Dyskinetic crisis in GNAO1-related disorders: clinical perspectives and management strategies.

Background: GNAO1-related disorders (GNAO1-RD) encompass a diverse spectrum of neurodevelopmental and movement disorders arising from variants in the GNAO1 gene. Dyskinetic crises, marked by sudden and intense exacerbations of abnormal involuntary movements, present a significant challenge in GNAO1-RD. Objectives: This study aimed to establish a standardized framework for understanding dyskinetic crises, addressing crucial aspects such as definition, triggers, diagnostic criteria, complications, and management strategies. Methods: A Delphi consensus process was conducted involving international experts in GNAO1-RD. The panel of thirteen experts participated in three voting rounds, discussing 90 statements generated through a literature review and clinical expertise. Results: Consensus was achieved on 31 statements, defining dyskinetic crises as abrupt, paroxysmal episodes involving distinct abnormal movements in multiple body regions, triggered by emotional stress or infections. Dyskinetic crises may lead to functional impairment and complications, emphasizing the need for prompt recognition. While individualized pharmacological recommendations were not provided, benzodiazepines and clonidine were suggested for acute crisis management. Chronic treatment options included tetrabenazine, benzodiazepines, gabapentin, and clonidine. Deep brain stimulation should be considered early in the treatment of refractory or prolonged dyskinetic crisis. Conclusion: This consensus provides a foundation for understanding and managing dyskinetic crises in GNAO1-RD for clinicians, caregivers, and researchers. The study emphasizes the importance of targeted parental and caregiver education, which enables early recognition and intervention, thereby potentially minimizing both short- and long-term complications. Future research should concentrate on differentiating dyskinetic crises from other neurological events and investigating potential risk factors that influence their occurrence and nature. The proposed standardized framework improves clinical management, stakeholder communication, and future GNAO1-RD research.

Electrophysiological variability as marker of dystonia worsening under deep brain stimulation successive withdrawal and renewal effects.

DBS has been shown to be an effective intervention for neurological disorders. However, the intervention is complex and many aspects have not been understood. Various clinical situations have no solution and follow trial and error approaches. Dystonia is a movement disorder characterized by involuntary muscle contractions, which gives rise to abnormal movements and postures. Status dystonicus (SD) represents a life-threatening condition that requires urgent assessment and management. Electrophysiological markers for risk of symptom worsening and SD related patterns of evolution in patients treated with long-term deep brain stimulation (DBS), and specially under the effect of withdrawal and renewals of simulation are needed. To this end, we study the variability of neural synchronization as a mechanism for symptom generation under successive perturbations to a system, i.e. withdrawals and renewals of neuromodulation, through computational simulation of clinical profiles under different plasticity conditions. The simulation shows that the neuroplasticity makeup influences the variability of oscillation synchronization patterns in virtual "patients". The difference between the effect of different electrophysiological signatures is remarkable and under a certain condition (equal medium long term potentiation and long term depression) the situation resembles that of a stable equilibrium, putatively making the sudden worsening or change less likely. Stability of variability can only be observed in this condition and is clearly distinct from other scenarios. CONCLUSION: Our results demonstrate that the neuroplasticity makeup affects the variability of the oscillatory synchrony. This i) informs the shaping of the electrophysiological makeup and ii) might serve as a marker for clinical behavior.

Thirty Years of Global Deep Brain Stimulation: "Plus ça change, plus c'est la même chose"?

