Digital markers of motor speech impairments in spontaneous speech of patients with ALS-FTD spectrum disorders

OBJECTIVE

To evaluate automated digital speech measures, derived from spontaneous speech (picture descriptions), in assessing bulbar motor impairments in patients with ALS-FTD spectrum disorders (ALS-FTSD).

METHODS

Automated vowel algorithms were employed to extract two vowel acoustic measures: vowel space area (VSA), and mean second formant slope (F2 slope). Vowel measures were compared between ALS with and without clinical bulbar symptoms (ALS + bulbar (n = 49, ALSFRS-r bulbar subscore: x¯ = 9.8 (SD = 1.7)) vs. ALS-nonbulbar (n = 23), behavioral variant frontotemporal dementia (bvFTD, n = 25) without a motor syndrome, and healthy controls (HC, n = 32). Correlations with bulbar motor clinical scales, perceived listener effort, and MRI cortical thickness of the orobuccal primary motor cortex (oral PMC) were examined. We compared vowel measures to speaking rate, a conventional metric for assessing bulbar dysfunction.

RESULTS

ALS + bulbar had significantly reduced VSA and F2 slope than ALS-nonbulbar (|d|=0.94 and |d|=1.04, respectively), bvFTD (|d|=0.89 and |d|=1.47), and HC (|d|=0.73 and |d|=0.99). These reductions correlated with worse bulbar clinical scores (VSA: R = 0.33, p = 0.043; F2 slope: R = 0.38, p = 0.011), greater listener effort (VSA: R=-0.43, p = 0.041; F2 slope: p > 0.05), and cortical thinning in oral PMC (F2 slope: β = 0.0026, p = 0.017). Vowel measures demonstrated greater sensitivity and specificity for bulbar impairment than speaking rate, while showing independence from cognitive and respiratory impairments.

CONCLUSION

Automatic vowel measures are easily derived from a brief spontaneous speech sample, are sensitive to mild-moderate stage of bulbar disease in ALS-FTSD, and may present better sensitivity to bulbar impairment compared to traditional assessments such as speaking rate.

Myoclonus and Dystonia as Recurrent Presenting Features in Patients with the SCA21-Associated TMEM240 p.Pro170Leu Variant

Background

Spinocerebellar ataxia 21 (SCA21) is a rare neurological disorder caused by heterozygous variants in TMEM240. A growing, yet still limited number of reports suggested that hyperkinetic movements should be considered a defining component of the disease.

Case Series

We describe two newly identified families harboring the recurrent pathogenic TMEM240 p.Pro170Leu variant. Both index patients and the mother of the first proband developed movement disorders, manifesting as myoclonic dystonia and action-induced dystonia without co-occurring ataxia in one case, and pancerebellar syndrome complicated by action-induced dystonia in the other. We reviewed the literature on TMEM240 variants linked to hyperkinetic disorders, comparing our cases to described phenotypes.

Discussion

Adding to prior preliminary observations, our series highlights the relevance of hyperkinetic movements as clinically meaningful features of SCA21. TMEM240 mutation should be included in the differential diagnosis of myoclonic dystonia and ataxia-dystonia syndromes.

RANBP17 Overexpression Restores Nucleocytoplasmic Transport and Ameliorates Neurodevelopment in Induced DYT1 Dystonia Motor Neurons

DYT1 dystonia is a debilitating neurological movement disorder, and it represents the most frequent and severe form of hereditary primary dystonia. There is currently no cure for this disease due to its unclear pathogenesis. In our previous study utilizing patient-specific motor neurons (MNs), we identified distinct cellular deficits associated with the disease, including a deformed nucleus, disrupted neurodevelopment, and compromised nucleocytoplasmic transport (NCT) functions. However, the precise molecular mechanisms underlying these cellular impairments have remained elusive. In this study, we revealed the genome-wide changes in gene expression in DYT1 MNs through transcriptomic analysis. We found that those dysregulated genes are intricately involved in neurodevelopment and various biological processes. Interestingly, we identified that the expression level of RANBP17, a RAN-binding protein crucial for NCT regulation, exhibited a significant reduction in DYT1 MNs. By manipulating RANBP17 expression, we further demonstrated that RANBP17 plays an important role in facilitating the nuclear transport of both protein and transcript cargos in induced human neurons. Excitingly, the overexpression of RANBP17 emerged as a substantial mitigating factor, effectively restoring impaired NCT activity and rescuing neurodevelopmental deficits observed in DYT1 MNs. These findings shed light on the intricate molecular underpinnings of impaired NCT in DYT1 neurons and provide novel insights into the pathophysiology of DYT1 dystonia, potentially leading to the development of innovative treatment strategies.

Phenotype and natural history of mitochondrial membrane protein-associated neurodegeneration

Mitochondrial membrane protein-associated neurodegeneration (MPAN) is an ultraorphan neurogenetic disease from the group of neurodegeneration with brain iron accumulation (NBIA) disorders. Here we report cross-sectional and longitudinal data to define the phenotype, to assess disease progression and to estimate sample sizes for clinical trials. We enrolled patients with genetically confirmed MPAN from the Treat Iron-Related Childhood-Onset Neurodegeneration (TIRCON) registry and cohort study, and from additional sites. Linear mixed-effect modelling (LMEM) was used to calculate annual progression rates for the Unified Parkinson's Disease Rating Scale (UPDRS), Barry-Albright Dystonia (BAD) scale, Schwab and England Activities of Daily Living (SE-ADL) scale and the Pediatric Quality of Life Inventory (PedsQL). We investigated 85 MPAN patients cross-sectionally, with functional outcome data collected in 45. Median age at onset was 9 years and the median diagnostic delay was 5 years. The most common findings were gait disturbance (99%), pyramidal involvement (95%), dysarthria (90%), vision disturbances (82%), with all but dysarthria presenting early in the disease course. After 16 years with the disease, 50% of patients were wheelchair dependent. LMEM showed an annual progression rate of 4.5 points in total UPDRS. The total BAD scale score showed no significant progression over time. The SE-ADL scale and the patient- and parent-reported PedsQL showed a decline of 3.9%, 2.14 and 2.05 points, respectively. No patient subpopulations were identified based on longitudinal trajectories. Our cross-sectional results define the order of onset and frequency of symptoms in MPAN, which will inform the diagnostic process, help to shorten diagnostic delay and aid in counselling patients, parents and caregivers. Our longitudinal findings define the natural history of MPAN, reveal the most responsive outcomes and highlight the need for an MPAN-specific rating approach. Our sample size estimations inform the design of upcoming clinical trials.

An Evidence-Based Update on Anticholinergic Use for Drug-Induced Movement Disorders

Drug-induced movement disorders (DIMDs) are associated with use of dopamine receptor blocking agents (DRBAs), including antipsychotics. The most common forms are drug-induced parkinsonism (DIP), dystonia, akathisia, and tardive dyskinesia (TD). Although rare, neuroleptic malignant syndrome (NMS) is a potentially life-threatening consequence of DRBA exposure. Recommendations for anticholinergic use in patients with DIMDs were developed on the basis of a roundtable discussion with healthcare professionals with extensive expertise in DIMD management, along with a comprehensive literature review. The roundtable agreed that "extrapyramidal symptoms" is a non-specific term that encompasses a range of abnormal movements. As such, it contributes to a misconception that all DIMDs can be treated in the same way, potentially leading to the misuse and overprescribing of anticholinergics. DIMDs are neurobiologically and clinically distinct, with different treatment paradigms and varying levels of evidence for anticholinergic use. Whereas evidence indicates anticholinergics can be effective for DIP and dystonia, they are not recommended for TD, akathisia, or NMS; nor are they supported for preventing DIMDs except in individuals at high risk for acute dystonia. Anticholinergics may induce serious peripheral adverse effects (e.g., urinary retention) and central effects (e.g., impaired cognition), all of which can be highly concerning especially in older adults. Appropriate use of anticholinergics therefore requires careful consideration of the evidence for efficacy (e.g., supportive for DIP but not TD) and the risks for serious adverse events. If used, anticholinergic medications should be prescribed at the lowest effective dose and for limited periods of time. When discontinued, they should be tapered gradually.

