Parkinsonism originates in a discrete secondary and dystonia in a primary motor cortical-basal ganglia subcircuit.

Although manifesting contrasting phenotypes, Parkinson's disease and dystonia, the two most common movement disorders, can originate from similar pathophysiology. Previously, we demonstrated that lesioning (silencing) of a discrete dorsal region in the globus pallidus (rodent equivalent to globus pallidus externa) in rats and produced parkinsonism, while lesioning a nearby ventral hotspot-induced dystonia. Presently, we injected fluorescent-tagged multi-synaptic tracers into these pallidal hotspots (n = 36 Long Evans rats) and permitted 4 days for the viruses to travel along restricted connecting pathways and reach the motor cortex before sacrificing the animals. Viral injections in the Parkinson's hotspot fluorescent labeled a circumscribed region in the secondary motor cortex, while injections in the dystonia hotspot labeled within the primary motor cortex. Custom probability mapping and N200 staining affirmed the segregation of the cortical territories for Parkinsonism and dystonia to the secondary and primary motor cortices. Intracortical microstimulation localized territories specifically to their respective rostral and caudal microexcitable zones. Parkinsonian features are thus explained by pathological signaling within a secondary motor subcircuit normally responsible for initiation and scaling of movement, while dystonia is explained by abnormal (and excessive) basal ganglia signaling directed at primary motor corticospinal transmission.

Clinical features and power spectral entropy of electroencephalography in Wilson's disease with dystonia.

OBJECTIVE: To study the clinical features and power spectral entropy (PSE) of electroencephalography signals in Wilson's disease (WD) patients with dystonia. METHODS: Several scale evaluations were performed to assess the clinical features of WD patients. Demographic information and electroencephalography signals were obtained in all subjects. RESULTS: 34 WD patients with dystonia were recruited in the case group and 24 patients without dystonia were recruited in the control group. 20 healthy individuals were included in the healthy control group. The mean body mass index (BMI) in the case group was significantly lower than that in the controls (p < .05). The case group had significantly higher SAS, SDS, and Bucco-Facial-Apraxia Assessment scores (p < .05). Total BADS scores in the case group were lower than those in the control group (p < .01). Note that 94.11% of the case group presented with dysarthria and 70.59% of them suffered from dysphagia. Dysphagia was mainly related to the oral preparatory stage and oral stage. Mean power spectral entropy (PSE) values in the case group were significantly different (p < .05) from those in the control group and the healthy group across the different tasks. CONCLUSIONS: The patients with dystonia were usually accompanied with low BMI, anxiety, depression, apraxia, executive dysfunction, dysarthria and dysphagia. The cortical activities of the WD patients with dystonia seemed to be more chaotic during the eyes-closed and reading tasks but lower during the swallowing stages than those in the control group.

Pathophysiological mechanisms of oromandibular dystonia.

Oromandibular dystonia (OMD) is a rare form of focal idiopathic dystonia. OMD was clinically identified at the beginning of the 20th century, and the main clinical features have been progressively described over the years. However, OMD has several peculiarities that still remain unexplained, including the high rate of oral trauma, which is often related to the onset of motor symptoms. The purpose of this paper was to formulate a hypothesis regarding the pathophysiology of OMD, starting from the neuroanatomical basis of the masticatory and facial systems and highlighting the features that differentiate this condition from other forms of focal idiopathic dystonia. We provide a brief review of the clinical and etiological features of OMD as well as neurophysiological and neuroimaging findings obtained from studies in patients with OMD. We discuss possible pathophysiological mechanisms underlying OMD and suggest that abnormalities in sensory input processing may play a prominent role in OMD pathophysiology, possibly triggering a cascade of events that results in sensorimotor cortex network dysfunction. Finally, we identify open questions that future studies should address, including the effect of abnormal sensory input processing and oral trauma on the peculiar neurophysiological abnormalities observed in OMD.

Spasticity and Dystonia are Underidentified in Young Children at High Risk for Cerebral Palsy.

