Cost-Utility Analysis of Deep Brain Stimulation (DBS) for Generalized and Cervical Dystonia: A Perspective from Brazilian Healthcare.

OBJECTIVE: In the Brazilian public national healthcare system, botulinum toxin type A has traditionally been the sole treatment option for patients with dystonia. However, as of October 2022, Deep Brain Stimulation (DBS) garnered positive recommendations for the condition. This study aims to assess the cost-effectiveness of DBS in treating adults with generalized and cervical dystonia within the Brazilian healthcare context, considering its recent inclusion. METHODS: A systematic review identified randomized controlled trials (RCTs) assessing DBS efficacy in treating adults with generalized and cervical dystonia. Two cost-utility analyses compared the cost-effectiveness of DBS plus the Best Clinical Practice (BCP) to BCP alone. Markov models, which included three health states (no clinical improvement, clinical improvement, and death), employed a one-year cycle and a lifetime horizon. The study utilized both one-way and probabilistic sensitivity analyses. RESULTS: Two RCTs, one for each condition, revealed superior clinical improvement with DBS when compared to sham simulation. The Incremental Cost-Utility Ratio (ICUR) was $ 1,121.66 for generalized dystonia and $4,556.50 for cervical dystonia. Effectiveness discount rates and age at surgery were identified as influential parameters. In 1,000 Monte Carlo simulations, 99.9% of the ICUR values for generalized dystonia and 74.2 % for cervical dystonia fell below the cost-effectiveness threshold in Brazil ($8,146.64 per QALY). CONCLUSIONS: From the perspective of the Brazilian public health system, the combination of DBS and BCP appears to be cost-effective for the treatment of both generalized and cervical dystonia when compared to BCP alone.

Drumming performance and underlying muscle activities in a professional rock drummer with lower-limb dystonia: a case study.

Task-specific focal dystonia (TSFD), characterized by the loss of fine motor control and coordination, affects drummers' lower-limb movements. This study explores lower-limb dystonia's impact on drumming performance and underlying muscle activity in a professional rock drummer. The drummer executed an eight-beat pattern on a drum kit. The participant reported the occurrence of symptoms when he felt the abnormality such as the loss of control related to involuntary aspects of movement. We measured the peak amplitude of the bass drumhead vibration, synchronization errors as the time elapsed between the metronome onset and the bass drum onset, and amplitude of electromyographic (EMG) recordings centered on metronome beat. Dystonia symptoms primarily manifested in the initial beat, with fewer symptoms on syncopation of the third beat. Analysis revealed decreased bass-drum peak amplitude and earlier synchronization error during the initial beat. EMG measurements of 10 muscles in the affected right lower limb showed significant changes in the Biceps Femoris (BF), Tibialis Anterior (TA), Extensor Digitorum Longus (EDL), and Extensor Digitorum Brevis (EDB) muscles during symptom onset. We observed (1) earlier overactivation of the TA and EDL muscles during the leg lift-up motion or preparatory phase of pedaling, (2) reduced activation of the EDB muscle, and (3) increased activation of the BF muscle during the final pedaling movement when symptoms occurred. These findings suggest that lower-limb dystonia symptoms are characterized by a reduction in amplitude of the bass drumhead vibration and an increase in synchronization error, potentially due to premature overactivation of the ankle dorsiflexor muscles.

Microstructure of the cerebellum and its afferent pathways underpins dystonia in myoclonus dystonia.

BACKGROUND AND PURPOSE: Myoclonus dystonia due to a pathogenic variant in SGCE (MYC/DYT-SGCE) is a rare condition involving a motor phenotype associating myoclonus and dystonia. Dysfunction within the networks relying on the cortex, cerebellum, and basal ganglia was presumed to underpin the clinical manifestations. However, the microarchitectural abnormalities within these structures and related pathways are unknown. Here, we investigated the microarchitectural brain abnormalities related to the motor phenotype in MYC/DYT-SGCE. METHODS: We used neurite orientation dispersion and density imaging, a multicompartment tissue model of diffusion neuroimaging, to compare microarchitectural neurite organization in MYC/DYT-SGCE patients and healthy volunteers (HVs). Neurite density index (NDI), orientation dispersion index (ODI), and isotropic volume fraction (ISOVF) were derived and correlated with the severity of motor symptoms. Fractional anisotropy (FA) and mean diffusivity (MD) derived from the diffusion tensor approach were also analyzed. In addition, we studied the pathways that correlated with motor symptom severity using tractography analysis. RESULTS: Eighteen MYC/DYT-SGCE patients and 24 HVs were analyzed. MYC/DYT-SGCE patients showed an increase of ODI and a decrease of FA within their motor cerebellum. More severe dystonia was associated with lower ODI and NDI and higher FA within motor cerebellar cortex, as well as with lower NDI and higher ISOVF and MD within the corticopontocerebellar and spinocerebellar pathways. No association was found between myoclonus severity and diffusion parameters. CONCLUSIONS: In MYC/DYT-SGCE, we found microstructural reorganization of the motor cerebellum. Structural change in the cerebellar afferent pathways that relay inputs from the spinal cord and the cerebral cortex were specifically associated with the severity of dystonia.

