Hand Dystonia Research Articles

Complete Improvement of Severe Forearm Complex Regional Pain Syndrome with Six High-Dose Incobotulinumtoxin A Injections: Clinical Implications with Respect to the Literature

There is some evidence that injections of botulinum neurotoxin effectively reduce pain in complex regional pain syndromes (CRPSs). But no or little experience appears to exist for the application of incobotulinum neurotoxin type A (incoBoNT/A) in complex pain disorders. Here, a case of CRPS type I, characterized by severe symptoms in the left forearm is presented, showed significant continuous improvement following a series of six repetitive (painful) injections into the finger, hand, and forearm muscles of incoBoNT/A every 3 months, administered at declining doses varying between 500 and 100 U. Remarkably, this treatment regimen led to the complete resolution of pain, vaso- and sudomotor symptoms, and hand dystonia. This highlights the possible efficacy of incoBoNT/A in the treatment of CRPS and encourages the further exploration of incoBoNT/A’s role in the successful management of complex pain disorders.

First report of PURA syndrome in a Colombian patient with de novo missense variant c.692T>C (p.Phe231Ser)

We present the first documented case of PURA syndrome in Colombia. This rare neurological disease results from mutations in the PURA gene located on chromosome 5, leading to haploinsufficiency of the PUR-α protein. This protein is essential for early brain development and neuronal function. The patient, a seven-years-old boy, started showing dystonic hand movements at 14 days of age; at six, he had neurodevelopmental delay, generalized hypotonia, frequent episodes of apnea, and swallowing difficulties. Although other conditions were initially considered, such as Duchenne muscular dystrophy and neuronal ceroid lipofuscinosis, a whole exome sequencing revealed the pathogenic variant c.692T>C (p.Phe231Ser) in the exon 1 of the PURA gene, not previously reported in other patients. With this finding, we adopted a comprehensive management approach addressing the patient’s characteristics and alterations. Since the PURA syndrome is not on the list of orphan/rare diseases recognized by the Colombian Ministerio de Salud y Protección Social, we hope our report will contribute to its official recognition. The case shows the importance of considering rare diagnoses in patients with uncommon neurological symptoms, underlining the usefulness of genomic sequencing in diagnosis and the need for collaboration to optimize healthcare for patients with PURA syndrome and similar diseases.

Role of Accelerated Continuous Theta Burst Stimulation in Hand Dystonia: from Acute Phase to Maintenance Treatment

Role of Accelerated Continuous Theta Burst Stimulation in Hand Dystonia: from Acute Phase to Maintenance Treatment

Long-term motor learning in focal hand dystonia

ObjectiveBecause focal hand dystonia usually occurs in the over-learned stage, it would be valuable to know long-term motor learning characteristics and underlying pathophysiological features that might predispose to dystonia. MethodsWe conducted a case-control exploratory study of 15 visits over 12 weeks in the non-affected hand of a 4-finger sequence of 8 key presses in eight patients with FHD compared with eight age- and sex-matched, healthy volunteers (HVs). We studied the behavioral data and the physiological changes of the brain, including motor cortical excitability and cortical oscillations. ResultsThere was no significant difference in the time to reach 100 % accuracy between FHD and HV during the 80-day follow-up period. There was a statistically significant difference in the accuracy of sequential finger movement tasks between patients with FHD compared with HVs over 12 weeks, but post-hoc analysis with multiple comparion correction did not show difference. There were no significant differences in recruitment curve changes and task-related power changes of alpha and beta bands. ConclusionOver 12 weeks, FHD have motor learning capacity comparable to HVs and do not show pathophysiological abnormalities. SignificanceFurther studies would be valuable with more patients, more extended periods of practice, and more detailed electrophysiological explorations.

Bilateral hand dystonia following high-velocity thrust manipulation: a case report.