BACKGROUND: Early spasticity and dystonia identification in cerebral palsy is critical for guiding diagnostic workup and prompting targeted treatment early when it is most efficacious. However, differentiating spasticity from dystonia is difficult in young children with cerebral palsy. METHODS: We sought to determine spasticity and dystonia underidentification rates in children at high risk for cerebral palsy (following neonatal hypoxic-ischemic encephalopathy) by assessing how often child neurologists identified hypertonia alone versus specifying the hypertonia type as spasticity and/or dystonia by age 5 years. RESULTS: Of 168 children, 63 developed cerebral palsy and hypertonia but only 19 (30%) had their hypertonia type specified as spasticity and/or dystonia by age 5 years. CONCLUSIONS: Child neurologists did not specify the type of hypertonia in a majority of children at high risk of cerebral palsy. Because early tone identification critically guides diagnostic workup and treatment of cerebral palsy, these results highlight an important gap in current cerebral palsy care.

Comparison of cognitive performance between patients with Parkinson's disease and dystonia using an intraoperative recognition memory test.

Neuroscientific studies on the function of the basal ganglia often examine the behavioral performance of patients with movement disorders, such as Parkinson's disease (PD) and dystonia (DT), while simultaneously examining the underlying electrophysiological activity during deep brain stimulation surgery. Nevertheless, to date, there have been no studies comparing the cognitive performance of PD and DT patients during surgery. In this study, we assessed the memory function of PD and DT patients with the Montreal Cognitive Assessment (MoCA) and the Mini-Mental State Examination (MMSE). We also tested their cognitive performance during the surgery using a continuous recognition memory test. The results of the MoCA and MMSE failed to reveal significant differences between the PD and DT patients. Additionally, no significant difference was detected by the intraoperative memory test between the PD and DT patients. The intraoperative memory test scores were highly correlated with the MMSE scores and MoCA scores. Our data suggest that DT patients perform similarly to PD patients in cognitive tests during surgery, and intraoperative memory tests can be used as a quick memory assessment tool during surgery.

Sex related differences in nonmotor symptoms of patients with idiopathic blepharospasm.

Idiopathic blepharospasm shows a female predominance in prevalence, whether there are sex-related differences in distributions of nonmotor symptoms (NMSs) and predictors of quality of life are unknown. Four hundred and twenty-five patients with idiopathic blepharospasm were consecutively recruited, and underwent assessments including dystonia severity, mood disturbances, sleep disturbances, cognition, ocular symptoms, and quality of life. Frequencies and distributions of NMSs, and predictors of quality of life in female and male patients were investigated. NMSs existed in majority of male (94.0%) and female (95.8%) patients. The frequencies of depression, cognition dysfunction, and poor sleep quality were higher in female patients, while the frequency of excessive daytime sleepiness was higher in male patients. More female (79.5%) patients had multiple NMS domains affected than male (70.1%) patients (p = 0.040). Quality of life was associated with depression, anxiety and motor severity for female patients (adjusted R2 = 0.367, p < 0.001), while associated with depression, excessive daytime sleepiness and motor severity for male patients (adjusted R2 = 0.430, p < 0.001). The highly prevalent coexistence of multiple NMSs found in patients with blepharospasm support that blepharospasm is a network disorder. The sex-related differences in the pattern of NMSs and predictors of quality of life may aid the development of tailored management of blepharospasm.

Gut Microbiome and Serum Metabolome Alterations Associated with Isolated Dystonia.