BACKGROUND: The advent of deep brain stimulation (DBS) of the subthalamic nucleus (STN) for Parkinson's disease 30 years ago has ushered a global breakthrough of DBS as a universal method for therapy and research in wide areas of neurology and psychiatry. The literature of the last three decades has described numerous concepts and practices of DBS, often branded as novelties or discoveries. However, reading the contemporary publications often elicits a sense of déjà vu in relation to several methods, attributes, and practices of DBS. Here, we review various applications and techniques of the modern-era DBS and compare them with practices of the past. SUMMARY: Compared with modern literature, publications of the old-era functional stereotactic neurosurgery, including old-era DBS, show that from the very beginning multidisciplinarity and teamwork were often prevalent and insisted upon, ethical concerns were recognized, brain circuitries and rational for brain targets were discussed, surgical indications were similar, closed-loop stimulation was attempted, evaluations of surgical results were debated, and controversies were common. Thus, it appears that virtually everything done today in the field of DBS bears resemblance to old-time practices, or has been done before, albeit with partly other tools and techniques. Movement disorders remain the main indications for modern DBS as was the case for lesional surgery and old-era DBS. The novelties today consist of the STN as the dominant target for DBS, the tremendous advances in computerized brain imaging, the sophistication and versatility of implantable DBS hardware, and the large potential for research. KEY MESSAGES: Many aspects of contemporary DBS bear strong resemblance to practices of the past. The dominant clinical indications remain movement disorders with virtually the same brain targets as in the past, with one exception: the STN. Other novel brain targets - that are so far subject to DBS trials - are the pedunculopontine nucleus for gait freezing, the anteromedial internal pallidum for Gilles de la Tourette and the fornix for Alzheimer's disease. The major innovations and novelties compared to the past concern mainly the unmatched level of research activity, its high degree of sponsorship, and the outstanding advances in technology that have enabled multimodal brain imaging and the miniaturization, versatility, and sophistication of implantable hardware. The greatest benefit for patients today, compared to the past, is the higher level of precision and safety of DBS, and of all functional stereotactic neurosurgery.

Application of quantum machine learning using quantum kernel algorithms on multiclass neuron M-type classification.

The functional characterization of different neuronal types has been a longstanding and crucial challenge. With the advent of physical quantum computers, it has become possible to apply quantum machine learning algorithms to translate theoretical research into practical solutions. Previous studies have shown the advantages of quantum algorithms on artificially generated datasets, and initial experiments with small binary classification problems have yielded comparable outcomes to classical algorithms. However, it is essential to investigate the potential quantum advantage using real-world data. To the best of our knowledge, this study is the first to propose the utilization of quantum systems to classify neuron morphologies, thereby enhancing our understanding of the performance of automatic multiclass neuron classification using quantum kernel methods. We examined the influence of feature engineering on classification accuracy and found that quantum kernel methods achieved similar performance to classical methods, with certain advantages observed in various configurations.

The changing face of reported status dystonicus - A systematic review.

BACKGROUND: Status Dystonicus (SD) represents the most severe end of the spectrum of dystonia. We aimed to explore whether reported features of cases of SD have changed over time. METHODS: A systematic review of cases of SD reported from 2017 to 2023 and comparison of features to data extracted from 2 previous literature reviews (epochs 2012-2017 and pre-2012). RESULTS: From 53 papers, a total 206 SD episodes in 168 patients were identified from 2017 to 2023. Combining data from all 3 epochs, a total of 339 SD episodes were reported from 277 patients. SD episodes occurred mostly in children, with a trigger identified in 63.4% of episodes, most commonly infection/inflammation. Most reported underlying aetiologies were genetic (e.g. 49.5% between 2017 and 2023), including new associated aetiologies in each epoch. Deep Brain Stimulation (DBS)-related SD increased over time. Neurosurgical interventions were more frequently reported in later epochs. Across the epochs, return to or improvement post SD episode, compared to baseline was reported above 70%. Reported mortality was 4.9% most recently, compared to 11.4% and 7.9%, previously. CONCLUSIONS: SD episodes reported have more than doubled in the last 5 years. Reports of medication change-induced SD have become less frequent, whilst episodes of DBS-related SD have become more frequent. More dystonia aetiologies, including novel aetiologies have been reported in recent cohorts, reflecting advances in genetic diagnosis. Neurosurgical interventions are increasingly reported in the management of SD episodes, including novel use of intraventricular baclofen. Overall outcomes from SD remain largely unchanged over time. No prospective epidemiological studies of SD were identified.

Deep brain stimulation effect in genetic dyskinetic cerebral palsy: The case of ADCY5- related disease.

