Neurological Immune-Related Adverse Events Induced by Immune Checkpoint Inhibitors.

The use of immune checkpoint inhibitors (ICIs) for the treatment of various advanced and aggressive types of malignancy has significantly increased both survival and long-term remission rates. ICIs block crucial inhibitory pathways of the immune system, in order to trigger an aggravated immune response against the tumor. However, this enhanced immune activation leads to the development of numerous immune-related adverse events (irAEs), which may affect any system. Although severe neurological irAEs are relatively rare, they carry a high disability burden, and they can be potentially life-threatening. Therefore, clinicians must be alert and act promptly when individuals receiving ICIs present with new-onset neurological symptoms. In this narrative review, we have collected all the currently available data regarding the epidemiology, pathogenesis, clinical manifestations, diagnosis, and treatment of post-ICI neurological irAEs. This review aims to raise physicians' awareness, enrich their knowledge regarding disease pathogenesis, and guide them through the diagnosis and management of post-ICI neurological irAEs.

The Time Trajectory of Choroid Plexus Enlargement in Multiple Sclerosis.

Choroid plexus (CP) can be seen as a watchtower of the central nervous system (CNS) that actively regulates CNS homeostasis. A growing body of literature suggests that CP alterations are involved in the pathogenesis of multiple sclerosis (MS) but the underlying mechanisms remain elusive. CPs are enlarged and inflamed in relapsing-remitting (RRMS) but also in clinically isolated syndrome (CIS) and radiologically isolated syndrome (RIS) stages, far beyond MS diagnosis. Increases in the choroid plexus/total intracranial volume (CP/TIV) ratio have been robustly associated with increased lesion load, higher translocator protein (TSPO) uptake in normal-appearing white matter (NAWM) and thalami, as well as with higher annual relapse rate and disability progression in highly active RRMS individuals, but not in progressive MS. The CP/TIV ratio has only slightly been correlated with magnetic resonance imaging (MRI) findings (cortical or whole brain atrophy) and clinical outcomes (EDSS score) in progressive MS. Therefore, we suggest that plexus volumetric assessments should be mainly applied to the early disease stages of MS, whereas it should be taken into consideration with caution in progressive MS. In this review, we attempt to clarify the pathological significance of the temporal CP volume (CPV) changes in MS and highlight the pitfalls and limitations of CP volumetric analysis.

Apraxia Patterns for the Differentiation between Alzheimer's Disease and Frontotemporal Dementia Variants.

Background and Objectives: Despite the increasing use of biomarkers, differentiation between Alzheimer's disease (AD), behavioral variant Frontotemporal Dementia (bvFTD), and Primary Progressive Aphasia (PPA) remains a challenge. Apraxia is a supportive feature for diagnosing AD but is underrepresented in other dementia types. Herein, we investigated the presence and characteristic profiles of limb, verbal, and non-verbal apraxia in three major dementia types. Materials and Methods: Test for Upper Limb Apraxia (TULIA) and Apraxia Battery for Adults-2 (ABA-2) were administered in patients with AD (n = 22), bvFTD (n = 41), and PPA (n = 22), with 20 individuals serving as healthy controls (HC). Composite and subdomain scores were compared between each patient group and the HC. Praxis profiles indicative of each dementia type and a possible predictive value were sought. Results: Apraxia provided high diagnostic accuracy for detecting dementia compared with HC (sensitivity: 63.6-100%, specificity: 79.2-100%). Patients with AD performed worse when imitating intransitive gestures as well as pantomiming transitive gestures (mean differences: 2.10 and 3.12, respectively), compared with bvFTD. PPA patients, compared with bvFTD, had comparable results in limb, verbal, and non-verbal praxis assessments, despite the greater deterioration in the outcome. Compared with patients with AD, PPA had increased pathological outcomes in verbal (86.4% vs. 40.9%) and non-verbal apraxia (31.8% vs. 0%), while bvFTD had increased pathological outcomes in verbal apraxia (85.4% vs. 44.5%). Finally, apraxia is correlated with cognitive decline. Conclusions: Apraxia profile evaluation could contribute to the differentiation between AD and Frontotemporal Dementia (FTD). Both TULIA and ABA-2 are reliable tools that can be performed as bed-side tests in clinical practice.