The blink reflex and its modulation - Part 2: Pathophysiology and clinical utility

The blink reflex (BR) is integrated at the brainstem; however, it is modulated by inputs from various structures such as the striatum, globus pallidus, substantia nigra, and nucleus raphe magnus but also from afferent input from the peripheral nervous system. Therefore, it provides information about the pathophysiology of numerous peripheral and central nervous system disorders. The BR is a valuable tool for studying the integrity of the trigemino-facial system, the relevant brainstem nuclei, and circuits. At the same time, some neurophysiological techniques applying the BR may indicate abnormalities involving structures rostral to the brainstem that modulate or control the BR circuits. This is a state-of-the-art review of the clinical application of BR modulation; physiology is reviewed in part 1. In this review, we aim to present the role of the BR and techniques related to its modulation in understanding pathophysiological mechanisms of motor control and pain disorders, in which these techniques are diagnostically helpful. Furthermore, some BR techniques may have a predictive value or serve as a basis for follow-up evaluation. BR testing may benefit in the diagnosis of hemifacial spasm, dystonia, functional movement disorders, migraine, orofacial pain, and psychiatric disorders. Although the abnormalities in the integrity of the BR pathway itself may provide information about trigeminal or facial nerve disorders, alterations in BR excitability are found in several disease conditions. BR excitability studies are suitable for understanding the common pathophysiological mechanisms behind various clinical entities, elucidating alterations in top-down inhibitory systems, and allowing for follow-up and quantitation of many neurological syndromes.

Effects of onabotulinum toxin type A injections in patients with Meige's syndrome

BACKGROUND

 Meige's syndrome is a type of facial dystonia characterized by the simultaneous occurrence of blepharospasm and oromandibular dystonia. Although botulinum toxin type A (OBTA) injections are the standard treatment, evidence of their effectiveness and safety in this scenario is still lacking.

OBJECTIVE

 Our research aimed to evaluate the improvement and occurrence of side effects following injections of onabotulinum toxin type A (OBTA) in patients with Meige's syndrome.

METHODS

 Patients with Meige's syndrome undergoing botulinum toxin injections were enrolled in this study. We assessed dystonia intensity before and 14 days after OBTA injection using the Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS) to measure the response of symptoms in the eyes (blepharospasm) and mouth (oromandibular dystonia). Other variables, such as dosage, side effects, and demographic data, were also recorded.

RESULTS

 The study included 41 participants, with a mean age of 67.7 years and a female-to-male ratio of 3.5:1. The mean BFMDRS score before the injections was 8.89, and after 14 days, it was 2.88. The most reported side effect was ptosis, with a 7.3% incidence. OBTA significantly reduced dystonia severity (p < 0.0001). The clinical response for the blepharospasm component was superior to the oromandibular dystonia component.

CONCLUSION

 Our results support that OBTA seems to be an effective and safe therapeutic option for treating Meige's syndrome. The effect of OBTA was more pronounced in the treatment of blepharospasm than in oromandibular dystonia.

The integrated stress response pathway and neuromodulator signaling in the brain: lessons learned from dystonia

The integrated stress response (ISR) is a highly conserved biochemical pathway involved in maintaining proteostasis and cell health in the face of diverse stressors. In this Review, we discuss a relatively noncanonical role for the ISR in neuromodulatory neurons and its implications for synaptic plasticity, learning, and memory. Beyond its roles in stress response, the ISR has been extensively studied in the brain, where it potently influences learning and memory, and in the process of synaptic plasticity, which is a substrate for adaptive behavior. Recent findings demonstrate that some neuromodulatory neuron types engage the ISR in an "always-on" mode, rather than the more canonical "on-demand" response to transient perturbations. Atypical demand for the ISR in neuromodulatory neurons introduces an additional mechanism to consider when investigating ISR effects on synaptic plasticity, learning, and memory. This basic science discovery emerged from a consideration of how the ISR might be contributing to human disease. To highlight how, in scientific discovery, the route from starting point to outcomes can often be circuitous and full of surprise, we begin by describing our group's initial introduction to the ISR, which arose from a desire to understand causes for a rare movement disorder, dystonia. Ultimately, the unexpected connection led to a deeper understanding of its fundamental role in the biology of neuromodulatory neurons, learning, and memory.

Emergence of lingual dystonia and strabismus in early-onset SCN8A self-limiting familial infantile epilepsy

Pathogenic variants in SCN8A are associated with a broad phenotypic spectrum, including Self-Limiting Familial Infantile Epilepsy (SeLFIE), characterized by infancy-onset age-related seizures with normal development and cognition. Movement disorders, particularly paroxysmal kinesigenic dyskinesia typically arising after puberty, may represent another core symptom. We present the case of a 1-year-old girl with a familial disposition to self-limiting focal seizures from the maternal side and early-onset orofacial movement disorders associated with SCN8A-SeLFIE. Brain MRI was normal. Genetic testing revealed a maternally inherited SCN8A variant [c.4447G > A; p.(Glu1483Lys)]. After the introduction of valproic acid, she promptly achieved seizure control as well as complete remission of strabismus and a significant decrease in episodes of tongue deviation. Family history, genetic findings, and epilepsy phenotype are consistent with SCN8A-SeLFIE. Movement disorders are an important part of the SCN8A phenotypic spectrum, and this case highlights the novel early-onset orofacial movement disorders associated with this condition. The episodes of tongue deviation and protrusion suggest focal oromandibular (lingual) dystonia. Additionally, while infantile strabismus or esophoria is a common finding in healthy individuals, our case raises the possibility of an ictal origin of the strabismus. This study underscores the importance of recognizing and addressing movement disorders in SCN8A-SeLFIE patients, particularly the rare early-onset orofacial manifestations. It adds to the growing body of knowledge regarding the diverse clinical presentations of SCN8A-associated disorders and suggests potential avenues for clinical management and further research.

Structural brain heterogeneity underlying symptomatic and asymptomatic genetic dystonia: a multimodal MRI study

BACKGROUND

Most of DYT genotypes follow an autosomal dominant inheritance pattern with reduced penetrance; the mechanisms underlying the disease development remain unclear. The objective of the study was to investigate cortical thickness, grey matter (GM) volumes and white matter (WM) alterations in asymptomatic (DYT-A) and symptomatic dystonia (DYT-S) mutation carriers.

METHODS

Eight DYT-A (four DYT-TOR1A and four DYT-THAP1), 14 DYT-S (seven DYT-TOR1A, and seven DYT-THAP1), and 37 matched healthy controls underwent 3D T1-weighted and diffusion tensor (DT) MRI to study cortical thickness, cerebellar and basal ganglia GM volumes and WM microstructural changes.

RESULTS

DYT-S showed thinning of the frontal and motor cortical regions related to sensorimotor and cognitive processing, together with putaminal atrophy and subcortical microstructural WM damage of both motor and extra-motor tracts such as cerebral peduncle, corona radiata, internal and external capsule, temporal and orbitofrontal WM, and corpus callosum. DYT-A had cortical thickening of middle frontal areas and WM damage of the corona radiata.

CONCLUSIONS

DYT genes phenotypic expression is associated with alterations of both motor and extra-motor WM and GM regions. Asymptomatic genetic status is characterized by a very subtle affection of the WM motor pathway, together with an increased cortical thickness of higher-order frontal regions that might interfere with phenotypic presentation and disease manifestation.

