Outcome predictors of post-COVID conditions in the European Academy of Neurology COVID-19 registry.

Several neurological manifestations are part of the post-COVID condition. We aimed to: (1) evaluate the 6-month outcome in the cohort of patients with neurological manifestations during the COVID-19 acute phase and surviving the infection, and find outcome predictors; (2) define the prevalence and type of neurological symptoms persistent at six months after the infection. Data source was an international registry of patients with COVID-19 infection and neurological symptoms, signs or diagnoses established by the European Academy of Neurology. Functional status at six-month follow-up was measured with the modified Rankin scale (mRS), and defined as: "stable/improved" if the mRS at six months was equal as or lower than the baseline score; "worse" if it was higher than the baseline score. By October 30, 2022, 1,003 lab-confirmed COVID-19 patients were followed up for a median of 6.5 months. Compared to their pre-morbid status, 522 patients (52%) were stable/improved, whereas 465 (46%) were worse (functional status missing for 16). Age, hospitalization, several pre-COVID-19 comorbidities, and COVID-19 general complications were predictors of a worse status. Amongst neurological manifestations, stroke carried the highest risk for worse outcome (OR 5.96), followed by hyperactive delirium (2.8), and peripheral neuropathies (2.37). On the other hand, hyposmia/hypogeusia (0.38), headache (0.40), myalgia (0.45), and COVID-19 vaccination (0.52) were predictors of a favourable prognosis. Persisting neurological symptoms or signs were reported by 316/1003 patients (31.5%), the commonest being fatigue (n = 133), and impaired memory or concentration (n = 103). Our study identified significant long-term prognostic predictors in patients with COVID-19 and neurological manifestations.

The crosstalk between Stroke and Cancer: Incidence of cancer after a first-ever cerebrovascular event in a population-based study.

OBJECTIVES: To determine the cancer incidence after the first-ever cerebrovascular event (CVE) and compare it to the cancer incidence in the population from the same region. METHODS: We evaluated 1069 patients with a first-ever CVE (Ischaemic or haemorrhagic stroke and Transient Ischaemic Attack) from a prospective population registry of stroke and transient focal neurological attacks, diagnosed between 2009 and 2011. We conducted a structured search to identify cancer-related variables and case-fatality for a period of 8 years following CVE. Cancer incidence in CVE patients was compared to the North Region Cancer Registry (RORENO). RESULTS: We found that 90/1069 (8.4%) CVE patients developed cancer after a first-ever CVE. Overall cancer annual incidence rate was higher after a CVE (820/100,000, 95%CI: 619-1020) than in general population (513/100,000, 95%CI: 508-518). In the 45-54 age group cancer incidence post-CVE was 3.2-fold (RR, 95%CI: 1.6-6.4) higher compared to the general population, decreasing gradually in older age-groups. Median time between CVE and cancer was 3.2 years (IQR = 1.4-5.2). Lower respiratory tract and colorectal were the most frequent cancer types. In univariable models, male sex (sHR = 1.78, 95%CI: 1.17-2.72, p = 0.007), tobacco use (sHR = 2.04, 95%CI: 1.31-3.18, p = 0.002) and peripheral artery disease (sHR = 2.37, 95%CI: 1.10-5.13, p = 0.028) were associated to higher cancer risk after CVE. After adjustment, tobacco use (sHR = 1.84, 95%CI: 1.08-3.14, p = 0.026) remained associated to a higher risk of cancer. CONCLUSIONS: At the population level, patients presenting a first-ever CVE have higher cancer incidence, that is particularly prominent in younger age-groups. Higher cancer incidence, delayed cancer diagnosis and increased mortality post-CVE warrants further research on long-term cancer surveillance in first-ever CVE survivors.

Preanalytical stability of plasma/serum brain-derived tau.

