Medical management and positive outcome after prolonged recumbency in a case of equine herpesvirus myeloencephalopathy

A 17-year-old mare presenting with acute fever, weakness and bladder dysfunction was diagnosed with equine herpesvirus myeloencephalopathy (EHM). The mare become transiently recumbent, underwent parenteral fluid therapy, plasma infusion, steroidal/nonsteroidal anti-inflammatory drugs (SAID/NSAIDs) and bladder catheterization. After 10 days the mare was hospitalized. Neurological evaluation revealed ataxia and proprioceptive deficits mainly in the hind limbs. The mare was able to stand but unable to rise from recumbency or walk. Secondary complications included Escherichia coli cystitis, corneal ulcers and pressure sores. A full-body support sling was used for 21 days. Medical treatment included systemic antimicrobials, NSAIDs, gradual discontinuation of SAIDs, parenteral fluid therapy and bladder lavage. The mare tested positive for Varicellovirus equidalpha 1 (EHV-1) DNA in nasal swab and blood samples on day 13 and in urine samples on days 13 and 25 after the onset of fever. Neurological signs improved over a period of 34 days and the mare was discharged with mild hind limb weakness/ataxia. Secondary complications resolved within 2 weeks. At the eight-month follow-up, marked improvement in locomotory function had been achieved.

Genetic aspects of ataxias in a cohort of Turkish patients

INTRODUCTION

Ataxia is one of the clinical findings of the movement disorder disease group. Although there are many underlying etiological reasons, genetic etiology has an increasing significance thanks to the recently developing technology. The aim of this study is to present the variants detected in WES analysis excluding non-genetic causes, in patients with ataxia.

METHODS

Thirty-six patients who were referred to us with findings of ataxia and diagnosed through WES or other molecular genetic analysis methods were included in our study. At the same time, information such as the onset time of the complaints, consanguinity status between parents, and the presence of relatives with similar symptoms were evaluated. If available, the patient's biochemical and radiological test results were presented.

RESULTS

Thirty-six patients were diagnosed through WES or CES. The rate of detected autosomal recessive inheritance disease was 80.5%, while that of autosomal dominant inheritance disease was 19.5%. Abnormal cerebellum was detected on brain MRI images in 26 patients, while polyneuropathy was detected on EMG in eleven of them. While the majority of the patients were compatible with similar cases reported in the literature, five patients had different/additional features (variants in MCM3AP, AGTPBP1, GDAP2, and SH3TC2 genes).

CONCLUSIONS

The diagnosis of ataxia patients with unknown etiology is made possible thanks to these clues. Consideration of a genetic approach is recommended in patients with ataxia of unknown etiology.

The genetic basis of early-onset hereditary ataxia in Iran: results of a national registry of a heterogeneous population

BACKGROUND

To investigate the genetics of early-onset progressive cerebellar ataxia in Iran, we conducted a study at the Children's Medical Center (CMC), the primary referral center for pediatric disorders in the country, over a three-year period from 2019 to 2022. In this report, we provide the initial findings from the national registry.

METHODS

We selected all early-onset patients with an autosomal recessive mode of inheritance to assess their phenotype, paraclinical tests, and genotypes. The clinical data encompassed clinical features, the Scale for the Assessment and Rating of Ataxia (SARA) scores, Magnetic Resonance Imaging (MRI) results, Electrodiagnostic exams (EDX), and biomarker features. Our genetic investigations included single-gene testing, Whole Exome Sequencing (WES), and Whole Genome Sequencing (WGS).

RESULTS

Our study enrolled 162 patients from various geographic regions of our country. Among our subpopulations, we identified known and novel pathogenic variants in 42 genes in 97 families. The overall genetic diagnostic rate was 59.9%. Notably, we observed PLA2G6, ATM, SACS, and SCA variants in 19, 14, 12, and 10 families, respectively. Remarkably, more than 59% of the cases were attributed to pathogenic variants in these genes.

CONCLUSIONS

Iran, being at the crossroad of the Middle East, exhibits a highly diverse genetic etiology for autosomal recessive hereditary ataxia. In light of this heterogeneity, the development of preventive strategies and targeted molecular therapeutics becomes crucial. A national guideline for the diagnosis and management of patients with these conditions could significantly aid in advancing healthcare approaches and improving patient outcomes.

Purkinje cell dysfunction causes disrupted sleep in ataxic mice

Purkinje cell dysfunction disrupts movement and causes disorders such as ataxia. Recent evidence suggests that Purkinje cell dysfunction may also alter sleep regulation. Here, we used an ataxic mouse model generated by silencing Purkinje cell neurotransmission (L7Cre;Vgatfx/fx) to better understand how cerebellar dysfunction impacts sleep physiology. We focused our analysis on sleep architecture and electrocorticography (ECoG) patterns based on their relevance to extracting physiological measurements during sleep. We found that circadian activity is unaltered in the mutant mice, although their sleep parameters and ECoG patterns are modified. The L7Cre;Vgatfx/fx mutant mice have decreased wakefulness and rapid eye movement (REM) sleep, while non-rapid eye movement (NREM) sleep is increased. The mutants have an extended latency to REM sleep, which is also observed in human ataxia patients. Spectral analysis of ECoG signals revealed alterations in the power distribution across different frequency bands defining sleep. Therefore, Purkinje cell dysfunction may influence wakefulness and equilibrium of distinct sleep stages in ataxia. Our findings posit a connection between cerebellar dysfunction and disrupted sleep and underscore the importance of examining cerebellar circuit function in sleep disorders.

Reduction of Microvessel Number and Length in the Cerebellum of Purkinje Cell Degeneration Mice

Degenerative effects of nerve tissues are often accompanied by changes in vascularization. In this regard, knowledge about hereditary cerebellar degeneration is limited. In this study, we compared the vascularity of the individual cerebellar components of 3-month-old wild-type mice (n = 8) and Purkinje cell degeneration (pcd) mutant mice, which represent a model of hereditary cerebellar degeneration (n = 8). Systematic random samples of tissue sections were processed, and laminin was immunostained to visualize microvessels. A computer-assisted stereology system was used to quantify microvessel parameters including total number, total length, and associated densities in cerebellar layers. Our results in pcd mice revealed a 45% (p < 0.01) reduction in the total volume of the cerebellum, a 28% (p < 0.05) reduction in the total number of vessels and a lower total length, approaching 50% (p < 0.001), compared to the control mice. In pcd mutants, cerebellar degeneration is accompanied by significant reduction in the microvascular network that is proportional to the cerebellar volume reduction therefore does not change density of in the cerebellar gray matter of pcd mice.

Ataxia and Hypogonadism: a Review of the Associated Genes and Syndromes

The association of hypogonadism and cerebellar ataxia was first recognized in 1908 by Gordon Holmes. Since the seminal description, several heterogeneous phenotypes have been reported, differing for age at onset, associated features, and gonadotropins levels. In the last decade, the genetic bases of these disorders are being progressively uncovered. Here, we review the diseases associating ataxia and hypogonadism and the corresponding causative genes. In the first part of this study, we focus on clinical syndromes and genes (RNF216, STUB1, PNPLA6, AARS2, SIL1, SETX) predominantly associated with ataxia and hypogonadism as cardinal features. In the second part, we mention clinical syndromes and genes (POLR3A, CLPP, ERAL1, HARS, HSD17B4, LARS2, TWNK, POLG, ATM, WFS1, PMM2, FMR1) linked to complex phenotypes that include, among other features, ataxia and hypogonadism. We propose a diagnostic algorithm for patients with ataxia and hypogonadism, and we discuss the possible common etiopathogenetic mechanisms.

[Scale for the assessment and rating of ataxia (SARA): translation and cultural adaptation to German-speaking areas]

BACKGROUND/OBJECTIVE

The scale for the assessment and rating of ataxia (SARA) is a feasible assessment for the classification and evaluation of therapeutic interventions. In order to provide access to the SARA in German, the aim of this work was to translate the SARA into German and to adapt it according to international guidelines for German-speaking countries.

METHOD

The process involved six steps. The comprehensibility of the scale was assessed using interviews with potential users.

RESULTS

A total of nine physiotherapists and six physicians working in various clinical settings were interviewed, seven of them worked in Germany and four each in Austria and Switzerland. The interviews led to a refined version of the translation. The comprehensibility testing revealed no country-specific differences.

