A new perspective on the role of the frontoparietal regions in Stroop-like conflicts.

Humans are goal-directed; however, goal-unrelated information still affects us, but how? The Stroop task is often used to answer this question, relying on conflict (incongruency) between attributes, one targeted by the task and another irrelevant to the task. The frontal regions of the brain are known to play a crucial role in processing such conflict, as they show increased activity when we encounter incongruent stimuli. Notably, the Stroop stimuli also consist of conceptual dimensions, such as semantic or emotional content, that are independent of the attributes that define the conflict. Since the non-targeted attribute usually refers to the same conceptual dimension as the targeted-attribute, it is relevant to the task at hand. For example, when naming the emotion of an emotional face superimposed by an emotional word, both the targeted-attribute and the non-targeted attribute refer to the conceptual dimension "emotion". We designed an fMRI paradigm to investigate how conflicts between different conceptual dimensions impact us. Even though the conflict was task-irrelevant, incongruent stimuli resulted in longer reaction times, indicating a behavioral congruency effect. When examining the neural mechanisms that underlie this effect, we found that the frontal regions exhibited repetition suppression, while the bilateral intraparietal sulcus (IPS) showed a congruency effect linked to the behavioral effect. Taken together, these findings suggest that individuals are unable to completely ignore task-irrelevant information, and that the IPS plays a crucial role in processing such information.

Herpes simplex encephalitis in patients receiving chemotherapy and whole-brain radiation therapy.

Herpes simplex encephalitis (HSE) is a very severe infection of the central nervous system (CNS) caused mainly by herpes simplex virus type 1 (HSV-1) and occasionally by herpes simplex virus type 2 (HSV-2). After relapse or drug-resistant to chemotherapy, whole-brain radiation therapy (WBRT) is a mainstay of treatment in patients with both identifiable brain metastases and CNS lymphoma. Although HSV-1 encephalitis predominantly affects immunocompetent host, HSV encephalitis may be more common in immune-suppressed patients than is currently recognized. Disease presentation may be atypical including lack of pleocytosis in cerebrospinal fluid (CSF). We report four patients diagnosed with HSE following chemotherapy and WBRT. The occurrence of HSE in patients with cancer seems not to be increased compared to the general population, but as our case series shows, a high level of suspicion is needed by the treating physician to diagnose HSE early in patients presenting with new neurological symptoms following WBRT.

Safety of the BNT162b2 COVID-19 vaccine in multiple sclerosis (MS): Early experience from a tertiary MS center in Israel.

BACKGROUND AND PURPOSE: Although the COVID-19 vaccines are currently recommended for people with multiple sclerosis (MS), the fact that they were not specifically tested in people with MS raises uncertainty regarding their safety in this population. The purpose of this study was to report real-life safety data of the BNT162b2 COVID-19 vaccine in a cohort of MS patients. METHODS: An anonymous survey was distributed to 425 MS patients. Participants were asked general demographic and disease-related questions and specific questions regarding the safety profile of the COVID-19 vaccine. RESULTS: Of the 425 MS patients, 262 completed the questionnaire. The median (range) participant age was 42 (22-79) years, 199 participants were women (75.9%), and 66 participants (25.2%) had associated comorbidities. A total of 198 participants (75.6%) were treated with disease-modifying therapies. In all, 239 participants (91.2% of the responders) had received the BNT162b2 COVID-19 vaccine. Of these, 182 (76.1%) were aged <55 years, and 57 (23.9%) were aged >55 years. Adverse events were reported by 136 participants (56.9%; 52.5% of those aged <55 years and 40.3% of those aged >55 years; p = 0.1517) and 36 participants (15.1%) reported new or worsening neurological symptoms following the vaccination, the most frequent being sensory disturbances (21 participants, 58.3%). Most symptoms occurred within the first 24 h after vaccination and resolved within 3 days. A total of 28 participants (77.8%) did not require any medication to treat their symptoms. CONCLUSIONS: This survey indicates an overall favorable safety profile of the BNT162b2 vaccine in people with MS. These data should be confirmed in further prospective, large-scale studies.