Abnormal supplementary motor areas are associated with idiopathic and acquired blepharospasm

Blepharospasm is a common form of focal dystonia characterized by excessive and involuntary spasms of the orbicularis oculi. In addition to idiopathic blepharospasm, lesions in various brain regions can also cause acquired blepharospasm. Whether these two types of blepharospasm share a common brain network remains largely unknown. Herein, we performed lesion coactivation network mapping, based on meta-analytic connectivity modeling, to test whether lesions causing blepharospasm could be mapped to a common coactivation brain network. We then tested the abnormality of the network in patients with idiopathic blepharospasm (n = 42) compared with healthy controls (n = 44). We identified 21 cases of lesion-induced blepharospasms through a systematic literature search. Although these lesions were heterogeneous, they were part of a co-activated brain network that mainly included the bilateral supplementary motor areas. Coactivation of these regions defines a single brain network that encompasses or is adjacent to most heterogeneous lesions causing blepharospasm. Moreover, the bilateral supplementary motor area is primarily associated with action execution, visual motion, and imagination, and participates in finger tapping and saccades. They also reported decreased functional connectivity with the left posterior cingulate cortex in patients with idiopathic blepharospasm. These results demonstrate a common convergent abnormality of the supplementary motor area across idiopathic and acquired blepharospasms, providing additional evidence that the supplementary motor area is an important brain region that is pathologically impaired in patients with blepharospasm.

Content overlap of 91 dystonia symptoms among the seven most commonly used cervical dystonia scales

INTRODUCTION

Dystonia is a movement disorder characterized by sustained or intermittent muscle contractions. Cervical dystonia (CD) is the most common focal dystonia. There are several instruments assessing the symptoms of CD. However, different scales assess different features which may lead to poor patient evaluation.

AIM

The aim of the study was to evaluate the degree of overlap of most often used CD rating scales identified by the literature review.

METHODS

A thorough search of the Medline database was conducted in September 2021. Then the frequency of each scale was calculated, and 7 most common scales were included in the content overlap analysis using Jaccard index (0 - no overlap, 1 - full overlap).

RESULTS

Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS), Tsui score, Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS), Cervical Dystonia Impact Profile 58 (CDIP-58), Craniocervical Dystonia Questionnaire 24 (CDQ-24), Cervical Dystonia Severity Rating Scale (CDSS), Cervical Dystonia Severity Rating Scale (DDS) and The Dystonia Non-Motor Symptoms Questionnaire (DNMSQuest) were the most common scales. 91 CD symptoms were distinguished from 134 items used in the scales. The mean overlap among all scales was 0.17. 52 (62%) symptoms were examined by more than one scale. The CIDP-58 captured the highest number of symptoms (63.0%), while the CDSS captured the lowest number (8.0%). None of the symptoms were examined by seven instruments.

CONCLUSIONS

There was a very weak overlap among scales. High inconsistency between the scales may lead to highly different dystonia severity assessment in clinical practice. Thus, the instruments should be combined.

Genetic Update and Treatment for Dystonia

A neurological condition called dystonia results in abnormal, uncontrollable postures or movements because of sporadic or continuous muscular spasms. Several varieties of dystonia can impact people of all ages, leading to severe impairment and a decreased standard of living. The discovery of genes causing variations of single or mixed dystonia has improved our understanding of the disease's etiology. Genetic dystonias are linked to several genes, including pathogenic variations of VPS16, TOR1A, THAP1, GNAL, and ANO3. Diagnosis of dystonia is primarily based on clinical symptoms, which can be challenging due to overlapping symptoms with other neurological conditions, such as Parkinson's disease. This review aims to summarize recent advances in the genetic origins and management of focal dystonia.

Impact of Physiotherapy in the Treatment of Pain in Cervical Dystonia

Background

Cervical dystonia (CD) is the most common form of focal dystonia in adults. Studies show that physiotherapy (PT) in combination with BoNT has an effect on pain in cervical dystonia. We intended to test this hypothesis in a real-world setting to answer the question of whether pain is a good target symptom for prescribing PT. We also aimed to assess which form of PT is most appropriate for the treatment of pain.

Methods

Study design: cross-sectional survey-based study of 91 patients with a confirmed diagnosis of cervical dystonia. The survey consisted of a questionnaire on type, frequency and content of physiotherapy, an assessment of quality of life with the Craniocervical Dystonia Questionnaire 24 (CDQ 24) and subjective pain scores.

Results

53.8% of patients received physiotherapy, mostly a mixture of exercises to either correct the abnormal posture or to reduce the muscle tone. Additional therapies included stress-reducing exercises (14.3%), psychotherapy (9.9%) and EMG biofeedback (2.2%). Patients who received PT showed a non-significant tendency towards higher pain scores. The severity of dystonia-associated pain was significantly associated with the patients' quality of life (F (1,54) = 22.9, adjusted R2 = 0.286, p < 0.001).

Discussion

Pain is a frequent problem in patients with CD and severely affects quality of life. Physiotherapy could therefore be a valuable treatment option for patients with CD and pain.

Highlights

Our uncontrolled study illustrates the high frequency of physiotherapy in addition to BoNT treatment in a real-life cohort of patients with cervical dystonia. We were able to show that PT reduces patients' perceived pain in a patient reported outcome measure. This highlights the importance of PT in reducing CD-related pain, which considerably impairs quality of life.

Intraventricular baclofen for palliative management of acquired generalized dystonia in pediatric patients: a case series and literature review

Dystonia represents a significant source of disability in children. Generalized dystonia, which involves multiple body regions, leads to impaired mobility and motor function, resulting in substantial challenges in daily activities. Surgical treatments are used when medical treatments fail. Intrathecal baclofen (ITB) or deep brain stimulations (DBS) are the most employed surgical therapies. When these options are not feasible or ineffective, some authors have explored the use of intraventricular baclofen (IVB). In this report, we present four cases of pediatric patients with generalized dystonia who underwent treatment with IVB, resulting in notable improvements. To further explore the potential of this treatment modality, we conducted a comprehensive literature review. The findings from our study provide a comprehensive overview that can guide palliative management in similar cases.

Cervical motion alterations and brain functional connectivity in cervical dystonia

INTRODUCTION

Evaluating the neural correlates of sensorimotor control deficits in cervical dystonia (CD) is fundamental to plan the best treatment. This study aims to assess kinematic and resting-state functional connectivity (RS-FC) characteristics in CD patients relative to healthy controls.

METHODS

Seventeen CD patients and 14 age-/sex-matched healthy controls were recruited. Electromagnetic sensors were used to evaluate dystonic pattern, mean/maximal cervical movement amplitude and joint position error with eyes open and closed, and movement quality during target reaching with the head. RS-fMRI was acquired to compare the FC of brain sensorimotor regions between patients and controls. In patients, correlations between motion analysis and FC data were assessed.

RESULTS

CD patients relative to controls showed reduced mean and maximal cervical range of motion (RoM) in rotation both towards and against dystonia pattern and reduced total RoM in rotation both with eyes open and closed. They had less severe dystonia pattern with eyes open vs eyes closed. CD patients showed an altered movement quality and sensorimotor control during target reaching and a higher joint position error. Compared to controls, CD patients showed reduced FC between supplementary motor area (SMA), occipital and cerebellar areas, which correlated with lower cervical RoM in rotation both with eyes open and closed and with worse movement quality during target reaching.

CONCLUSIONS

FC alterations between SMA and occipital and cerebellar areas may represent the neural basis of cervical sensorimotor control deficits in CD patients. Electromagnetic sensors and RS-fMRI might be promising tools to monitor CD and assess the efficacy of rehabilitative interventions.

The natural course of idiopathic cervical dystonia

Idiopathic cervical dystonia (ICD) is by far the largest subgroup of dystonia. Still, its natural course is largely unknown. We studied the natural course of 100 ICD patients from our botulinum toxin clinics (age at ICD onset 45.8 ± 13.5 years, female/male ratio 2.0) over a period of 17.5 ± 11.5 years with follow-ups during botulinum toxin therapy and with semi-structured interviews. Two courses of ICD could be distinguished by symptom development of more or less than 6 months. ICD-type 2 was less frequent (19% vs 81%, p < 0.001), had a more rapid onset (8.7 ± 8.0 weeks vs 3.8 ± 3.5 years), a higher remission rate (92% vs 5%, p < 0.001) and a higher prevalence of excessive psychological stress preceding ICD (63% vs 1%, p < 0.001). In both ICD-types, the plateau phase was non-progressive. Significant differences in patient age at ICD onset, latency and extent of remission, female/male ratio and prevalence of family history of dystonia could not be detected. ICD is a non-progressive disorder. ICD-type 1 represents the standard course. ICD-type 2 features rapid onset, preceding excessive psychological stress and a high remission rate. These findings will improve prognosis, treatment strategies and understanding of underlying disease mechanisms. They contradict the widespread fear of patients of a constant and continued decline of their condition. Excessive psychological stress may be an epigenetic factor triggering the manifestation of genetically predetermined dystonia.