Suspected paroxysmal dyskinesia in four small-breed dogs: Clinical presentation, diagnosis, management and prognosis.

This case report details the clinical presentation, diagnosis, management and prognosis of paroxysmal dyskinesia (PD) in four small-breed dogs, each weighing under 6 kg: A 7-year-old spayed female Pomeranian, an 8-year-old female mixed breed, a 1-year-old female Pomeranian and a 9-year-old castrated male Poodle. These dogs were referred to our hospital due to movement disorders. Diagnosis was facilitated by video recordings of the episodes, assessing motor activity, consciousness, episode duration, any pre- or post-episodic behaviour as well as the presence of autonomic signs. Magnetic resonance imaging conducted on two of the dogs returned unremarkable results. Treatment trials included a gluten-free diet for all four dogs, with two also receiving acetazolamide. This intervention led to a decrease in the frequency of abnormal movement in all patients. Our findings suggest that PD in dogs can be effectively diagnosed through detailed symptom description using videos and questionnaires. Furthermore, once diagnosed, a combination of nutritional and medical management can be beneficial.

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

BACKGROUND: 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. OBJECTIVE: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

Motor imagery ability in patients with functional dystonia.

INTRODUCTION: Motor imagery (MI) involves recreating a movement mentally without physically performing the movement itself. MI has a positive impact on motor performance, motor learning and neural plasticity. We analysed the connection between motor imagination and altered movement execution in individuals with dystonia, a complex sensorimotor disorder. The aim of our study was to examine MI ability in patients with functional dystonia (FD) in comparison to organic dystonia (OD). METHODS: Our case-control study involved 46 patients, 22 with FD and 24 with OD. The assessment consisted of specific questionnaire and standardized motor, cognitive and psychiatric scales. The KVIQ-20 was used to test MI in each patient. RESULTS: Patients with FD scored lower on both global visual and kinaesthetic scales of the KVIQ-20 exam compared to patients with OD (63.1 ± 18.5 vs. 73.7 ± 13.2, and 54.9 ± 21.9 vs. 68.8 ± 18.2, respectively). Patients with FD also exhibited visual and/or kinaesthetic MI impairment in different body segments. The internal perspective when imagining movements was preferred in both patients with FD and OD. CONCLUSION: FD patients showed global dysfunction of visual and kinaesthetic MI abilities. Techniques for MI improvements might have a potential role in dystonia rehabilitation.

Wilson's Disease in Childhood and the Challenges in Its Diagnosis: A Case Report.

Wilson's disease is a genetic neurometabolic disorder affecting copper metabolism in the body. It occurs due to mutations in the ATP7B gene. Here, we report a case of a 12-year-old boy, born out of a second-degree consanguineous marriage, who presented with complaints of jaundice for the past one year, poor scholastic performance, and behavioral abnormalities for the past one month. There was a history of multiple suicides in the maternal family, and liver disorder in the maternal uncle. Various examinations revealed jaundice, Kayser-Fleischer ring in eyes, and dystonia of the extremities with hepatosplenomegaly. Copper studies were inconclusive, and neuroimaging showed characteristic findings specific for Wilson's disease. The child was treated with a low-copper diet, vitamin K, oral zinc acetate, oral D-penicillamine, trihexyphenidyl, baclofen, clonazepam, and propranolol.

Movement disorders of the stomatognathic system: A blind spot between dentistry and medicine.

