Head tremor and pain in cervical dystonia

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.

Head movement dynamics in dystonia: a multi-centre retrospective study using visual perceptive deep learning

Dystonia is a neurological movement disorder characterised by abnormal involuntary movements and postures, particularly affecting the head and neck. However, current clinical assessment methods for dystonia rely on simplified rating scales which lack the ability to capture the intricate spatiotemporal features of dystonic phenomena, hindering clinical management and limiting understanding of the underlying neurobiology. To address this, we developed a visual perceptive deep learning framework that utilizes standard clinical videos to comprehensively evaluate and quantify disease states and the impact of therapeutic interventions, specifically deep brain stimulation. This framework overcomes the limitations of traditional rating scales and offers an efficient and accurate method that is rater-independent for evaluating and monitoring dystonia patients. To evaluate the framework, we leveraged semi-standardized clinical video data collected in three retrospective, longitudinal cohort studies across seven academic centres. We extracted static head angle excursions for clinical validation and derived kinematic variables reflecting naturalistic head dynamics to predict dystonia severity, subtype, and neuromodulation effects. The framework was also applied to a fully independent cohort of generalised dystonia patients for comparison between dystonia sub-types. Computer vision-derived measurements of head angle excursions showed a strong correlation with clinically assigned scores. Across comparisons, we identified consistent kinematic features from full video assessments encoding information critical to disease severity, subtype, and effects of neural circuit interventions, independent of static head angle deviations used in scoring. Our visual perceptive machine learning framework reveals kinematic pathosignatures of dystonia, potentially augmenting clinical management, facilitating scientific translation, and informing personalized precision neurology approaches.

An Exploratory, Randomized, Double-Blind Clinical Trial of Dipraglurant for Blepharospasm

BACKGROUND

Blepharospasm is treated with botulinum toxin, but obtaining satisfactory results is sometimes challenging.

OBJECTIVE

The aim is to conduct an exploratory trial of oral dipraglurant for blepharospasm.

METHODS

This study was an exploratory, phase 2a, randomized, double-blind, placebo-controlled trial of 15 participants who were assigned to receive a placebo or dipraglurant (50 or 100 mg) and assessed over 2 days, 1 and 2 hours following dosing. Outcome measures included multiple scales rated by clinicians or participants, digital video, and a wearable sensor.

RESULTS

Dipraglurant was well tolerated, with no obvious impact on any of the measurement outcomes. Power analyses suggested fewer subjects would be required for studies using a within-subject versus independent group design, especially for certain measures. Some outcome measures appeared more suitable than others.

CONCLUSION

Although dipraglurant appeared well tolerated, it did not produce a trend for clinical benefit. The results provide valuable information for planning further trials in blepharospasm. © 2024 International Parkinson and Movement Disorder Society.

Efficacy and Safety of DaxibotulinumtoxinA for Injection in Cervical Dystonia: ASPEN-1 Phase 3 Randomized Controlled Trial

BACKGROUND AND OBJECTIVES

ASPEN-1 was a phase 3, randomized, double-blind, placebo-controlled study to evaluate the efficacy, duration of response, and safety of 2 doses of DaxibotulinumtoxinA for Injection (DAXI), a novel botulinum toxin type A formulation in participants with cervical dystonia (CD).

METHODS

Adults (aged 18-80 years) with moderate-to-severe CD (Toronto Western Spasmodic Torticollis Rating Scale [TWSTRS] total score ≥20) were enrolled at 60 sites across 9 countries in Europe and North America. Participants were randomized (3:3:1) to single-dose intramuscular DAXI 125U, 250U, or placebo and followed for up to 36 weeks after injection. The primary end point was change from baseline in TWSTRS total score averaged across weeks 4 and 6. Key secondary end points included duration of effect, Clinical and Patient Global Impression of Change (CGIC, PGIC), TWSTRS subscale scores, and safety. Multiplicity-adjusted intent-to-treat hypothesis tests with multiple imputation were performed using ANCOVA and Cochran-Mantel-Haenszel analyses.

RESULTS

Of 444 individuals screened, 301 were randomized to DAXI 125U (n = 125) or 250U (n = 130) or placebo (n = 46). DAXI 125U and 250U significantly improved the mean TWSTRS total score vs placebo (least squares mean [standard error] difference vs placebo: DAXI 125U, -8.5 [1.93], p < 0.0001; DAXI 250U, -6.6 [1.92], p = 0.0006). The median duration of effect (time from treatment until loss of ≥80% of the peak improvement in average TWSTRS total score achieved at weeks 4 and 6) was 24.0 (95% confidence interval 20.3-29.1) weeks with DAXI 125U and 20.3 (16.7-24.0) weeks with DAXI 250U. Significant improvements were also observed with DAXI in CGIC and PGIC responder rates and TWSTRS subscales. Treatment-related treatment-emergent adverse events (TEAEs) were reported by 29.6% of participants with DAXI 125U, 23.8% with DAXI 250U, and 17.4% with placebo, with injection site pain being the most common overall. The most frequently reported treatment-related TEAEs of interest in DAXI 125U, DAXI 250U, and placebo, respectively, were muscular weakness (4.8%, 2.3%, 0%), musculoskeletal pain (2.4%, 3.1%, 0%), and dysphagia (1.6%, 3.8%, 0%).

