Tracking the habituation of the event-related EEG potential in automatic change detection using an auditory two-tone oddball paradigm

The mismatch negativity and the P3a of the event-related EEG potential reflect the electrocortical response to a deviant stimulus in a series of stimuli. Although both components have been investigated in various paradigms, these paradigms usually incorporate many repetitions of the same deviant, thus leaving open whether both components vary as a function of the deviant's position in a series of deviant stimuli-i.e. whether they are subject to qualitative/quantitative habituation from one instantiation of a deviant to the next. This is so because the detection of mismatch negativity/P3a in the event-related EEG potential requires an averaging over dozens or hundreds of stimuli, i.e. over many instantiations of the deviant per participant. The present study addresses this research gap. We used a two-tone oddball paradigm implementing only a small number of (deviant) stimuli per participant, but applying it to a large number of participants (n > 230). Our data show that the mismatch negativity amplitude exhibits no decrease as a function of the deviant's position in a series of (standard and) deviant stimuli. Importantly, only after the very first deviant stimulus, a distinct P3a could be detected, indicative of an orienting reaction and an attention shift, and thus documenting a dissociation of mismatch negativity and P3a.

Changes in brain structure in subjects with resistance to thyroid hormone due to THRB mutations

BACKGROUND

Being critical for brain development and neurocognitive function thyroid hormones may have an effect on behaviour and brain structure. Our exploratory study aimed to delineate the influence of mutations in the thyroid hormone receptor (TR) ß gene on brain structure.

METHODS

High-resolution 3D T1-weighted images were acquired in 21 patients with a resistance to thyroid hormone ß (RTHß) in comparison to 21 healthy matched-controls. Changes in grey and white matter, as well as cortical thickness were evaluated using voxel-based morphometry (VBM) and diffusion tensor imaging (DTI).

RESULTS

RTHß patients showed elevated circulating fT4 & fT3 with normal TSH concentrations, whereas controls showed normal thyroid hormone levels. RTHß patients revealed significantly higher scores in a self-rating questionnaire for attention deficit hyperactivity disorder (ADHD). Imaging revealed alterations of the corticospinal tract, increased cortical thickness in bilateral superior parietal cortex and decreased grey matter volume in bilateral inferior temporal cortex and thalamus.

CONCLUSION

RTHb patients exhibited structural changes in multiple brain areas. Whether these structural changes are causally linked to the abnormal behavioral profile of RTHß which is similar to ADHD, remains to be determined.

Cluster Headache Genomewide Association Study and Meta-Analysis Identifies Eight Loci and Implicates Smoking as Causal Risk Factor

OBJECTIVE

The objective of this study was to aggregate data for the first genomewide association study meta-analysis of cluster headache, to identify genetic risk variants, and gain biological insights.

METHODS

A total of 4,777 cases (3,348 men and 1,429 women) with clinically diagnosed cluster headache were recruited from 10 European and 1 East Asian cohorts. We first performed an inverse-variance genomewide association meta-analysis of 4,043 cases and 21,729 controls of European ancestry. In a secondary trans-ancestry meta-analysis, we included 734 cases and 9,846 controls of East Asian ancestry. Candidate causal genes were prioritized by 5 complementary methods: expression quantitative trait loci, transcriptome-wide association, fine-mapping of causal gene sets, genetically driven DNA methylation, and effects on protein structure. Gene set and tissue enrichment analyses, genetic correlation, genetic risk score analysis, and Mendelian randomization were part of the downstream analyses.

RESULTS

The estimated single nucleotide polymorphism (SNP)-based heritability of cluster headache was 14.5%. We identified 9 independent signals in 7 genomewide significant loci in the primary meta-analysis, and one additional locus in the trans-ethnic meta-analysis. Five of the loci were previously known. The 20 genes prioritized as potentially causal for cluster headache showed enrichment to artery and brain tissue. Cluster headache was genetically correlated with cigarette smoking, risk-taking behavior, attention deficit hyperactivity disorder (ADHD), depression, and musculoskeletal pain. Mendelian randomization analysis indicated a causal effect of cigarette smoking intensity on cluster headache. Three of the identified loci were shared with migraine.

INTERPRETATION

This first genomewide association study meta-analysis gives clues to the biological basis of cluster headache and indicates that smoking is a causal risk factor. ANN NEUROL 2023;94:713-726.