Secondary Central Nervous System Demyelinating Disorders in the Elderly: A Narrative Review.

Secondary demyelinating diseases comprise a wide spectrum group of pathological conditions and may either be attributed to a disorder primarily affecting the neurons or axons, followed by demyelination, or to an underlying condition leading to secondary damage of the myelin sheath. In the elderly, primary demyelinating diseases of the central nervous system (CNS), such as multiple sclerosis, are relatively uncommon. However, secondary causes of CNS demyelination may often occur and in this case, extensive diagnostic workup is usually needed. Infectious, postinfectious, or postvaccinal demyelination may be observed, attributed to age-related alterations of the immune system in this population. Osmotic disturbances and nutritional deficiencies, more commonly observed in the elderly, may lead to conditions such as pontine/extrapontine myelinolysis, Wernicke encephalopathy, and demyelination of the posterior columns of the spinal cord. The prevalence of malignancies is higher in the elderly, sometimes leading to radiation-induced, immunotherapy-related, or paraneoplastic CNS demyelination. This review intends to aid clinical neurologists in broadening their diagnostic approach to secondary CNS demyelinating diseases in the elderly. Common clinical conditions leading to secondary demyelination and their clinical manifestations are summarized here, while the current knowledge of the underlying pathophysiological mechanisms is additionally presented.

The Experience of a Tertiary Reference Hospital in the Study of Rare Neurological Diseases.

Background and Objectives: Rare diseases (RDs) are life-threatening or chronically impairing conditions that affect about 6% of the world's population. RDs are often called 'orphan' diseases, since people suffering from them attract little support from national health systems. Aim: The aim of this study is to describe the clinical characteristics of, and the available laboratory examinations for, patients who were hospitalized in a tertiary referral center and finally received a diagnosis associated with a Rare Neurological Disease (RND). Materials and Methods: Patients that were hospitalized in our clinic from 1 January 2014 to 31 March 2022 and were finally diagnosed with an RND were consecutively included. The RND classification was performed according to the ORPHAcode system. Results: A total of 342 out of 11.850 (2.9%) adult patients admitted to our department during this period received a diagnosis associated with an RND. The most common diagnosis (N = 80, 23%) involved an RND presenting with dementia, followed by a motor neuron disease spectrum disorder (N = 64, 18.7%). Family history indicative of an RND was present in only 21 patients (6.1%). Fifty-five (16%) people had previously been misdiagnosed with another neurological condition. The mean time delay between disease onset and diagnosis was 4.24 ± 0.41 years. Conclusions: Our data indicate that a broad spectrum of RNDs may reach a tertiary Neurological Center after a significant delay. Moreover, our data underline the need for a network of reference centers, both at a national and international level, expected to support research on the diagnosis and treatment of RND.

Emergence of artistic talent in logopenic variant of primary progressive aphasia: a case report.

The case report covers the investigation of a 59-year-old woman, with the diagnosis of logopenic variant of primary progressive aphasia (lvPPA), who presented de novo visual artistic talent after the onset of language deficits. Similar cases have been described in patients with semantic and non-fluent/agrammatic variants of primary progressive aphasia. However, this is the first related case with lvPPA reported in the literature. Upon her initial visit at the Neurology department in 2020, a neurological and neuropsychological assessment were conducted to establish the diagnosis. A neuropsychological reassessment was performed in 2022. Neuroimaging data indicated decreased blood flow of the left hemisphere, while neuropsychological deficits were diffuse with predominant language production disorder. A description of the patient's portraits and suggestions regarding possible neural mechanisms associated with the manifestation of this ability are provided.

How Early Is Early Multiple Sclerosis?