INTRODUCTION: We investigated the effects of matrix type and reagent batch changes on diagnostic performances and longitudinal trajectories of brain-derived tau (BD-tau). METHODS: We evaluated (i) Cohort 1: paired EDTA plasma and serum from Alzheimer biomarker-positive older adults versus controls (n = 26); and (ii) Cohort 2: n = 79 acute ischemic stroke patients with 265 longitudinal samples across four time points. RESULTS: In Cohort 1, plasma and serum BD-tau were strongly correlated (rho = 0.96, p < 0.0001) with similar diagnostic performances (AUCs >99%) and correlations with CSF total-tau (rho = 0.93-0.94, p < 0.0001). However, absolute concentrations were ∼40% higher in plasma versus serum. In Cohort 2, first and repeated BD-tau measurements showed a near-perfect correlation (rho = 0.96, p < 0.0001), with no significant between-batch concentration differences. In longitudinal analyses, substituting ∼10% of the first-run concentrations for the remeasured values showed overlapping estimated trajectories without significant differences at any time point. DISCUSSION: BD-tau has equivalent diagnostic accuracies, but non-interchangeable absolute concentrations, in plasma versus serum. Furthermore, the analytical robustness is unaffected by batch-to-batch reagent variations. HIGHLIGHTS: Brain-derived tau (BD-tau) is a novel blood-based biomarker that quantifies tau protein of CNS origin. Effects of preanalytical handling procedures on the quality and reproducibility of BD-tau measures are unknown. In two cohorts of n = 105 participants, we compared BD-tau concentrations and diagnostic performances in paired plasma and serum samples, and evaluated impacts of batch-to-batch reagent variations. Paired plasma and serum showed equivalent diagnostic performances to separate amyloid-positive AD from amyloid-negative controls, indicating both can be used independently. Repeated measurements and longitudinal trajectories of plasma BD-tau were unaffected by batch-to-batch reagent variation.

Predictors of cognitive dysfunction one-year post COVID-19.

OBJECTIVES: (a) To characterize the frequency of objective cognitive deficits and self-perceived cognitive difficulties and (b) to explore demographic and clinical predictors of cognitive dysfunction and cognitive complaints. METHOD: One hundred and ten adults diagnosed with COVID-19 between March and November 2020, aged ≤ 74 years underwent a brief neuropsychological evaluation 12 months after infection, which included: Brief Visuospatial Memory Test-Revised, California Verbal Learning Test, and Symbol Digit Modalities Test. T scores < 38 were considered abnormal performance; cognitive dysfunction was defined as ≥ 2 abnormal tests. Participants also completed Broadbent's Cognitive Failure Questionnaires (CFQ), Hospital Anxiety and Depression Scale, Modified Fatigue Impact Scale, and Short-Form Health Survey. CFQ ≥ 43 was considered indicative of cognitive complaints. RESULTS: Twenty participants (18.2%) had cognitive dysfunction and 36 (33.3%) had cognitive complaints. Cognitive dysfunction was related to lower education, preinfection history of headache/migraine, and acute COVID-19 symptoms of headache and sleep disturbance. Cognitive complaints were more likely to occur in women, those with fewer years of education, and acute COVID-19 symptoms of headache and sleep disturbance. Cognitive complaints were also significantly related to symptoms of anxiety, depression, and fatigue. Sex and psychopathology were not significant predictors of cognitive dysfunction. Modest associations were found between CFQ total score and cognitive test performance. DISCUSSION: A subset of individuals develops cognitive difficulties in the context of post-COVID syndrome. Results may support the protective effect of education, a known proxy of cognitive reserve. COVID-19 infection symptoms of headache and sleep disturbance appear to be risk factors for long-term cognitive difficulties. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Comparative features and outcomes of major neurological complications of COVID-19.

BACKGROUND AND PURPOSE: The aim of this study was to assess the neurological complications of SARS-CoV-2 infection and compare phenotypes and outcomes in infected patients with and without selected neurological manifestations. METHODS: The data source was a registry established by the European Academy of Neurology during the first wave of the COVID-19 pandemic. Neurologists collected data on patients with COVID-19 seen as in- and outpatients and in emergency rooms in 23 European and seven non-European countries. Prospective and retrospective data included patient demographics, lifestyle habits, comorbidities, main COVID-19 complications, hospital and intensive care unit admissions, diagnostic tests, and outcome. Acute/subacute selected neurological manifestations in patients with COVID-19 were analysed, comparing individuals with and without each condition for several risk factors. RESULTS: By July 31, 2021, 1523 patients (758 men, 756 women, and nine intersex/unknown, aged 16-101 years) were registered. Neurological manifestations were diagnosed in 1213 infected patients (79.6%). At study entry, 978 patients (64.2%) had one or more chronic general or neurological comorbidities. Predominant acute/subacute neurological manifestations were cognitive dysfunction (N = 449, 29.5%), stroke (N = 392, 25.7%), sleep-wake disturbances (N = 250, 16.4%), dysautonomia (N = 224, 14.7%), peripheral neuropathy (N = 145, 9.5%), movement disorders (N = 142, 9.3%), ataxia (N = 134, 8.8%), and seizures (N = 126, 8.3%). These manifestations tended to differ with regard to age, general and neurological comorbidities, infection severity and non-neurological manifestations, extent of association with other acute/subacute neurological manifestations, and outcome. CONCLUSIONS: Patients with COVID-19 and neurological manifestations present with distinct phenotypes. Differences in age, general and neurological comorbidities, and infection severity characterize the various neurological manifestations of COVID-19.

