Publications

17 Apr

Short-term effects of transcranial direct current stimulation on motor speech in Parkinson's disease: a pilot study

Introduction: Hypokinetic dysarthria (HD) is a common motor speech symptom of Parkinson's disease (PD) which does not respond well to PD treatments. We investigated short-term effects of transcranial direct current stimulation (tDCS) on HD in PD using acoustic analysis of speech. Based on our previous studies we focused on stimulation of the right superior temporal gyrus (STG) - an auditory feedback area.

Methods: In 14 PD patients with HD, we applied anodal, cathodal and sham tDCS to the right STG using a cross-over design. A protocol consisting of speech tasks was performed prior to and immediately after each stimulation session. Linear mixed models were used for the evaluation of the effects of each stimulation condition on the relative change of acoustic parameters. We also performed a simulation of the mean electric field induced by tDCS.

Results: Linear mixed model showed a statistically significant effect of the stimulation condition on the relative change of median duration of silences longer than 50 ms (p = 0.015). The relative change after the anodal stimulation (mean = -5.9) was significantly lower as compared to the relative change after the sham stimulation (mean = 12.8), p = 0.014.

11 Apr

Grading system for assessing the confidence in the epileptogenic zone reported in published studies: A Delphi consensus study

Objective: This study was undertaken to develop a standardized grading system based on expert consensus for evaluating the level of confidence in the localization of the epileptogenic zone (EZ) as reported in published studies, to harmonize and facilitate systematic reviews in the field of epilepsy surgery.

Methods: We conducted a Delphi study involving 22 experts from 18 countries, who were asked to rate their level of confidence in the localization of the EZ for various theoretical clinical scenarios, using different scales. Information provided in these scenarios included one or several of the following data: magnetic resonance imaging (MRI) findings, invasive electroencephalography summary, and postoperative seizure outcome.

Results: The first explorative phase showed an overall interrater agreement of .347, pointing to large heterogeneity among experts' assessments, with only 17% of the 42 proposed scenarios associated with a substantial level of agreement. A majority showed preferences for the simpler scale and single-item scenarios. The successive Delphi voting phases resulted in a majority consensus across experts, with more than two thirds of respondents agreeing on the rating of each of the tested single-item scenarios.

11 Apr

Reply to: Questioning the cycad theory of Kii ALS-PDC causation

We read with great interest the Correspondence to our recent Review (Menšíková, K. et al. Endemic parkinsonism: clusters, biology and clinical features. Nat. Rev. Neurol. 19, 599–616 (2023)¹) by Kokubo and colleagues (Kokubo, Y., Morimoto, S. & Yoshida, M. Questioning the cycad theory of Kii ALS–PDC causation. Nat. Rev. Neurol. https://doi.org/10.1038/s41582-024-00936-0 (2024)²). We are aware that Kokubo — together with the late S. Kuzuhara — systematically studied amyotrophic lateral sclerosis–parkinsonism–dementia complex (ALS–PDC) on the Kii Peninsula for more than 30 years. They authored and co-authored numerous papers about this endemic disease, some of them with one of us (R.S.). We therefore considered the comments raised by Kokubo et al. carefully, and here we respond to the questions that they have raised.

Kokubo et al. state that the use of cycad seed in herbal and folk medicine, and as a tonic in children, is very rare. However, in the northeastern Kii (Hohara) focus of ALS–PDC, the seed of Cycas revoluta was prescribed throughout the 1980s by kitoshi (folk medicine practitioners) and dispensed by local pharmacies for the oral treatment of various ailments, including diarrhoea, dysmenorrhoea, gonorrhoea, tuberculosis and neuralgia, in accordance with published guidance³. 