CONCLUSION

A German version of the SARA authorized by the co-author of the original publication, is now available. The results provide methodological insights into the translation process of observation-based standardized assessments.

A Review of Brain and Pituitary Gland MRI Findings in Patients with Ataxia and Hypogonadism

The association of cerebellar ataxia and hypogonadism occurs in a heterogeneous group of disorders, caused by different genetic mutations often associated with a recessive inheritance. In these patients, magnetic resonance imaging (MRI) plays a pivotal role in the diagnostic workflow, with a variable involvement of the cerebellar cortex, alone or in combination with other brain structures. Neuroimaging involvement of the pituitary gland is also variable. Here, we provide an overview of the main clinical and conventional brain and pituitary gland MRI imaging findings of the most common genetic mutations associated with the clinical phenotype of ataxia and hypogonadism, with the aim of helping neuroradiologists in the identification of these disorders.

Neuropathy, ataxia, retinitis pigmentosa: a case of a mother and two siblings

AIM

We describe the ophthalmic manifestations of Neuropathy, ataxia, retinitis pigmentosa (NARP) syndrome in three related patients.

METHODS

We examined a mother and her two children, who were carriers of the mt 8993T>G mutation. The mother, patient I, is the first known carrier within the family pedigree. Patients II and III are her children from a non-carrier father. NARP syndrome and the heteroplasmy levels were established prior to the first referral of the patients to the Ophthalmology department.We performed a visual acuity testing, followed by a biomicroscopic and fundus examination, as well as additional multimodal imaging testing: optical coherence tomography (OCT) and fundus autofluorescence (FAF), and functional testing: electroretinogram and visual field.

RESULTS

All patients had the clinical manifestations of NARP syndrome, which were variably expressed symptomatically, on the fundus exams, electroretinogram, and visual fields.

CONCLUSIONS

Once genetically established, NARP syndrome, as other mitochondrial disorders, has a very variable progression with different degrees of severity. A multimodal approach involving both neurological and ophthalmological diagnosis of NARP syndrome is necessary in order to establish the course of the disease and the measures to be taken.

Expanding the Spectrum of Stress-Induced Childhood-Onset Neurodegeneration with Variable Ataxia and Seizures (CONDSIAS)

Stress-induced childhood-onset neurodegeneration with variable ataxia and seizures (CONDSIAS) is an extremely rare, autosomal recessive neurodegenerative disorder. It is caused by biallelic pathogenic variants in the ADPRS gene, which encodes an enzyme involved in DNA repair, and is characterized by exacerbations in relation to physical or emotional stress, and febrile illness. We report a 24-year-old female, who was compound heterozygous for two novel pathogenic variants revealed by whole exome sequencing. Additionally, we summarize the published cases of CONDSIAS. In our patient, onset of symptoms occurred at 5 years of age and consisted of episodes of truncal dystonic posturing, followed half a year later by sudden diplopia, dizziness, ataxia, and gait instability. Progressive hearing loss, urinary urgency, and thoracic kyphoscoliosis ensued. Present neurological examination revealed dysarthria, facial mini-myoclonus, muscle weakness and atrophy of hands and feet, leg spasticity with clonus, truncal and appendicular ataxia, and spastic-ataxic gait. Hybrid [18F]-fluorodeoxyglucose (FDG) positron emission tomography/magnetic resonance imaging (PET/MRI) of the brain revealed cerebellar atrophy, particularly of the vermis, with corresponding hypometabolism. MRI of the spinal cord showed mild atrophy. After informed consent from the patient, we initiated experimental, off-label treatment with minocycline, a poly-ADP-polymerase (PARP) inhibitor, which has shown beneficial effects in a Drosophila fly model. The present case report expands the list of known pathogenic variants in CONDIAS and presents details of the clinical phenotype. Future studies will reveal whether PARP inhibition is an effective treatment strategy for CONDIAS.

Uncertainty of Vowel Predictions as a Digital Biomarker for Ataxic Dysarthria

Dysarthria is a common manifestation across cerebellar ataxias leading to impairments in communication, reduced social connections, and decreased quality of life. While dysarthria symptoms may be present in other neurological conditions, ataxic dysarthria is a perceptually distinct motor speech disorder, with the most prominent characteristics being articulation and prosody abnormalities along with distorted vowels. We hypothesized that uncertainty of vowel predictions by an automatic speech recognition system can capture speech changes present in cerebellar ataxia. Speech of participants with ataxia (N=61) and healthy controls (N=25) was recorded during the "picture description" task. Additionally, participants' dysarthric speech and ataxia severity were assessed on a Brief Ataxia Rating Scale (BARS). Eight participants with ataxia had speech and BARS data at two timepoints. A neural network trained for phoneme prediction was applied to speech recordings. Average entropy of vowel tokens predictions (AVE) was computed for each participant's recording, together with mean pitch and intensity standard deviations (MPSD and MISD) in the vowel segments. AVE and MISD demonstrated associations with BARS speech score (Spearman's rho=0.45 and 0.51), and AVE demonstrated associations with BARS total (rho=0.39). In the longitudinal cohort, Wilcoxon pairwise signed rank test demonstrated an increase in BARS total and AVE, while BARS speech and acoustic measures did not significantly increase. Relationship of AVE to both BARS speech and BARS total, as well as the ability to capture disease progression even in absence of measured speech decline, indicates the potential of AVE as a digital biomarker for cerebellar ataxia.

A Review of Ocular Movement Abnormalities in Hereditary Cerebellar Ataxias

Cerebellar ataxias are a wide heterogeneous group of disorders that may present with fine motor deficits as well as gait and balance disturbances that have a significant influence on everyday activities. To review the ocular movements in cerebellar ataxias in order to improve the clinical knowledge of cerebellar ataxias and related subtypes. English papers published from January 1990 to May 2022 were selected by searching PubMed services. The main search keywords were ocular motor, oculomotor, eye movement, eye motility, and ocular motility, along with each ataxia subtype. The eligible papers were analyzed for clinical presentation, involved mutations, the underlying pathology, and ocular movement alterations. Forty-three subtypes of spinocerebellar ataxias and a number of autosomal dominant and autosomal recessive ataxias were discussed in terms of pathology, clinical manifestations, involved mutations, and with a focus on the ocular abnormalities. A flowchart has been made using ocular movement manifestations to differentiate different ataxia subtypes. And underlying pathology of each subtype is reviewed in form of illustrated models to reach a better understanding of each disorder.

The Development of a New Patient-Reported Outcome Measure in Recessive Ataxias: The Person-Reported Ataxia Impact Scale

Autosomal recessive cerebellar ataxias (ARCAs) are inherited neurological disorders that can affect both the central and peripheral nervous systems. To assess the effects of interventions according to the perception of people affected, patient-reported outcome measures (PROMs) must be available. This paper presents the development process of the Person-Reported Ataxia Impact Scale (PRAIS), a new PROM in recessive ataxias, and the documentation of its content validity, interpretability, and construct validity (structural and discriminant). The development followed the PROMIS framework and the Food and Drug Administration guidelines. A mixed-method study design was used to develop the PROM. A systematic review of the literature, semistructured interviews, and discussion groups was conducted to constitute an item pool. Experts' consultation helped formulate items, and the questionnaire was sent online to be completed by people affected. Statistical analyses were performed to assess the structural and discriminant validity. A total of 125 people affected by recessive ataxia completed the questionnaire. The factor analysis confirmed the three components: physical functions and activities, mental functions, and social functions. The statistical analysis showed that it can discriminate between stages of mobility and level of autonomy. It showed very good levels of internal consistency (0.79 to 0.89). The Person-Reported Ataxia Impact Scale (PRAIS) is a 38-item questionnaire that assesses the manifestations and impacts of the disease according to the perception of people affected by recessive ataxia. It can be used in clinical and research settings.

Bridging the gap between statistical significance and clinical relevance: A systematic review of minimum clinically important difference (MCID) thresholds of scales reported in movement disorders research

Background

Minimum clinically important difference (MCID) is the smallest change in an outcome measure that is considered clinically meaningful. Using validated MCID thresholds for outcomes powers trials adequately to detect meaningful treatment effects, aids in their interpretation and guides development of new outcome measures.

Objectives

To provide a comprehensive summary of MCID thresholds of various symptom severity scales reported in movement disorder.