Movement disorders of the stomatognathic system include oromandibular dystonia (OMD), oral dyskinesia, sleep/awake bruxism, functional (psychogenic) stomatognathic movement disorders (FSMDs), tremors, and hemimasticatory spasm (HMS). Most patients first consult dentists or oral surgeons. The differential diagnoses of these involuntary movements require both neurological and dental knowledge and experience, and some of these movement disorders are likely to be diagnosed as bruxism or temporomandibular disorders (TMDs) by dental professionals. However, excepting movement disorder specialists, neurologists may find it difficult to differentially diagnose these disorders. Patients may visit numerous medical and dental specialties for several years until a diagnosis is made. Therefore, movement disorders of the oral region may represent a blind spot between dentistry and medicine.The present narrative review aimed to describe the clinical characteristics and differential diagnoses of some movement disorders, as well as the problems bridging dentistry and medicine. Movement disorders have the following characteristic clinical features: OMD - task specificity, sensory tricks and the morning benefit; FSMDs - inconsistent and incongruous symptoms, spreading to multiple sites and the lack of sensory tricks; and HMS - the paroxysmal contraction of unilateral jaw-closing muscles, the persistence of symptoms during sleep and the loss of a silent period. A careful differential diagnosis is essential for the adequate and effective treatment of each involuntary movement. Refining the latest definition of bruxism may be necessary to prevent the misdiagnosis of involuntary movements as bruxism.Both dental and medical professionals should take an interest in the movement disorders of the stomatognathic system, and these disorders should be diagnosed and treated by a multidisciplinary team.

IRF2BPL-Related Disorder, Causing Neurodevelopmental Disorder with Regression, Abnormal Movements, Loss of Speech and Seizures (NEDAMSS) Is Characterized by Pathology Consistent with DRPLA.

BACKGROUND: Childhood neurodegenerative diseases often pose a challenge to clinicians to diagnose because of the degree of genetic heterogeneity and variable presentations. Here, we present a child with progressive neurodegeneration consisting of spasticity, dystonia, and ataxia in which postmortem pathological analysis led to the diagnosis of interferon regulatory factor 2 binding protein like (IRF2BPL)-related disorder. METHODS: Detailed postmortem gross and histological examination was conducted, and findings consistent with dentatorubral-pallidoluysian atrophy (DRPLA) and included polyglutamine (polyQ) inclusions. Follow up testing for the CAG repeat expansion at ATN1 was non-diagnostic. RESULTS: Subsequent exome sequencing reanalysis of the research exome identified a pathogenic de novo IRF2BPL variant. The IRF2BPL c.562C>T, p.(Arg188Ter) variant, distal to the polyQ repeat tract, results in variable mRNA levels depending on the cell type examined with decreased mRNA in the brain, as well as destabilization of the protein product and corresponding downstream molecular abnormalities in patient derived cells. CONCLUSION: We provide the first detailed pathological description for IRF2BPL-related disorder, termed NEDAMSS (neurodevelopmental disorder with regression, abnormal movements, loss of speech and seizures; Mendelian Inheritance in Man, 618088) and evidence for the inclusion of this condition in the differential diagnosis of spastic-ataxic neurodegenerative conditions, reminiscent of DRPLA. Although the individuals with NEDAMSS do not carry an expansion, the polyQ repeat tract may play a role in the pathological inclusions that would represent a novel disease mechanism for polyQ repeats. © 2024 International Parkinson and Movement Disorder Society.

Phenomenological patterns and aetiological spectrum in patients visiting a tertiary care Movement disorders service in India: An observational study.

OBJECTIVE: Although previous studies have described phenomenological diagnoses, they lacked description of aetiological spectrum in patients visiting movement disorders (MD) service. Herein, we classify the MD phenomenology and describe aetiology wise distribution of each phenomenology in patients visiting a tertiary care movement disorders service. METHODS: Collected information included demographic profile (age of onset, age at presentation, gender, duration of illness before presentation), predominant MD phenomenology [such as parkinsonism, dystonia, ataxia, tremor, chorea, ballism, myoclonus, tics, stereotypy, restless legs syndrome (RLS) and others], diagnostic evaluations and detected aetiology. RESULTS: This observational study included 1140 MD patients over a span of 5 years. The median (IQR) age of onset was 49 (35-60) years and age at presentation was 54 (40-65) years, with median duration of illness being 36 (18-72) months. Nearly two-third of patients were males (M:F=731:409). Parkinsonism (n=494, 43.3 %) was the most common MD phenomenology observed, followed by dystonia (n=219, 19.2 %), ataxia (n=125, 11 %), tremor (n=118, 10.4 %), myoclonus (n=73, 6.4 %), chorea (n=40, 3.5 %), spasticity (n=22, 1.9 %), tics (n=8, 0.7 %), and RLS (n=8, 0.7 %). Thirty-three (2.9 %) patients were grouped under miscellaneous MDs. Overall, neurodegenerative disorders (57.4 %) were the most common cause of MDs. Parkinson's disease, genetic dystonia, essential tremor, genetic ataxias, hemifacial spasm, and Huntington's disease were the most common aetiologies for parkinsonism, dystonia, tremor, ataxia, myoclonus, and chorea, respectively. CONCLUSION: Parkinsonism was the most common phenomenology observed in MD patients, and was followed by dystonia, ataxia and tremor. Neurodegenerative disorders were the most common aetiology detected.