11 Apr

Screening and differential diagnosis of delirium in neurointensive stroke patients

Diagnosing delirium in neurointensive care is difficult because symptoms of delirium, such as inappropriate speech, may be related to aphasia due to primary brain injury. Therefore, validated screening tools are needed. The aim of this study was to compare two Czech versions of already validated screening tools - the Confusion Assessment Method for the Intensive Care Unit (CAM-ICU) and the Intensive Care Delirium Screening Checklist (ICDSC) - in a cohort of acute stroke patients. We also aimed to assess the pitfalls of delirium detection in the context of non-convulsive status epilepticus (NCSE). We analysed 138 stroke patients admitted to the neurological intensive care unit (ICU) or stroke unit. According to expert judgement, which was used as the gold standard, 38 patients (27.54%) developed delirium. The sensitivity and specificity of the ICDSC were 91.60% and 95.33%, respectively, and the positive and negative predictive values were 76.76% and 98.54%, respectively. Similarly, the sensitivity and specificity of CAM-ICU were 75.63% and 96.74%, respectively, and the positive and negative predictive values were 79.65% and 95.93%, respectively. We did not detect an episode of NCSE mimicking delirium in any of our stroke patients who were judged to be delirious by expert assessment.

7 Mar

EEG-Meta-Microstates: Towards a More Objective Use of Resting-State EEG Microstate Findings Across Studies

Over the last decade, EEG resting-state microstate analysis has evolved from a niche existence to a widely used and well-accepted methodology. The rapidly increasing body of empirical findings started to yield overarching patterns of associations of biological and psychological states and traits with specific microstate classes. However, currently, this cross-referencing among apparently similar microstate classes of different studies is typically done by "eyeballing" of printed template maps by the individual authors, lacking a systematic procedure. To improve the reliability and validity of future findings, we present a tool to systematically collect the actual data of template maps from as many published studies as possible and present them in their entirety as a matrix of spatial similarity. The tool also allows importing novel template maps and systematically extracting the findings associated with specific microstate maps from ongoing or published studies. The tool also allows importing novel template maps and systematically extracting the findings associated with specific microstate maps in the literature. The analysis of 40 included sets of template maps indicated that: (i) there is a high degree of similarity of template maps across studies, (ii) similar template maps were associated with converging empirical findings, and (iii) representative meta-microstates can be extracted from the individual studies. 

7 Mar

Coupling between beta band and high frequency oscillations as a clinically useful biomarker for DBS

Beta hypersynchrony was recently introduced into clinical practice in Parkinson's disease (PD) to identify the best stimulation contacts and for adaptive deep brain stimulation (aDBS) sensing. However, many other oscillopathies accompany the disease, and beta power sensing may not be optimal for all patients. The aim of this work was to study the potential clinical usefulness of beta power phase-amplitude coupling (PAC) with high frequency oscillations (HFOs). Subthalamic nucleus (STN) local field potentials (LFPs) from externalized DBS electrodes were recorded and analyzed in PD patients (n = 19). Beta power and HFOs were evaluated in a resting-state condition; PAC was then studied and compared with the electrode contact positions, structural connectivity, and medication state. Beta-HFO PAC (mainly in the 200-500 Hz range) was observed in all subjects. PAC was detectable more specifically in the motor part of the STN compared to beta power and HFOs. Moreover, the presence of PAC better corresponds to the stimulation setup based on the clinical effect. PAC is also sensitive to the laterality of symptoms and dopaminergic therapy, where the greater PAC cluster reflects the more affected side and medication "off" state. Coupling between beta power and HFOs is known to be a correlate of the PD "off" state. 

7 Mar

Screening for dysphagia in patients with relapsing-remitting multiple sclerosis

Background: In multiple sclerosis (MS), dysphagia is an important and common clinical symptom. Although often overlooked and underdiagnosed, it can have a significant impact on a patient's life, including social integration, and it can lead to malnutrition, aspiration pneumonia, and suffocation, i.e., life-threatening complications. Early detection of dysphagia is essential to prevent these risks. However, the optimal screening method and the inter-relationship between different methods used for dysphagia screening are not clear. The aim of this study was to compare the diagnostic performance of a simple question about swallowing problems, the DYsphagia in MUltiple Sclerosis (DYMUS) swallowing questionnaire, and the Timed Water Swallowing Test (TWST) to detect dysphagia in people with relapsing-remitting MS (RRMS).

Methods: Patients with MS were asked about subjective swallowing difficulties and, regardless of their response, completed the DYMUS questionnaire and underwent the TWST at their routine follow-up visit. Patients with at least one positive screening method were offered an objective assessment of swallowing function using the Fiberoptic Endoscopic Evaluation of Swallowing (FEES). The results were statistically analyzed and correlated with demographic and MS-related parameters.