Methods

We conducted systematic review of the literature and included studies of one or more movement disorders, and reporting MCID scales.

Results

2763 reports were screened. Final review included 32 studies. Risk of bias (RoB) assessment showed most studies were of good quality. Most commonly evaluated scale was Unified Parkinson's Disease Rating Scale (UPDRS) (11 out of 32). Four studies assessing MDS-UPDRS had assessed its different sub-parts, reporting a change of 2.64,3.05,3.25 and 0.9 points to detect clinically meaningful improvement and 2.45,2.51,4.63 and 0.8 points to detect clinically meaningful worsening, for the Part I, II, III and IV, respectively. For Parts II + III, I + II + III and I + II + III + IV, MCID thresholds reported for clinically meaningful improvement were 5.73, 4.9, 6.7 and 7.1 points respectively; while those for clinically meaningful worsening were 4.7, 4.2, 5.2 and 6.3 points, respectively. MCID thresholds reported for other scales included Abnormal Involuntary Movement Scale (AIMS), Toronto Western Spasmodic Torticollis Rating Scale (TWSRS), and Burke-Fahn-Marsden Dystonia Scale (BFMD).

Conclusion

This review summarizes all the MCID thresholds currently reported in Movement disorders research and provides a comprehensive resource for future trials, highlighting the need for standardized and validated MCID scales in movement disorder research.

Optimizing Communication in Ataxia: A Multifaceted Approach to Alternative and Augmentative Communication (AAC)

The progression of multisystem neurodegenerative diseases such as ataxia significantly impacts speech and communication, necessitating adaptive clinical care strategies. With the deterioration of speech, Alternative and Augmentative Communication (AAC) can play an ever increasing role in daily life for individuals with ataxia. This review describes the spectrum of AAC resources available, ranging from unaided gestures and sign language to high-tech solutions like speech-generating devices (SGDs) and eye-tracking technology. Despite the availability of various AAC tools, their efficacy is often compromised by the physical limitations inherent in ataxia, including upper limb ataxia and visual disturbances. Traditional speech-to-text algorithms and eye gaze technology face challenges in accuracy and efficiency due to the atypical speech and movement patterns associated with the disease.In addressing these challenges, maintaining existing speech abilities through rehabilitation is prioritized, complemented by advances in digital therapeutics to provide home-based treatments. Simultaneously, projects incorporating AI driven solutions aim to enhance the intelligibility of dysarthric speech through improved speech-to-text accuracy.This review discusses the complex needs assessment for AAC in ataxia, emphasizing the dynamic nature of the disease and the importance of regular reassessment to tailor communication strategies to the changing abilities of the individual. It also highlights the necessity of multidisciplinary involvement for effective AAC assessment and intervention. The future of AAC looks promising with developments in brain-computer interfaces and the potential of voice banking, although their application in ataxia requires further exploration.

Disentangling Cerebellar and Parietal Contributions to Gait and Body Schema: A Repetitive Transcranial Magnetic Stimulation Study

The overlap between motor and cognitive signs resulting from posterior parietal cortex (PPC) and cerebellar lesions can mask their relative contribution in the sensorimotor integration process. This study aimed to identify distinguishing motor and cognitive features to disentangle PPC and cerebellar involvement in two sensorimotor-related functions: gait and body schema representation. Thirty healthy volunteers were enrolled and randomly assigned to PPC or cerebellar stimulation. Sham stimulation and 1 Hz-repetitive-Transcranial-Magnetic-Stimulation were delivered over P3 or cerebellum before a balance and a walking distance estimation task. Each trial was repeated with eyes open (EO) and closed (EC). Eight inertial measurement units recorded spatiotemporal and kinematic variables of gait. Instability increased in both groups after real stimulation: PPC inhibition resulted in increased instability in EC conditions, as evidenced by increased ellipse area and range of movement in medio-lateral and anterior-posterior (ROMap) directions. Cerebellar inhibition affected both EC (increased ROMap) and EO stability (greater displacement of the center of mass). Inhibitory stimulation (EC vs. EO) affected also gait spatiotemporal variability, with a high variability of ankle and knee angles plus different patterns in the two groups (cerebellar vs parietal). Lastly, PPC group overestimates distances after real stimulation (EC condition) compared to the cerebellar group. Stability, gait variability, and distance estimation parameters may be useful clinical parameters to disentangle cerebellar and PPC sensorimotor integration deficits. Clinical differential diagnosis efficiency can benefit from this methodological approach.

CHARON: An Imaging-Based Diagnostic Algorithm to Navigate Through the Sea of Hereditary Degenerative Ataxias

The complexity in diagnosing hereditary degenerative ataxias lies not only in their rarity, but also in the variety of different genetic conditions that can determine sometimes similar and overlapping clinical findings. In this light, Magnetic Resonance Imaging (MRI) plays a key role in the evaluation of these conditions, being a fundamental diagnostic tool needed not only to exclude other causes determining the observed clinical phenotype, but also to proper guide to an adequate genetic testing. Here, we propose an MRI-based diagnostic algorithm named CHARON (Characterization of Hereditary Ataxias Relying On Neuroimaging), to help in disentangling among the numerous, and apparently very similar, hereditary degenerative ataxias. Being conceived from a neuroradiological standpoint, it is based primarily on an accurate evaluation of the observed MRI findings, with the first and most important being the pattern of cerebellar atrophy. Along with the evaluation of the presence, or absence, of additional signal changes and/or supratentorial involvement, CHARON allows for the identification of a small groups of ataxias sharing similar imaging features. The integration of additional MRI findings, demographic, clinical and laboratory data allow then for the identification of typical, and in some cases pathognomonic, phenotypes of hereditary ataxias.

Effect of high frequency repetitive transcranial magnetic stimulation (rTMS) on the balance and the white matter integrity in patients with relapsing-remitting multiple sclerosis: A long-term follow-up study

OBJECTIVES

Repetitive Transcranial Magnetic Stimulation (rTMS) is considered as a safe and non-invasive developing technique used as a therapeutic method for patients with Relapsing-Remitting Multiple Sclerosis (RRMS) who suffer from disturbances in gait and balance. The aim of our study is to evaluate the long-term effect of high frequency rTMS as a therapeutic option for truncal ataxia in RRMS patients and to assess its impact on the integrity of the white matter (WMI), measured in the form of anisotropy metrics using diffusion tensor imaging (DTI).

METHODS

The study was conducted in two phases: phase I; a randomized, single-blind, sham-controlled phase and phase II was a 12 months longitudinal open-label prospective phase. Phase I of the trial involved the randomization of 43 patients with RRMS and truncal ataxia to either real (n = 20) or sham (n = 19) rTMS (2 participants from each treatment group were excluded from the study; one developed a relapse before treatment, 2 declined to participate, and one did not show up). Phase II involved providing 12 actual treatments cycles to all patients; each cycle length is 4 weeks, repeated four times on a trimonthly basis, forming a total of 48 sessions. DTI was used for assessment of the WMI. All patients performed DTI 3 times: Imaging sessions were conducted at the screening visit, at the end of phase I, and after the last session in phase II for the first, second and third sessions respectively. A figure-of-8-shape coil, employing rTMS protocol and located over the cerebellum, was used. rTMS protocol is formed of 20 trains formed of 50 stimuli with 20 s apart (5 Hz of 80 % of resting Motor Threshold "MT"). The Berg Balance Scale (BBS), Time up and go (TUG) test, and 10-m walk test (10MWT) were first evaluated at the start of each cycle and just after the final rTMS session.

RESULTS

The genuine rTMS group's 10MWT, TUG, and BBS showed substantial improvement (p < 0.01), which is continued to be improved throughout the study Timeline, with a significant difference observed following the final rTMS session (P< 0.001). A longitudinal increase in FA was observed in both the Cerebello-Thalamo-Cortical (CTC) and Cortico-Ponto-Cerebellar (CPC) bilateral, as indicated by means of Fractional Anisotropy (FA) measures (p < 0.05).

CONCLUSION

In ataxic RRMS patients, high frequency rTMS over the cerebellum has a long-term beneficial impact on both balance and WMI.