Thrust manipulation is one of the most commonly used techniques for managing musculoskeletal pain in clinical practice. This involves the application of a high-velocity, low-amplitude force directed to the joints with the intent of achieving joint cavitation. This current case report describes a female in her mid-20s who presented with excessive bilateral and involuntary hand muscle contractions after bilateral thrust manipulation. Dystonia appeared both at rest and during voluntary movements but was aggravated by actions such as finger flexion or spreading and disappeared during sleep. A diagnosis of complex regional pain syndrome (CRPS) type I combined with dystonia was made. Prednisolone administered between 2 and 5 weeks after symptom onset significantly reduced CRPS symptoms, but intramuscular botulinum toxin injection 5 weeks after symptom onset was ineffective at controlling her symptoms. Seven weeks after symptom onset, the patient was administered 2 mg trihexyphenidyl oral twice a day, 2.5 mg diazepam oral twice a day and 5 mg baclofen oral three times a day for 1 month and this significantly reduced dystonia, but complete resolution was not achieved. Clinicians should be aware that dystonia is a rare complication of thrust manipulation.

Amelioration of Focal Hand Dystonia via Low-Frequency Repetitive Somatosensory Stimulation.

Dystonia presents a growing concern based on evolving prevalence insights. Previous research found that, in cervical dystonia, high-frequency repetitive somatosensory stimulation (RSS; HF-RSS) applied on digital nerves paradoxically diminishes sensorimotor inhibitory mechanisms, whereas low-frequency RSS (LF-RSS) increases them. However, direct testing on affected body parts was not conducted. This study aims to investigate whether RSS applied directly to forearm muscles involved in focal hand dystonia can modulate cortical inhibitory mechanisms and clinical symptoms. We applied HF-RSS and LF-RSS, the latter either synchronously or asynchronously, on forearm muscles involved in dystonia. Outcome measures included paired-pulse somatosensory evoked potentials, spatial lateral inhibition measured by double-pulse somatosensory evoked potentials, short intracortical inhibition tested with transcranial magnetic stimulation, electromyographic activity from dystonic muscles, and behavioral measures of hand function. Both synchronous and asynchronous low-frequency somatosensory stimulation improved cortical inhibitory interactions, indicated by increased short intracortical inhibition and lateral spatial inhibition, as well as decreased amplitude of paired-pulse somatosensory evoked potentials. Opposite effects were observed with high-frequency stimulation. Changes in electrophysiological markers were paralleled by behavioral outcomes: although low-frequency stimulations improved hand function tests and reduced activation of dystonic muscles, high-frequency stimulation operated in an opposite direction. Our findings confirm the presence of abnormal homeostatic plasticity in response to RSS in the sensorimotor system of patients with dystonia, specifically in inhibitory circuits. Importantly, this aberrant response can be harnessed for therapeutic purposes through the application of low-frequency electrical stimulation directly over dystonic muscles. © 2024 The Author(s). Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Bradykinesia in dystonic hand tremor: kinematic analysis and clinical rating

Bradykinesia in dystonic hand tremor: kinematic analysis and clinical rating

Focal task-specific hand dystonia related to esports in a rhythm gamer: A case report

Focal task-specific hand dystonia related to esports in a rhythm gamer: A case report

Quantifying abnormal writing kinematics in writer's cramp using a novel software platform.

Writer's cramp is a task-specific focal hand dystonia, which is diagnosed clinically. Quantification of defect in WC is done using clinical scales, while digitized platforms are lacking. To design and test a platform that can differentiate and quantify the abnormal kinematics of writing using a software interface and to validate it in adult-onset isolated writer's cramp (WC). A native platform was designed using Java and Wacom Intuos pro tablet and the data analyzed using a MATLAB-based platform called Large Data-Based Evaluation of Kinematics in Handwriting (LEKH). We standardized this new platform by comparing the handwriting between patients with WC and age, and gender and education-matched healthy controls, using standard tasks to assess the kinematics. Comparison of the writing of right-handed WC patients (N = 21) and 39 healthy controls (N = 39) showed that patients differed from controls in the frequency of strokes (P < 0.001), number of inversions of velocity (P < 0.001), number of breaks (P = 0.02), air time and paper time (P < 0.001). Using the LEKH platform, the kinematic profile of patients with WC could be differentiated from healthy controls. Studies in larger samples will be needed to derive statistical models that can differentiate the flexion and extension types of WC which can help in muscle selection and to quantify the effects of treatment.

Globus Pallidus Lesion With Iron Deposition and Dopaminergic Denervation in a Patient With a Pathogenic SLC6A1 Variant: A Case Report.