DISCUSSION

This study demonstrated that DAXI, at doses of 125U and 250U, is an effective, safe, long-acting, and well-tolerated treatment for CD.

TRIAL REGISTRATION INFORMATION

ClinicalTrials.gov identifier (NCT03608397, submitted July 11, 2018) and EU Clinical Trials Register (ClinicalTrialsRegister.eu EudraCT identifier 2018-000446-19, submitted September 13, 2018). First participant enrolled on June 11, 2018. Trial registration was performed in accordance with the Food and Drug Administration Amendments Act (FDAAA 801), which stipulates that the responsible party register an applicable clinical trial not later than 21 calendar days after enrolling the first human participant (42 CFR 11.24).

CLASSIFICATION OF EVIDENCE

This study provides Class I evidence that in adults with moderate-to-severe idiopathic cervical dystonia, DAXI reduces dystonia more effectively than placebo.

Botulinum Toxin Injections to the Obliquus Capitis Inferioris Muscle for Dynamic Cervical Dystonia Improves Subjective Patient Outcomes

The obliquus capitis inferioris (OCI) muscle is a significant driver of cervical dystonia with torticaput movements and a no-no head tremor. Limited data are available on the efficacy of OCI injections on patient outcomes. Our study aims to determine whether the botulinum toxin injection into OCI improves subjective patient quality of life in those with dystonic head tremors. A retrospective chart review was performed for 25 patients receiving injections into the OCI for a dystonic head tremor at the London Movement Disorders Clinic between January 2020 and January 2022. Toronto Western Spasmodic Torticollis Scale-2 (TWSTRS-2) subscale scores for disability and pain, TWSTRS-PSYCH scores, and the global impression of severity were extracted. The average TWSTRS-2 disability subscale change was -2.8 points (p < 0.003). The average TWSTRS-2 pain subscale change was -4.6 points (p < 0.003). The average TWSTRS-PSYCH score prior to injection was 5.6. After injection, the average score was 3.7 (p < 0.004). The patient self-reported average global impression of severity before injection was 7.0; after this, it was 4.2 (p < 0.0003). The OCI injection showed significant improvement in retrospective patient self-reported outcomes; it should be considered early in the treatment plan for cervical dystonia with a no-no head tremor.

[Pain and cervical dystonia]

BACKGROUND

Dystonia is a hyperkinetic movement disorder that results in twisting, cramps and tremors due to sustained or intermittent muscle contractions. Cervical dystonia is the most common form of dystonia, in which the head, neck and/or shoulder areas are affected. In addition to these motor symptoms, pain and psychiatric symptoms are frequent in (cervical) dystonia.

OBJECTIVE

Description of the incidence and evaluation of pain in cervical dystonia, summary and discussion of treatment options and effects.

MATERIAL AND METHODS

In this review article the results in the scientific literature on pain in dystonia are summarized and discussed.

RESULTS

Compared to other forms of dystonia, pain occurs most frequently in patients with cervical dystonia. A large proportion of patients with cervical dystonia suffer from pain, which contributes most to impairment of the patient. The motor symptoms of dystonia are usually treated with botulinum toxin injections. These have a muscle relaxing effect and also relieve pain. The study situation on the occurrence and treatment of pain in other forms of dystonia is so far very limited. Pain can dominate the clinical picture in patients with cervical dystonia. Evaluation of pain in cervical dystonia can be performed using standardized questionnaires.

CONCLUSION

It is important to ask patients with cervical dystonia about pain and to consider it in treatment planning and evaluation. Vice versa, if pain is present the possibility of a causative dystonia should also be considered. For pain assessment there are some newly developed questionnaires to assess pain in a standardized way in patients with dystonia. Further research is needed to better understand the pathomechanisms of pain in dystonia.

Clinical characteristics of patients with migraine accompanied by tremor

OBJECTIVES

Migraine and tremor share some genetic mutation sites, and clinical studies have also confirmed their correlation. This study aims to explore the clinical and electrophysiological characteristics of migraine patients with concomitant tremor, and to analyze the relevant influential factors of tremor occurrence.