BACKGROUND: Cerebral Palsy (CP) represents a frequent cause of disability in childhood. Early in life, genetic disorders may present with motor dysfunction and diagnosed as CP. Establishing the primary, genetic etiology allows more accurate prognosis, genetic counselling, and planning for symptomatic interventions in homogeneous etiological groups. Deep brain stimulation (DBS) is recommended in refractory movement disorders, including isolated pediatric dystonias. For dystonia evolving in more complex associations in genetic CP, the effect of DBS is still understudied and currently only sporadically described. OBJECTIVES: To report the effect of DBS applied to the globus pallidus pars interna (GPi) in children with complex movement disorders caused by pathogenic ADCY5 variants, diagnosed as dyskinetic CP previous to genetic diagnostic. METHODS: We conducted a retrospective study on evolution of treatment with DBS in ADCY5-related disease. A standardized proforma including the different type of movement disorders and associated neurological signs was completed at each follow-up time, based on video recordings, as well as functional assessments used in children with CP. RESULTS: Four children (mean of age, 13 ± 2.9 years) received GPi-DBS. The same de novo pathogenic missense variant (c.1252C > T, p.R418W) was identified in three out of four and a splice site variant (c.2088 + 2G > T) in one subject. Developmental delay and overlapping features including axial hypotonia, chorea, dystonic attacks, myoclonus, and cranial dyskinesia were present. The median age at DBS was 9 years and follow-up with DBS, 2.6 years. We identified a pattern of clinical response with early suppression of dystonic attacks, followed by improvement of myoclonus and facial dyskinesia. Effect on chorea was delayed and more limited. Two patients gained notable functional benefit related to sitting, standing, gait, use of upper limbs and speech. CONCLUSION: ADCY5-related disease may benefit from GPi-DBS. The most significant clinical response relates to the early and sustained benefit on dystonic attacks and a variable but still positive response on the other hyperkinetic features. Genetic etiology of CP will contribute to further elucidate genotype-phenotype correlations and to refine DBS indication as network-related symptomatic interventions.

Highlighting the Dystonic Phenotype Related to GNAO1.

BACKGROUND: Most reported patients carrying GNAO1 mutations showed a severe phenotype characterized by early-onset epileptic encephalopathy and/or chorea. OBJECTIVE: The aim was to characterize the clinical and genetic features of patients with mild GNAO1-related phenotype with prominent movement disorders. METHODS: We included patients diagnosed with GNAO1-related movement disorders of delayed onset (>2 years). Patients experiencing either severe or profound intellectual disability or early-onset epileptic encephalopathy were excluded. RESULTS: Twenty-four patients and 1 asymptomatic subject were included. All patients showed dystonia as prominent movement disorder. Dystonia was focal in 1, segmental in 6, multifocal in 4, and generalized in 13. Six patients showed adolescence or adulthood-onset dystonia. Seven patients presented with parkinsonism and 3 with myoclonus. Dysarthria was observed in 19 patients. Mild and moderate ID were present in 10 and 2 patients, respectively. CONCLUSION: We highlighted a mild GNAO1-related phenotype, including adolescent-onset dystonia, broadening the clinical spectrum of this condition. © 2022 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Comparison of methylation episignatures in KMT2B- and KMT2D-related human disorders.

Aim & methods: To investigate peripheral blood methylation episignatures in KMT2B-related dystonia (DYT-KMT2B), the authors undertook genome-wide methylation profiling of ∼2 M CpGs using a next-generation sequencing-based assay and compared the findings with those in controls and patients with KMT2D-related Kabuki syndrome type 1 (KS1). Results: A total of 1812 significantly differentially methylated CpG positions (false discovery rate < 0.05) were detected in DYT-KMT2B samples compared with controls. Multi-dimensional scaling analysis showed that the 10 DYT-KMT2B samples clustered together and separately from 29 controls and 10 with pathogenic variants in KMT2D. The authors found that most differentially methylated CpG positions were specific to one disorder and that all (DYT-KMT2B) and most (Kabuki syndrome type 1) methylation alterations in CpG islands were gain of methylation events. Conclusion: Using sensitive methylation profiling methodology, the authors replicated recent reports of a methylation episignature for DYT-KMT2B. These findings will facilitate the development of episignature-based assays to improve diagnostic accuracy.

The authors compared the DNA methylation patterns in blood from individuals with two rare neurodevelopmental disorders (childhood-onset dystonia [DYT-KMT2B] and Kabuki syndrome type 1) and healthy control samples. These two disorders are associated with pathogenic variants in KMT2B and KMT2D, which encode proteins with related functions but cause distinct inherited disorders. Comparison of the methylation patterns in the two disorders showed that most DNA regions with altered methylation patterns differed between the two disorders and controls. These findings suggest that analyzing DNA methylation patterns could improve diagnostic testing for these disorders and might provide insights into how the clinical features of these disorders are caused.

Efficacy of Caffeine in ADCY5-Related Dyskinesia: A Retrospective Study.