Peripheral neuropathy in Parkinson's disease: prevalence and functional impact on gait and balance.

Peripheral neuropathy is a common problem in patients with Parkinson's disease. Peripheral neuropathy's prevalence in Parkinson's disease varies between 4.8-55%, compared with 9% in the general population. It remains unclear whether peripheral neuropathy leads to decreased motor performance in Parkinson's disease, resulting in impaired mobility and increased balance deficits. We aimed to determine the prevalence and type of peripheral neuropathy in Parkinson's disease patients and evaluate its functional impact on gait and balance. A cohort of consecutive Parkinson's disease patients assessed by movement disorders specialists based on the UK Brain Bank criteria underwent clinical, neurophysiological (nerve conduction studies and quantitative sensory testing) and neuropathological (intraepidermal nerve fibre density in skin biopsy punches) evaluation to characterize the peripheral neuropathy type and aetiology using a cross-sectional design. Gait and balance were characterized using wearable health-technology in OFF and ON medication states, and the main parameters were extracted using validated algorithms. A total of 99 Parkinson's disease participants with a mean age of 67.2 (±10) years and mean disease duration of 6.5 (±5) years were assessed. Based on a comprehensive clinical, neurophysiological and neuropathological evaluation, we found that 40.4% of Parkinson's disease patients presented peripheral neuropathy, with a predominance of small fibre neuropathy (70% of the group). In the OFF state, the presence of peripheral neuropathy was significantly associated with shorter stride length (P = 0.029), slower gait speed (P = 0.005) and smaller toe-off angles (P = 0.002) during straight walking; significantly slower speed (P = 0.019) and smaller toe-off angles (P = 0.007) were also observed during circular walking. In the ON state, the above effects remained, albeit moderately reduced. With regard to balance, significant differences between Parkinson's disease patients with and without peripheral neuropathy were observed in the OFF medication state during stance with closed eyes on a foam surface. In the ON states, these differences were no longer observable. We showed that peripheral neuropathy is common in Parkinson's disease and influences gait and balance parameters, as measured with mobile health-technology. Our study supports that peripheral neuropathy recognition and directed treatment should be pursued in order to improve gait in Parkinson's disease patients and minimize balance-related disability, targeting individualized medical care.

Fluid biomarkers in stroke: From animal models to clinical care.

Stroke is a leading cause of death and disability worldwide. Stroke prevention, early diagnosis, and efficient acute treatment are priorities to successfully impact stroke death and disability. Fluid biomarkers may improve stroke differential diagnostic, patient stratification for acute treatment, and post-stroke individualized rehabilitation. In the present work, we characterized the use of stroke animal models in fluid biomarker research through a systematic review of PubMed and Scopus databases, followed by a literature review on the translation to the human stroke care setting and future perspectives in the field. We found increasing numbers of publications but with limited translation to the clinic. Animal studies are very heterogeneous, do not account for several human features present in stroke, and, importantly, only a minority of such studies used human cohorts to validate biomarker findings. Clinical studies have found appealing candidates, both protein and circulating nucleic acids, to contribute to a more personalized stroke care pathway. Still, brain tissue complexity and the fact that different brain pathologies share lesion biomarkers make this task challenging due to biomarker low specificity. Moreover, the study design and lack of validation cohorts may have precluded a formal integration of biomarkers in different steps of stroke diagnosis and treatment. To overcome such issues, recent pivotal studies on biomarker dynamics in individual patients are providing added value to diagnosis and anticipating patients' early prognosis. Presently, the most consistent protein biomarkers for stroke diagnosis and short- and long-term prognosis are associated with tissue damage at neuronal (TAU), axonal (NFL), or astroglial (GFAP and S100ß) levels. Most promising nucleic acids are microRNAs (miR), due to their stability in plasma and ease of access. Still, clinical validation and standardized quantitation place them a step behind compared protein as stroke biomarkers. Ultimately, the definition of clinically relevant biomarker panels and optimization of fast and sensitive biomarker measurements in the blood, together with their combination with clinical and neuroimaging data, will pave the way toward personalized stroke care.

Signatures of glial activity can be detected in the CSF proteome.