Dystonia is a complex neurological movement disorder characterized by involuntary muscle contractions. Increasing studies implicate the microbiome as a possible key susceptibility factor for neurological disorders, but the relationship between the gut microbiota and dystonia remains poorly explored. Here, the gut microbiota of 57 patients with isolated dystonia and 27 age- and environment-matched healthy controls was analyzed by 16S rRNA gene amplicon sequencing. Further, integrative analysis of the gut microbiome and serum metabolome measured by high-performance liquid chromatography-mass spectrometry was performed. No difference in α-diversity was found, while ß-diversity was significantly different, with a more heterogeneous community structure among dystonia patients than among controls. The most significant changes in dystonia highlighted an increase in Clostridiales, including Blautia obeum, Dorea longicatena, and Eubacterium hallii, and a reduction in Bacteroides vulgatus and Bacteroides plebeius. The functional analysis revealed that genes related to tryptophan and purine biosynthesis were more abundant in gut microbiota from patients with dystonia, while genes linked to citrate cycle, vitamin B6, and glycan metabolism were less abundant. The evaluation of serum metabolites revealed altered levels of l-glutamic acid, taurine, and d-tyrosine, suggesting changes in neurotransmitter metabolism. The most modified metabolites strongly inversely correlated with the abundance of members belonging to the Clostridiales, revealing the effect of the gut microbiota on neurometabolic activity. This study is the first to reveal gut microbial dysbiosis in patients with isolated dystonia and identified potential links between gut microbiota and serum neurotransmitters, providing new insight into the pathogenesis of isolated dystonia. IMPORTANCE Dystonia is the third most common movement disorder after essential tremor and Parkinson's disease. However, the cause for the majority of cases is not known. This is the first study so far that reveals significant alterations of gut microbiome and correlates the alteration of serum metabolites with gut dysbiosis in patients with isolated dystonia. We demonstrated a general overrepresentation of Clostridiales and underrepresentation of Bacteroidetes in patients with dystonia in comparison with healthy controls. The functional analysis found that genes related to the biosynthesis of tryptophan, which is the precursor of the neurotransmitter serotonin, were more active in isolated dystonia patients. Altered levels of several serum metabolites were found to be associated with microbial changes, such as d-tyrosine, taurine, and glutamate, indicating differences in neurotransmitter metabolism in isolated dystonia. Integrative analysis suggests that neurotransmitter system dysfunction may be a possible pathway by which the gut microbiome participates in the development of dystonia. The gut microbiome changes provide new insight into the pathogenesis of dystonia, suggesting new potential therapeutic directions.

Inhibition of endoplasmic reticulum stress reverses synaptic plasticity deficits in striatum of DYT1 dystonia mice.

BACKGROUND AND OBJECTIVE: Striatal plasticity alterations caused by endoplasmic reticulum (ER) stress is supposed to be critically involved in the mechanism of DYT1 dystonia. In the current study, we expanded this research field by investigating the critical role of ER stress underlying synaptic plasticity impairment imposed by mutant heterozygous Tor1a+/- in a DYT1 dystonia mouse model. METHODS: Heterozygous Tor1a+/- mouse model for DYT1 dystonia was established. Wild-type (Tor1a+/+, N=10) and mutant (Tor1a+/-, N=10) mice from post-natal day P25 to P35 were randomly distributed to experimental and control groups. Patch-clamp and current-clamp recordings of SPNs were conducted with intracellular electrodes for electrophysiological analyses. Striatal changes of the direct and indirect pathways were investigated via immunofluorescence. Golgi-Cox staining was conducted to observe spine morphology of SPNs. To quantify postsynaptic signaling proteins in striatum, RNA-Seq, qRT-PCR and WB were performed in striatal tissues. RESULTS: Long-term depression (LTD) was failed to be induced, while long-term potentiation (LTP) was further strengthened in striatal spiny projection neurons (SPNs) from the Tor1a+/- DYT1 dystonia mice. Spine morphology analyses revealed a significant increase of both number of mushroom type spines and spine width in Tor1a+/- SPNs. In addition, increased AMPA receptor function and the reduction of NMDA/AMPA ratio in the postsynaptic of Tor1a+/- SPNs was observed, along with increased ER stress protein levels in striatum of Tor1a+/- DYT1 dystonia mice. Notably, ER stress inhibitors, tauroursodeoxycholic acid (TUDCA), could rescue LTD as well as AMPA currents. CONCLUSION: The current study illustrated the role of ER stress in mediating structural and functional plasticity alterations in Tor1a+/- SPNs. Inhibition of the ER stress by TUDCA is beneficial in reversing the deficits at the cellular and molecular levels. Remedy of dystonia associated neurological and motor functional impairment by ER stress inhibitors could be a recommendable therapeutic agent in clinical practice.