BACKGROUND: ADCY5-related dyskinesia is characterized by early-onset movement disorders. There is currently no validated treatment, but anecdotal clinical reports and biological hypotheses suggest efficacy of caffeine. OBJECTIVE: The aim is to obtain further insight into the efficacy and safety of caffeine in patients with ADCY5-related dyskinesia. METHODS: A retrospective study was conducted worldwide in 30 patients with a proven ADCY5 mutation who had tried or were taking caffeine for dyskinesia. Disease characteristics and treatment responses were assessed through a questionnaire. RESULTS: Caffeine was overall well tolerated, even in children, and 87% of patients reported a clear improvement. Caffeine reduced the frequency and duration of paroxysmal movement disorders but also improved baseline movement disorders and some other motor and nonmotor features, with consistent quality-of-life improvement. Three patients reported worsening. CONCLUSION: Our findings suggest that caffeine should be considered as a first-line therapeutic option in ADCY5-related dyskinesia. © 2022 International Parkinson and Movement Disorder Society.

Judith Balkányi-Lepintre (1912-1982): first woman neurosurgeon, first woman war neurosurgeon, and first woman pediatric neurosurgeon in France.

Recently, a series of historical reports portrayed the first women neurosurgeons in various countries. One such woman, a pioneer on many levels, remained unrecognized: Judith Balkányi-Lepintre. She was the first woman neurosurgeon in France, the first woman war neurosurgeon for the French Army, and the first woman pediatric neurosurgeon in France. Born in 1912 to a Hungarian Jewish family, she graduated with honors from medical school in Budapest in 1935, then moved to Paris where she started neurosurgical training in 1937 at L'Hôpital de la Pitié under the mentorship of Clovis Vincent, the founder of French neurosurgery. Shortly after marrying a French colleague in 1940, she had to escape the Geheime Staatspolizei (Gestapo) in Paris and ended up in Algeria, where she joined the French Army of De Gaulle. As a neurosurgeon, she participated in the campaigns of Italy and France between 1943 and 1945. After the war, she returned to work at La Pitié Hospital. In 1947, she defended her doctoral thesis, "Treatment of cranio-cerebral wounds by projectiles and their early complications." Soon thereafter, she joined Europe's first dedicated children's hospital, Hôpital Necker-Enfants Malades in Paris, and contributed to the establishment of pediatric neurosurgery in France. She remained clinically and academically active at Necker until her death in 1982 but was never promoted.

Electrophysiological Signature and the Prediction of Deep Brain Stimulation Withdrawal and Insertion Effects.

Deep brain stimulation (DBS) serves as a treatment for neurological and psychiatric disorders, such as Parkinson's disease (PD), essential tremor, dystonia, Tourette Syndrome (GTS), Huntington's disease, and obsessive-compulsive disorder (OCD). There is broad experience with the short-term effects of DBS in individual diseases and their signs/symptoms. However, even in acute treatment and for the same disorder or a given disorder, a prediction of effect is not perfect. Even further, the factors that influence the long-term effect of DBS and its withdrawal are hardly characterized. In this work, we aim to shed light on an important topic, the question of "DBS dependency." To address this, we make use of the Kuramoto model of phase synchronization (oscillation feature) endowed with neuroplasticity to study the effects of DBS under successive withdrawals and renewals of neuromodulation as well as influence of treatment duration in de novo DBS "patients." The results of our simulation show that the characteristics of neuroplasticity have a profound effect on the stability and mutability of oscillation synchronization patterns across successive withdrawal and renewal of DBS in chronic "patients" and also in de novo DBS "patients" with varying duration of treatment (here referred to as the "number of iterations"). Importantly, the results demonstrate the strong effect of the individual neuroplasticity makeup on the behavior of synchrony of oscillatory activity that promotes certain disorder/disease states or symptoms. The effect of DBS-mediated neuromodulation and withdrawal is highly dependent on the makeup of the neuroplastic signature of a disorder or an individual.

Childhood-onset progressive dystonia associated with pathogenic truncating variants in CHD8.