Single-cell transcriptomics has revealed specific glial activation states associated with the pathogenesis of neurodegenerative diseases, such as Alzheimer's and Parkinson's disease. While these findings may eventually lead to new therapeutic opportunities, little is known about how these glial responses are reflected by biomarker changes in bodily fluids. Such knowledge, however, appears crucial for patient stratification, as well as monitoring disease progression and treatment responses in clinical trials. Here, we took advantage of well-described mouse models of ß-amyloidosis and α-synucleinopathy to explore cerebrospinal fluid (CSF) proteome changes related to their respective proteopathic lesions. Nontargeted liquid chromatography-mass spectrometry revealed that the majority of proteins that undergo age-related changes in CSF of either mouse model were linked to microglia and astrocytes. Specifically, we identified a panel of more than 20 glial-derived proteins that were increased in CSF of aged ß-amyloid precursor protein- and α-synuclein-transgenic mice and largely overlap with previously described disease-associated glial genes identified by single-cell transcriptomics. Our results also show that enhanced shedding is responsible for the increase of several of the identified glial CSF proteins as exemplified for TREM2. Notably, the vast majority of these proteins can also be quantified in human CSF and reveal changes in Alzheimer's disease cohorts. The finding that cellular transcriptome changes translate into corresponding changes of CSF proteins is of clinical relevance, supporting efforts to identify fluid biomarkers that reflect the various functional states of glial responses in cerebral proteopathies, such as Alzheimer's and Parkinson's disease.

COVID-19 vaccination hesitancy among people with chronic neurological disorders: A position paper.

BACKGROUND AND PURPOSE: Health risks associated with SARS-CoV-2 infection are undisputed. Moreover, the capability of vaccination to prevent symptomatic, severe, and fatal COVID-19 is recognized. There is also early evidence that vaccination can reduce the chance for long COVID-19. Nonetheless, the willingness to get vaccinated and receive booster shots remains subpar among people with neurologic disorders. Vaccine scepticism not only jeopardizes collective efforts to end the COVID-19 pandemic but puts individual lives at risk, as some chronic neurologic diseases are associated with a higher risk for an unfavorable COVID-19 course. METHODS: In this position paper, the NeuroCOVID-19 Task Force of the European Academy of Neurology (EAN) summarizes the current knowledge on the prognosis of COVID-19 among patients with neurologic disease, elucidates potential barriers to vaccination coverage, and formulates strategies to overcome vaccination hesitancy. A survey among the Task Force members on the phenomenon of vaccination hesitancy among people with neurologic disease supports the lines of argumentation. RESULTS: The study revealed that people with multiple sclerosis and other nervous system autoimmune disorders are most skeptical of SARS-CoV-2 vaccination. The prevailing concerns included the chance of worsening the pre-existing neurological condition, vaccination-related adverse events, and drug interaction. CONCLUSIONS: The EAN NeuroCOVID-19 Task Force reinforces the key role of neurologists as advocates of COVID-19 vaccination. Neurologists need to argue in the interest of their patients about the overwhelming individual and global benefits of COVID-19 vaccination. Moreover, they need to keep on eye on this vulnerable patient group, its concerns, and the emergence of potential safety signals.

Short- and long-term outcome and predictors in an international cohort of patients with neuro-COVID-19.

BACKGROUND AND PURPOSE: Despite the increasing number of reports on the spectrum of neurological manifestations of COVID-19 (neuro-COVID), few studies have assessed short- and long-term outcome of the disease. METHODS: This is a cohort study enrolling adult patients with neuro-COVID seen in neurological consultation. Data were collected prospectively or retrospectively in the European Academy of Neurology NEuro-covid ReGistrY ((ENERGY). The outcome at discharge was measured using the modified Rankin Scale and defined as 'stable/improved' if the modified Rankin Scale score was equal to or lower than the pre-morbid score, 'worse' if the score was higher than the pre-morbid score. Status at 6 months was also recorded. Demographic and clinical variables were assessed as predictors of outcome at discharge and 6 months. RESULTS: From July 2020 to March 2021, 971 patients from 19 countries were included. 810 (83.4%) were hospitalized. 432 (53.3%) were discharged with worse functional status. Older age, stupor/coma, stroke and intensive care unit (ICU) admission were predictors of worse outcome at discharge. 132 (16.3%) died in hospital. Older age, cancer, cardiovascular complications, refractory shock, stupor/coma and ICU admission were associated with death. 262 were followed for 6 months. Acute stroke or ataxia, ICU admission and degree of functional impairment at discharge were predictors of worse outcome. 65/221 hospitalized patients (29.4%) and 10/32 non-hospitalized patients (24.4%) experienced persisting neurological symptoms/signs. 10/262 patients (3.8%) developed new neurological complaints during the 6 months of follow-up. CONCLUSIONS: Neuro-COVID is a severe disease associated with worse functional status at discharge, particularly in older subjects and those with comorbidities and acute complications of infection.