Incidence of AChR Ab-positive myasthenia gravis in Israel: A population-based study.

BACKGROUND: The incidence of myasthenia gravis (MG) has traditionally been low, ranging between 2-6/106 . Several recent epidemiological studies have reported a higher incidence. We, therefore, aimed to assess and characterize the incidence of MG in Israel. METHODS: We retrospectively reviewed the records of all four laboratories that performed the acetylcholine receptor antibody (AChR Ab) test in Israel between 1994 and 2013 and documented the number of newly diagnosed seropositive MG patients each year. To assure that data indeed reflect only newly diagnosed patients, patient's names and ID numbers were screened at the Hadassah medical center database since 1978, the year when the test was first performed in Israel. In order to calculate the annual incidence of the disease, the population at risk was derived from the annual publication of the Israeli Central Bureau of Statistics. RESULTS: The annual incidence of MG for this time period was 13.1/106 inhabitants. The mean incidence of MG between 1994 and 2003 was 7.695/106 /y, while the mean incidence between 2004 and 2013 was 18.49/106 (P < .0001). Mean age of diagnosis between 1994 and 2003 was 56.65 ± 0.9351, while between 2004 and 2013, it was 59.89 ± 0.5336 (P = .0012). Male to female (M:F) incidence ratio in the years 1994-2003 and 2004-2013 was 2:3.2 and 3:1.8, respectively, reflecting increased incidence among males (P < .0001). CONCLUSIONS: The incidence of MG in Israel has increased significantly during the last decade, especially among males of older age. These findings may reflect an etiological role of an environmental factor, increased awareness, and increased longevity in general.

Neurologic complications of immune checkpoint inhibitors.

Immune checkpoint inhibitors (ICPIs) have recently emerged as a novel treatment for cancer. These agents, transforming the field of oncology, are not devoid of toxicity and cause immune-related side effects which can involve any organ including the nervous system. In this study, we present 9 patients (7 men and 2 women) with neurologic complications secondary to ICPI treatment. These included meningoencephalitis, limbic encephalitis, polyradiculitis, cranial polyneuropathy, myasthenic syndrome and myositis. Four patients received dual ICPI therapy comprised of programmed cell death-1 and cytotoxic lymphocyte associated protein-4 blocking antibodies. Median time to onset of neurologic adverse event during immune checkpoint inhibitor treatment was 8 weeks (range 5 days-19 weeks). In all patients ICPIs were stopped and corticosteroids were initiated, resulting in a marked improvement in seven out of nine patients. Two patients, one with myositis and one with myasthenic syndrome, died. In two patients ICPI therapy was resumed after resolution of the neurological adverse event with no additional neurologic complications. This series highlights the very broad spectrum of neurological complications of ICPIs, emphasizes the need for expedited diagnosis and suggests that withholding treatment early, accompanied with steroid therapy, carries the potential of complete resolution of the neurological immune-mediated condition. Thus, a high level of suspicion and rapid initiation of corticosteroids are mandatory to prevent uncontrolled clinical deterioration, which might be fatal.

Is Head Computerized Tomography Indicated for the Workup of Headache in Patients with Intact Neurological Examination.

INTRODUCTION: The use of neuroimaging as part of the initial workup in the emergency department (ED) for patients with atraumatic headache is increasing, whereas the proportion of cases in which clinically significant intracranial pathology is detected is decreasing. In the last few decades, the exposure to medical ionized radiation from utilization of computer tomography (CT) increased dramatically, raising concern about radiation-induced cancer. Different guidelines were suggested to address the role of neuroimaging in the investigation of adult patients presenting to the ED with nontraumatic headache. MATERIALS AND METHODS: We retrospectively evaluated data from all consecutive patients who underwent a head CT in the ED for the evaluation of headache during 2015. Patients were included only if a normal neurologic examination was documented. RESULTS: In total, 422 patients were included. About 43.4% of scans were normal. Most abnormal findings were sinusitis (148 patients, 35%) or ischemic changes. Seven CT scans (1.6%) showed clinically significant findings requiring an immediate change in management. CONCLUSION: A normal neurologic examination, even when performed by a neurologist, does not rule out a significant secondary cause for headache. A CT scan in the ED is indicated for patients presenting with severe nonremitting headache who never had neuroimaging in the past.