Task-related brain activity in upper limb dystonia revealed by simultaneous fNIRS and EEG

OBJECTIVE

The aim of this study was to explore differences in brain activity and connectivity using simultaneous electroencephalography and near-infrared spectroscopy in patients with focal dystonia during handwriting and finger-tapping tasks.

METHODS

Patients with idiopathic right upper limb focal dystonia and controls were assessed by simultaneous near-infrared spectroscopy and electroencephalography during the writing and finger-tapping tasks in terms of the mu-alpha, mu-beta, beta and low gamma power and effective connectivity, as well as relative changes in oxyhemoglobin (oxy-Hb) and deoxyhemoglobin using a channel-wise approach with a mixed-effect model.

RESULTS

Patients exhibited higher oxy-Hb levels in the right and left motor cortex and supplementary motor area during writing, but lower oxy-Hb levels in the left sensorimotor and bilateral somatosensory area during finger-tapping compared to controls. During writing, patients showed increased low gamma power in the bilateral sensorimotor cortex and less mu-beta and beta attenuation compared to controls. Additionally, patients had reduced connectivity between the supplementary motor area and the left sensorimotor cortex during writing. No differences were observed in terms of effective connectivity in either task. Finally, patients failed to attenuate the mu-alpha, mu-beta, and beta rhythms during the finger-tapping task.

CONCLUSIONS

Cortical blood flow and EEG spectral power differ between controls and dystonia patients, depending on the task. Writing increased blood flow and altered connectivity in dystonia patients, and it also decreased slow-band attenuation. Finger-tapping decreased blood flow and slow-band attenuation.

SIGNIFICANCE

Simultaneous fNIRS and EEG may show relevant information regarding brain dynamics in movement disorders patients in unconstrained environments.

Focused Ultrasound for Treatment of Movement Disorders: A Review of Non-Food and Drug Administration Approved Indications

INTRODUCTION

MRI-guided focused ultrasound (FUS) is an incisionless thermo-ablative procedure that may be used to treat medication-refractory movement disorders, with a growing number of potential anatomic targets and clinical applications. As of this article's publication, the only US Food and Drug Administration (FDA)-approved uses of FUS for movement disorders are thalamotomy for essential tremor (ET) and tremor-dominant Parkinson's Disease (PD), and pallidotomy for other cardinal symptoms of PD. We present a state-of-the-art review on all non-FDA approved indications of FUS for movement disorders, beyond the most well-described indications of ET and PD. Our objective was to summarize the safety and efficacy of FUS in this setting and provide a roadmap for future directions of FUS for movement disorders.

METHODS

A state-of-the-art review was conducted on use of FUS for non-FDA approved movement disorders. All movement disorders excluding FDA-approved uses for ET and PD were included.

RESULTS

A total of 25 studies on 172 patients were included. In patients with tremor plus dystonia syndromes (n = 6), ventralis intermediate nucleus of the thalamus (VIM)-FUS gave >50% tremor reduction, with no improvement in dystonia and worsened dystonia in 2/6 patients. Ventral-oralis complex (VO)-FUS gave >50% improvement for focal hand dystonia (n = 6) and 100% return to musical performance in musician's dystonia (n = 6). In patients with multiple sclerosis (MS) and tremor (n = 3), improvement in tremor was seen in 2 patients with a favorable skull density ratio; no MS disease change was noted after VIM-FUS. In patients with tremor and comorbid ataxia syndromes (n = 3), none were found to have worsened ataxia after VIM-FUS; all had clinically significant tremor improvement. Subthalamic nucleus (STN)-FUS for PD (n = 49) gave approximately 50% improvement in PD motor symptoms, with dystonia and mild dyskinesias as possible adverse effects. Cerebellothalamic tract (CTT-FUS) for ET (n = 42) gave 55-90% tremor improvement, with gait dysfunction as a rare persistent adverse effect. Pallidothalamic tract (PTT-FUS) for PD (n = 50) gave approximately 50% improvement in motor symptoms, with mild speech dysfunction as a possible adverse effect.

CONCLUSION

VIM-FUS appeared safe and effective for heterogenous tremor etiologies, and VO-FUS appeared most effective for isolated segmental dystonia. STN-FUS was effective for PD symptom reduction; postoperative dystonia and mild on-medication dyskinesias required medical management. Tractography-based targeting with CTT-FUS for ET and PTT-FUS for PD demonstrated promising early results. Larger prospective trials with long-term follow-up are needed to the evaluate the safety and efficacy non-FDA approved indications for FUS.

Safety and efficacy of intrathecal baclofen trials for the treatment of hypertonia: a retrospective cohort study

OBJECTIVE

Intrathecal baclofen (ITB) is an effective treatment for refractory hypertonia in children. ITB has long been effective for the treatment of spasticity, and indications have naturally evolved to include dystonia and mixed pediatric movement disorders (PMDs). The established uses for ITB trials are insurance prerequisite, mixed tone, and family request. Despite agreement for ITB therapy by a multidisciplinary group of subspecialists in a complex PMD program, insurance companies often require an ITB trial be performed. A longitudinal cohort was identified to determine the safety and efficacy of ITB trials and to determine the utility of test dosing in this population.

METHODS

Retrospective data analysis was performed for patients with hypertonia who underwent ITB bolus trials at the authors' institution between 2021 and 2023. Nonmodifiable risk factors and clinical variables were collected.

RESULTS

Thirty-one patients (11 female) underwent 32 ITB trials. Of these patients, 67.7% had a diagnosis of mixed hypertonia, 32.3% pure spasticity, and 9.1% secondary dystonia. The mean age at test dose was 12.8 years, and 58.1% of patients were born premature. The mode Gross Motor Function Classification System score was 5. The mean difference in Barry-Albright Dystonia Scale (BADS) scores was -7.33 points (p = 0.01) at 2.5 hours postoperatively. The mean difference in upper-extremity modified Ashworth Scale (mAS) scores was -5.36 points (p = 0.003), and that for lower-extremity mAS scores was -6.61 (p < 0.001). In total, 21.9% of patients developed a post-dural puncture headache. Conversion to a permanent baclofen pump was performed in 22/32 (68.8%) patients. Of those who did not pursue pump placement, 1 patient had high surgical risk, 1 had an ineffective response, 1 had a bad reaction to the test dose and cited both regression and increased discomfort, and 2 declined despite an effective trial owing to family preferences.

CONCLUSIONS

ITB trials require hospitalization in some form and carry risks of procedural complications. The decision to pursue a trial should be made on a case-by-case basis by clinicians and should not be determined by insurance companies. The complication rate of ITB trials is high, and a test dose is unnecessary in this fragile population.

Loss-of-function of GNAL dystonia gene impairs striatal dopamine receptors-mediated adenylyl cyclase/ cyclic AMP signaling pathway

Loss-of-function mutations in the GNAL gene are responsible for DYT-GNAL dystonia. However, how GNAL mutations contribute to synaptic dysfunction is still unclear. The GNAL gene encodes the Gαolf protein, an isoform of stimulatory Gαs enriched in the striatum, with a key role in the regulation of cAMP signaling. Here, we used a combined biochemical and electrophysiological approach to study GPCR-mediated AC-cAMP cascade in the striatum of the heterozygous GNAL (GNAL+/-) rat model. We first analyzed adenosine type 2 (A2AR), and dopamine type 1 (D1R) receptors, which are directly coupled to Gαolf, and observed that the total levels of A2AR were increased, whereas D1R level was unaltered in GNAL+/- rats. In addition, the striatal isoform of adenylyl cyclase (AC5) was reduced, despite unaltered basal cAMP levels. Notably, the protein expression level of dopamine type 2 receptor (D2R), that inhibits the AC5-cAMP signaling pathway, was also reduced, similar to what observed in different DYT-TOR1A dystonia models. Accordingly, in the GNAL+/- rat striatum we found altered levels of the D2R regulatory proteins, RGS9-2, spinophilin, Gβ5 and β-arrestin2, suggesting a downregulation of D2R signaling cascade. Additionally, by analyzing the responses of striatal cholinergic interneurons to D2R activation, we found that the receptor-mediated inhibitory effect is significantly attenuated in GNAL+/- interneurons. Altogether, our findings demonstrate a profound alteration in the A2AR/D2R-AC-cAMP cascade in the striatum of the rat DYT-GNAL dystonia model, and provide a plausible explanation for our previous findings on the loss of dopamine D2R-dependent corticostriatal long-term depression.