Differences in Implicit Attitudes in West and East Germans as Measured by the Go/NoGo Association Task and Event-related EEG Potentials

BACKGROUND AND OBJECTIVE

Implicit social cognition refers to attitudes and stereotypes that may reside outside conscious awareness and control but that still affect human behavior. In particular, the implicit favoritism of an ingroup, to which an individual belongs, as opposed to an outgroup, to which the individual does not belong, characterized as ingroup bias, is of interest and is investigated here.

METHOD

We used a Go/NoGo association task (GNAT) and behavioral and electroencephalographic (event-related EEG potential [ERP] analysis) measures to investigate the implicit bias toward cities in East Germany, West Germany, and Europe, in 16 individuals each from West and East Germany (mixed gender, M age = 24). The GNAT assesses an individual's Go and NoGo responses for a given association between a target category and either pole (positive or negative) of an evaluative dimension.

RESULTS

Behavioral measures revealed slightly faster reaction times to the combination of European city names and negative, as compared with positive, evaluative words in both groups. ERP analysis showed an increased negativity at 400-800 ms poststimulus in the incongruent conditions of East German city/positive word pairings (in West Germans) and West German city/positive word pairings (in East Germans).

CONCLUSION

An implicitly moderately negative evaluation of Europe by both groups was exhibited based on the behavioral data, and an increased level of conflict arising from the "incongruent" pairings (ie, as manifestation of an implicitly negative attitude toward East Germany in West Germans, and toward West Germany in East Germans) was exhibited based on the electrophysiological data.

On the quest for hidden ovarian teratomas in therapy-refractory anti-NMDA receptor encephalitis: a case report

BACKGROUND

Anti-NMDA-receptor (anti-NMDAR) encephalitis is often associated with ovarian teratoma (OT). The best management of anti-NMDAR encephalitis patients with normal imaging studies (pelvic ultrasound/MRI) but clinically high risk of OT (e.g., female, adult, black) is unclear. We report on the surprising diagnostic quest in a young black woman with anti-NMDAR encephalitis, in whom invasive procedures could finally disclose two OTs that were hidden from the initial non-invasive diagnostics.

CASE REPORT

The patient presented with a one-week history of psychotic symptoms, developing oro-facial dyskinesia, seizures and coma, eventually requiring mechanical ventilation. NMDA-receptor antibodies were positive in serum and cerebrospinal fluid. Pelvic MRI and transabdominal ultrasound were normal. Exploratory laparoscopy was also unremarkable at first, but due to a suspicious echogenic mass (15 mm) in the right ovary on perioperative transvaginal ultrasound, an ovarian incision was performed which led to the detection of a first OT and its removal via ovarian-preserving cystectomy. Following a severe therapy-refractory clinical course despite aggressive immunotherapy and tumor removal, 6 months later bilateral oophorectomy was performed as ultima ratio, disclosing a second micro-OT (6 mm) in the left ovary. Unfortunately, the patient has not improved clinically yet.

CONCLUSIONS

In therapy-refractory anti-NMDAR encephalitis with high risk of OT, small and bilateral OTs hidden from primary non-invasive diagnostics should be considered, which may trigger further invasive diagnostic procedures.

Reduced pituitary size in subjects with mutations in the THRB gene and thyroid hormone resistance

BACKGROUND

Thyroid hormone action is mediated by two forms of thyroid hormone receptors (α, β) with differential tissue distribution. Thyroid hormone receptor β (TRβ) mutations lead to resistance to thyroid hormone action in tissues predominantly expressing the β form of the receptor (pituitary, liver). This study seeks to identify the effects of mutant TRβ on pituitary size.

METHODS

High-resolution 3D T1-weighted magnetic resonance images were acquired in 19 patients with RTHβ in comparison to 19 healthy matched controls. Volumetric measurements of the pituitary gland were performed independently and blinded by four different raters (two neuroradiologists, one neurologist, one neuroscientist).

RESULTS

Patients with mutant TRβ (resistance to thyroid hormone β, RTHβ) showed elevated free tri-iodothyronine/thyroxine levels with normal thyroid-stimulating hormone levels, whereas healthy controls showed normal thyroid hormone levels. Imaging revealed smaller pituitary size in RTHβ patients in comparison to healthy controls (F(1,35) = 7.05, P = 0.012, partial η2 = 0.17).