SLC6A1-related disorders encompass heterogeneous neuropsychiatric manifestations through GABAergic dysregulation, without any specific abnormalities on brain MRI, nor evidence of dopaminergic cell loss on I123-FP-β-CIT SPECT. We report here a case of globus pallidus lesions and dopaminergic denervation in a patient with a pathogenic SLC6A1 variant. A 26-year-old female patient with intellectual disability, behavioral, and psychiatric disorders treated by neuroleptics for many years developed a parkinsonian syndrome associated with mild hand dystonia and chorea. A 3T brain MRI and I123-FP-β-CIT SPECT were performed. MRI of the brain found bilateral pallidal lesions consistent with neurodegeneration with iron accumulation. The I123-FP-β-CIT SPECT showed bilateral striatal presynaptic dopaminergic denervation. Whole-genome sequencing revealed a pathogenic SLC6A1 de novo variant. No additional variant was found in any of the genes responsible for Neurodegeneration with Brain Iron Accumulation (NBIA). This is a description of dopaminergic denervation and globus pallidus lesions with iron accumulation related to a SLC6A1 pathogenic variant. These findings expand the phenotype of SLC6A1-related disorder and suggest that it could be considered as a differential diagnosis of NBIA.

MRI-Guided Focused Ultrasound for the Treatment of Dystonia: A Narrative Review.

Contemporary surgical management of dystonia includes neuromodulation via deep brain stimulation (DBS) or ablative techniques such as radiofrequency (RF) ablation. MRI-guided focused ultrasound (MRgFUS) is an emerging modality that uses high-intensity ultrasound to precisely ablate targets in the brain; this is incisionless, potentially avoiding the surgical risks of a burr hole and transcortical tract to reach the anatomical target. There is some evidence of efficacy in essential tremor and Parkinson's disease (PD), but, to date, there is no study aggregating the evidence of MRgFUS in dystonia. In this narrative review, we searched Medline, Embase, CINAHL, EBSCO, and ClinicalTrials.gov for primary studies and clinical trials on MRgFUS in the treatment of dystonia. Data were analyzed concerning dystonia phenotype, reported outcomes, and complications. PD-related dystonia was also included within the scope of the review. Using our search criteria, six articles on the use of MRgFUS in adult dystonia and three articles on the use of FUS in dystonia in PD were included. Four trials on the use of FUS in dystonia were also found on ClinicalTrials.gov, one of which was completed in December 2013. All included studies showed evidence of symptomatic improvement, mostly in focal hand dystonia; improvements were also found in dystonia-associated tremor, cervicobrachial dystonia, and dystonia-associated chronic neuropathic painas well as PD-related dystonia. Reported complications included transient neurological deficits and persistent arm pain in one study. However, the evidence is limited to level-4 case series at present. MRgFUS is an emerging modality that appears to be safe and effective, particularly in focal hand dystonia, without major adverse effects. However, the quality of evidence is low at present, and long-term outcomes are unknown. High-quality prospective studies comparing MRgFUS to other surgical techniques will be useful in determining its role in the management of dystonia.

An overview of rehabilitation approaches for focal hand dystonia in musicians: A scoping review

Objective To provide a comprehensive overview of rehabilitation treatment strategies for focal hand dystonia (FHD) in musicians, examining their evolution and effectiveness. Data Sources A systematic search of five databases, PubMed, PEDro, Cochrane Library, Trip, and Google Scholar, to identify relevant articles on FHD rehabilitation. The last search was performed on 20 December 2023. Methods Inclusion criteria were applied to 190 initially identified articles, resulting in 17 articles for review. Exclusions were made for duplicates, irrelevant titles, abstracts, and non-rehabilitation interventions. Results Ten different rehabilitation approaches were identified over 20 years. While no definitive intervention protocol exists, a multimodal approach is commonly recommended. Conclusions This scoping review underscores the diversity of rehabilitation strategies for FHD. It suggests the potential of multimodal approaches, emphasizing the need for further large-scale clinical efficacy studies.

Effects of ventro-oral thalamic deep brain stimulation in a patient with musician’s dystonia: illustrative case

BACKGROUND Musician’s dystonia is a task-specific focal hand dystonia characterized by involuntary contraction of muscles while playing a musical instrument. Current treatment options are often insufficient. OBSERVATIONS We present the effects of ventro-oral thalamic deep brain stimulation in a patient with musician’s dystonia. The patient was a 67-year-old pianist with musician’s dystonia who underwent deep brain stimulation with the ventralis oralis anterior and posterior nuclei of the thalamus as targets. The Tubiana and Chamagne rating scale was used to evaluate the effects of stimulation. The outcome was evaluated independently by four clinicians in a blinded manner at 3 months postoperatively. There was a distinct reduction of symptoms during stimulation. At 15 months postoperatively, the beneficial effect remained. No lasting side effects were observed. LESSONS Further studies are warranted to evaluate the safety and long-term efficacy of this treatment modality.