Originally described as a risk factor for autism, CHD8 loss-of-function variants have recently been associated with a wider spectrum of neurodevelopmental abnormalities. We further expand the CHD8-related phenotype with the description of two unrelated patients who presented with childhood-onset progressive dystonia. Whole-exome sequencing conducted in two independent laboratories revealed a CHD8 nonsense variant in one patient and a frameshift variant in the second. The patients had strongly overlapping phenotypes characterized by generalized dystonia with mild-to-moderate neurodevelopmental comorbidity. Deep brain stimulation led to clinical improvement in both cases. We suggest that CHD8 should be added to the growing list of neurodevelopmental disorder-associated genes whose mutations can also result in dystonia-dominant phenotypes.

Deep brain stimulation in Lesch-Nyhan disease: outcomes from the patient's perspective.

AIM: To provide insight into outcome and long-term safety and efficacy of deep brain stimulation (DBS), from the perspective of individuals with Lesch-Nyhan disease (LND) and their families. METHOD: We used patient-centered outcome measures to assess long-term outcomes of DBS for 14 individuals (mean [SD] age 10y 10mo [5y 6mo], range 5-23y, all males) with LND, after an average duration of 5y 6mo (range 11mo-10y 5mo) after surgery. We compared these results with a comprehensive review of previously published cases. RESULTS: Patients and their families reported that DBS of the globus pallidus can be effective both for motor and behavioral disturbances in LND. However, outcome measures were often not significantly changed owing to substantial variability among individuals, and were overall less positive than in previous reports based on clinician assessments. In addition, there was an unexpectedly high rate of adverse events, tempering overall enthusiasm for the procedure. INTERPRETATION: Although DBS might be an effective treatment for LND, more research is needed to understand the reasons for response variability and the unusually high rates of adverse events before DBS can be recommended for these patients. What this paper adds Individuals with Lesch-Nyhan disease and their families report variable efficacy of deep brain stimulation. Long-term outcomes are associated with a high adverse event rate.

Striatal and cerebellar vesicular acetylcholine transporter expression is disrupted in human DYT1 dystonia.

Early-onset torsion dystonia (TOR1A/DYT1) is a devastating hereditary motor disorder whose pathophysiology remains unclear. Studies in transgenic mice suggested abnormal cholinergic transmission in the putamen, but this has not yet been demonstrated in humans. The role of the cerebellum in the pathophysiology of the disease has also been highlighted but the involvement of the intrinsic cerebellar cholinergic system is unknown. In this study, cholinergic neurons were imaged using PET with 18F-fluoroethoxybenzovesamicol, a radioligand of the vesicular acetylcholine transporter (VAChT). Here, we found an age-related decrease in VAChT expression in the posterior putamen and caudate nucleus of DYT1 patients versus matched controls, with low expression in young but not in older patients. In the cerebellar vermis, VAChT expression was also significantly decreased in patients versus controls, but independently of age. Functional connectivity within the motor network studied in MRI and the interregional correlation of VAChT expression studied in PET were also altered in patients. These results show that the cholinergic system is disrupted in the brain of DYT1 patients and is modulated over time through plasticity or compensatory mechanisms.

Does pallidal neuromodulation influence cognitive decline in Huntington's disease?

OBJECTIVE: Huntington's disease (HD) is an autosomal dominant neurodegenerative disorder associated with motor, psychiatric and cognitive deterioration over time. To date, Continuous Electrical Neuromodulation (CEN) of the globus pallidus internus (GPi) has been reported to improve chorea but little is known about cognitive progression in these patients. We propose to examine CEN impact on expected cognitive decline throughout long-term neuropsychological assessment of a cohort of HD patients. METHOD: 13 consecutive HD patients underwent GPi neuromodulation between January 2008 and February 2019. Over a 5-year follow-up period, they received systematic pre- and post-operative assessment according to the existing protocol in our unit. The main outcome measure was the total score obtained on the Mattis Dementia Rating Scale (MDRS) as an indicator of global cognitive function. RESULTS: Chorea decreased in all patients postoperatively with a mean improvement of 56% despite disease progression over time, according to previous studies. Moreover we found that the global cognitive profile of HD patients treated with CEN was stable during the first 3 years of treatment. CONCLUSION: We report an unexpected positive influence of GPi continuous electrical neuromodulation on the progression of global cognitive functioning in operated HD patients. This is the most important group of patients treated with this method to our knowledge whatever the sample size remains small. This result provides promising evidence of GPi-CEN efficacy not only in reducing chorea, but also in delaying cognitive decline in HD patients operated at an early stage of the disease.