Long-term follow-up of task-specific tremor after thalamotomy: a retrospective observational study

OBJECTIVE

This study aimed to report the long-term results of thalamotomy in 23 patients with task-specific tremor.

METHODS

Data of 23 patients with task-specific tremor who underwent ventralis intermedius nucleus and posterior part of ventro-oral nucleus thalamotomy at the Tokyo Women's Medical University Hospital between 2010 and 2022 were retrospectively analyzed. To evaluate neurological conditions, the severity of task-specific tremor was divided into 0 (no tremor), 1 (slightly tremulous), 2 (moderately tremulous), 3 (accomplishing tasks with great difficulty), and 4 (unable to complete tasks). We also used the subscores "handwriting" (0-4) and "spiral drawing" (0-4) of the Clinical Rating Scales for Tremor. Evaluation scales were presented as medians and interquartile ranges.

RESULTS

The severities of task-specific tremor were 3.0 (3.0-4.0) preoperatively and 0.0 (0.0-0.0, p < 0.0001) at the last available evaluation. The writing and spiral drawing of the Clinical Rating Scales for Tremor significantly improved from 3.0 (3.0-4.0) and 3.0 (2.0-3.0) preoperatively, respectively, to 0.0 (0.0-0.0, p < 0.0001) and 0.0 (0.0-0.0, p < 0.0001) at the last available evaluation, respectively. The mean clinical follow-up period was 62.7 ± 26.0 months. Seven (30.4%) patients had focal hand dystonia, which newly developed on the ipsilateral side of the tremor at 2-45 months after the surgery. No serious complications were observed.

INTERPRETATION

Thalamotomy significantly improves task-specific tremor with high long-term efficacy, and long-term follow-up is important because focal hand dystonia can develop postoperatively.

Increased electrode impedance as an indicator for early detection of deep brain stimulation (DBS) hardware Infection: Clinical experience and in vitro study

BACKGROUND

When deep brain stimulation (DBS) infections are identified, they are often too advanced to treat without complete hardware removal. New objective markers to promptly identify DBS infections are needed. We present a patient with GPi (globus pallidus interna) DBS for dystonia, where the electrode impedance unexpectedly increased 3-months post-operatively, followed by serologic and hematologic markers of inflammation at 6-months, prompting explantation surgery. We recreated these conditions in a laboratory environment to analyze the pattern of changing of electrical impedance across the contacts of a DBS lead following Staphylococcus biofilm formation.

METHODS

A stainless-steel culture chamber containing 1 % brain heart infusion agar was used. A DBS electrode was dipped in peptone water containing a strain of S. aureus and subsequently introduced into the chamber. The apparatus was incubated at 37 °C for 6 days. Impedance was measured at 24hr intervals. A control experiment without S. Aureus inoculation was used to determine changes in impedance over a period of 6-days.

RESULTS

The mean monopolar impedance on day-1 was 751.8 ± 23.8 Ω and on day-3 was 1004.8 ± 68.7 Ω, a 33.7 % rise (p = 0.007). A faint biofilm formation could be seen around the DBS lead by day-2 and florid growth by day-3. After addition of the linezolid solution, a 15.9 % decrease in monopolar impedance was observed from day 3-6 (p = 0.003).

CONCLUSION

This study gives insight into impedance trends following a hardware infection in DBS. Increased impedance outside expected norms may be valuable for early prediction of infection. Furthermore, timely management using antibiotics might reduce the frequency of infection-related explant surgeries.

Treatment of oromandibular dystonia with botulinum toxin A improves apnea in a teenager with quadriplegic cerebral palsy: A case report

This report describes a 15-year-old female with known spastic and dystonic quadriplegic cerebral palsy (CP), Gross Motor Function Classification System IV, and obstructive sleep apnea (OSA). She experienced decreased apneic episodes after receiving onabotulinumtoxin A (BoNT-A) injections for the treatment of oromandibular dystonia (OMD). After her OSA diagnosis, she initially received injections to the bilateral masseter and temporalis muscles with no effect on the frequency of nightly apneic episodes. Subsequently, the bilateral lateral pterygoid muscles were added and she was later noted to have fewer apneic episodes overnight. This case report describes the use of BoNT-A in the muscles of mastication for management of OMD and the ensuing improvement in OSA in a teenager with CP.

A Critical Appraisal of the Whack-a-Mole and Swivel Chair Signs in the Diagnosis of Functional Movement Disorders

BACKGROUND

The demonstration of positive signs during neurological examination is a cornerstone of the diagnosis of functional movement disorders, however, the available data supporting the diagnostic value of some of these signs is limited.

OBJECTIVES

To determine the diagnostic value (sensitivity and specificity) of the "whack-a-mole" (WAM) and "swivel chair" (SC) tests in patients with functional movement disorders (FMD).

METHODS

We enrolled patients with functional and organic movements in the WAM test if they exhibited tremor, dystonia, myoclonus, chorea, or tics. For the SC test, patients with a gait disorder as their primary impairment were recruited. Two blinded movement disorder specialists rated the presence of these signs in edited videos.

RESULTS

Inclusion criteria were met by 42 patients with FMD and 65 patients with organic movement disorders. Both tests demonstrated high specificity (means, 78% and 96%), but their sensitivity was low (means, 52% and 37%). Interobserver agreement for the WAM sign was 0.77 in the FMD group, against 0.28 in patients with organic movement disorders, whereas Movement Disorders Clinical Practice for Review Only for the SC sign was 0.69 in both groups.

CONCLUSIONS

The present study indicates that physicians must be cautious in the application and interpretation of these clinical signs in the diagnosis of functional movement disorders, and they should be carefully considered and used as necessary.

Excessive psychological stress preceding the onset of idiopathic cervical dystonia

Idiopathic cervical dystonia (ICD) is the largest subgroup of dystonia. Psychological stress as a triggering factor has long been discussed, but detailed descriptions are lacking. We report on a group of 13 patients with ICD and preceding excessive psychological stress (age at ICD onset 39.0 ± 13.9 years, 7 females, 6 males). The observation period was 7.8 ± 5.0 years. Excessive psychological stress included partner conflicts (divorce and separation, domestic violence), special familial burdens, legal disputes and migration. It started 8.3 ± 3.9 months before ICD onset. In 85% of our patients (typical cases), ICD developed within 5.8 ± 4.4 weeks, then lasted 18.5 ± 8.3 months, before it started to remit 2.7 ± 0.8 years after its onset to 54.5 ± 35.3% of its maximal severity. Idiopathic dystonia is thought to be based upon a genetic predisposition triggered by epigenetic factors. Our study suggests that excessive psychological stress could be one of them. Pathophysiologic elements are only vaguely identified, but could include the endoplasmic reticulum stress response, cerebellar 5HT-2A receptors and the metabolism of heat shock proteins. Whilst the clinical presentation of ICD preceded by excessive psychological stress is typical, its course is atypical with rapid onset and fast and substantial remission.