Early plasma biomarker dynamic profiles are associated with acute ischemic stroke outcomes.

BACKGROUND: Early outcome prediction after acute ischemic stroke (AIS) might be improved with blood-based biomarkers. We investigated whether the longitudinal profile of a multi-marker panel could predict the outcome of successfully recanalized AIS patients. METHODS: We used ultrasensitive single-molecule array (Simoa) to measure glial fibrillary acidic protein (GFAP), neurofilament light chain (NfL), total-tau (t-tau) and ELISA for brevican in a prospective study of AIS patients with anterior circulation large vessel occlusion successfully submitted to thrombectomy. Plasma was obtained at admission, upon treatment, 24 h and 72 h after treatment. Clinical and neuroimaging outcomes were assessed independently. RESULTS: Thirty-five patients (64.8%) had good early clinical or neuroimaging outcome. Baseline biomarker levels did not distinguish between outcomes. However, longitudinal intra-individual biomarker changes followed different dynamic profiles with time and according to outcome. GFAP levels exhibited an early and prominent increase between admission and just after treatment. NfL increase was less pronounced between admission and up to 24 h. T-tau increased between treatment and 24 h. Interestingly, GFAP rate-of-change (pg/ml/h) between admission and immediately after recanalization had a good discriminative capacity between clinical outcomes (AUC = 0.88, p < 0.001), which was higher than admission CT-ASPECTS (AUC = 0.75, p < 0.01). T-tau rate-of-change provided moderate discriminative capacity (AUC = 0.71, p < 0.05). Moreover, in AIS patients with admission CT-ASPECTS <9 both GFAP and NfL rate-of-change were good outcome predictors (AUC = 0.82 and 0.77, p < 0.05). CONCLUSION: Early GFAP, t-tau and NfL rate-of-change in plasma can predict AIS clinical and neuroimaging outcome after successful recanalization. Such dynamic measures match and anticipate neuroimaging predictive capacity, potentially improving AIS patient stratification for treatment, and targeting individualized stroke care.

Timely and Blood-Based Multiplex Molecular Profiling of Acute Stroke.

Stroke is a leading cause of death and disability in the world. To address such a problem, early diagnosis and tailored acute treatment represent one of the major priorities in acute stroke care. Since the efficacy of reperfusion treatments is highly time-dependent, there is a critical need to optimize procedures for faster and more precise diagnosis. We provide a concise review of the most relevant and well-documented blood-protein biomarkers that exhibit greater potential for translational to clinical practice in stroke differential diagnosis and to differentiate ischemic stroke from hemorrhagic stroke, followed by an overview of the most recent point-of-care technological approaches to address this problem. The integration of fluid-based biomarker profiling, using point-of-care biosensors with demographic, clinical, and neuroimaging parameters in multi-dimensional clinical decision-making algorithms, will be the next step in personalized stroke care.

Neuro-COVID frequency and short-term outcome in the Northern Portuguese population.

BACKGROUND AND PURPOSE: COVID-19-related acute neurological phenotypes are being increasingly recognised, with neurological complications reported in more than 30% of hospitalised patients. However, multicentric studies providing a population-based perspective are lacking. METHODS: We conducted a retrospective multicentric study at five hospitals in Northern Portugal, representing 45.1% of all hospitalised patients in this region, between 1 March and 30 June 2020. RESULTS: Among 1261 hospitalised COVID-19 patients, 457 (36.2%) presented neurological manifestations, corresponding to a rate of 357 per 1000 in the North Region. Patients with neurologic manifestations were younger (68.0 vs. 71.2 years, p = 0.002), and the most frequent neurological symptoms were headache (13.4%), delirium (10.1%), and impairment of consciousness (9.7%). Acute well-defined central nervous system (CNS) involvement was found in 19.1% of patients, corresponding to a rate of 217 per 1000 hospitalised patients in the whole region. Assuming that all patients with severe neurological events were hospitalised, we extrapolated our results to all COVID-19 patients in the region, estimating that 116 will have a severe neurological event, corresponding to a rate of nine per 1000 (95% CI = 7-11). Overall case fatality in patients presenting neurological manifestations was 19.8%, increasing to 32.6% among those with acute well-defined CNS involvement. CONCLUSIONS: We characterised the population of hospitalised COVID-19 patients in Northern Portugal and found that neurological symptoms are common and associated with a high degree of disability at discharge. CNS involvement with criteria for in-hospital admission was observed in a significant proportion of patients. This knowledge provides the tools for adequate health planning and for improving COVID-19 multidisciplinary patient care.