Toll-like receptor 3 deficiency decreases epileptogenesis in a pilocarpine model of SE-induced epilepsy in mice.

OBJECTIVE: Epilepsy affects 60 million people worldwide. Despite the development of antiepileptic drugs, up to 35% of patients are drug refractory with uncontrollable seizures. Toll-like receptors (TLRs) are central components of the nonspecific innate inflammatory response. Because TLR3 was recently implicated in neuronal plasticity, we hypothesized that it may contribute to the development of epilepsy after status epilepticus (SE). METHODS: To test the involvement of TLR3 in epileptogenesis, we used the pilocarpine model for SE in TLR3-deficient mice and their respective wild-type controls. In this model, a single SE event leads to spontaneous recurrent seizures (SRS). Two weeks after SE, mice were implanted with wireless electroencephalography (EEG) transmitters for up to 1 month. The impact of TLR3 deficiency on SE was assessed using separate cohorts of mice regarding EEG activity, seizure progression, hippocampal microglial distribution, and expression of the proinflammatory cytokines tumor necrosis factor (TNF)α and interferon (IFN)ß. RESULTS: Our data indicate that TLR3 deficiency reduced SRS, microglial activation, and the levels of the proinflammatory cytokines TNFα and IFNß, and increased survival following SE. SIGNIFICANCE: This study reveals novel insights into the pathophysiology of epilepsy and the contribution of TLR3 to disease progression. Our results identify the TLR3 pathway as a potential future therapeutic target in SE.

Toll-Like Receptor-4 Inhibitor TAK-242 Attenuates Motor Dysfunction and Spinal Cord Pathology in an Amyotrophic Lateral Sclerosis Mouse Model.

Neuroinflammation contributes to amyotrophic lateral sclerosis (ALS) progression. TLR4, a transmembrane protein that plays a central role in activation of the innate immune system, has been shown to induce microglial activation in ALS models. TLR4 is up-regulated in the spinal cords of hSOD1G93A mice. We aimed to examine the effects of specific TLR4 inhibition on disease progression and survival in the hSOD1G93A mouse model of ALS. Immunologic effect of TLR4 inhibition in vitro was measured by the effect of TAK-242 treatment on LPS-induced splenocytes proliferation. hSOD1G93A transgenic mice were treated with TAK-242, a selective TLR4 inhibitor, or vehicle. Survival, body weight, and motor behavior were monitored. To evaluate in vivo immunologic modifications associated with TAK-242 treatment, we measured serum IL-1ß in the plasma, as well as IL-1ß and TNF-α mRNAs in the spinal cord in wild-type mice and in TAK-242-treated and vehicle-treated early symptomatic hSOD1G93A mice. Immunohistochemical analysis of motor neurons, astrocytes, and microglial reactivity in the spinal cords were performed on symptomatic (100 days old) TAK-242-treated and vehicle-treated hSOD1G93A mice. In vitro, splenocytes taken from 100 days old hSOD1G93A mice showed significantly increased proliferation when exposed to LPS (p = 0.0002), a phenomenon that was reduced by TAK-242 (p = 0.0179). TAK-242 treatment did not attenuate body weight loss or significantly affect survival. However, TAK-242-treated hSOD1G93A mice showed temporary clinical delay in disease progression evident in the ladder test and hindlimb reflex measurements. Plasma IL-1ß levels were significantly reduced in TAK-242-treated compared to vehicle-treated hSOD1G93A mice (p = 0.0023). TAK-242 treatment reduced spinal cord astrogliosis and microglial activation and significantly attenuated spinal cord motor neuron loss at early disease stage (p = 0.0259). Compared to wild-type animals, both IL-1ß and TNF-α mRNAs were significantly upregulated in the spinal cords of hSOD1G93A mice. Spinal cord analysis in TAK-242-treated hSOD1G93A mice revealed significant attenuation of TNF-α mRNA (p = 0.0431), but no change in IL-1ß mRNA. TLR4 inhibition delayed disease progression, attenuated spinal cord astroglial and microglial reaction, and reduced spinal motor neuron loss in the ALS hSOD1G93A mouse model. However, this effect did not result in increased survival. To our knowledge, this is the first report on TAK-242 treatment in a neurodegenerative disease model. Further studies are warranted to assess TLR4 as a therapeutic target in ALS.