Clinimetrics of the Italian version of the Montreal Cognitive Assessment (MoCA) in adult-onset idiopathic focal dystonia

This study aimed at assessing the clinimetrics of the Montreal Cognitive Assessment (MoCA) in an Italian cohort of patients with adult-onset idiopathic focal dystonia (AOIFD). N = 86 AOIFD patients and N = 92 healthy controls (HCs) were administered the MoCA. Patients further underwent the Trail-Making Test (TMT) and Babcock Memory Test (BMT), being also screened via the Beck Depression Inventory-II (BDI-II) and the Dimensional Apathy Scale (DAS). Factorial structure and internal consistency were assessed. Construct validity was tested against TMT, BMT, BDI-II and DAS scores, whilst diagnostics against the co-occurrence of a defective performance on at least one TMT measure and on the BMT. Case-control discrimination was examined. The association between MoCA scores and motor-functional measures was explored. The MoCA was underpinned by a mono-component structure and acceptably reliable at an internal level. It converged towards TMT and BMT scores, as well as with the DAS, whilst diverging from the BDI-II. Its adjusted scores accurately detected cognitive impairment (AUC = .86) at a cut-off of < 17.212. The MoCA discriminated patients from HCs (p < .001). Finally, it was unrelated to disease duration and severity, as well as to motor phenotypes. The Italian MoCA is a valid, diagnostically sound and feasible cognitive screener in AOIFD patients.

Cerebellar Modulation of Sensorimotor Associative Plasticity Is Impaired in Cervical Dystonia

BACKGROUND

In recent years, cervical dystonia (CD) has been recognized as a network disorder that involves not only the basal ganglia but other brain regions, such as the primary motor and somatosensory cortex, brainstem, and cerebellum. So far, the role of the cerebellum in the pathophysiology of dystonia is only poorly understood.

OBJECTIVE

The objective of this study was to investigate the role of the cerebellum on sensorimotor associative plasticity in patients with CD.

METHODS

Sixteen patients with CD and 13 healthy subjects received cerebellar transcranial direct current stimulation (ctDCS) followed by a paired associative stimulation (PAS) protocol based on transcranial magnetic stimulation that induces sensorimotor associative plasticity. Across three sessions the participants received excitatory anodal, inhibitory cathodal, and sham ctDCS in a double-blind crossover design. Before and after the intervention, motor cortical excitability and motor symptom severity were assessed.

RESULTS

PAS induced an increase in motor cortical excitability in both healthy control subjects and patients with CD. In healthy subjects this effect was attenuated by both anodal and cathodal ctDCS with a stronger effect of cathodal stimulation. In patients with CD, anodal stimulation suppressed the PAS effect, whereas cathodal stimulation had no influence on PAS. Motor symptom severity was unchanged after the intervention.

CONCLUSIONS

Cerebellar modulation with cathodal ctDCS had no effect on sensorimotor associative plasticity in patients with CD, in contrast with the net inhibitory effect in healthy subjects. This is further evidence that the cerebello-thalamo-cortical network plays a role in the pathophysiology of dystonia. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Classical homocystinuria presenting with transient basal ganglia pathology and dystonia

Classical homocystinuria is caused by pathogenic variants in the CBS gene leading to a deficiency of the vitamin B6-dependent enzyme cystathionine beta synthase. The disease is typically associated with high blood homocysteine concentrations. Clinical features include developmental delay/intellectual disability, psychiatric problems, thromboembolism, lens dislocation, and marfanoid habitus. We report on a child with classical homocystinuria presenting with acute episodes of dystonia and symmetrical basal ganglia abnormalities mimicking a mitochondrial disease. After starting treatment with vitamin B6, homocysteine levels rapidly normalized and dystonic episodes did not re-occur. Moreover, brain-imaging findings almost completely disappeared. The case illustrates that homocystinuria should be considered as a treatable differential diagnosis of dystonia.

Identifying Effective Treatments for Dystonia in Patients With Cerebral Palsy: A Precision Therapeutics Approach

Recent focus on improving the recognition of dystonia in cerebral palsy (DCP) has highlighted the need for more effective treatments. Evidence supports improved functional outcomes with early interventions for patients with cerebral palsy, but it is not known which interventions are most effective for DCP. Current pharmacologic recommendations for DCP are based largely on anecdotal evidence, with medications demonstrating minimal to moderate improvements in dystonia and variable efficacy between patients. Patients, families, and clinicians have identified the need for new and improved treatments in DCP, naming this as the top research theme in a recent Neurology® publication. Precision therapeutics focuses on providing early effective interventions that are individualized to every patient and can guide research priorities to improve treatments for DCP. This commentary outlines current obstacles to improving treatment of DCP and addresses how precision therapeutics can address each of these obstacles through 4 key components: (1) identification of predictive biomarkers to select patients likely to develop DCP in the future and for whom early intervention may be appropriate to delay or prevent full manifestation of dystonia, (2) stratification of patients with DCP into subgroups according to shared features (clinical, functional, biochemical, etc) to provide a targeted intervention based on those shared features, (3) administration of an individualized dose of an effective intervention to ensure adequate concentrations of the therapeutic entity at the site of action, and (4) monitoring of objective biomarkers of response to intervention. With implementation of each of these components of precision therapeutics, new and more effective treatments for every person with DCP can be realized.

Clinical Spectrum, Radiological Correlation and Outcome of Movement Disorders in Wilson's Disease

Introduction

Movement disorders are the commonest clinical presentation in patients with neurological Wilson's disease (NWD). There are very few studies evaluating the spectrum, severity and their correlation with magnetic resonance imaging (MRI) changes of movement disorders in NWD.

Objective

To study the spectrum, topographic distribution, radiological correlate, temporal course and outcome in our cohort of NWD patients.

Methods

Retrospective chart review of the NWD patients having movement disorders was performed and analyzed.

Results

Sixty-nine patients (males- 47) with NWD were analysed and the mean age at the onset of neurological symptoms was 13.6 ± 6.6 years (median 13 years; range 7-37 years). The first neurological symptom was movement disorder in 55 (79.7%) patients. Tremor (43.6%) and dystonia (41.8%) was the commonest movement disorder as the first neurological symptom. Dystonia (76.8%) was the most common overall movement disorder followed by parkinsonism (52.1%) and tremors (47.8%). Chorea (10.1%), myoclonus (1.4%) and ataxia (1.4%) were the least common movement disorder. Putamen was the most common affected site (95.6%) followed by caudate nucleus (73.9%), thalamus (60.8%), midbrain (59.4%), internal capsule (49.2%), pons (46.3%). Putamen was the most common area of abnormality in dystonia (98%), tremors (85%). Caudate (75%) and putamen (75%) was the most common areas of abnormality in parkinsonism. Favourable outcome was observed in 42 patients (60.8%) following treatment.

Conclusion

Dystonia is the most common movement disorder in NWD in isolation or in combination with parkinsonism and tremors. Putamen is the most common radiological site of lesions and more frequently affected in patients with dystonia and tremors. Favourable outcome does occur with appropriate medical and surgical treatment.

Physiological Recordings of the Cerebellum in Movement Disorders

The cerebellum plays an important role in movement disorders, specifically in symptoms of ataxia, tremor, and dystonia. Understanding the physiological signals of the cerebellum contributes to insights into the pathophysiology of these movement disorders and holds promise in advancing therapeutic development. Non-invasive techniques such as electroencephalogram and magnetoencephalogram can record neural signals with high temporal resolution at the millisecond level, which is uniquely suitable to interrogate cerebellar physiology. These techniques have recently been implemented to study cerebellar physiology in healthy subjects as well as individuals with movement disorders. In the present review, we focus on the current understanding of cerebellar physiology using these techniques to study movement disorders.

Temporal Signature of Task-Specificity in Isolated Focal Laryngeal Dystonia

BACKGROUND AND OBJECTIVE

Laryngeal dystonia (LD) is focal task-specific dystonia, predominantly affecting speech but not whispering or emotional vocalizations. Prior neuroimaging studies identified brain regions forming a dystonic neural network and contributing to LD pathophysiology. However, the underlying temporal dynamics of these alterations and their contribution to the task-specificity of LD remain largely unknown. The objective of the study was to identify the temporal-spatial signature of altered cortical oscillations associated with LD pathophysiology.

METHODS

We used high-density 128-electrode electroencephalography (EEG) recordings during symptomatic speaking and two asymptomatic tasks, whispering and writing, in 24 LD patients and 22 healthy individuals to investigate the spectral dynamics, spatial localization, and interregional effective connectivity of aberrant cortical oscillations within the dystonic neural network, as well as their relationship with LD symptomatology.