A plea for equitable global access to COVID-19 diagnostics, vaccination and therapy: The NeuroCOVID-19 Task Force of the European Academy of Neurology.

Coronavirus disease 2019 (COVID-19), a multi-organ disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), continues to challenge health and care systems around the globe. The pandemic has disrupted acute neurology services and routine patient care and has impacted the clinical course in patients with chronic neurological disease. COVID-19 appears to have exposed inequalities of societies and healthcare systems and had a disproportionate impact on already vulnerable communities. The next challenge will be to set up initiatives to stop disparities in all aspects related to COVID-19. From the medical perspective, there is a need to consider inequalities in prevention, treatment and long-term consequences. Some of the issues of direct relevance to neurologists are summarised. With this appraisal, the European Academy of Neurology NeuroCOVID-19 Task Force intends to raise awareness of the potential impact of COVID-19 on inequalities in healthcare and calls for action to prevent disparity at individual, national and supranational levels.

Motor, cognitive and mobility deficits in 1000 geriatric patients: protocol of a quantitative observational study before and after routine clinical geriatric treatment - the ComOn-study.

BACKGROUND: Motor and cognitive deficits and consequently mobility problems are common in geriatric patients. The currently available methods for diagnosis and for the evaluation of treatment in this vulnerable cohort are limited. The aims of the ComOn (COgnitive and Motor interactions in the Older populatioN) study are (i) to define quantitative markers with clinical relevance for motor and cognitive deficits, (ii) to investigate the interaction between both motor and cognitive deficits and (iii) to assess health status as well as treatment outcome of 1000 geriatric inpatients in hospitals of Kiel (Germany), Brescia (Italy), Porto (Portugal), Curitiba (Brazil) and Bochum (Germany). METHODS: This is a prospective, explorative observational multi-center study. In addition to the comprehensive geriatric assessment, quantitative measures of reduced mobility and motor and cognitive deficits are performed before and after a two week's inpatient stay. Components of the assessment are mobile technology-based assessments of gait, balance and transfer performance, neuropsychological tests, frailty, sarcopenia, autonomic dysfunction and sensation, and questionnaires to assess behavioral deficits, activities of daily living, quality of life, fear of falling and dysphagia. Structural MRI and an unsupervised 24/7 home assessment of mobility are performed in a subgroup of participants. The study will also investigate the minimal clinically relevant change of the investigated parameters. DISCUSSION: This study will help form a better understanding of symptoms and their complex interactions and treatment effects in a large geriatric cohort.

Plasma neurofilament light chain: an early biomarker for hereditary ATTR amyloid polyneuropathy.

Background: Transthyretin amyloidosis due to V30M mutation (ATTR-V30M) is the most frequent hereditary ATTR amyloidosis. Besides neurophysiological measures, there are no biomarkers to detect preclinical disease or monitor disease progression. CSF or plasma neurofilament light chain (pNfL) have recently been considered sensitive biomarkers to quantitate neuro-axonal damage in several disorders of the peripheral and central nervous system.Objective: Characterise plasma NfL levels in a series of untreated ATTR-V30M patients stratified by clinical severity using a cross-sectional retrospective study design.Methods: Sixty ATTR-V30M patients and 16 controls from 2 independent cohorts were analysed for pNfL by single-molecule array assay (SIMOA) technique. Disease severity was assessed with Polyneuropathy Disability Score.Results: pNfL is elevated in ATTR-V30M patients as a function of disease severity in both cohorts. Moreover, pNfL discriminates asymptomatic mutation carriers from early symptomatic patients (AUC = 0.97; p < .001) with high sensitivity (92.3%) and specificity (93.8%). pNfL elevation (>66.9 pg/mL) also discriminates patients with sensory neuropathy from patients with motor neuropathy (AUC = 0.91; p < .01) with a sensitivity of 61.5% and a specificity of 92.3%.Conclusion: pNfL is an easily accessible biomarker to establish ATTR-V30M disease conversion and to monitor disease progression. pNfL could be used as efficacy measure of disease-oriented therapies in clinical and pre-clinical trials.