Analysis of static plantar pressure data with capsule networks: Diagnosing ataxia in MS patients with a deep learning-based approach

In this study, it was aimed to detect ataxia in patients with Multiple Sclerosis (MS) by utilizing static plantar pressure data and capsule networks (CapsNet), one of the deep learning (DL) architectures. CapsNet is also equipped with a robust dynamic routing mechanism that determines the output of the next capsule. MS is a chronic nervous system disease that shows its effect in the central nervous system and manifests itself with attacks. One of the most common and challenging symptoms of MS is known as ataxia. Ataxia causes loss of control of limb muscle tone or gait disorders, leading to loss of balance and coordination. The diagnosis of ataxia in MS is applied employing the standard Expanded Disability Status Scale (EDSS) score. However, due to reasons such as physician misconception, diagnosis differences among physicians, and incorrect patient information, more unbiased solutions are required for the diagnosis. The results included Sensitivity at 96.34 % ± 1.71, Specificity at 98.11 % ± 2.04, Precision at 98.08 % ± 2.16, and Accuracy at 97.13 % ± 0.33. The main motivation of the study is to show that these deep learning methods can successfully detect ataxia in MS patients using static plantar pressure data. The high-performance measurements of sensitivity, specificity, precision and accuracy emphasize that the proposed system can be an effective tool in clinical practice. In addition, it was concluded that the proposed autonomous system would be a support mechanism to assist the physician in the detection of ataxia in patients with MS.

The Scale for Assessment and Rating of Ataxia Is Reliable and Valid in the Telehealth Setting for Patients With Cerebellar Ataxia

OBJECTIVE

Health care has increasingly expanded into a hybrid in-person/telehealth model. Patients with a variety of health conditions, including cerebellar ataxia, have received virtual health evaluations; however, it remains unknown whether some outcome measures that clinicians utilize in the telehealth setting are reliable and valid. The goal of this project is to evaluate the psychometric properties of the Scale for Assessment and Rating of Ataxia (SARA) for patients with cerebellar ataxia in the telehealth setting.

METHODS

Nineteen individuals with cerebellar impairments were recruited on a voluntary basis. Participants completed 2 30-minute testing sessions during which a clinical examination and the SARA were performed. One session was performed in person, and the other session was assessed remotely. Outcome measure performance was video recorded in both environments and independently scored by 4 additional raters with varying levels of clinical experience (ranging from 6 months to 29 years). Concurrent validity was assessed with the Spearman rank order correlation coefficient (α < .05), comparing the virtual SARA scores to their gold standard in-person scores. Interrater reliability was evaluated with the intraclass correlation coefficient (ICC) (2,4) (α < .05).

RESULTS

Fourteen of the 19 participants completed both in-person and telehealth SARA evaluations. We found that the in-person SARA and the telehealth SARA have large concurrent validity (Spearman rho significant at the 2-tailed α of .01 = 0.90; n = 14). Additionally, raters of varying years of experience had excellent interrater reliability for both the in-person SARA (ICC [2,4] = 0.97; n = 19) and the telehealth SARA (ICC [2,4] = 0.98; n = 14).

CONCLUSION

Our results show that the telehealth SARA is comparable to the in-person SARA. Additionally, raters of varying years of clinical experience were found to have excellent interrater reliability scores for both remote and in-person SARA evaluations.

IMPACT

Our study shows that the SARA can be used in the telehealth setting for patients with ataxia.

Quadriplegia, Dysphagia and Ataxia Manifested in a Child With COVID-19 Related Acute Necrotizing Encephalopathy: A Case Report

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2, presents primarily with respiratory symptoms. However, children with COVID-19 are usually asymptomatic or mild acute symptoms and also neurological manifestations have also been observed. We report the case of a 7-year-old girl who presented with high fever and altered mental status, leading to a diagnosis of COVID-19 and acute necrotizing encephalopathy (ANE). The patient received intensive medical care in the intensive care unit and subsequently underwent rehabilitation programs due to neurological functional sequelae. Neurological complications in COVID-19, including ANE, may result from potential viral nerve involvement, cytokine storms, and the blood-brain barrier disruption. Early rehabilitation plays a pivotal role in managing COVID-19-related neurological complications and enhancing patients' functional outcomes. Further research is essential to gain a better understanding of the mechanisms and treatment strategies for neurological manifestations in pediatric COVID-19 patients, particularly those with multisystem inflammatory syndrome in child.

Classic and Atypical Late Infantile Neuronal Ceroid Lipofuscinosis in Latin America: Clinical and Genetic Aspects, and Treatment Outcome with Cerliponase Alfa

Introduction

Late infantile neuronal ceroid lipofuscinosis type 2 (CLN2), is a neurodegenerative autosomal recessive disease caused by TPP1 gene variants, with a spectrum of classic and atypical phenotypes. The aim of treatment is to slow functional decline as early as possible in an attempt to improve quality of life and survival. This study describes the clinical characteristics as well as the response to treatment with cerliponase alfa.

Materials and methods

A retrospective study was conducted in five Latin-American countries, using clinical records from patients with CLN2. Clinical follow-up and treatment variables are described. A descriptive and bivariate statistical analysis was performed.

Results

A total of 36 patients were observed (range of follow-up of 61-110 weeks post-treatment). At presentation, patients with the classic phenotype (n = 16) exhibited regression in language (90%), while seizures were the predominant symptom (87%) in patients with the atypical phenotype (n = 20). Median age of symptom onset and time to first specialized consultation was 3 (classical) and 7 (atypical) years, while the median time interval between onset of symptoms and treatment initiation was 4 years (classical) and 7.5 (atypical). The most frequent variant was c.827 A > T in 17/72 alleles, followed by c.622C > T in 6/72 alleles. All patients were treated with cerliponase alfa, and either remained functionally stable or had a loss of 1 point on the CLN2 scale, or up to 2 points on the Wells Cornel and Hamburg scales, when compared to pretreatment values.

Discussion and conclusion

This study reports the largest number of patients with CLN2 currently on treatment with cerliponase alfa in the world. Data show a higher frequency of patients with atypical phenotypes and a high allelic proportion of intron variants in our region. There was evidence of long intervals until first specialized consultation, diagnosis, and enzyme replacement therapy. Follow-up after the initiation of cerliponase alfa showed slower progression or stabilization of the disease, associated with adequate clinical outcomes and stable functional scores. These improvements were consistent in both clinical phenotypes.

Functional ataxia in a specialized ataxia center

BACKGROUND

Functional gait is a disorder of ambulation and balance internally inconsistent and incongruent with the phenotypic spectrum of neurological gait disorders.

OBJECTIVES

This paper aims to clinically characterize patients with functional ataxia.

METHODS

Patients with functional ataxia were analyzed out of 1350 patients in Ataxia Unit of the Federal University of São Paulo circa 2008 to 2022.

RESULTS

Thirteen patients (1 %) presented with functional ataxia; all female, with a median age of 34.8 years. Six (46.2 %) had psychiatric comorbidities and 7 (53.8 %) endorsed a trigger. Diagnostic features included variable base and stride (100 %), "huffing and puffing" (30.7 %), knee-buckling (30.7 %), uneconomic posturing (38.5 %), tightrope walking (23 %), and trembling gait (15.4 %). Remarkably, no falls were reported in any case. 53.8 % recovered fully or partially, despite no treatment.

CONCLUSIONS

Variability of base and stride are universal features of functional ataxia, yet falls are inconspicuous. Functional Ataxia is rare even in a specialized ataxia center.

A multi-faceted approach to unravel coding and non-coding gene fusions and target chimeric proteins in ataxia

Ataxia represents a heterogeneous group of neurodegenerative disorders characterized by a loss of balance and coordination, often resulting from mutations in genes vital for cerebellar function and maintenance. Recent advances in genomics have identified gene fusion events as critical contributors to various cancers and neurodegenerative diseases. However, their role in ataxia pathogenesis remains largely unexplored. Our study Hdelved into this possibility by analyzing RNA sequencing data from 1443 diverse samples, including cell and mouse models, patient samples, and healthy controls. We identified 7067 novel gene fusions, potentially pivotal in disease onset. These fusions, notably in-frame, could produce chimeric proteins, disrupt gene regulation, or introduce new functions. We observed conservation of specific amino acids at fusion breakpoints and identified potential aggregate formations in fusion proteins, known to contribute to ataxia. Through AI-based protein structure prediction, we identified topological changes in three high-confidence fusion proteins-TEN1-ACOX1, PEX14-NMNAT1, and ITPR1-GRID2-which could potentially alter their functions. Subsequent virtual drug screening identified several molecules and peptides with high-affinity binding to fusion sites. Molecular dynamics simulations confirmed the stability of these protein-ligand complexes at fusion breakpoints. Additionally, we explored the role of non-coding RNA fusions as miRNA sponges. One such fusion, RP11-547P4-FLJ33910, showed strong interaction with hsa-miR-504-5p, potentially acting as its sponge. This interaction correlated with the upregulation of hsa-miR-504-5p target genes, some previously linked to ataxia. In conclusion, our study unveils new aspects of gene fusions in ataxia, suggesting their significant role in pathogenesis and opening avenues for targeted therapeutic interventions.Communicated by Ramaswamy H. Sarma.