Evaluation of the efficacy and safety of MRI-guided focused ultrasound (MRgFUS) for focal hand dystonia: study protocol for an open-label non-randomised clinical trial

IntroductionMRI-guided focused ultrasound (MRgFUS) thalamotomy provides an exciting development in the field of minimally invasive stereotactic neurosurgery. Current treatment options for focal hand dystonia are limited, with potentially more effective...

Unilateral focused ultrasound subthalamotomy in early Parkinson’s disease: a pilot study

BackgroundUnilateral focused ultrasound subthalamotomy (FUS-STN) improves motor features of Parkinson’s disease (PD) in moderately advanced patients. The less invasive nature of FUS makes its early application in PD feasible. We...

Muscle Ultrasound in Clinical Neurology: Diagnostic Uses and Guidance of Botulinum Toxin Injection

Muscle ultrasound (MUS) is increasingly used by neurologists, neuropediatricians, neurosurgeons, specialized radiologists and anaesthesiologists for the imaging-supported diagnosis of neuromuscular disorders. Especially, MUS is highly sensitive in detecting fasciculations in motor neuron diseases, and in revealing intensive care unit acquired weakness. Hereditary and inflammatory myopathies are associated with distinct patters of echo-intensity changes of affected muscles. Moreover, MUS can be used for guiding needle biopsy of muscle lesions, and for targeting intramuscular botulinum neurotoxin (BoNT) injection in neurological disorders with muscle hyperactivity. MUS-guidance of BoNT injection is especially recommendable in complex cervical dystonia, in task-related hand dystonia (writer’s cramp, musician dystonia), and in children and adolescents with cerebral palsy. Modern ultrasound technologies such as sono-elastography, tissue Doppler, and high-definition microvasculature imaging allow for novel diagnostic and therapeutic uses. Recently, an international expert group reported consensus guidelines for neuromuscular ultrasound training. The present review provides a concise overview of well-established diagnostic and therapeutic applications of MUS in clinical neurology, with specific focus at MUS for targeting intramuscular BoNT injections.

Anatomical categorization of isolated non-focal dystonia: novel and existing patterns using a data-driven approach.

According to expert consensus, dystonia can be classified as focal, segmental, multifocal, and generalized, based on the affected body distribution. To provide an empirical and data-driven approach to categorizing these distributions, we used a data-driven clustering approach to compare frequency and co-occurrence rates of non-focal dystonia in pre-defined body regions using the Dystonia Coalition (DC) dataset. We analyzed 1,618 participants with isolated non-focal dystonia from the DC database. The analytic approach included construction of frequency tables, variable-wise analysis using hierarchical clustering and independent component analysis (ICA), and case-wise consensus hierarchical clustering to describe associations and clusters for dystonia affecting any combination of eighteen pre-defined body regions. Variable-wise hierarchical clustering demonstrated closest relationships between bilateral upper legs (distance = 0.40), upper and lower face (distance = 0.45), bilateral hands (distance = 0.53), and bilateral feet (distance = 0.53). ICA demonstrated clear grouping for the a) bilateral hands, b) neck, and c) upper and lower face. Case-wise consensus hierarchical clustering at k = 9 identified 3 major clusters. Major clusters consisted primarily of a) cervical dystonia with nearby regions, b) bilateral hand dystonia, and c) cranial dystonia. Our data-driven approach in a large dataset of isolated non-focal dystonia reinforces common segmental patterns in cranial and cervical regions. We observed unexpectedly strong associations between bilateral upper or lower limbs, which suggests that symmetric multifocal patterns may represent a previously underrecognized dystonia subtype.

Reliability and Validity of the Embouchure Dystonia Severity Rating Scale.