22 Feb

A model of human neural networks reveals NPTX2 pathology in ALS and FTLD

Human cellular models of neurodegeneration require reproducibility and longevity, which is necessary for simulating age-dependent diseases. Such systems are particularly needed for TDP-43 proteinopathies¹, which involve human-specific mechanisms^2-5 that cannot be directly studied in animal models. Here, to explore the emergence and consequences of TDP-43 pathologies, we generated induced pluripotent stem cell-derived, colony morphology neural stem cells (iCoMoNSCs) via manual selection of neural precursors⁶. Single-cell transcriptomics and comparison to independent neural stem cells⁷ showed that iCoMoNSCs are uniquely homogenous and self-renewing. Differentiated iCoMoNSCs formed a self-organized multicellular system consisting of synaptically connected and electrophysiologically active neurons, which matured into long-lived functional networks (which we designate iNets). Neuronal and glial maturation in iNets was similar to that of cortical organoids⁸. Overexpression of wild-type TDP-43 in a minority of neurons within iNets led to progressive fragmentation and aggregation of the protein, resulting in a partial loss of function and neurotoxicity. Single-cell transcriptomics revealed a novel set of misregulated RNA targets in TDP-43-overexpressing neurons and in patients with TDP-43 proteinopathies exhibiting a loss of nuclear TDP-43. 

22 Feb

Facial emotion processing in patients with borderline personality disorder as compared with healthy controls: an fMRI and ECG study

Background: Maladaptive behaviors and interpersonal difficulties in patients with borderline personality disorder (BPD) seem connected to biased facial emotion processing. This bias is often accompanied by heightened amygdala activity in patients with BPD as compared to healthy controls. However, functional magnetic resonance imaging (fMRI) studies exploring differences between patients and healthy controls in facial emotion processing have produced divergent results. The current study explored fMRI and heart rate variability (HRV) correlates of negative facial emotion processing in patients with BPD and healthy controls.

Methods: The study included 30 patients with BPD (29 females; age: M = 24.22, SD = 5.22) and 30 healthy controls (29 females; M = 24.66, SD = 5.28). All participants underwent the "faces" task, an emotional face perception task, in an fMRI session simultaneously with ECG. In this task, participants are presented with emotional expressions of disgust, sadness, and fear (as a negative condition) and with the same pictures in a scrambled version (as a neutral condition).

22 Feb

Influence of metabolic state and body composition on the action of pharmacological treatment of migraine

Migraine is a disabling neurovascular disorder among people of all ages, with the highest prevalence in the fertile years, and in women. Migraine impacts the quality of life of affected individuals tremendously and, in addition, it is associated with highly prevalent metabolic diseases, such as obesity, diabetes mellitus and thyroid dysfunction. Also, the clinical response to drugs might be affected in patients with metabolic disease due to body composition and metabolic change. Therefore, the efficacy of antimigraine drugs could be altered in patients with both migraine and metabolic disease. However, knowledge of the pharmacology and the related clinical effects of antimigraine drugs in patients with metabolic disease are limited. Therefore, and given the clinical relevance, this article provides a comprehensive overview of the current research and hypotheses related to the influence of metabolic state and body composition on the action of antimigraine drugs. In addition, the influence of antimigraine drugs on metabolic functioning and, vice versa, the influence of metabolic diseases and its hormonal modulating medication on migraine activity is outlined. Future exploration on personalizing migraine treatment to individual characteristics is necessary to enhance therapeutic strategies, especially given its increasing significance in recent decades.

2 Feb

Exploring the impact of intensified multiple session tDCS over the left DLPFC on brain function in MCI: a randomized control trial

Transcranial direct current stimulation combined with cognitive training (tDCS-cog) represents a promising approach to combat cognitive decline among healthy older adults and patients with mild cognitive impairment (MCI). In this 5-day-long double-blinded randomized trial, we investigated the impact of intensified tDCS-cog protocol involving two trains of stimulation per day on working memory (WM) enhancement in 35 amnestic and multidomain amnestic MCI patients. Specifically, we focused to improve WM tasks relying on top-down attentional control and hypothesized that intensified tDCS would enhance performance of visual object matching task (VOMT) immediately after the stimulation regimen and at a 1-month follow-up. Secondarily, we explored whether the stimulation would augment online visual working memory training. Using fMRI, we aimed to elucidate the neural mechanisms underlying the intervention effects by analyzing BOLD activations during VOMT. Our main finding revealed no superior after-effects of tDCS-cog over the sham on VOMT among individuals with MCI as indicated by insignificant immediate and long-lasting after-effects. Additionally, the tDCS-cog did not enhance online training as predicted. The fMRI analysis revealed brain activity alterations in right insula that may be linked to tDCS-cog intervention..