METHODS

We retrospectively analyzed the clinical data of 217 migraine patients who visited the Third Affiliated Hospital of Qiqihar Medical University from June 2022 to October 2023. The Clinical Rating Scale for Tremor (CRST), Numerical Rating Scale (NRS), Generalized Anxiety Disorder-7 (GAD-7), and Patient Health Questionnaire-9 (PHQ-9) were respectively used to assess the tremor symptoms, degree of headache, anxiety, and depression of patients. All patients underwent routine head MR scanning and electromyography examination, and were divided into a migraine with tremor group and a migraine without tremor group based on the electromyogram examination.

RESULTS

The migraine with tremor group and the migraine without tremor group were included 52 patients (23.96%) and 165 patients (76.04%), respectively. Compared with the migraine without tremor group, the migraine with tremor group had a longer course and duration of headache, higher frequency of headache attacks, higher NRS score, GAD-7 score, and PHQ-9 score, and fewer weekly physical exercises. The differences were statistically significant (all P<0.05). There were no statistically significant differences in the presence or absence of prodromal headache and white matter hyperintensities (WMHs) between the 2 groups (both P>0.05). The evaluation results of the CRST showed that out of 217 migraine patients, 39 patients (17.97%) were accompanied by tremors. The electromyographic results showed that all 52 migraine patients with tremors had upper limb tremors, including 28 migraine patients with postural tremors and 24 migraine patients with static tremors. Compared with the migraine patients with static tremors, the migraine patients with postural tremors had lower average frequency, peak frequency, and headache onset frequency (all P<0.05). Multiple linear regression analysis showed that frequency of physical exercise, duration of illness, frequency of headache attacks, NRS score, GAD-7 score, and PHQ-9 score were risk factors for migraine patients with concomitant tremors (all P<0.05).

CONCLUSIONS

Patients with migraine mainly experience upper limb postural tremors. Reduced physical exercise, long course of disease, long duration of headache, frequent headache attacks, severe headache, anxiety, and depression are risk factors for migraine patients with concomitant tremors.

An analysis of the efficacy of botulinum neurotoxin type a in treating cervical dystonia

BACKGROUND

The first-line treatment for cervical dystonia (CD) consists of repeated intramuscular injections of botulinum toxin (BoNT). However, the efficacy in some patients may be unsatisfactory and they may discontinue treatment.

OBJECTIVE

To examine the factors associated with the maximum rate of remission in patients with CD after initial botulinum neurotoxin type A (or botulinum toxin type A abbreviated as BTX-A or BoNT-A) treatment.

METHODS

Patients with CD who received BoNT-A injections were evaluated using the Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS) and the Tsui scale, with follow-up endpoints lasting until the start of the second injection. Patients who did not receive a second injection of BoNT-A were followed up for at least 5 months. The maximum remission rates were determined using the lowest Tsui and TWSTRS total scores during the follow-up period. We obtained basic information about these patients such as age, gender, duration of disease, presence of additional disease, types of torticollis, presence of anxiety, depression, tremors, single-photon emission computed tomography (SPECT) findings, injected dose, and so on from their medical records.

RESULTS

A total of 70 patients with CD participated in this study, with males comprising 35.7% (25 individuals) with an average age of 45 ± 14 years old. The duration of disease was an independent risk factor for determining whether a complete remission has been attained using the Tsui scale (odds ratio [OR] = 0.978, 95% confidence interval [CI]: 0.959-0.997, P= 0.026). The optimal cut-off point for predicting patients who were unable to achieve complete remission based on duration of disease was 7.5 months (AUG = 0.711). Patients with CD with additional disease had greater difficulty achieving complete remission than those with CD alone based on TWSTRS assessments (P= 0.049). During the study, approximately 17% of all participants reported experiencing adverse reactions that lasted between 1 to 3 weeks before disappearing.

CONCLUSION

BoNT is an effective and safe method for treating CD. The maximum remission rates of patients after their first injections are influenced by the duration of their disease. Thus, treatment using BoNT injections must be administered as soon as possible.

Tauopathies: new perspectives and challenges

BACKGROUND

Tauopathies are a class of neurodegenerative disorders characterized by neuronal and/or glial tau-positive inclusions.

MAIN BODY

Clinically, tauopathies can present with a range of phenotypes that include cognitive/behavioral-disorders, movement disorders, language disorders and non-specific amnestic symptoms in advanced age. Pathologically, tauopathies can be classified based on the predominant tau isoforms that are present in the inclusion bodies (i.e., 3R, 4R or equal 3R:4R ratio). Imaging, cerebrospinal fluid (CSF) and blood-based tau biomarkers have the potential to be used as a routine diagnostic strategy and in the evaluation of patients with tauopathies. As tauopathies are strongly linked neuropathologically and genetically to tau protein abnormalities, there is a growing interest in pursuing of tau-directed therapeutics for the disorders. Here we synthesize emerging lessons on tauopathies from clinical, pathological, genetic, and experimental studies toward a unified concept of these disorders that may accelerate the therapeutics.