The development and further optimization of the diagnostic criteria for multiple sclerosis (MS) emphasize the establishment of an early and accurate diagnosis. So far, numerous studies have revealed the significance of early treatment administration for MS and its association with slower disease progression and better late outcomes of the disease with regards to disability accumulation. However, according to current research results, both neuroinflammatory and neurodegenerative processes may exist prior to symptom initiation. Despite the fact that a significant proportion of individuals with radiologically isolated syndrome (RIS) progress to MS, currently, there is no available treatment approved for RIS. Therefore, our idea of "early treatment administration" might be already late in some cases. In order to detect the individuals who will progress to MS, we need accurate biomarkers. In this review, we present notable research results regarding the underlying pathology of MS, as well as several potentially useful laboratory and neuroimaging biomarkers for the identification of high-risk individuals with RIS for developing MS. This review aims to raise clinicians' awareness regarding "subclinical" MS, enrich their understanding of MS pathology, and familiarize them with several potential biomarkers that are currently under investigation and might be used in clinical practice in the future for the identification of individuals with RIS at high risk for conversion to definite MS.

Genetic causes of acute encephalopathy in adults: beyond inherited metabolic and epileptic disorders.

Acute encephalopathy is a widely used term, implying a rapidly progressive multifocal or diffuse brain dysfunction, caused by acute structural disturbance or a myriad of metabolic, toxic, epileptic, or infection-related factors. Apart from the more common acquired causes, a broad range of rare inherited disorders may produce spells of encephalopathy in adulthood, posing diagnostic challenges to clinicians. Among the latter, neurometabolic disorders and epileptic syndromes constitute typical examples. Interestingly, certain genetic entities have the potential to provoke episodic changes of cognition, via alternative, neither metabolic nor epileptic, mechanisms. Our aim is to provide a short and focused overview of their clinicoradiological features and potential pathophysiology. As the neurogenetic landscape is rapidly evolving, it is important to be familiar with these chameleons, in order to provide swift diagnosis and proper genetic counselling.

Preliminary validation of the apraxia battery for adults-second edition (ABA-2) in Greek patients with dementia.

BACKGROUND: Apraxia is considered a supportive feature in Alzheimer's disease (AD) patients. It has been reported that patients with frontotemporal dementia (FTD) may present apraxia, especially in the buccofacial area. The Apraxia Battery for Adults (ABA-2) is a brief and practical battery for praxis impairment and has been validated in Greek post-stroke patients. AIM: To validate and evaluate ABA-2 test, translated and culturally adapted, in a sample of Greek demented patients. PATIENTS AND METHODS: Patients diagnosed with FTD (n = 20) and AD (n = 20) were included in the study. Age-, gender-, and education- matched healthy controls (n = 20) were also tested. All participants completed Adenbrooke's Cognitive Examination-Revised (ACE-R), Frontal Rating Scale (FRS), Frontal Behavioral Inventory (FBI), and ABA-2 battery. Sensitivity and specificity of ABA-2 were calculated, as well as its consistency and statistical significance for diagnosing apraxia. RESULTS: The ABA-2 was able to differentiate demented patients from healthy controls with a sensitivity of 77.5% and specificity of 95%. Its validity was confirmed with Cronbach's alpha coefficient > 0.7, indicating satisfactory internal reliability. Statistically significant differences were found when comparing total ABA-2 score (p < 0.0001), as well as 3 out of 6 subtests of ABA-2, between the two study groups. Age, gender and education were not correlated with ABA-2 score. CONCLUSION: ABA-2 is a valid, reliable and sensitive battery to differentiate demented patients from healthy individuals in the Greek population. We propose the modification of ABA-2 to a 5-subtest tool, to be administered as a bed-side test.

Long-Term Efficacy Outcomes of Natalizumab vs. Fingolimod in Patients With Highly Active Relapsing-Remitting Multiple Sclerosis: Real-World Data From a Multiple Sclerosis Reference Center.