Pallidal and Thalamic Deep Brain Stimulation in the Treatment of Unilateral Dystonia: A Prospective Assessment.

BACKGROUND: The complexities of unilateral dystonia have led to exploring simultaneous (dual) globus pallidus internus (GPi) and motor ventral thalamus (Vim/Vop) deep brain stimulation (DBS), yet detailed assessments are lacking. OBJECTIVES: To assess the efficacy of GPi, Vim/Vop, and dual DBS in unilateral dystonia. METHODS: Three patients with unilateral dystonia (two idiopathic, one acquired), implanted with two DBS electrodes targeting ipsilateral Vim/Vop and GPi, were included. Three stimulation modalities were assessed. First, one electrode was activated, then the other, and finally, both electrodes were activated simultaneously. RESULTS: DBS yielded substantial symptomatic reductions in all three evaluated stimulation modalities. Patients exhibited varying responses regarding quality-of-life and depressive symptoms. Treatment satisfaction didn't align with clinical improvements, potentially affected by unrealistic expectations. CONCLUSIONS: This study contributes critical insights into GPi, Vim/Vop and simultaneous stimulation for unilateral dystonia. The safety of the procedure underscores the promise of this approach.

Management of neurological symptoms in Lesch-Nyhan disease: A systematic review.

Lesch-Nyhan Disease (LND) is an X-linked recessive genetic disorder arising from hypoxanthine phosphoribosyltransferase 1 gene mutations, leading to a complete deficiency. LND presents a complex neurological profile characterized by generalized dystonia, motor dysfunctions and self-injurious behavior, which management is challenging. We conducted a systematic review of studies assessing the efficacy of pharmacological and non-pharmacological interventions in management of neurological symptoms in LND (PROSPERO registration number:CRD42023446513). Among 34 reviewed full-text papers; 22 studies were rated as having a high risk of bias. Considerable heterogeneity was found in studies regarding the timing of treatment implementation, adjunctive treatments and outcome assessment. Single-patient studies and clinical trials often showed contradictory results, while therapeutic failures were underreported. S-Adenosylmethionine and Deep Brain Stimulation were the most studied treatment methods and require further research to address inconsistencies. The evidence from levodopa studies underlines that optimal timing of treatment implementation should be thoroughly investigated. Standardized study design and reducing publication bias are crucial to overcome current limitations of assessing intervention efficacy in LND.

Central Mechanisms and Pathophysiology of Laryngeal Dystonia: An Up-to-Date Review.

OBJECTIVE: Laryngeal dystonia (LD), previously termed spasmodic dysphonia, is an isolated focal dystonia that involves involuntary, uncontrolled contractions of the laryngeal muscles during speech. It is a severely disabling condition affecting patients' work and social lives through prevention of normal speech production. Our understanding of the pathophysiology of LD and available therapeutic options are currently limited. The aim of this short review is to provide an up-to-date summary of what is known about the central mechanisms and the pathophysiology of LD. METHODS: A systematic review of the literature was performed searching Embase, CINHAL, Medline, and Cochrane with the cover period January 1990-October 2023 with a search strategy (("Laryngeal dystonia" OR "Spasmodic dysphonia") AND ("Central Mechanism" OR "Pathophysiology")). Original studies involving LD patients that discussed central mechanisms and/or pathophysiology of LD were chosen. RESULTS: Two hundred twenty-six articles were identified of which 27 articles were included to formulate this systematic review following the screening inclusion and exclusion criteria. LD is a central neurological disorder involving a multiregional altered neural network. Affected neural circuits not only involve the motor control circuit, but also the feedforward, and the feedback circuits of the normal speech production neural network, involving higher-order planning, somatosensory perception and integration regions of the brain. CONCLUSION: Speech production is a complex process, and LD is a central neurological disorder involving multiregional neural network connectivity alteration reflecting this. Neuromodulation targeting the central nervous system could therefore be considered and explored as a new potential therapeutic option for LD in the future, and should assist in elucidating the underlying central mechanisms responsible for causing the condition.

Thalamic ventral-Oralis complex/rostral zona incerta deep brain stimulation for midline tremor.