Combined treatment with C16 peptide and angiopoietin-1 confers neuroprotection and reduces inflammation in 3-nitropropionic acid-induced dystonia mice.

Dystonia is a disorder associated with abnormalities in many brain regions including the basal ganglia and cerebellum. The toxin 3-Nitropropionic acid (3-NP) can induce neuropathologies in the mice striatum and nigra substance, including excitotoxicity, neuroinflammation, and extensive neuronal atrophy, characterized by progressive motor dysfunction, dystonia, and memory loss, mimicking those observed in humans. We established a mouse model of dystonia by administering 3-NP. Given the reported neuroprotective effects of the endothelial growth factor angiopoietin-1 (Ang-1) and the anti-inflammatory integrin αvß3 binding peptide C16, we performed this study to evaluate their combined effects on 3-NP striatal toxicity and their therapeutic potential with multiple methods using an in vivo mouse model. Sixty mice were equally and randomly divided into three groups: control, 3-NP treatment, and 3-NP+C16+Ang-1 treatment. Behavioral and electrophysiological tests were conducted and the effect of the combined C16+Ang-1 treatment on neural function recovery was determined. We found that C16+Ang-1 treatment alleviated 3-NP-induced behavioral, biochemical, and cellular alterations in the central nervous system and promoted function recovery by restoring vascular permeability and reducing inflammation in the micro-environment. In conclusion, our results confirmed the neuroprotective effect of combined C16+Ang-1 treatment and suggest their potential as a complementary therapeutic against 3-NP-induced dystonia.

Functional dystonia in the foot and ankle.

AIMS: To assess the characteristic clinical features, management, and outcome of patients who present to orthopaedic surgeons with functional dystonia affecting the foot and ankle. METHODS: We carried out a retrospective search of our records from 2000 to 2019 of patients seen in our adult tertiary referral foot and ankle unit with a diagnosis of functional dystonia. RESULTS: A total of 29 patients were seen. A majority were female (n = 25) and the mean age of onset of symptoms was 35.3 years (13 to 71). The mean delay between onset and diagnosis was 7.1 years (0.5 to 25.0). Onset was acute in 25 patients and insidious in four. Of the 29 patients, 26 had a fixed dystonia and three had a spasmodic dystonia. Pain was a major symptom in all patients, with a coexisting diagnosis of chronic regional pain syndrome (CRPS) made in nine patients. Of 20 patients treated with Botox, only one had a good response. None of the 12 patients who underwent a surgical intervention at our unit or elsewhere reported a subjective overall improvement. After a mean follow-up of 3.2 years (1 to 12), four patients had improved, 17 had remained the same, and eight reported a deterioration in their condition. CONCLUSION: Patients with functional dystonia typically presented with a rapid onset of fixed deformity after a minor injury/event and pain out of proportion to the deformity. Referral to a neurologist to rule out neurological pathology is advocated, and further management should be carried out in a movement disorder clinic. Response to treatment (including Botulinum toxin (Botox) injections) is generally poor. Surgery in this group of patients is not recommended and may worsen the condition. The overall prognosis remains poor. Cite this article: Bone Joint J 2021;103-B(6):1127-1132.

DNAJC6 mutation causing cranial-onset dystonia with tremor dominant levodopa non-responsive parkinsonism: A novel phenotype.

DNAJC6 mutation causes two types of phenotypes: slowly progressive parkinsonism with levodopa response and rapidly progressive parkinsonism with additional manifestations like intellectual disability, epilepsy etc. We report a new phenotype wherein an adolescent girl developed blepharospasm followed by jaw opening, lingual and cervical dystonia followed by tremors of limbs (rest and action) with rigidity, bradykinesia. The dystonia-parkinsonism phenotype has not been described. She had novel homozygous missense mutation in DNAJC6 gene.