Background: Natalizumab (NTZ) and fingolimod (FTY) are second-line disease modifying treatments (DMTs) approved for Relapsing - Remitting Multiple Sclerosis (RRMS). Few studies are available on a direct comparison between NTZ and FTY, based on post-marketing experience, with conflicting results and reporting relatively short follow-up period. Aim: We hereby report real-world experience of a MS Center with respect to NTZ vs. FTY comparison in terms of efficacy and safety, referencing long-term follow-up. Methods: We used retrospective data for all patients that received 2nd-line treatment NTZ (since May 2007) or FTY (since September 2011). Primary endpoints were, among others, annual EDSS score (mean change from baseline), time to disability worsening or improvement, Annualized Relapse Rate (ARR) after 12 and 24 months and upon total treatment duration, time to first relapse and time to radiological progression. Results: A total of 138 unmatched patients, 84 treated with NTZ and 54 treated with FTY were included. Following Propensity Score (PS) matching, 31 patients in each group were retained. Mean follow-up period for NTZ- and FTY-treated patients was 4.43 ± 0.29 and 3.59 ± 0.32 years (p = 0.057), respectively. In the matched analysis, time to disability improvement and time to disability worsening was comparable between groups. A higher proportion of patients remained free of relapse under NTZ, compared to FTY (Log Rank test p = 0.021, HR: 0.25, 95% CI: 0.08-0.8), as well as free of MRI activity (Log Rank test p = 0.006, HR: 0.26, 95% CI: 0.08-0.6). Treatment discontinuation due to MRI activity was significantly higher for FTY-treated patients compared to NTZ (Log Rank test p = 0.019, HR: 0.12, 95% CI: 0.05-0.76). Conclusion: Our results indicate toward NTZ superiority with respect to relapse and MRI activity outcomes. The fact that NTZ-treated patients may achieve long-standing clinical and radiological remission points toward the need for long follow-up data.

Hereditary diffuse leukoencephalopathy with spheroids mimicking primary progressive aphasia: report of a Greek case.

INTRODUCTION: Hereditary diffuse leukoencephalopathy with spheroids (HDLS) is an adult onset leukodystrophy, causally related to mutations in the colony-stimulating factor 1 receptor (CSF1R) gene. We report the unique case of a Greek HDLS patient, demonstrating an unusual phenotype, reminiscent of primary progressive aphasia (PPA). METHODS: A 63-year-old woman was referred with a 2-year history of deteriorating language and memory deficits, apathy, and two generalized tonic-clonic seizures. Neurological and neuropsychological examination revealed prominent aphasia with a pattern consistent with nonfluent variant of PPA. However, brain MRI disclosed confluent T2 and FLAIR white matter hyperintensities with frontal emphasis, whereas genetic testing corroborated the diagnosis of HDLS. DISCUSSION: PPA-like patterns may rarely develop in the context of HDLS. Prompt diagnosis of this leukoencephalopathy is essential, since preliminary data suggest that it could represent a potentially treatable disorder.

Primary progression in NMOSD. Does it really exist?

Acute myelitis, in conjunction with a longitudinally extensive MRI pattern, is a core feature of aquaporin 4 IgG-associated neuromyelitis optica spectrum disorders (NMOSD). According to current diagnostic criteria for transverse myelitis and NMOSD, clinical worsening should not exceed 3-4 weeks from attack onset. Recently, we were able to document, through frequent clinical examination and radiological follow-up, the unusual case of an ab initio progressive myelopathy, ultimately attributed to aquaporin-4 autoimmunity. Although this case might merely represent an overlooked cluster of individual clinical attacks, it could, however, draw attention to the controversial concept of disease progression in the context of NMOSD.

Reduced expression of L-selectin in T-cells correlates with relative lymphocyte increase in patients with RRMS treated with natalizumab - functional implication towards PML risk.