CONCLUSIONS

Since tauopathies are still untreatable diseases, efforts have been made to depict clinical and pathological characteristics, identify biomarkers, elucidate underlying pathogenesis to achieve early diagnosis and develop disease-modifying therapies.

Head tremor in cervical dystonia: Quantifying severity with computer vision

BACKGROUND

Head tremor (HT) is a common feature of cervical dystonia (CD), usually quantified by subjective observation. Technological developments offer alternatives for measuring HT severity that are objective and amenable to automation.

OBJECTIVES

Our objectives were to develop CMOR (Computational Motor Objective Rater; a computer vision-based software system) to quantify oscillatory and directional aspects of HT from video recordings during a clinical examination and to test its convergent validity with clinical rating scales.

METHODS

For 93 participants with isolated CD and HT enrolled by the Dystonia Coalition, we analyzed video recordings from an examination segment in which participants were instructed to let their head drift to its most comfortable dystonic position. We evaluated peak power, frequency, and directional dominance, and used Spearman's correlation to measure the agreement between CMOR and clinical ratings.

RESULTS

Power averaged 0.90 (SD 1.80) deg2/Hz, and peak frequency 1.95 (SD 0.94) Hz. The dominant HT axis was pitch (antero/retrocollis) for 50%, roll (laterocollis) for 6%, and yaw (torticollis) for 44% of participants. One-sided t-tests showed substantial contributions from the secondary (t = 18.17, p < 0.0001) and tertiary (t = 12.89, p < 0.0001) HT axes. CMOR's HT severity measure positively correlated with the HT item on the Toronto Western Spasmodic Torticollis Rating Scale-2 (Spearman's rho = 0.54, p < 0.001).

CONCLUSIONS

We demonstrate a new objective method to measure HT severity that requires only conventional video recordings, quantifies the complexities of HT in CD, and exhibits convergent validity with clinical severity ratings.

Tremor Syndromes: An Updated Review

Tremor is the most commonly encountered movement disorder in clinical practice. A wide range of pathologies may manifest with tremor either as a presenting or predominant symptom. Considering the marked etiological and phenomenological heterogeneity, it would be desirable to develop a classification of tremors that reflects their underlying pathophysiology. The tremor task force of the International Parkinson Disease and Movement Disorders Society has worked toward this goal and proposed a new classification system. This system has remained a prime topic of scientific communications on tremor in recent times. The new classification is based on two axes: 1. based on the clinical features, history, and tremor characteristics and 2. based on the etiology of tremor. In this article, we discuss the key aspects of the new classification, review various tremor syndromes, highlight some of the controversies in the field of tremor, and share the potential future perspectives.

Tourette Syndrome and Driving

BACKGROUND

Driving ability may be impaired in patients with various movement disorders, but it has not been studied in patients with Tourette syndrome (TS).

CASES

We describe a series of 6 patients from our large cohort of TS patients followed in our movement disorders clinic in whom severe tics have had interfered with their driving abilities. The motor tics involved facial muscles and caused visual impairment because of frequent blinking and transient blepharospasm (dystonic tic), but complex limb and truncal tics also seriously impacted their driving.

CONCLUSIONS

Although majority of patients with TS have no functional impairment, severe motor tics in some patients may adversely affect their driving ability, potentially causing danger to themselves and others. Screening for such troublesome tics should be considered in patients with TS, particularly in teenagers who are being evaluated for driver's licensing.

The Dystonia Coalition: A Multicenter Network for Clinical and Translational Studies

Dystonia is a movement disorder characterized by sustained or intermittent muscle contractions causing abnormal postures, repetitive movements, or both. Research in dystonia has been challenged by several factors. First, dystonia is uncommon. Dystonia is not a single disorder but a family of heterogenous disorders with varied clinical manifestations and different causes. The different subtypes may be seen by providers in different clinical specialties including neurology, ophthalmology, otolaryngology, and others. These issues have made it difficult for any single center to recruit large numbers of subjects with specific types of dystonia for research studies in a timely manner. The Dystonia Coalition is a consortium of investigators that was established to address these challenges. Since 2009, the Dystonia Coalition has encouraged collaboration by engaging 56 sites across North America, Europe, Asia, and Australia. Its emphasis on collaboration has facilitated establishment of international consensus for the definition and classification of all dystonias, diagnostic criteria for specific subtypes of dystonia, standardized evaluation strategies, development of clinimetrically sound measurement tools, and large multicenter studies that document the phenotypic heterogeneity and evolution of specific types of dystonia.