CONCLUSION

RTHβ subjects have impaired sensitivity to thyroid hormones, along with decreased size of the pituitary gland.

Headache Attributed to Vaccination Against COVID-19 (Coronavirus SARS-CoV-2) with the ChAdOx1 nCoV-19 (AZD1222) Vaccine: A Multicenter Observational Cohort Study

INTRODUCTION

The most frequently reported neurological adverse event of ChAdOx1 nCoV-19 (AZD1222) vaccine is headache in 57.5%. Several cases of cerebral venous thrombosis (CVT) have developed after vaccination. Headache is the leading symptom of CVT. For the differential diagnosis of headaches attributed to this vaccine and headaches attributed to CVT, it is of central clinical importance whether and, if so, how the phenotypes and course of these headaches can be differentiated. The study aims to examine in detail the phenotype of headache attributed to this vaccine.

METHODS

Data on the clinical features and corresponding variables were recorded using a standardized online questionnaire in this multicenter observational cohort study. The primary outcomes of this study are the clinical features of headaches after vaccination.

FINDINGS

A total of 2464 participants reported headaches after vaccination with the ChAdOx1 nCoV-19 (AZD1222) vaccine. On average, headaches occurred 14.5 ± 21.6 h after vaccination and lasted 16.3 ± 30.4 h. A bilateral location was described by 75.8% of participants. This is most often found on the forehead (40.0%) and temples (31.4%); 50.4% reported a pressing and 37.7% a dull pain character. Headache intensity was most often severe (38.7%), moderate (35.2%), or very severe (15.5%). Accompanying symptoms were most commonly fatigue (44.8%), chills (36.1%), exhaustion (34.9%), and fever (30.4%).

CONCLUSION

Headaches attributed to COVID-19 vaccination with the ChAdOx1 nCoV-19 (AZD1222) vaccine demonstrate an extensive and characteristic complex of symptoms. The findings have several important clinical implications for the differentiation of post-vaccinal headache and other primary as well as secondary headaches.

Paraneoplastic encephalomyeloradiculits with multiple autoantibodies against ITPR-1, GFAP and MOG: case report and literature review

Background

Recently, antibodies against the alpha isoform of the glial-fibrillary-acidic-protein (GFAPα) were identified in a small series of patients with encephalomyelitis. Coexisting autoantibodies (NMDA receptor, GAD65 antibodies) have been described in a few of these patients. We describe a patient with rapidly progressive encephalomyeloradiculitis and a combination of anti-ITPR1, anti-GFAP and anti-MOG antibodies.

Case presentation and literature review

A 44-year old caucasian woman with a flu-like prodrome presented with meningism, progressive cerebellar signs and autonomic symptoms, areflexia, quadriplegia and respiratory insufficiency. MRI showed diffuse bilateral T2w-hyperintense brain lesions in the cortex, white matter, the corpus callosum as well as a longitudinal lesion of the medulla oblongata and the entire spinal cord. Anti-ITPR1, anti-GFAP and anti-MOG antibodies were detected in cerebrospinal fluid along with lymphocytic pleocytosis. Borderline tumor of the ovary was diagnosed. Thus, the disease of the patient was deemed to be paraneoplastic. The patient was treated by surgical removal of tumor, steroids, immunoglobulins, plasma exchange and rituximab. Four months after presentation, the patient was still tetraplegic, reacted with mimic expressions to pain or touch and could phonate solitary vowels. An extensive literature research was performed.

Conclusion

Our case and the literature review illustrate that multiple glial and neuronal autoantibodies can co-occur, that points to a paraneoplastic etiology, above all ovarian teratoma or thymoma. Clinical manifestation can be a mixture of typically associated syndromes, e.g. ataxia associated with anti-ITPR1 antibodies, encephalomyelitis with anti-GFAPα antibodies and longitudinal extensive myelitis with anti-MOG antibodies.

Supplementary Information

The online version contains supplementary material available at 10.1186/s42466-021-00145-w.