A scoping review

One of the most relevant challenges for healthcare providers during the COVID- 19 pandemic has been assuring the continuity of care to patients with complex health needs such as people living with rare diseases (RDs). The COVID-19 pandemic accelerated the healthcare sector's digital transformation agenda. The delivery of telemedicine services instead of many face-to-face procedures has been expanded and, many healthcare services not directly related to COVID-19 treatments shifted online remotely. Many hospitals, specialist centres, patients and families started to use telemedicine because they were forced to. This trend could directly represent a good practice on how care services could be organized and continuity of care could be ensured for patients. If done properly, it could boast improved patient outcomes and become a post COVID-19 major shift in the care paradigm. There is a fragmented stakeholders spectrum, as many questions arise on: how is e-health interacting with 'traditional' healthcare providers; about the role of the European Reference Networks (ERNs); if remote care can retain a human touch and stay patient centric. The manuscript is one of the results of the European Brain Council (EBC) Value of Treatment research project on rare brain disorders focusing on progressive ataxias, dystonia and phenylketonuria with the support of Academic Partners and in collaboration with European Reference Networks (ERNs) experts, applying empirical evidence from different European countries. The main purpose of this work is to investigate the impact of the COVID-19 pandemic on the continuity of care for ataxias, dystonia and phenylketonuria (PKU) in Europe. The analysis carried out makes it possible to highlight the critical points encountered and to learn from the best experiences. Here, we propose a scoping review that investigates this topic, focusing on continuity of care and novel methods (e.g., digital approaches) used to reduce the care disruption. This scoping review was designed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for scoping reviews (PRISMA-ScR) standards. This work showed that the implementation of telemedicine services was the main measure that healthcare providers (HCPs) put in place and adopted for mitigating the effects of disruption or discontinuity of the healthcare services of people with rare neurological diseases and with neurometabolic disorders in Europe.

Cerebellar Volumetry in Ataxias: Relation to Ataxia Severity and Duration

Cerebellar atrophy is the neuropathological hallmark of most ataxias. Hence, quantifying the volume of the cerebellar grey and white matter is of great interest. In this study, we aim to identify volume differences in the cerebellum between spinocerebellar ataxia type 1 (SCA1), SCA3 and SCA6 as well as multiple system atrophy of cerebellar type (MSA-C). Our cross-sectional data set comprised mutation carriers of SCA1 (N=12), SCA3 (N=62), SCA6 (N=14), as well as MSA-C patients (N=16). Cerebellar volumes were obtained from T1-weighted magnetic resonance images. To compare the different atrophy patterns, we performed a z-transformation and plotted the intercept of each patient group's model at the mean of 7 years of ataxia duration as well as at the mean ataxia severity of 14 points in the SARA sum score. In addition, we plotted the extrapolation at ataxia duration of 0 years as well as 0 points in the SARA sum score. Patients with MSA-C demonstrated the most pronounced volume loss, particularly in the cerebellar white matter, at the late time intercept. Patients with SCA6 showed a pronounced volume loss in cerebellar grey matter with increasing ataxia severity compared to all other patient groups. MSA-C, SCA1 and SCA3 showed a prominent atrophy of the cerebellar white matter. Our results (i) confirmed SCA6 being considered as a pure cerebellar grey matter disease, (ii) emphasise the involvement of cerebellar white matter in the neuropathology of SCA1, SCA3 and MSA-C, and (iii) reflect the rapid clinical progression in MSA-C.

Disbalanced recruitment of crossed and uncrossed cerebello-thalamic pathways during deep brain stimulation is predictive of delayed therapy escape in essential tremor

BACKGROUND

Thalamic deep brain stimulation (DBS) is an efficacious treatment for drug-resistant essential tremor (ET) and the dentato-rubro-thalamic tract (DRT) constitutes an important target structure. However, up to 40% of patients habituate and lose treatment efficacy over time, frequently accompanied by a stimulation-induced cerebellar syndrome. The phenomenon termed delayed therapy escape (DTE) is insufficiently understood. Our previous work showed that DTE clinically is pronounced on the non-dominant side and suggested that differential involvement of crossed versus uncrossed DRT (DRTx/DRTu) might play a role in DTE development.

METHODS

We retrospectively enrolled right-handed patients under bilateral thalamic DBS >12 months for ET from a cross-sectional study. They were characterized with the Fahn-Tolosa-Marin Tremor Rating Scale (FTMTRS) and Scale for the Assessment and Rating of Ataxia (SARA) scores at different timepoints. Normative fiber tractographic evaluations of crossed and uncrossed cerebellothalamic pathways and volume of activated tissue (VAT) studies together with [18F]Fluorodeoxyglucose positron emission tomography were applied.

RESULTS

A total of 29 patients met the inclusion criteria. Favoring DRTu over DRTx in the non-dominant VAT was associated with DTE (R2 = 0.4463, p < 0.01) and ataxia (R2 = 0.2319, p < 0.01). Moreover, increasing VAT size on the right (non-dominant) side was associated at trend level with more asymmetric glucose metabolism shifting towards the right (dominant) dentate nucleus.

CONCLUSION

Our results suggest that a disbalanced recruitment of DRTu in the non-dominant VAT induces detrimental stimulation effects on the dominant cerebellar outflow (together with contralateral stimulation) leading to DTE and thus hampering the overall treatment efficacy.

Syndrome of Irreversible Lithium-Effectuated Neurotoxicity (SILENT): A Preventable Cerebellar Disorder

We report a case study of a 60-year-old man with bipolar disorder on stable lithium treatment who developed severe toxicity while admitted to ICU with sepsis and multiorgan failure. Despite unchanged lithium administration, his serum levels escalated due to renal dysfunction, resulting in lithium toxicity. After regaining consciousness, he exhibited a cerebellar syndrome marked by ataxia, tremor, and scanning speech. MRI revealed cerebellar atrophy. Following discontinuation of lithium and hemodialysis, the patient's symptoms remained static. The patient was diagnosed with syndrome of irreversible lithium-effectuated neurotoxicity (SILENT), a chronic cerebellar disorder characterized by persistent ataxia, nystagmus, and gait abnormalities extending beyond two months post-lithium exposure. The disorder has a predilection for cerebellar and basal ganglia dysfunction. MRI findings include cerebellar gliosis and atrophy and leptomeningeal enhancement. This case report highlights that SILENT is both preventable and permanent, urging heightened awareness among clinicians to facilitate early detection and intervention. Patients on lithium with compromised renal function or fever necessitate vigilant lithium level monitoring, dose adjustment, or cessation, to forestall enduring morbidity. This case emphasizes the significance of recognizing and managing SILENT, particularly in critical care settings, to mitigate long-term cerebellar impairment and optimize patient outcomes.

Instrumented assessment of gait disturbance in PMM2-CDG adults: a feasibility analysis

BACKGROUND

Congenital disorders of glycosylation (CDG) are genetic diseases caused by impaired synthesis of glycan moieties linked to glycoconjugates. Phosphomannomutase 2 deficiency (PMM2-CDG), the most frequent CDG, is characterized by prominent neurological involvement. Gait disturbance is a major cause of functional disability in patients with PMM2-CDG. However, no specific gait assessment for PMM2-CDG is available. This study analyses gait-related parameters in PMM2-CDG patients using a standardized clinical assessment and instrumented gait analysis (IGA).

RESULTS

Seven adult patients with a molecular diagnosis of PMM2-CDG were followed-up from February 2021 to December 2022 and compared to a group of healthy control (HC) subjects, matched for age and sex. Standardized assessment of disease severity including ataxia and peripheral neuropathy along with isometric muscle strength and echo-biometry measurements at lower limbs were performed. IGA spatiotemporal parameters were obtained by means of a wearable sensor in basal conditions. PMM2-CDG patients displayed lower gait speed, stride length, cadence and symmetry index, compared to HC. Significant correlations were found among the used clinical scales and between disease severity (NCRS) scores and the gait speed measured by IGA. Variable reduction of knee extension strength and a significant decrease of lower limb muscle thickness with conserved echo intensity were found in PMM2-CDG compared to HC.