Innate defense mechanisms against HSV-1 infection in the target tissues, skin and brain.

Herpes simplex virus type 1 (HSV-1) initiates productive infection in mucocutaneous tissues to cause cold sores and establishes latent infection in the trigeminal ganglia. Under certain circumstances, HSV-1 may cause encephalitis. Here, we compared host innate defenses against HSV-1 in the two clinically relevant tissues, skin and brain, using a unique ex vivo system of organ culture. Upon HSV-1 infection and spread, apoptosis induction was observed in the skin, but not in brain tissues. While the two tissues elicited interferon (IFN-ß) response upon HSV1 infection, IFN induction was more robust in the skin compared to the brain. Moreover, antiviral response to exogenous IFNß treatment was much stronger in the skin compared to brain tissues. This observation was not related to the availability of the IFN receptor on cells' surface. Taken together, our study demonstrates differential innate antiviral responses to HSV-1 infection that may be exploited in future development of selective and tissue-specific anti-viral treatments.

Acute disseminated encephalomyelitis: current knowledge and open questions.

Acute disseminated encephalomyelitis (ADEM) is usually an acute, multi-focal, and monophasic immune-mediated disease of the central nervous system. The disorder is mainly a condition of the pediatric age group, but neurologists are also involved in the management of adult patients. The lack of defined diagnostic criteria for ADEM underlies the limited understanding of its epidemiology, etiology, pathogenesis, course, prognosis, therapy, as well as the association with, and distinction from, multiple sclerosis. The present review summarizes current knowledge and outlines unanswered questions the answers to which should be eventually provided through a synergistic combination of clinical and basic research.

Steroid-responsive, progressive, focal measles virus brain infection.

Chronic measles virus infection of the brain causes subacute sclerosing panencephalitis (SSPE), a progressive, relentless fatal disorder. We report a 52-year-old male who developed focal, chronic persistent measles virus infection of the brain following interferon and ribavirin therapy for hepatitis C, and who responded to steroid therapy. This case, diametrically different from SSPE, has 2 unique features, its focal nature and its permissive response to steroids, that may add to the understanding of the pathogenesis of SSPE and the mechanism enabling viruses to evade the immune response and establish persistent brain infection.

Different modes of herpes simplex virus type 1 spread in brain and skin tissues.

Herpes simplex virus type 1 (HSV-1) initially infects the skin and subsequently spreads to the nervous system. To investigate and compare HSV-1 mode of propagation in the two clinically relevant tissues, we have established ex vivo infection models, using native tissues of mouse and human skin, as well as mouse brain, maintained in organ cultures. HSV-1, which is naturally restricted to the human, infects and spreads in the mouse and human skin tissues in a similar fashion, thus validating the mouse model. The spread of HSV-1 in the skin was concentric to form typical plaques of limited size, predominantly of cytopathic cells. By contrast, HSV-1 spread in the brain tissue was directed along specific neuronal networks with no apparent cytopathic effect. Two additional differences were noted following infection of the skin and brain tissues. First, only a negligible amount of extracellular progeny virus was produced of the infected brain tissues, while substantial quantity of infectious progeny virus was released to the media of the infected skin. Second, antibodies against HSV-1, added following the infection, effectively restricted viral spread in the skin but have no effect on viral spread in the brain tissue. Taken together, these results reveal that HSV-1 spread within the brain tissue mostly by direct transfer from cell to cell, while in the skin the progeny extracellular virus predominates, thus facilitating the infection to new individuals.