Distinct patterns of dyskinetic and dystonic features following D1 or D2 receptor stimulation in a mouse model of parkinsonism.

L-DOPA-induced dyskinesia (LID) is a significant complication of dopamine replacement therapy in Parkinson's disease (PD), and the specific role of different dopamine receptors in this disorder is poorly understood. We set out to compare patterns of dyskinetic behaviours induced by the systemic administration of L-DOPA and D1 or D2 receptor (D1R, D2R) agonists in mice with unilateral 6-hydroxydopamine lesions. Mice were divided in four groups to receive increasing doses of L-DOPA, a D1R agonist (SKF38393), a D2/3 agonist (quinpirole), or a selective D2R agonist (sumanirole). Axial, limb and orofacial abnormal involuntary movements (AIMs) were rated using a well-established method, while dystonic features were quantified in different body segments using a new rating scale. Measures of abnormal limb and trunk posturing were extracted from high-speed videos using a software for markerless pose estimation (DeepLabCut). While L-DOPA induced the full spectrum of dyskinesias already described in this mouse model, SKF38393 induced mostly orofacial and limb AIMs. By contrast, both of the D2-class agonists (quinpirole, sumanirole) induced predominantly axial AIMs. Dystonia ratings revealed that these agonists elicited marked dystonic features in trunk/neck, forelimbs, and hindlimbs, which were overall more severe in sumanirole-treated mice. Accordingly, sumanirole induced pronounced axial bending and hindlimb divergence in the automated video analysis. In animals treated with SKF38393, the only appreciable dystonic-like reaction consisted in sustained tail dorsiflexion and stiffness. We next compared the effects of D1R or D2R selective antagonists in L-DOPA-treated mice, where only the D2R antagonist had a significant effect on dystonic features. Taken together these results indicate that the dystonic components of LID are predominantly mediated by the D2R.

Rescue of striatal long-term depression by chronic mGlu5 receptor negative allosteric modulation in distinct dystonia models.

An impairment of long-term synaptic plasticity is considered as a peculiar endophenotype of distinct forms of dystonia, a common, disabling movement disorder. Among the few therapeutic options, broad-spectrum antimuscarinic drugs are utilized, aimed at counteracting abnormal striatal acetylcholine-mediated transmission, which plays a crucial role in dystonia pathophysiology. We previously demonstrated a complete loss of long-term synaptic depression (LTD) at corticostriatal synapses in rodent models of two distinct forms of isolated dystonia, resulting from mutations in the TOR1A (DYT1), and GNAL (DYT25) genes. In addition to anticholinergic agents, the aberrant excitability of striatal cholinergic cells can be modulated by group I metabotropic glutamate receptor subtypes (mGlu1 and 5). Here, we tested the efficacy of the negative allosteric modulator (NAM) of metabotropic glutamate 5 (mGlu) receptor, dipraglurant (ADX48621) on striatal LTD. We show that, whereas acute treatment failed to rescue LTD, chronic dipraglurant rescued this form of synaptic plasticity both in DYT1 mice and GNAL rats. Our analysis of the pharmacokinetic profile of dipraglurant revealed a relatively short half-life, which led us to uncover a peculiar time-course of recovery based on the timing from last dipraglurant injection. Indeed, striatal spiny projection neurons (SPNs) recorded within 2 h from last administration showed full expression of synaptic plasticity, whilst the extent of recovery progressively diminished when SPNs were recorded 4-6 h after treatment. Our findings suggest that distinct dystonia genes may share common signaling pathway dysfunction. More importantly, they indicate that dipraglurant might be a potential novel therapeutic agent for this disabling disorder.

Motor Cortex Activation During Writing in Focal Upper-Limb Dystonia: An fNIRS Study.