CONCLUSIONS

The study elucidates different components of gait disturbance in PMM2-CDG patients and shows advantages of using wearable sensor-based IGA in this frame. IGA parameters may potentially serve as quantitative measures for follow-up or outcome quantification in PMM2-CDG.

Mitochondrial damage and impaired mitophagy contribute to disease progression in SCA6

Spinocerebellar ataxia type 6 (SCA6) is a neurodegenerative disease that manifests in midlife and progressively worsens with age. SCA6 is rare, and many patients are not diagnosed until long after disease onset. Whether disease-causing cellular alterations differ at different disease stages is currently unknown, but it is important to answer this question in order to identify appropriate therapeutic targets across disease duration. We used transcriptomics to identify changes in gene expression at disease onset in a well-established mouse model of SCA6 that recapitulates key disease features. We observed both up- and down-regulated genes with the major down-regulated gene ontology terms suggesting mitochondrial dysfunction. We explored mitochondrial function and structure and observed that changes in mitochondrial structure preceded changes in function, and that mitochondrial function was not significantly altered at disease onset but was impaired later during disease progression. We also detected elevated oxidative stress in cells at the same disease stage. In addition, we observed impairment in mitophagy that exacerbates mitochondrial dysfunction at late disease stages. In post-mortem SCA6 patient cerebellar tissue, we observed metabolic changes that are consistent with mitochondrial impairments, supporting our results from animal models being translatable to human disease. Our study reveals that mitochondrial dysfunction and impaired mitochondrial degradation likely contribute to disease progression in SCA6 and suggests that these could be promising targets for therapeutic interventions in particular for patients diagnosed after disease onset.

Neuropathy in ARSACS is demyelinating but without typical nerve enlargement in nerve ultrasound

BACKGROUND

To specify peripheral nerve affection in autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) by correlating high-resolution nerve ultrasound and nerve conduction studies.

METHODS

We assessed a cohort of 11 ARSACS patients with standardized nerve conduction studies and high-resolution ultrasound of peripheral nerves and compared nerve ultrasound findings to a healthy control group matched for age, sex, size and weight.

RESULTS

Mean age of patients was 39.0 (± 14.1) years and disease duration at assessment 30.6 (± 12.5) years. All patients presented with a spasticity, ataxia and peripheral neuropathy. Neuropathy appeared to be primarily demyelinating in 9/11 cases and was not classifiable in 2/11 cases due to not evocable potentials. Nerve ultrasound revealed a normal ultrasound pattern sum score (UPSS) in each ARSACS patient and no significant nerve enlargement compared to the control group.

CONCLUSIONS

Peripheral neuropathy in ARSACS showed primarily demyelinating rather than axonal characteristics and presented without nerve enlargement. As demyelinating neuropathies do commonly present enlarged nerves we recommend further genetic testing of the SACS gene in patients who present with this combination of demyelinating neuropathy without nerve enlargement. ARSACS cases that initially presented only with neuropathy without spasticity or ataxia and therefore were misdiagnosed as Charcot-Marie-Tooth disease are supporting this suggestion.

A Systematic Review of the Spectrum and Prevalence of Non-motor Symptoms in Multiple System Atrophy

BACKGROUND

Patients with Multiple System Atrophy (MSA) frequently report non-motor symptoms, and several research groups have highlighted this.

OBJECTIVE

We systematically searched for and reviewed papers assessing prevalence of non-motor symptoms (NMS) in MSA patients as reported in the scientific literature.

METHODS

We performed a systematic review of studies of subjects with MSA (involving > 10 patients) who were assessed for NMS, published in the English literature in PUBMED and EMBASE databases from 1947-2022.

RESULTS

23 research papers, with data from 2648 clinically diagnosed and 171 pathologically verified cases of MSA were included, along with 238 controls. Mean age for MSA cases was 61.3 (9.2) years, mean disease duration 3.6 (2.7) years. 57.9% were male. Our analysis showed that the prevalence of cognitive issues in MSA varied widely (between 15-100%); dementia per se was uncommon, but assessment in advanced stages of MSA is impacted by unintelligible speech (which may be noted in a quarter of cases). The prevalence of depressive symptoms in MSA was between 44-88%. Sleep disturbances were reported by 17-89%, with REM-sleep behaviour disorder (RBD) rates as high as 75%. Pain was reported by 40-47% of patients: rheumatic or musculoskeletal sources of pain being commonest. Fatigue was reported by 29-60% of patients. Symptoms of autonomic failure in MSA were seen in 34-96.5% patients at baseline.

CONCLUSION

In routine clinical practice, NMS in MSA are under-recognised by clinicians. These impact hugely on patient quality of life and contribute to their overall morbidity. A methodical ascertainment of these complaints will address an unmet need, and lead to a more holistic approach of care for individuals with MSA.

Upper limb intention tremor assessment: opportunities and challenges in wearable technology

BACKGROUND

Tremors are involuntary rhythmic movements commonly present in neurological diseases such as Parkinson's disease, essential tremor, and multiple sclerosis. Intention tremor is a subtype associated with lesions in the cerebellum and its connected pathways, and it is a common symptom in diseases associated with cerebellar pathology. While clinicians traditionally use tests to identify tremor type and severity, recent advancements in wearable technology have provided quantifiable ways to measure movement and tremor using motion capture systems, app-based tasks and tools, and physiology-based measurements. However, quantifying intention tremor remains challenging due to its changing nature.

METHODOLOGY & RESULTS

This review examines the current state of upper limb tremor assessment technology and discusses potential directions to further develop new and existing algorithms and sensors to better quantify tremor, specifically intention tremor. A comprehensive search using PubMed and Scopus was performed using keywords related to technologies for tremor assessment. Afterward, screened results were filtered for relevance and eligibility and further classified into technology type. A total of 243 publications were selected for this review and classified according to their type: body function level: movement-based, activity level: task and tool-based, and physiology-based. Furthermore, each publication's methods, purpose, and technology are summarized in the appendix table.

CONCLUSIONS

Our survey suggests a need for more targeted tasks to evaluate intention tremors, including digitized tasks related to intentional movements, neurological and physiological measurements targeting the cerebellum and its pathways, and signal processing techniques that differentiate voluntary from involuntary movement in motion capture systems.

Investigation of RFC1 tandem nucleotide repeat locus in diverse neurodegenerative outcomes in an Indian cohort

An intronic bi-allelic pentanucleotide repeat expansion mutation, (AAGGG)400-2000, at AAAAG repeat locus in RFC1 gene, is known as underlying genetic cause in cases with cerebellar ataxia, neuropathy, and vestibular areflexia syndrome (CANVAS) and late-onset sporadic ataxia. Biallelic positive cases carry a common recessive risk haplotype, "AAGA," spanning RFC1 gene. In this study, our aim is to find prevalence of bi-allelic (AAGGG)exp in Indian ataxia and other neurological disorders and investigate the complexity of RFC1 repeat locus and its potential association with neurodegenerative diseases in Indian population-based cohorts. We carried out repeat number and repeat type estimation using flanking PCR and repeat primed PCR (AAAAG/AAAGG/AAGGG) in four Indian disease cohorts and healthy controls. Haplotype assessment of suspected cases was done by genotyping and confirmed by Sanger sequencing. Blood samples and consent of all the cases and detailed clinical details of positive cases were collected in collaboration with A.I.I.M.S. Furthermore, comprehension of RFC1 repeat locus and risk haplotype analysis in Indian background was performed on the NGS data of Indian healthy controls by ExpansionHunter, ExpansionHunter Denovo, and PHASE analysis, respectively. Genetic screening of RFC1-TNR locus in 1998 uncharacterized cases (SCA12: 87; uncharacterized ataxia: 1818, CMT: 93) and 564 heterogenous controls showed that the frequency of subjects with bi-allelic (AAGGG)exp are 1.15%, < 0.05%, 2.15%, and 0% respectively. Two RFC1 positive sporadic late-onset ataxia cases, one bi-allelic (AAGGG)exp and another, (AAAGG)~700/(AAGGG)exp, had recessive risk haplotype and CANVAS symptoms. Long normal alleles, 15-27, are significantly rare in ataxia cohort. In IndiGen control population (IndiGen; N = 1029), long normal repeat range, 15-27, is significantly associated with A3G3 and some rare repeat motifs, AGAGG, AACGG, AAGAG, and AAGGC. Risk-associated "AAGA" haplotype of the original pathogenic expansion of A2G3 was found associated with the A3G3 representing alleles in background population. Apart from bi-allelic (AAGGG)exp, we report cases with a new pathogenic expansion of (AAAGG)exp/(AAGGG)exp in RFC1 and recessive risk haplotype. We found different repeat motifs at RFC1 TNR locus, like AAAAG, AAAGG, AAAGGG, AAAAGG, AAGAG, AACGG, AAGGC, AGAGG, and AAGGG, in Indian background population except ACAGG and (AAAGG)n/(AAGGG)n. Our findings will help in further understanding the role of long normal repeat size and different repeat motifs, specifically AAAGG, AAAGGG, and other rare repeat motifs, at the RFC1 locus.