Embouchure dystonia (ED) is a task-specific movement disorder that leads to loss of fine motor control of the embouchure and tongue muscles in wind musicians. In contrast to musicians' hand dystonia, no validated severity rating for ED exists, posing a major obstacle for structured assessment in scientific and clinical settings. The aim of this study is to validate an ED severity rating scale (EDSRS) allowing for a standardized estimation of symptom severity in ED. The EDSRS was set up as a composite score of six items evaluating audio-visual disease symptoms during the performance of three standardized musical tasks (sustained notes, scales, and fourths) separately for each body side. For validation, 17 musicians with ED underwent standardized audiovisual recordings during performance. Anonymized and randomized recordings were assessed by two experts in ED (raters). Statistical analysis included metrics of consistency, reliability, and construct validity with the fluctuation of the fundamental frequency of the acoustic signal (F0) (extracted in an audio analysis of the sustained notes). The EDSRS showed high internal consistency (Cronbach's α = 0.975-0.983, corrected item-total correlations r = 0.90-0.96), interrater reliability (intraclass correlation coefficient [ICC] for agreement/consistency = 0.94/0.96), intrarater reliability over time (ICC per rater = 0.93/0.87) and good precision (standard error of measurement = 2.19/2.65), and correlated significantly with F0 variability (r = 0.55-0.60, p = 0.011-0.023). The developed EDSRS is a valid and reliable tool for the assessment of ED severity in the hands of trained expert raters. Its easy applicability makes it suitable not only for routine clinical practice but also for scientific studies.

Impact of Botulinum Toxin Along with Task-Specific Training in Post-Stroke Quality of Life in Focal Hand Dystonia

Objective: To investigate the impact of BOTOX, along with task-specific training, on focal hand dystonia in post-stroke patients and to determine the correlation between quality of life and motor outcomes in upper extremity dystonic patients. Methodology: A quasi-experimental involving 20 patients, study was conducted at Holy Family Hospital (HFH), Chambeli Institute of Rehabilitation in Rawalpindi, and Neurocounsel Clinic in Islamabad. A convenient sampling technique was utilized to select participants for inclusion in the study. Assessments were conducted at four time points: baseline (0 weeks), 4 weeks, 8 weeks, and 12 weeks. The assessment tools used were the Abductor Digiti Minimi Abduction (ADDA) test, Modified Ashworth Scale (MAS), and Stroke-Specific Quality of Life (SS-QoL) questionnaire. Repeated measures ANOVA was employed to analyze mean differences in data across various weeks. The associations between scales were evaluated using Spearman's rho and Pearson correlation coefficients, based on different variables. Results: The mean age was 42.7 ± 10.45 years. The study included 14 males and 6 females. Repeated measures ANOVA indicated a significant difference between MAS scores for upper extremity and quality of life in post-stroke dystonic patients, with a p-value of 0.001**. A strong positive correlation coefficient was found between MAS and SS-QoL through Spearman's correlation analysis, with a p-value of less than 0.05. Conclusion: The administration of Type a Botulinum toxin, coupled with task-specific training, not only exhibited improvements in upper limb motor outcomes but also in the quality of life of focal hand dystonic patients after a stroke.

Abnormalities in the face primary motor cortex in oromandibular dystonia

ObjectiveTo comprehensively investigate excitability in face and hand M1 and sensorimotor integration in oromandibular dystonia (OMD) patients. MethodsShort-interval intracortical inhibition (SICI), intracortical facilitation (ICF), short (SAI) and long (LAI) afferent inhibition were investigated in face and hand M1 using transcranial magnetic stimulation protocols in 10 OMD patients. Data were compared with those obtained in 10 patients with focal hand dystonia (FHD), in 10 patients with blepharospasm (BSP), and 10 matched healthy subjects (HS). ResultsResults demonstrated that in OMD patients SICI was reduced in face M1 (p < 0.001), but not in hand M1, compared to HS. In FHD, SICI was significantly impaired in hand M1 (p = 0.029), but not in face M1. In BSP, SICI was normal in both face and hand M1 while ICF and LAI were normal in all patient groups and cortical area tested. SAI was significantly reduced (p = 0.003) only in the face M1 of OMD patients. ConclusionsIn OMD, SICI and SAI were significantly reduced. These abnormalities are specific to the motor cortical area innervating the muscular district involved in focal dystonia. SignificanceIn OMD, the integration between sensory inflow and motor output seem to be disrupted at cortical level with topographic specificity.