BACKGROUND: Functional imaging studies have associated dystonia with abnormal activation in motor and sensory brain regions. Commonly used techniques such as functional magnetic resonance imaging impose physical constraints, limiting the experimental paradigms. Functional near-infrared spectroscopy (fNIRS) offers a new noninvasive possibility for investigating cortical areas and the neural correlates of complex motor behaviors in unconstrained settings. METHODS: We compared the cortical brain activation of patients with focal upper-limb dystonia and controls during the writing task under naturalistic conditions using fNIRS. The primary motor cortex (M1), the primary somatosensory cortex (S1), and the supplementary motor area were chosen as regions of interest (ROIs) to assess differences in changes in both oxyhemoglobin (oxy-Hb) and deoxyhemoglobin (deoxy-Hb) between groups. RESULTS: Group average activation maps revealed an expected pattern of contralateral recruitment of motor and somatosensory cortices in the control group and a more bilateral pattern of activation in the dystonia group. Between-group comparisons focused on specific ROIs revealed an increased activation of the contralateral M1 and S1 cortices and also of the ipsilateral M1 cortex in patients. CONCLUSIONS: Overactivity of contralateral M1 and S1 in dystonia suggest a reduced specificity of the task-related cortical areas, whereas ipsilateral activation possibly indicates a primary disorder of the motor cortex or an endophenotypic pattern. To our knowledge, this is the first study using fNIRS to assess cortical activity in dystonia during the writing task under natural settings, outlining the potential of this technique for monitoring sensory and motor retraining in dystonia rehabilitation.

Hyperbilirubinemia and Asphyxia in Children With Dyskinetic Cerebral Palsy.

BACKGROUND: We aimed to study the clinical, etiologic, and radiological characteristics in children with dyskinetic cerebral palsy (DCP) and to compare the etiologic subtypes of hyperbilirubinemia and perinatal asphyxia. METHODS: This is a cross-sectional, observational study that enrolled consecutive children with DCP, aged one to 14 years. RESULTS: Sixty-five children with DCP were evaluated. Most children were boys (77%, n = 50), and term gestation (80%, n = 52). Presenting concerns were global developmental delay (97%, n = 63) and involuntary movements (60%, n = 39). Hyperbilirubinemia (66%, n = 43) and perinatal asphyxia (29%, n = 19) were the most important causes. The majority (83%, n = 54) of children were severely disabled (level V and IV). The hyperbilirubinemia group had significant motor delay (63% vs 37%, P = 0.03) and upward gaze palsy (69.7% vs 31.5%, P = 0.005) when compared with the perinatal asphyxia group. Hyperbilirubinemia significantly involved pallidi (86% vs 10% P = 0.0001) and subthalamic nucleus (26% vs none, P = 0.01), whereas asphyxia significantly involved the putamen (58% vs none, P = 0.0001), thalamus (63% vs none, P = 0.0001), and periventricular white matter (79% vs 19%, P = 0.0001). CONCLUSIONS: DCP is the dominant type of cerebral palsy seen in term-born babies with severe dystonia, developmental delay, and motor impairment. Hyperbilirubinemia is the major cause of DCP in the study. Hyperbilirubinemia is associated with motor delay, upward gaze palsy, prominent dystonia, and involvement of globus pallidi and subthalamic nuclei.

Muscle Tone Physiology and Abnormalities.

The simple definition of tone as the resistance to passive stretch is physiologically a complex interlaced network encompassing neural circuits in the brain, spinal cord, and muscle spindle. Disorders of muscle tone can arise from dysfunction in these pathways and manifest as hypertonia or hypotonia. The loss of supraspinal control mechanisms gives rise to hypertonia, resulting in spasticity or rigidity. On the other hand, dystonia and paratonia also manifest as abnormalities of muscle tone, but arise more due to the network dysfunction between the basal ganglia and the thalamo-cerebello-cortical connections. In this review, we have discussed the normal homeostatic mechanisms maintaining tone and the pathophysiology of spasticity and rigidity with its anatomical correlates. Thereafter, we have also highlighted the phenomenon of network dysfunction, cortical disinhibition, and neuroplastic alterations giving rise to dystonia and paratonia.