Clinical characteristics of headache after vaccination against COVID-19 (coronavirus SARS-CoV-2) with the BNT162b2 mRNA vaccine: a multicentre observational cohort study

The novel coronavirus SARS-CoV-2 causes the infectious disease COVID-19. Newly developed mRNA vaccines can prevent the spread of the virus. Headache is the most common neurological symptom in over 50% of those vaccinated. Detailed information about the clinical characteristics of this form of headache has not yet been described. The aim of the study is to examine in detail the clinical characteristics of headaches occurring after vaccination against COVID-19 with the BNT162b2 mRNA COVID-19 vaccine for the first time. In a multicentre observational cohort study, data on the clinical features and corresponding variables were recorded using a standardized online questionnaire. The questionnaire was circulated to 12 000 residential care homes of the elderly as well as tertiary university hospitals in Germany and the United Arab Emirates. The primary outcomes of this study are the clinical features of headache after vaccination. Comorbidities, treatment with medication and sociodemographic variables are also analysed. A total of 2349 participants reported headaches after vaccination with the BNT162b2 mRNA COVID-19 vaccine. Headaches occur an average of 18.0 ± 27.0 h after vaccination and last an average duration of 14.2 ± 21.3 h. Only 9.7% of those affected also report headaches resulting from previous vaccinations. In 66.6% of the participants, headache occurs as a single episode. A bilateral location is indicated by 73.1% of the participants. This is most often found on the forehead (38.0%) and temples (32.1%). A pressing pain character is indicated by 49.2% and 40.7% report a dull pain character. The pain intensity is most often moderate (46.2%), severe (32.1%) or very severe (8.2%). The most common accompanying symptoms are fatigue (38.8%), exhaustion (25.7%) and muscle pain (23.4%). Headaches after COVID-19 vaccination show an extensive complex of symptoms. The constellation of accompanying symptoms together with the temporal and spatial headache characteristics delimit a distinctive headache phenotype.

Studying Implicit Attitudes Towards Smoking: Event-Related Potentials in the Go/NoGo Association Task

Cigarette smoking and other addictive behaviors are among the main preventable risk factors for several severe and potentially fatal diseases. It has been argued that addictive behavior is controlled by an automatic-implicit cognitive system and by a reflective-explicit cognitive system, that operate in parallel to jointly drive human behavior. The present study addresses the formation of implicit attitudes towards smoking in both smokers and non-smokers, using a Go/NoGo association task (GNAT), and behavioral and electroencephalographic (EEG) measures. The GNAT assesses, via quantifying participants’ reaction times, the strength of association between a target category and either pole of an evaluative dimension (positive or negative). EEG analysis is performed to determine the temporal course of the event-related potential (ERP) components underlying Go/NoGo decisions and implicit attitude formation. Both smokers and non-smokers showed prolonged reaction times to smoking-related pictures when the pictures were coupled with positive evaluative words (“incongruent condition”). This indicates negative implicit attitudes towards smoking in both groups alike at the time point of the behavioral response (600–700 ms post-stimulus). However, only the non-smokers, not the smokers, were found to show a delay of the N200 component in the incongruent condition. This is interpreted as reflecting ambivalent or even positive implicit attitudes towards smoking in the smoker group at the time point of the N200 (300–400 ms post-stimulus). Our study thus provides evidence for the hypothesis that implicit attitudes are subject to changes within several hundred milliseconds after stimulus presentation, and can be altered in the course of their formation.

The Suppression of Taboo Word Spoonerisms Is Associated With Altered Medial Frontal Negativity: An ERP Study

The constant internal monitoring of speech is a crucial feature to ensure the fairly error-free process of speech production. It has been argued that internal speech monitoring takes place through detection of conflict between different response options or “speech plans.” Speech errors are thought to occur because two (or more) competing speech plans become activated, and the speaker is unable to inhibit the erroneous plan(s) prior to vocalization. A prime example for a speech plan that has to be suppressed is the involuntary utterance of a taboo word. The present study seeks to examine the suppression of involuntary taboo word utterances. We used the “Spoonerisms of Laboratory Induced Predisposition” (SLIP) paradigm to elicit two competing speech plans, one being correct and one embodying either a taboo word or a non-taboo word spoonerism. Behavioral data showed that inadequate speech plans generally were effectively suppressed, although more effectively in the taboo word spoonerism condition. Event-related potential (ERP) analysis revealed a broad medial frontal negativity (MFN) after the target word pair presentation, interpreted as reflecting conflict detection and resolution to suppress the inadequate speech plan. The MFN was found to be more pronounced in the taboo word spoonerism compared to the neutral word spoonerism condition, indicative of a higher level of conflict when subjects suppressed the involuntary utterance of taboo words.