Objectives: Natalizumab (NTZ), a treatment indicated for patients with highly active Relapsing - Remitting Multiple Sclerosis (RRMS), is known to induce increased relative frequency of lymphocytes. Progressive Multifocal Leukoencephalitis (PML) is a rare but serious adverse event related to NTZ. Moreover, reduced L-selectin (CD62L) expression in T-cells in cryopreserved samples of patients with RRMS under NTZ has been proposed as a biomarker of pre-PML state. We explore the association between L-selectin expression in T-cells and hematological parameters in freshly processed samples of patients with RRMS under NTZ.Methods: We studied L-selectin expression in patients with: RRMS under NTZ (n=34), fingolimod (FTY, n=14), interferon-beta (IFNß, n=22), glatiramer acetate (GA, N=17); in 9 patients with secondary progressive (SP) MS and in 6 healthy controls. Twenty-two patients under NTZ and 6 patients under FTY were followed for 18 months. One NTZ-treated patient developed PML during the study.Results: Patients under NTZ exhibited increased relative frequency of lymphocytes (40.02±1.45) compared to patients under first-line treatment (30.57±1.68, p<0.001) and to patients with SPMS (29±1.56, p=0.02), and a lower mean L-selectin expression in (69.39±1.73) compared to patients under first-line treatment (79.1±1.17, p=0.003). A negative correlation between the relative frequency of CD4+CD62L+ T-cells and the absolute lymphocyte counts (Pearson's r=0.367, p=0.033) was observed.Discussion: We hereby provide mechanistic insight in a possible pathway implicated in NTZ-related PML risk. These results further underline the need for thorough validation of L-selectin expression in T-cells as a potential pre-PML biomarker.

Estimating Everyday Neuropsychological Functioning in Multiple Sclerosis: Reliability and Validity of the Greek Multiple Sclerosis Neuropsychological Questionnaire.

The Multiple Sclerosis Neuropsychological Questionnaire is a brief screening questionnaire for the assessment of everyday neuropsychological competence of patients with Multiple Sclerosis. The aim of the present study was to examine psychometric properties of the Greek version of the instrument. One hundred and three MS patients and 60 informants participated in the present study and completed the questionnaire. From the initial patient sample, 51 participants completed broadly used neuropsychological tests and measures estimating cognitive failures and depression. Moreover, after a six-month interval the MSNQ was administered to 58 patients from the initial sample in order to explore test-retest reliability. Cronbach's α was 0.92 and 0.93 for patient and informant forms, respectively. The patient form was correlated significantly with measures of cognitive failures and depression. Low correlations were found between the informant form and performance on cognitive tests. In regard to the patient form, significant correlation was observed between repeated administrations and, psychometrically, the three-factor structure was preferable than the one-factor structure. The present study confirms the already established pattern of correlations among the two MSNQ forms, neuropsychological test performance and depression measurements. Additional research is needed in order to define a cut-off score for the MSNQ-I providing further information about the diagnostic interpretability of the instrument.

Charcot-Marie-Tooth Disease 1X Simulating Paraparetic Guillain-Barre Syndrome.

X-linked Charcot-Marie-Tooth disease (CMT 1X) is the second most common form of inherited demyelinating neuropathy. It is established that patients suffering from CMT 1X can have episodes of hemiparesis, paraparesis, quadriparesis, ataxia, aphasia, and dysarthria, which can be fully reversible, and 'trigger' factors for these episodes are usually febrile illness, high altitudes, hyperventilation, and physical activity. We describe a 22-year-old patient with a history of viral infection and sleep deprivation who presented to our department because of acute difficulty in walking and neurophysiological findings suggesting Guillain-Barre syndrome. The patient's phenotype was compatible with CMT disease and within hours he showed remarkable improvement of his muscle strength without receiving any medical treatment. Any other metabolic, infectious, vasculitic, hematological, paraneoplastic, or infiltrative cause of polyneuropathy was excluded with laboratory work-up. Diagnosis of CMT 1X was confirmed with repeated neurophysiological study and genetic testing of his and his mother's blood, demonstrating the Arg75Trp [CGG to TGG,(R75W)] mutation on exon2 of gap junction protein beta 1. CMT 1X should be considered in patients with a phenotype compatible with the disease, rapid improvement of their clinical manifestations, and neurophysiological findings consistent with a hereditary, demyelinating neuropathy.