RESULTS

Symptomatic speaking in LD patients was characterized by significantly increased gamma synchronization in the middle/superior frontal gyri, primary somatosensory cortex, and superior parietal lobule, establishing the altered prefrontal-parietal loop. Hyperfunctional connectivity from the left middle frontal gyrus to the right superior parietal lobule was significantly correlated with the age of onset and the duration of LD symptoms. Asymptomatic whisper in LD patients had not no statistically significant changes in any frequency band, whereas asymptomatic writing was characterized by significantly decreased synchronization of beta-band power localized in the right superior frontal gyrus.

CONCLUSION

Task-specific oscillatory activity of prefrontal-parietal circuitry is likely one of the underlying mechanisms of aberrant heteromodal integration of information processing and transfer within the neural network leading to dystonic motor output. © 2023 International Parkinson and Movement Disorder Society.

Probing the inhibitory motor circuits in adductor laryngeal dystonia during a dystonia-unrelated task

BACKGROUND

The pathophysiology of adductor laryngeal dystonia (AdLD) remains unknown; however, there is growing evidence that dystonia is associated with disruptions in the inhibitory regulation of sensorimotor cortical areas. Using functional MRI (fMRI) and transcranial magnetic stimulation (TMS) complementarily, we previously demonstrated an overly activated laryngeal motor cortex and revealed correlations between blood-oxygen-level dependent (BOLD) activation and intracortical inhibition in a phonation (dystonia-related) task in adductor laryngeal dystonia (AdLD).

OBJECTIVE

Here, we aimed to characterize the brain-based findings in the primary motor cortex (M1) during a dystonia-unrelated (finger tapping) task in AdLD and controls (CTL).

METHODS

We examined the between-group differences in task-dependent BOLD activation and intracortical inhibition, measured by the TMS-evoked cortical silent period (cSP), in the M1. The correlations between fMRI and TMS responses were assessed.

RESULTS

There is more broadly dispersed BOLD activation, not confined to the hand motor cortex, and reduced intracortical inhibition in AdLD compared to CTL. Further, there are more positive correlations between cSP and BOLD activation in a task unrelated to dystonic symptoms in AdLD compared with CTL. This is in contrast to our previous work that demonstrated fewer positive correlations in AdLD during a dystonic phonation task.

CONCLUSIONS

In unaffected musculature activation, there is dispersed BOLD activation that is correlated with intracortical inhibition suggesting a possible compensatory strategy in the non-dystonic muscles.

Improvement of speed-accuracy tradeoff during practice of a point-to-point task in children with acquired dystonia

The tradeoff between speed and accuracy is a well-known constraint for human movement, but previous work has shown that this tradeoff can be modified by practice, and the quantitative relationship between speed and accuracy may be an indicator of skill in some tasks. We have previously shown that children with dystonia are able to adapt their movement strategy in a ballistic throwing game to compensate for increased variability of movement. Here, we test whether children with dystonia can adapt and improve skills learned on a trajectory task. We use a novel task in which children move a spoon with a marble between two targets. Difficulty is modified by changing the depth of the spoon. Our results show that both healthy children and children with acquired dystonia move more slowly with the more difficult spoons, and both groups improve the relationship between speed and spoon difficulty following 1 wk of practice. By tracking the marble position in the spoon, we show that children with dystonia use a larger fraction of the available variability, whereas healthy children adopt a much safer strategy and remain farther from the margins, as well as learning to adapt and have more control over the marble's utilized area by practice. Together, our results show that both healthy children and children with dystonia choose trajectories that compensate for risk and inherent variability, and that the increased variability in dystonia can be modified with continued practice.NEW & NOTEWORTHY This study provides insights into the adaptability of children with dystonia in learning a point-to-point task. We show that these children adjust their strategies to account for increased difficulty in the task. Our findings underscore the potential of task-specific practice in improving motor skills and show higher level of signal-dependent noise can be controlled through repetition and learned strategies, which provides an avenue for the quantitative evaluation of rehabilitation strategies in this challenging group.

Blood neurofilament light chain as a surrogate marker for dystonia

BACKGROUND AND PURPOSE

Dystonia is a heterogeneous movement disorder, and it remains unclear whether neurodegeneration is involved. Neurofilament light chain (NfL) is a biosignature of neurodegeneration. We aimed to investigate whether plasma NfL levels were elevated and associated with disease severity in patients with dystonia.

METHOD

We enrolled 231 unrelated dystonia patients (isolated dystonia n = 203; combined dystonia n = 28) and 54 healthy controls from movement disorder clinics. Clinical severity was evaluated using the Fahn Marsden Dystonia Rating Scale, the Unified Dystonia Rating Scale, and the Global Dystonia Rating Scale. Blood NfL levels were measured by single-molecule array.

RESULTS

Plasma NfL levels were significantly higher in those with generalized dystonia compared to those with focal dystonia (20.1 ± 8.8 vs. 11.7 ± 7.2 pg/mL; p = 0.01) or controls (p < 0.01), while the level was comparable between the focal dystonia group and controls (p = 0.08). Furthermore, the dystonia combined with parkinsonism group had higher NfL levels than the isolated dystonia group (17.4 ± 6.2 vs. 13.5 ± 7.5 pg/mL; p = 0.04). Notably, whole-exome sequencing was performed in 79 patients and two patients were identified as having likely pathogenic variants: one had a heterozygous c.122G>A (p.R41H) variant in THAP1 (DYT6) and the other carried a c.1825G>A (p.D609N) substitution in ATP1A3 (DYT12). No significant correlation was found between plasma NfL levels and dystonia rating scores.

CONCLUSION

Plasma NfL levels are elevated in patients with generalized dystonia and dystonia combined with parkinsonism, suggesting that neurodegeneration is involved in the disease process of this subgroup of patients.

Novel Genetic and Phenotypic Expansion in GOSR2-Related Progressive Myoclonus Epilepsy

Biallelic variants in the Golgi SNAP receptor complex member 2 gene (GOSR2) have been reported in progressive myoclonus epilepsy with neurodegeneration. Typical clinical features include ataxia and areflexia during early childhood, followed by seizures, scoliosis, dysarthria, and myoclonus. Here, we report two novel patients from unrelated families with a GOSR2-related disorder and novel genetic and clinical findings. The first patient, a male compound heterozygous for the GOSR2 splice site variant c.336+1G>A and the novel c.364G>A,p.Glu122Lys missense variant showed global developmental delay and seizures at the age of 2 years, followed by myoclonus at the age of 8 years with partial response to clonazepam. The second patient, a female homozygous for the GOSR2 founder variant p.Gly144Trp, showed only mild fine motor developmental delay and generalized tonic-clonic seizures triggered by infections during adolescence, with seizure remission on levetiracetam. The associated movement disorder progressed atypically slowly during adolescence compared to its usual speed, from initial intention tremor and myoclonus to ataxia, hyporeflexia, dysmetria, and dystonia. These findings expand the genotype-phenotype spectrum of GOSR2-related disorders and suggest that GOSR2 should be included in the consideration of monogenetic causes of dystonia, global developmental delay, and seizures.

Status Dystonicus in Subacute Sclerosing Panencephalitis-A Rare Presentation in Emergency

Dystonia has been described in a few cases with SSPE, but there are only very few reports with status dystonicus and none from South India. Here, we report a six-year-old child presenting with severe dystonic posturing of all four limbs and trunk for 10 days duration following a febrile illness and initially treated elsewhere as viral encephalitis. Scalp EEG showed periodic high-amplitude slow wave discharges. MRI brain showed T2/FLAIR hyperintensity in bilateral frontal, left parietal, and deep white matter, extending across the corpus collosum with diffuse cerebral atrophy. The titer for IgG antibodies to measles virus by ELISA was 1:625, suggestive of SSPE. With medications, dystonia used to subside transiently; however, the patient had worsening of symptoms and showed gradual deterioration.