2 Feb

Engineered human H-chain ferritin with reversed charge of the internal cavity exhibits RNA-mediated spongelike effect for loading RNA/DNA-binding molecules

Ferritins are globular proteins with an internal cavity that enables the encapsulation of a plethora of low-mass compounds. Unfortunately, the overall negative surface charge of ferritin's internal cavity hampers efficient loading of negatively charged molecules. Therefore, we produced a genetically engineered human H-chain ferritin containing a cationic RKRK domain, reversing the natural net charge of the cavity to positive, thus allowing for efficient encapsulation of negatively charged siRNA. Due to the reversed, positive charge mediated by RKRK domains, the recombinant ferritin produced in E. coli inherently carries a load of bacterial RNA inside its cavity, turning the protein into an effective sponge possessing high affinity for DNA/RNA-binding substances that can be loaded with markedly higher efficiency compared to the wildtype protein. Using doxorubicin as payload, we show that due to its loading through the RNA sponge, doxorubicin is released in a sustained manner, with a cytotoxicity profile similar to the free drug. In summary, this is the first report demonstrating a ferritin/nucleic acid hybrid delivery vehicle with a broad spectrum of properties exploitable in various fields of biomedical applications.

2 Feb

Low prevalence of neural autoantibodies in perioperative cerebrospinal fluid samples of epilepsy surgery patients: A multicenter prospective study

bjective: Refractory epilepsy may have an underlying autoimmune etiology. Our aim was to assess the prevalence of neural autoantibodies in a multicenter national prospective cohort of patients with drug-resistant epilepsy undergoing epilepsy surgery utilizing comprehensive clinical, serologic, and histopathological analyses.

Methods: We prospectively recruited patients undergoing epilepsy surgery for refractory focal epilepsy not caused by a brain tumor from epilepsy surgery centers in the Czech Republic. Perioperatively, we collected cerebrospinal fluid (CSF) and/or serum samples and performed comprehensive commercial and in-house assays for neural autoantibodies. Clinical data were obtained from the patients' medical records, and histopathological analysis of resected brain tissue was performed.

Results: Seventy-six patients were included, mostly magnetic resonance imaging (MRI)-lesional cases (74%). Mean time from diagnosis to surgery was 21 ± 13 years. Only one patient (1.3%) had antibodies in the CSF and serum (antibodies against glutamic acid decarboxylase 65) in relevant titers; histology revealed focal cortical dysplasia (FCD) III (FCD associated with hippocampal sclerosis [HS]). 

23 Jan

Penumbral Rescue by normobaric O = O administration in patients with ischemic stroke and target mismatch proFile (PROOF): Study protocol of a phase IIb trial

Rationale: Oxygen is essential for cellular energy metabolism. Neurons are particularly vulnerable to hypoxia. Increasing oxygen supply shortly after stroke onset could preserve the ischemic penumbra until revascularization occurs.

Aims: PROOF investigates the use of normobaric oxygen (NBO) therapy within 6 h of symptom onset/notice for brain-protective bridging until endovascular revascularization of acute intracranial anterior-circulation occlusion.

Methods and design: Randomized (1:1), standard treatment-controlled, open-label, blinded endpoint, multicenter adaptive phase IIb trial.

Study outcomes: Primary outcome is ischemic core growth (mL) from baseline to 24 h (intention-to-treat analysis). Secondary efficacy outcomes include change in NIHSS from baseline to 24 h, mRS at 90 days, cognitive and emotional function, and quality of life. Safety outcomes include mortality, intracranial hemorrhage, and respiratory failure. Exploratory analyses of imaging and blood biomarkers will be conducted.