Recent issues in herpes simplex encephalitis.

Herpes simplex encephalitis (HSE) remains the most important cause of fatal sporadic encephalitis in man. Caused by herpes simplex virus type 1 (HSV-1), and more rarely by HSV-2, it can have devastating clinical consequences for the patient, especially when the instigation of acyclovir therapy has been delayed by more than 2 days or more. Even with acyclovir treatment, nearly a third of patients may die or suffer significant morbidity. Both host and viral factors may interact to affect the clinical phenotype. Here we consider some of the recently published management guidelines for HSE and comment on various current issues of contention. The latter includes the timing and frequency of cerebrospinal fluid examinations for the polymerase chain reaction detection of HSV, decisions regarding acyclovir therapy including the consequences of delay in its initiation, and the use of corticosteroids in the disease.

Steroids in bacterial meningitis: yes.

Bacterial meningitis is an infectious condition associated with severe morbidity and mortality, even with rapid diagnosis and appropriate antibiotic therapy. Despite decrease in the rate of bacterial meningitis brought about by vaccination programs against Haemophilus influenzae type-B and Streptococcus pneumonia, the incidence of meningitis is still unacceptably high and acute treatment remains the mainstay of therapy. The infection is accompanied by intense inflammatory response, which may carry deleterious effects upon the tissue. This led to the possibility of adjuvant corticosteroid therapy, as an anti-inflammatory agent, in bacterial meningitis. The debate focuses on the rational and evidence supporting and refuting such an approach.

Lack of migraine in headaches of familial dysautonomia patients.

Familial Dysautonomia (FD) is an autosomal recessive genetic disease where autonomic and sensory functions are defective affecting many body systems including the vascular. Plasma level of the neurotransmitter Calcitonin Gene Related Peptide (CGRP) is decreased in FD patients. This compound has been implicated to take part in the pathogenesis of migraine. We aimed to evaluate the symptoms of headaches in FD patients and to test the hypothesis that these patients will have a low incidence of migrainous headache. Sixty-five FD patients were evaluated by a medical headache questionnaire. Mean age was 23.73 + 10.82 years (mean 21 years) and there were 37 males (57 %).Thirty-eight patients (58.5 %) described having episodic headache conforming to criteria of tension headache, and in 17 of those 38 (44.7 %) headache were dependent on changes in blood pressure, except from one patient who had complaints that matched diagnosis of acephalic migraine. None of the patients had symptoms compatible with migraine or cluster headache. Results show that the headache is a very common complaint in FD, there is lack of migraine symptoms in this group. This might be attributed to defective sensory innervation and deficiency of CGRP. FD could be regarded as a human model for CGRP deficiency when studying the pathogenesis of migraine.

Update on herpes virus infections of the nervous system.

Herpes simplex viruses types 1 and 2 (HSV-1 and HSV-2) are human neurotropic viruses that establish latent infection in dorsal root ganglia (DRG) for the entire life of the host. From the DRG they can reactivate to cause human morbidity and mortality. Although they vary, in part, in the clinical disorders they cause, and in their molecular structure, they share several features that govern the biology of their infection of the human nervous system. HSV-1 is the causative agent of encephalitis, corneal blindness, and several peripheral nervous system disorders; HSV-2 is responsible for meningoencephalitis in neonates and meningitis in adults. The biology of their ability to establish latency, maintain it for the entire life of the host, reactivate, and cause primary and recurrent disease is being studied in animal models and in humans. This review covers recent advances in understanding the biology and pathogenesis of HSV-related disease.

The relatively good outcome of cerebellum-brainstem ischemic strokes.