BACKGROUND: Midline Tremor is defined as an isolated or combined tremor that affects the neck, trunk, jaw, tongue, and/or voice and could be part of Essential Tremor (ET), or dystonic tremor. The clinical efficacy of deep brain stimulation for Midline Tremor has been rarely reported. The Ventral Intermediate Nucleus and Globus Pallidus Internus are the preferred targets, but with variable outcomes. Thalamic Ventral-Oralis (VO) complex and Zona Incerta (ZI) are emerging targets for tremor control in various etiologies. OBJECTIVE: To report on neuroradiological, neurophysiological targeting and long-term efficacy of thalamic Ventral-Oralis complex and Zona Incerta deep brain stimulation in Midline Tremor. METHODS: Three patients (two males and one female) with Midline Tremor in dystonic syndromes were recruited for this open-label study. Clinical, surgical, neurophysiological intraoperative testing and long-term follow-up data are reported. RESULTS: Intraoperative testing and reconstruction of volume of tissue activated confirmed the position of the electrodes in the area stimulated between the thalamic Ventral-Oralis complex and Zona Incerta in all patients. All three patients showed optimal control of both tremor and dystonic features at short-term (6 months) and long-term follow-up (up to 6 years). No adverse events occurred. CONCLUSION: In the syndromes of Midline Tremor of various origins, the best target for DBS might be difficult to identify. Our results showed that thalamic Ventral-Oralis complex/Zona Incerta may be a viable and safe option even in specific forms of tremor with axial distribution.

Neural correlates of anxiety in adult-onset isolated dystonia.

Psychiatric disturbances are commonly associated with adult-onset isolated dystonia (AOID); however, the mechanisms underlying psychiatric abnormalities in AOID remain unknown. We aimed to investigate the structural and functional brain changes in AOID patients with anxiety, and identify imaging biomarkers for diagnosing anxiety. Structural and functional magnetic resonance was performed on 69 AOID patients and 35 healthy controls (HCs). The Hamilton Anxiety Scale (HAMA) was used to assess anxiety symptoms in AOID patients and assign patients to AOID with and without anxiety groups. Group differences in grey matter volume, amplitude of low-frequency fluctuations (ALFF), fractional ALFF, and regional homogeneity (ReHo) were evaluated. Area under the receiver operating characteristic curve (ROC AUC) was used as a metric to identify imaging biomarkers for diagnosing anxiety. AOID patients with anxiety exhibited an increased ALFF and ReHo in the left angular gyrus (ANG.L) compared with those without and HCs (voxel P<0.001 and cluster P<0.05, corrected using GRF). A significant positive correlation was observed between ALFF (r = 0.627, P<0.001) and ReHo (r = 0.515, P<0.001) in the ANG.L and HAMA scores in AOID patients. ALFF and ReHo in the ANG.L exhibited an ROC AUC of 0.904 and 0.851, respectively, in distinguishing AOID patients with anxiety from those without and an ROC AUC of 0.887 and 0.853, respectively, in distinguishing AOID patients with anxiety from HCs. These findings provide new insights into the pathophysiology of psychiatric disturbances and highlight potential candidate biomarkers for identifying anxiety in AOID patients.

BDNF-Regulated Modulation of Striatal Circuits and Implications for Parkinson's Disease and Dystonia.

Neurotrophins, particularly brain-derived neurotrophic factor (BDNF), act as key regulators of neuronal development, survival, and plasticity. BDNF is necessary for neuronal and functional maintenance in the striatum and the substantia nigra, both structures involved in the pathogenesis of Parkinson's Disease (PD). Depletion of BDNF leads to striatal degeneration and defects in the dendritic arborization of striatal neurons. Activation of tropomyosin receptor kinase B (TrkB) by BDNF is necessary for the induction of long-term potentiation (LTP), a form of synaptic plasticity, in the hippocampus and striatum. PD is characterized by the degeneration of nigrostriatal neurons and altered striatal plasticity has been implicated in the pathophysiology of PD motor symptoms, leading to imbalances in the basal ganglia motor pathways. Given its essential role in promoting neuronal survival and meditating synaptic plasticity in the motor system, BDNF might have an important impact on the pathophysiology of neurodegenerative diseases, such as PD. In this review, we focus on the role of BDNF in corticostriatal plasticity in movement disorders, including PD and dystonia. We discuss the mechanisms of how dopaminergic input modulates BDNF/TrkB signaling at corticostriatal synapses and the involvement of these mechanisms in neuronal function and synaptic plasticity. Evidence for alterations of BDNF and TrkB in PD patients and animal models are reviewed, and the potential of BDNF to act as a therapeutic agent is highlighted. Advancing our understanding of these mechanisms could pave the way toward innovative therapeutic strategies aiming at restoring neuroplasticity and enhancing motor function in these diseases.