High-fidelity transmission of high-frequency burst stimuli from peripheral nerve to thalamic nuclei in children with dystonia.

High-frequency peripheral nerve stimulation has emerged as a noninvasive alternative to thalamic deep brain stimulation for some patients with essential tremor. It is not known whether such techniques might be effective for movement disorders in children, nor is the mechanism and transmission of the peripheral stimuli to central brain structures understood. This study was designed to investigate the fidelity of transmission from peripheral nerves to thalamic nuclei in children with dystonia undergoing deep brain stimulation surgery. The ventralis intermediate (VIM) thalamus nuclei showed a robust evoked response to peripheral high-frequency burst stimulation, with a greatest response magnitude to intra-burst frequencies between 50 and 100 Hz, and reliable but smaller responses up to 170 Hz. The earliest response occurred at 12-15 ms following stimulation onset, suggesting rapid high-fidelity transmission between peripheral nerve and thalamic nuclei. A high-bandwidth, low-latency transmission path from peripheral nerve to VIM thalamus is consistent with the importance of rapid and accurate sensory information for the control of coordination and movement via the cerebello-thalamo-cortical pathway. Our results suggest the possibility of non-invasive modulation of thalamic activity in children with dystonia, and therefore the possibility that a subset of children could have beneficial clinical response without the need for invasive deep brain stimulation.

The Central Effects of Botulinum Toxin in Dystonia and Spasticity.

In dystonic and spastic movement disorders, however different in their pathophysiological mechanisms, a similar impairment of sensorimotor control with special emphasis on afferentation is assumed. Peripheral intervention on afferent inputs evokes plastic changes within the central sensorimotor system. Intramuscular application of botulinum toxin type A (BoNT-A) is a standard evidence-based treatment for both conditions. Apart from its peripheral action on muscle spindles, a growing body of evidence suggests that BoNT-A effects could also be mediated by changes at the central level including cerebral cortex. We review recent studies employing electrophysiology and neuroimaging to investigate how intramuscular application of BoNT-A influences cortical reorganization. Based on such data, BoNT-A becomes gradually accepted as a promising tool to correct the maladaptive plastic changes within the sensorimotor cortex. In summary, electrophysiology and especially neuroimaging studies with BoNT-A further our understanding of pathophysiology underlying dystonic and spastic movement disorders and may consequently help develop novel treatment strategies based on neural plasticity.

Botulinum Neurotoxin Injections in Childhood Opisthotonus.

Opisthotonus refers to abnormal axial extension and arching of the trunk produced by excessive contractions of the paraspinal muscles. In childhood, the abnormal posture is most often related to dystonia in the setting of hypoxic injury or a number of other acquired and genetic etiologies. The condition is often painful, interferes with ambulation and quality of life, and is challenging to treat. Therapeutic options include oral benzodiazepines, oral and intrathecal baclofen, botulinum neurotoxin injections, and deep brain stimulation. Management of opisthotonus within the pediatric population has not been systematically reviewed. Here, we describe a series of seven children who presented to our institution with opisthotonus in whom symptom relief was achieved following administration of botulinum neurotoxin injections.

Variant recurrence confirms the existence of a FBXO31-related spastic-dystonic cerebral palsy syndrome.

The role of genetics in the causation of cerebral palsy has become the focus of many studies aiming to unravel the heterogeneous etiology behind this frequent neurodevelopmental disorder. A recent paper reported two unrelated children with a clinical diagnosis of cerebral palsy, who carried the same de novo c.1000G > A (p.Asp334Asn) variant in FBXO31, encoding a widely studied tumor suppressor not previously implicated in monogenic disease. We now identified a third individual with the recurrent FBXO31 de novo missense variant, featuring a spastic-dystonic phenotype. Our data confirm a link between variant FBXO31 and an autosomal dominant neurodevelopmental disorder characterized by prominent motor dysfunction.