Paraneoplastic movement disorders

Paraneoplastic movement disorders are diverse autoimmune neurological illnesses occurring in the context of systemic cancer, either in isolation or as part of a multifocal neurological disease. Movement phenomena may be ataxic, hypokinetic (parkinsonian), or hyperkinetic (myoclonus, chorea, or other dyskinetic disorders). Some disorders mimic neurodegenerative or hereditary illnesses. The subacute onset and coexisting nonclassic features of paraneoplastic disorders aid distinction. Paraneoplastic autoantibodies provide further information regarding differentiating cancer association, disease course, and treatment responses. A woman with cerebellar ataxia could have metabotropic glutamate receptor 1 autoimmunity, in the setting of Hodgkin lymphoma, a mild neurological phenotype and response to immunotherapy. A different woman, also with cerebellar ataxia, could have Purkinje cytoplasmic antibody type 1 (anti-Yo), accompanying ovarian adenocarcinoma, a rapidly progressive phenotype and persistent disabling deficits despite immune therapy. The list of antibody biomarkers is growing year-on-year, each with its own ideal specimen type for detection (serum or CSF), accompanying neurological manifestations, cancer association, treatment response, and prognosis. Therefore, a profile-based approach to screening both serum and CSF is recommended. Immune therapy trials are generally undertaken, and include one or more of corticosteroids, IVIg, plasma exchange, rituximab, or cyclophosphamide. Symptomatic therapies can also be employed for hyperkinetic disorders.

Phenytoin-induced cerebellar atrophy: A case for reversibility of neurological decline

This case serves as a reminder of the infrequent, yet consequential occurrence of cerebellar degeneration linked to phenytoin usage. Whilst emphasizes the importance of monitoring patients on long-term phenytoin therapy, and it further suggests considering employing bedside imaging tools such as Ultrasound fusion imaging for follow-up of patients at risk of this type of disorder. We present a case study involving a 23-year-old woman who experienced significant neurological impairment resulting in severe cerebellar atrophy while undergoing phenytoin treatment. On cessation of phenytoin, the patient exhibited improvement with enhanced cerebellar function.

Scrub typhus with opsoclonus-myoclonus-ataxia-seizure as primary presentations

Scrub typhus is a simple acute febrile illness with rash or an eschar, with up to one-fifth of the patients complicated with the nervous system. Hence, certain cases present to physicians with rather a different systemic manifestation and incidentally have been diagnosed with scrub typhus. We present two such cases of scrub typhus with neurological manifestations. The first case was of a 14-year-old boy with no previous history of any comorbidities who presented with bilateral opsoclonus with multifocal spontaneous myoclonus with cerebellar ataxia with a preceding history of fever and acute gastroenteritis. The second case of a 30-year-old gentleman with no previous history of any comorbidities presented to us with generalized tonic-clonic seizures and spontaneous multifocal myoclonus with a preceding history of fever. Both cases had no motor, sensory, cerebellar, or autonomic involvement. The pathophysiology of central nervous system (CNS) infections in scrub typhus is attributed to three major mechanisms of vasculitis, direct invasion, and immune-mediated. CNS involvement in scrub typhus is a significant marker for risk of mortality or morbidity. The most common CNS manifestations in scrub include meningitis, encephalitis, and seizures. Opsoclonus, myoclonus, and parkinsonism are comparatively rare manifestations.Scrub typhus infection must be considered in the differential diagnosis of clinical neurological features with even a remote history of acute febrile illnesses in endemic regions like ours, despite the absence of any eschar, rashes, and unremarkable neuroimaging.

Metabolic Determinants of Cerebellar Circuit Formation and Maintenance

Cells configure their metabolism in a synchronized and timely manner to meet their energy demands throughout development and adulthood. Transitions of developmental stages are coupled to metabolic shifts, such that glycolysis is highly active during cell proliferation, whereas oxidative phosphorylation prevails in postmitotic states. In the cerebellum, metabolic transitions are remarkable given its protracted developmental timelines. Such distinctive feature, along with its high neuronal density and metabolic demands, make the cerebellum highly vulnerable to metabolic insults. Despite the expansion of metabolomic approaches to uncover biological mechanisms, little is known about the role of metabolism on cerebellar development and maintenance. To illuminate the intricate connections between metabolism, physiology, and cerebellar disorders, we examined here the impact of metabolism on cerebellar growth, maturation, and adulthood through the lens of inborn errors of metabolism.

AAGGG repeat expansions trigger RFC1-independent synaptic dysregulation in human CANVAS Neurons

Cerebellar ataxia with neuropathy and vestibular areflexia syndrome (CANVAS) is a late onset, recessively inherited neurodegenerative disorder caused by biallelic, non-reference pentameric AAGGG(CCCTT) repeat expansions within the second intron of replication factor complex subunit 1 (RFC1). To investigate how these repeats cause disease, we generated CANVAS patient induced pluripotent stem cell (iPSC) derived neurons (iNeurons) and utilized calcium imaging and transcriptomic analysis to define repeat-elicited gain-of-function and loss-of-function contributions to neuronal toxicity. AAGGG repeat expansions do not alter neuronal RFC1 splicing, expression, or DNA repair pathway functions. In reporter assays, AAGGG repeats are translated into pentapeptide repeat proteins that selectively accumulate in CANVAS patient brains. However, neither these proteins nor repeat RNA foci were detected in iNeurons, and overexpression of these repeats in isolation did not induce neuronal toxicity. CANVAS iNeurons exhibit defects in neuronal development and diminished synaptic connectivity that is rescued by CRISPR deletion of a single expanded allele. These phenotypic deficits were not replicated by knockdown of RFC1 in control neurons and were not rescued by ectopic expression of RFC1. These findings support a repeat-dependent but RFC1-independent cause of neuronal dysfunction in CANVAS, with important implications for therapeutic development in this currently untreatable condition.

The Role of the Cerebellum in Learning to Predict Reward: Evidence from Cerebellar Ataxia

Recent findings in animals have challenged the traditional view of the cerebellum solely as the site of motor control, suggesting that the cerebellum may also be important for learning to predict reward from trial-and-error feedback. Yet, evidence for the role of the cerebellum in reward learning in humans is lacking. Moreover, open questions remain about which specific aspects of reward learning the cerebellum may contribute to. Here we address this gap through an investigation of multiple forms of reward learning in individuals with cerebellum dysfunction, represented by cerebellar ataxia cases. Nineteen participants with cerebellar ataxia and 57 age- and sex-matched healthy controls completed two separate tasks that required learning about reward contingencies from trial-and-error. To probe the selectivity of reward learning processes, the tasks differed in their underlying structure: while one task measured incremental reward learning ability alone, the other allowed participants to use an alternative learning strategy based on episodic memory alongside incremental reward learning. We found that individuals with cerebellar ataxia were profoundly impaired at reward learning from trial-and-error feedback on both tasks, but retained the ability to learn to predict reward based on episodic memory. These findings provide evidence from humans for a specific and necessary role for the cerebellum in incremental learning of reward associations based on reinforcement. More broadly, the findings suggest that alongside its role in motor learning, the cerebellum likely operates in concert with the basal ganglia to support reinforcement learning from reward.

