiatric comorbidities should be taken into consideration in CD treatment.

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 Prevalence and Correlation of Non-motor Symptoms in Adult Patients with Idiopathic Focal or Segmental Dystonia

Background

Idiopathic focal dystonia is a motor syndrome associated with dysfunction of basal ganglia circuits. Observations have suggested that many other non-motor symptoms may also be part of the clinical picture. The aim was to assess the prevalence and correlation of non-motor symptoms in patients with common idiopathic focal or segmental dystonia.

Methods

In a single-center cross-sectional case–control study, we evaluated the presence of pain, neuropsychiatric symptoms, and sleep alterations in 28 patients with blepharospasm, 28 patients with cervical dystonia, 24 patients with writer’s cramp, and 80 control subjects matched for sex, age, and schooling. We obtained clinical and demographic data, and evaluated patients using the Fahn–Marsden Dystonia Rating Scale and other specific scales for dystonia. All subjects completed the following questionnaires: Beck Depression Inventory, Beck Anxiety Inventory, Social Phobia Inventory, Apathy Scale, Epworth Sleepiness Scale, Pittsburgh Sleep Quality Index, Brief Pain Scale, and the World Health Organization Quality of Life brief scale.

Results

The patients presented more symptoms of depression, anxiety, and apathy than the control subjects. They also reported worse quality of sleep and more pain complaints. Patients with blepharospasm were the most symptomatic subgroup. The patients had worse quality of life, and the presence of pain and symptoms of apathy and depression were the main influences for these findings, but not the severity of motor symptoms.

Discussion

Patients with dystonia, especially those with blepharospasm, showed higher prevalence of symptoms of depression, anxiety, apathy, worse quality of sleep, and pain. These symptoms had a negative impact on their quality of life.

Central Effects of Botulinum Neurotoxin-Evidence from Human Studies

For more than three decades, Botulinum neurotoxin (BoNT) has been used to treat a variety of clinical conditions such as spastic or dystonic disorders by inducing a temporary paralysis of the injected muscle as the desired clinical effect. BoNT is known to primarily act at the neuromuscular junction resulting in a biochemical denervation of the treated muscle. However, recent evidence suggests that BoNT’s pharmacological properties may not only be limited to local muscular denervation at the injection site but may also include additional central effects. In this review, we report and discuss the current evidence for BoNT’s central effects based on clinical observations, neurophysiological investigations and neuroimaging studies in humans. Collectively, these data strongly point to indirect mechanisms via changes to sensory afferents that may be primarily responsible for the marked plastic effects of BoNT on the central nervous system. Importantly, BoNT-related central effects and consecutive modulation and/or reorganization of the brain may not solely be considered “side-effects” but rather an additional therapeutic impact responsible for a number of clinical observations that cannot be explained by merely peripheral actions.

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.

Injection of high dose botulinum-toxin A leads to impaired skeletal muscle function and damage of the fibrilar and non-fibrilar structures

Botulinum-toxin A (BoNT/A) is used for a wide range of conditions. Intramuscular administration of BoNT/A inhibits the release of acetylcholine at the neuromuscular junction from presynaptic motor neurons causing muscle-paralysis. The aim of the present study was to investigate the effect of high dose intramuscular BoNT/A injections (6 UI = 60 pg) on muscle tissue. The gait pattern of the rats was significantly affected 3 weeks after BoNT/A injection. The ankle joint rotated externally, the rats became flat footed, and the stride length decreased after BoNT/A injection. Additionally, there was clear evidence of microstructural changes on the tissue level by as evidenced by 3D imaging of the muscles by Synchrotron Radiation X-ray Tomographic Microscopy (SRXTM). Both the fibrillar and the non-fibrillar tissues were affected. The volume fraction of fibrillary tissue was reduced significantly and the non-fibrillar tissue increased. This was accompanied by a loss of the linear structure of the muscle tissue. Furthermore, gene expression analysis showed a significant upregulation of COL1A1, MMP-2, TGF-b1, IL-6, MHCIIA and MHCIIx in the BoNT/A injected leg, while MHVIIB was significantly downregulated.

IN CONCLUSION

The present study reveals that high dose intramuscular BoNT/A injections cause microstructural damage of the muscle tissue, which contributes to impaired gait.

The Frequency and Self-perceived Impact on Daily Life of Motor and Non-motor Symptoms in Cervical Dystonia

BACKGROUND

Evidence suggests that non-motor symptoms (NMS) are the most important predictors of decreased health-related quality of life (HR-QoL) in patients with cervical dystonia (CD). In this study, we evaluate an NMS screening list and examine the influence of motor symptoms and NMS on HR-QoL.

METHODS

In 40 patients with CD, the frequency of NMS was evaluated using an extended NMS questionnaire. Furthermore, patients composed a list of their 5 most burdensome motor symptoms and NMS and scored the severity of predefined symptoms. HR-QoL was examined with the RAND 36-item Health Survey.

RESULTS

Of 40 patients, 38 experienced NMS (median number of NMS, 6.5; range, 0-13; maximum, 15). The self-perceived most burdensome symptoms were tremor/jerks, pain, sleep disturbances, daily-life limitations, and fatigue. Also, of the predefined symptom list, tremor and fatigue were identified as the most disturbing. Several domains of HR-QoL were significantly influenced by NMS, whereas motor symptoms had only a small influence on the physical functioning domain of HR-QoL.

CONCLUSION

Our findings highlight the impact of NMS on HR-QoL and emphasize the importance of a standardized, validated NMS questionnaire for patients with dystonia. This would enable us to monitor the effect of treatment for motor symptoms and NMS on an individual basis and improve treatment options.

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.

Association Analysis of NALCN Polymorphisms rs1338041 and rs61973742 in a Chinese Population with Isolated Cervical Dystonia

Background. A genome-wide association study (GWAS) demonstrated a possible association between cervical dystonia (CD) and a sodium leak channel, nonselective (NALCN) gene. However, the association between NALCN and CD was largely unknown in Asian population. The present study was carried out to examine the associations between the two single nucleotide polymorphisms (SNPs) rs1338041 and rs61973742 in the NALCN gene and CD in a Chinese population. Methods. In a cohort of 201 patients with isolated CD, we genotyped the two SNPs rs1338041 and rs61973742 using polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP). We also included 289 unrelated, age- and sex-matched healthy controls (HCs) from the same region. Result. No significant differences were observed in either the genotype distributions or the minor allele frequencies (MAFs) of the two SNPs between the CD patients and the HCs. There were no significant differences between early-onset and late-onset CD patients, between patients with and without a positive family history of dystonia, or between patients with and without tremor or sensory tricks. Conclusion. Lack of association between the SNPs of NALCN and CD suggests that the SNPs of NALCN do not play a role in CD in a Chinese population.

Identification and management of tardive dyskinesia: A case series and literature review

Tardive dyskinesia (TD) is a serious, disabling and potentially permanent, neurological hyperkinetic movement disorder that occurs after months or years of taking dopamine receptor-blocking agents. The pathophysiology of TD is complex, multifactorial and still not fully understood. Although there is no identified effective and standard treatment for TD, several agents have been tried for the management of this motor disturbance. The aim of this case series is to review the literature in regard to the identification, diagnosis and the treatment of TD with anticholinergics, anticholinergic medication withdrawal, cholinergic agents, botulinum toxin intramuscular injections, tetrabenazine, levetiracetam, propranolol and zolpidem, and to describe one case of TD that responded favorably to clonazepam and two cases of TD that responded favorably to Ginkgo biloba.