Accelerometer-derived sleep measures in idiopathic dystonia: A UK Biobank cohort study

BACKGROUND

Sleep disturbance is an increasingly recognized non-motor trait in dystonia, with varying findings reported to date. Here, we examine sleep in a UK Biobank derived dystonia cohort using subjective self-reported sleep symptoms and objective accelerometer-derived sleep measures, with comparison to a control population.

METHODS

A total of 241 dystonia cases were compared to 964 matched controls in analysis of self-reported sleep symptoms and changes in sleep architecture using wrist-worn triaxial accelerometers.

RESULTS

Dystonia participants had poorer self-reported sleep patterns compared to controls. Accelerometery measurements demonstrated later sleep times, reduced time in bed, and shifts in circadian rhythm. No association was observed with pain, and only limited relationships with psychiatric symptoms.

DISCUSSION

This study demonstrates the utility of accelerometers in longer term evaluation of sleep in dystonia, for measurement of disturbance and response to treatment. Compared to controls, altered sleep and circadian rhythm were more common in dystonia patients which may contribute to the clinical phenotype.

Cerebellar deep brain stimulation for the treatment of movement disorders in cerebral palsy

OBJECTIVE

Cerebral palsy (CP) represents the most common childhood physical disability that encompasses disorders of movement and posture attributed to nonprogressive disturbances that occurred in the developmental fetal or infant brain. Dyskinetic CP (DCP), the second most common type of CP after spastic forms, refers to a subset of patients in whom dystonia and choreoathetosis are the predominant motor manifestations. Most children with CP have abnormal brain MRI studies indicative of cortical and deep gray matter damage consistent with hypoxic ischemic encephalopathy, which may preclude or suggest decreased efficacy of standard deep brain stimulation (DBS) targets. The cerebellum has been posited as an attractive target for treatment of DCP because it is frequently spared from hypoxic ischemic damage and has shown promise in alleviating patient symptoms both in early work in the 1970s and in more recent case series with DBS.

METHODS

The authors performed bilateral cerebellar DBS implantation, targeting the dentate nucleus (DN) and cerebellar outflow pathway, in 3 patients with DCP. Leads were connected to a pulse generator that senses local field potentials during chronic continuous DBS. The authors report their surgical methods, examples of chronic cerebellar local field potential recordings, and preliminary clinical outcomes. Motor outcomes were assessed using the Burke-Fahn-Marsden Dystonia Rating Scale.

RESULTS

Three patients 14-22 years old with DCP and MRI evidence of structural damage to the basal ganglia were offered cerebellar stimulation targeting the DN. All patients tolerated the procedure well and demonstrated improvement in subjective motor function as well as objective improvement in the Burke-Fahn-Marsden Dystonia Rating Scale movement subscale, although the range of responses was variable (19%-40%). Patients experienced subjective improvement in motor function including ease of hand movements and coordination, gait, head control, speech, decreased overflow, and diminished muscle tightness.

CONCLUSIONS

DBS of the dentate nuclei in patients with DCP appears to be safe and shows preliminary evidence of clinical benefit. New chronic sensing technology may allow for determination of in vivo mechanisms of network disruption in DCP and allow for further understanding of the effects of neuromodulation on brain physiology. Larger studies with long-term follow up will be required to further elucidate the clinical benefits of this therapy. This report addresses a gap in the literature regarding the technical approach to image-based stereotactic targeting and chronic neural recording in the DN.

Eye-Closure Rate Modulation in Blepharospasm

Background

Blepharospasm (BSP) is a type of focal dystonia and a number of patients with BSP have relatives also affected by BSP. The objective of this study was to quantify eye closure rates during activities of daily living in individuals with BSP and individuals without BSP with and without a first-degree relative with BSP.

Methods

37 patients with BSP (BSP group), 10 asymptomatic volunteers with a first-degree relative with BSP (RELATIVES group) and 25 asymptomatic volunteers without relatives with BSP (HV group) were recruited. The number of eye closures for each task were counted per 60 seconds, with a video recording. Within and between groups statistical comparisons of eye-closure rates were performed.

Results

The eye-closure rates of the RELATIVES group were not different from the BSP group for the majority of the tasks (except for watching television), and the HV group (for all tasks). The rate of eye closures in the BSP group compared to HV, was significantly increased in two tasks, resting and watching television.

Discussion

Eye closure rate varies considerably during activities of daily living in all groups. Individuals with first degree relative with BSP are more likely to have increased eye closure rate at rest.

Tackling the neurological manifestations in Wilson's disease - currently available treatment options

INTRODUCTION

Wilson's disease (WD) is a potentially treatable, inherited disorder resulting from impaired copper metabolism. Pathological copper accumulation causes a range of symptoms, most commonly hepatic and a wide spectrum of neurological symptoms including tremor, dystonia, chorea, parkinsonism, dysphagia, dysarthria, gait and posture disturbances. To reduce copper overload, anti-copper drugs are used that improve liver function and neurological symptoms in up to 85% of patients. However, in some WD patients, treatment introduction leads to neurological deterioration, and in others, neurological symptoms persist with no improvement or improvement only after several years of treatment, severely affecting the patient's quality of life.

AREAS COVERED

This review appraises the evidence on various pharmacological and non-pharmacological therapies, neurosurgical procedures and liver transplantation for the management of neurological WD symptoms. The authors also discuss the neurological symptoms of WD, causes of deterioration and present symptomatic treatment options.

EXPERT OPINION

Based on case and series reports, current recommendations and expert opinion, WD treatment is focused mainly on drugs leading to negative copper body metabolism (chelators or zinc salts) and copper-restricted diet. Treatment of WD neurological symptoms should follow general recommendations of symptomatic treatment. Patients should be always considered individually, especially in the case of severe, disabling neurological symptoms.

Neuroimaging-based analysis of DBS outcomes in pediatric dystonia: Insights from the GEPESTIM registry

INTRODUCTION

Deep brain stimulation (DBS) is an established treatment in patients of various ages with pharmaco-resistant neurological disorders. Surgical targeting and postoperative programming of DBS depend on the spatial location of the stimulating electrodes in relation to the surrounding anatomical structures, and on electrode connectivity to a specific distribution pattern within brain networks. Such information is usually collected using group-level analysis, which relies on the availability of normative imaging resources (atlases and connectomes). Analysis of DBS data in children with debilitating neurological disorders such as dystonia would benefit from such resources, especially given the developmental differences in neuroimaging data between adults and children. We assembled pediatric normative neuroimaging resources from open-access datasets in order to comply with age-related anatomical and functional differences in pediatric DBS populations. We illustrated their utility in a cohort of children with dystonia treated with pallidal DBS. We aimed to derive a local pallidal sweetspot and explore a connectivity fingerprint associated with pallidal stimulation to exemplify the utility of the assembled imaging resources.

METHODS

An average pediatric brain template (the MNI brain template 4.5-18.5 years) was implemented and used to localize the DBS electrodes in 20 patients from the GEPESTIM registry cohort. A pediatric subcortical atlas, analogous to the DISTAL atlas known in DBS research, was also employed to highlight the anatomical structures of interest. A local pallidal sweetspot was modeled, and its degree of overlap with stimulation volumes was calculated as a correlate of individual clinical outcomes. Additionally, a pediatric functional connectome of 100 neurotypical subjects from the Consortium for Reliability and Reproducibility was built to allow network-based analyses and decipher a connectivity fingerprint responsible for the clinical improvements in our cohort.

RESULTS

We successfully implemented a pediatric neuroimaging dataset that will be made available for public use as a tool for DBS analyses. Overlap of stimulation volumes with the identified DBS-sweetspot model correlated significantly with improvement on a local spatial level (R = 0.46, permuted p = 0.019). The functional connectivity fingerprint of DBS outcomes was determined to be a network correlate of therapeutic pallidal stimulation in children with dystonia (R = 0.30, permuted p = 0.003).

CONCLUSIONS

Local sweetspot and distributed network models provide neuroanatomical substrates for DBS-associated clinical outcomes in dystonia using pediatric neuroimaging surrogate data. Implementation of this pediatric neuroimaging dataset might help to improve the practice and pave the road towards a personalized DBS-neuroimaging analyses in pediatric patients.