Progressive Ataxia and Palatal Tremor Is Not Associated with IgLON5 Antibodies: Results From Two Cases

Progressive ataxia and palatal tremor (PAPT) and anti-IgLON5 disease share possible clinical presentations. Furthermore, both have been associated to a tauopathy mainly affecting the brainstem. Nonetheless, anti-IgLON5 antibodies have never been tested in PAPT. We report on two PAPT cases without evidence of anti-IgLON5 antibodies in both CSF and serum. Despite common clinical and pathological characteristics, PAPT and IgLON5 disease are two distinct entities.

Impact of specialist ataxia centres on health service resource utilisation and costs across Europe: cross-sectional survey

BACKGROUND

Little is known about the costs of treating ataxia and whether treatment at a specialist ataxia centre affects the cost of care. The aim of this study was to investigate whether patients who attended specialist ataxia centres in three European countries reported differences in their health care use and costs compared with patients who did not attend a specialist ataxia centre. We compared mean resource use and health service costs per patient affected by ataxia in the United Kingdom, Italy and Germany over a 12-month period. Data were obtained from a survey distributed to people with ataxia in the three countries. We compared mean resource use for each contact type and costs, stratifying patients by whether they were currently attending a specialist ataxia centre or had never attended one.

RESULTS

Responses were received from 181 patients from the United Kingdom, 96 from Italy and 43 from Germany. Differences in the numbers of contacts for most types of health service use between the specialist ataxia centre and non-specialist ataxia centre groups were non-significant. In the United Kingdom the mean total cost per patient was €2209 for non-specialist ataxia centre patients and €1813 for specialist ataxia centre patients (P = 0.59). In Italy these figures were €2126 and €1971, respectively (P = 0.84). In Germany they were €2431 and €4087, respectively (P = 0.19). Inpatient stays made the largest contribution to total costs.

CONCLUSIONS

Within each country, resource use and costs were broadly similar for specialist ataxia centre and non-specialist ataxia centre groups. There were differences between countries in terms of health care contacts and costs.

PTRH2 is Necessary for Purkinje Cell Differentiation and Survival and its Loss Recapitulates Progressive Cerebellar Atrophy and Ataxia Seen in IMNEPD Patients

Hom ozygous variants in the peptidyl-tRNA hydrolase 2 gene (PTRH2) cause infantile-onset multisystem neurologic, endocrine, and pancreatic disease. The objective is to delineate the mechanisms underlying the core cerebellar phenotype in this disease. For this, we generated constitutive (Ptrh2LoxPxhCMVCre, Ptrh2-/- mice) and Purkinje cell (PC) specific (Ptrh2LoxPxPcp2Cre, Ptrh2ΔPCmice) Ptrh2 mutant mouse models and investigated the effect of the loss of Ptrh2 on cerebellar development. We show that Ptrh2-/- knockout mice had severe postnatal runting and lethality by postnatal day 14. Ptrh2ΔPC PC specific knockout mice survived until adult age; however, they showed progressive cerebellar atrophy and functional cerebellar deficits with abnormal gait and ataxia. PCs of Ptrh2ΔPC mice had reduced cell size and density, stunted dendrites, and lower levels of ribosomal protein S6, a readout of the mammalian target of rapamycin pathway. By adulthood, there was a marked loss of PCs. Thus, we identify a cell autonomous requirement for PTRH2 in PC maturation and survival. Loss of PTRH2 in PCs leads to downregulation of the mTOR pathway and PC atrophy. This suggests a molecular mechanism underlying the ataxia and cerebellar atrophy seen in patients with PTRH2 mutations leading to infantile-onset multisystem neurologic, endocrine, and pancreatic disease.

French Translation and Cross-cultural Adaptation of the Scale for the Assessment and Rating of Ataxia

The Scale for the Assessment and Rating of Ataxia (SARA) is a widely used scale for assessing the severity of ataxia in clinics, natural history studies, and treatment trials worldwide. However, no French translation with validated cross-cultural adaptation is available. This study aimed to translate and adapt the SARA into French. The translation process was conducted according to the ISPOR guidelines for the translation and cultural adaptation process for patient-reported outcomes. A total of five translators, an expert committee, and two physiotherapists took part in the process to assess and ensure comprehension and language equivalences of the final French version. A few misinterpretations were pointed out during the translation process and were changed accordingly by the translation team. The French version of the SARA is ready to be used in clinical and research settings with French-speaking populations living with ataxia.

Quantification of Upper Limb Movements in Patients with Hereditary or Idiopathic Ataxia

Assessment of ataxic movements is usually based on clinical judgment. Technical devices can be employed in the quantification of ataxic movements in addition to clinical evaluation. The effect of maximal speed in upper limb movements in ataxia patients has not been quantified. The aim was to quantify upper limb movements in patients with hereditary or idiopathic ataxia and to find features of movement that are characteristic for ataxia. We examined 19 patients with degenerative ataxia and 21 healthy controls. An ad hoc system comprising a touch screen, an accelerometer, and a gyroscope was used to measure speed, angular acceleration, consistency, and accuracy of upper limb movements. The movements were quantified during finger-to-nose test that the patients were asked to perform at their own pace and as fast as possible. Disease severity was estimated by using the Scale for the Assessment and Rating of Ataxia (SARA). The mean SARA score of the patients was 13.5. Compared to the controls the performance of the patients was slow (p < 0.001) and arrhythmic (p < 0.001), but end-point accuracy on the touch screen was intact. The SARA score correlated with the standard deviation of amplitude of angular acceleration in Z-axis (F(1,17) = 15.00, p < 0.001 with R2 = 0.47). Upper limb movements of the patients with degenerative ataxia were slower and more arrhythmic than those in the controls. The patients retained spatial end-point accuracy.

ATP2B2 de novo variants as a cause of variable neurodevelopmental disorders that feature dystonia, ataxia, intellectual disability, behavioral symptoms, and seizures

PURPOSE

ATP2B2 encodes the variant-constrained plasma-membrane calcium-transporting ATPase-2, expressed in sensory ear cells and specialized neurons. ATP2B2/Atp2b2 variants were previously linked to isolated hearing loss in patients and neurodevelopmental deficits with ataxia in mice. We aimed to establish the association between ATP2B2 and human neurological disorders.

METHODS

Multinational case recruitment, scrutiny of trio-based genomics data, in silico analyses, and functional variant characterization were performed.

RESULTS

We assembled 7 individuals harboring rare, predicted deleterious heterozygous ATP2B2 variants. The alleles comprised 5 missense substitutions that affected evolutionarily conserved sites and 2 frameshift variants in the penultimate exon. For 6 variants, a de novo status was confirmed. Unlike described patients with hearing loss, the individuals displayed a spectrum of neurological abnormalities, ranging from ataxia with dystonic features to complex neurodevelopmental manifestations with intellectual disability, autism, and seizures. Two cases with recurrent amino-acid variation showed distinctive overlap with cerebellar atrophy-associated ataxia and epilepsy. In cell-based studies, all variants caused significant alterations in cytosolic calcium handling with both loss- and gain-of-function effects.

CONCLUSION

Presentations in our series recapitulate key phenotypic aspects of Atp2b2-mouse models and underline the importance of precise calcium regulation for neurodevelopment and cerebellar function. Our study documents a role for ATP2B2 variants in causing heterogeneous neurodevelopmental and movement-disorder syndromes.

A Novel de novo KIF1A Mutation in a Patient with Ataxia, Intellectual Disability and Mild Foot Deformity

Early-onset ataxias are often difficult to diagnose due to the genetic and phenotypic heterogeneity of patients. Whole exome sequencing (WES) is a powerful method for determining causative mutations of early-onset ataxias. We report a case in which a novel de novo KIF1A mutation was identified in a patient with ataxia, intellectual disability and mild foot deformity.A patient presented with sporadic forms of ataxia with mild foot deformity, intellectual disability, peripheral neuropathy, pyramidal signs, and orthostatic hypotension. WES was used to identify a novel de novo mutation in KIF1A, a known causative gene of neurodegeneration and spasticity with or without cerebellar atrophy or cortical visual impairment syndrome (NESCAVS).We report a novel phenotype of NESCAVS that is associated with a novel de novo missense mutation in KIF1A, which provides valuable information for the diagnosis of NESCAVS even in the era of WES. Early rehabilitation of patients with NESCAVS may prevent symptom worsening and improve the disease course.