BACKGROUND: Our clinical experience suggests that the outcome of cerebellum-brainstem ischemic strokes is better than that of hemispheric ischemic strokes. METHODS: Within the setting of 2 national Israeli prospective stroke surveys, we analyzed risk factors, etiology, severity at presentation, and prognosis of first ischemic cerebellum-brainstem stroke (259 patients), comparing with strokes within the anterior circulation (1,029 patients). RESULTS: Patients with cerebellum-brainstem strokes were younger and had less frequently atrial fibrillation and congestive heart failure. Cardioembolic etiology was significantly less prevalent (p < 0.001). Severity at presentation was milder (p < 0.001). At discharge, worsening of the modified Rankin Scale was present in a smaller number of patients (p < 0.001); more returned to their home (p < 0.001). Six-month and 1-year mortality were lower (p < 0.001 for both). Adjusted logistic regression models showed that patients with cerebellum-brainstem strokes had 50% smaller chances of dying (OR 0.55; 95% CI 0.31-0.98) and a smaller chance of worsening of the modified Rankin Scale at discharge (OR 0.61; 95% CI 0.46-0.82). CONCLUSIONS: Cerebellum-brainstem strokes are less frequently cardioembolic, have a less severe presentation, and carry a better immediate and long-term prognosis.

Epilepsy following herpes simplex encephalitis - A case series.

BACKGROUND: Herpes simplex encephalitis (HSE) is associated with severe mortality and morbidity. Its incidence is estimated at 1:250 000, and the typical symptomatology of acute disease including headaches, mental state disturbances, confusion, sleepiness, and seizures. The chronic phase of the disease is occasionally characterized by epilepsy and neurological deficits. STUDY RATIONALE: The present retrospective single-center study aims to identify risk factors for predicting the development of epilepsy (epileptogenesis) following HSE. METHODS: Medical records were screened for patients older than 18 years, hospitalized between January 2005 and September 2019 with a diagnosis of "encephalitis" and "herpes simplex virus, HSV" infection. HSE diagnosis was based on an analysis of the cerebrospinal fluid with positive HSV testing results. RESULTS: Twenty-three patients fit our inclusion criteria: fever and behavioral changes, followed by seizures, were reported in 58.3 % of patients. On follow-up (59.7 ± 38.8 months), eight patients (34.8 %) developed epilepsy. Pathological imaging and EEG were correlated with acute symptomatic seizures (ASS). ASS was associated with an 8-fold risk increase to develop post-encephalitis epilepsy (PE). PE was associated with younger age but not with CSF results, imaging, or EEG. CONCLUSION: Our retrospective single-center study on PE, following HSE, shows that younger age and ASS were associated with PE. Brain imaging, CSF analysis, and EEG were not associated with the development of epilepsy following HSE.

Patient and caregiver perceptions of the social impact of advanced Parkinson's disease and dyskinesias.

Parkinson's disease (PD) exacts a physical and emotional toll on both patients and family. The aim of this study was to compare patient and caregiver perceptions of the social consequences of basic symptoms of PD and levodopa-induced dyskinesias. Forty patients with PD and dyskinesias and 35 of their caregivers completed a self-report questionnaire on the impact of PD and dyskinesias on their feelings of security and embarrassment and participation in family/social events, and indicated their preference for the "on" (with dyskinesias) or the "off" (without dyskinesias) state. The patients scored significantly higher than the caregivers did on the negative social impact of the disease in general (p = 0.002) and of the dyskinesias in particular (p = 0.03). Nevertheless, the patients expressed a significantly greater preference for the "on" state (83 %) than the caregivers (59 %) (p = 0.03). Preferences turned to be reverse in direction among spouse-caregivers who significantly preferred the "off" state (54 %) than the patients (25 %) (p = 0.04). Although patients have a worse perception of the effects of PD than their caregivers do, they prefer the more independent "on" state, whereas their caregivers prefer the "off" state.