18 Jan

How registry data are used to inform activities for stroke care quality improvement across 55 countries: A cross-sectional survey of Registry of Stroke Care Quality (RES-Q) hospitals

Background and purpose: The Registry of Stroke Care Quality (RES-Q) is a worldwide quality improvement data platform that captures performance and quality measures, enabling standardized comparisons of hospital care. The aim of this study was to determine if, and how, RES-Q data are used to influence stroke quality improvement and identify the support and educational needs of clinicians using RES-Q data to improve stroke care.

Methods: A cross-sectional self-administered online survey was administered (October 2021-February 2022). Participants were RES-Q hospital local coordinators responsible for stroke data collection. Descriptive statistics are presented.

Results: Surveys were sent to 1463 hospitals in 74 countries; responses were received from 358 hospitals in 55 countries (response rate 25%). RES-Q data were used "always" or "often" to: develop quality improvement initiatives (n = 213, 60%); track stroke care quality over time (n = 207, 58%); improve local practice (n = 191, 53%); and benchmark against evidence-based policies, procedures and/or guidelines to identify practice gaps (n = 179, 50%). 

18 Jan

Global stroke statistics 2023: Availability of reperfusion services around the world

Background: Disparities in the availability of reperfusion services for acute ischemic stroke are considerable globally and require urgent attention. Contemporary data on the availability of reperfusion services in different countries are used to provide the necessary evidence to prioritize where access to acute stroke treatment is needed.

Aims: To provide a snapshot of published literature on the provision of reperfusion services globally, including when facilitated by telemedicine or mobile stroke unit services.

Methods: We searched PubMed to identify original articles, published up to January 2023 for the most recent, representative, and relevant patient-level data for each country. Keywords included thrombolysis, endovascular thrombectomy and telemedicine. We also screened reference lists of review articles, citation history of articles, and the gray literature. The information is provided as a narrative summary.

Results: Of 11,222 potentially eligible articles retrieved, 148 were included for review following de-duplications and full-text review. 

18 Jan

Neuroimaging-based classification of PTSD using data-driven computational approaches: A multisite big data study from the ENIGMA-PGC PTSD consortium

Background: Recent advances in data-driven computational approaches have been helpful in devising tools to objectively diagnose psychiatric disorders. However, current machine learning studies limited to small homogeneous samples, different methodologies, and different imaging collection protocols, limit the ability to directly compare and generalize their results. Here we aimed to classify individuals with PTSD versus controls and assess the generalizability using a large heterogeneous brain datasets from the ENIGMA-PGC PTSD Working group.

Methods: We analyzed brain MRI data from 3,477 structural-MRI; 2,495 resting state-fMRI; and 1,952 diffusion-MRI. First, we identified the brain features that best distinguish individuals with PTSD from controls using traditional machine learning methods. Second, we assessed the utility of the denoising variational autoencoder (DVAE) and evaluated its classification performance. Third, we assessed the generalizability and reproducibility of both models using leave-one-site-out cross-validation procedure for each modality.

18 Jan

Levodopa may modulate specific speech impairment in Parkinson's disease: an fMRI study

Hypokinetic dysarthria (HD) is a difficult-to-treat symptom affecting quality of life in patients with Parkinson's disease (PD). Levodopa may partially alleviate some symptoms of HD in PD, but the neural correlates of these effects are not fully understood. The aim of our study was to identify neural mechanisms by which levodopa affects articulation and prosody in patients with PD. Altogether 20 PD patients participated in a task fMRI study (overt sentence reading). Using a single dose of levodopa after an overnight withdrawal of dopaminergic medication, levodopa-induced BOLD signal changes within the articulatory pathway (in regions of interest; ROIs) were studied. We also correlated levodopa-induced BOLD signal changes with the changes in acoustic parameters of speech. We observed no significant changes in acoustic parameters due to acute levodopa administration. After levodopa administration as compared to the OFF dopaminergic condition, patients showed task-induced BOLD signal decreases in the left ventral thalamus (p = 0.0033). The changes in thalamic activation were associated with changes in pitch variation (R = 0.67, p = 0.006), while the changes in caudate nucleus activation were related to changes in the second formant variability which evaluates precise articulation (R = 0.70, p = 0.003).