Incident anti-LGI1 autoimmune encephalitis during dementia with Lewy bodies: when Occam razor is a double-edged sword

In Dementia with Lewy bodies (DLB), rapid cognitive decline and seizures seldom complicate the typical clinical course. Nevertheless, concurrent, treatable conditions may be responsible. We report a case of DLB with superimposed anti-LGI1 encephalitis, emphasizing the importance of thorough diagnostic reasoning beyond the simplest explanation amid distinct clinical cues.

Is the clinical phenotype impact the prognosis in dementia with Lewy bodies?

INTRODUCTION

The first predominant clinical symptoms of dementia with Lewy bodies (DLB) are highly variable; however, the prognosis based on initial predominant symptoms remains poorly understood.

METHODS

Multicenter retrospective study in 4 French expert neurological centers. Patients were categorized in 3 groups according to their first more predominant symptoms: cognitive, psychiatric, or motor.

RESULTS

Analysis of 310 DLB patients. The mean age was 73.5 years old (SD 7.5) including 32.3% of women. The mean follow-up was 7.25 years (SD 3.6). We observed that the full clinical picture was more frequent in the motor group than in the cognitive group (p = 0.01); male gender and age at onset were associated with a significant excess risk of instantaneous mortality (p = 0.01).

CONCLUSION

Initial symptoms may affect the clinical course of patients, but no significant difference in mortality was observed.

A Unique Perspective on Lead Compounds for Dementia with the Lewy Body

Dementia with Lewy Bodies is a neurodegenerative disorder characterised by abnormal α-Synuclein aggregate accumulation in Lewy Bodies and Lewy Neurites and the most common form of dementia after Alzheimer's disease. The presynaptic protein alpha-synuclein (α-Syn) regulates synaptic vesicle trafficking and the subsequent release of neurotransmitters in the brain. These aggregates go through a number of crucial stages, such as aggregation, oligomerization, and fibrillation. Treatment of this disorder is generally symptomatic. This necessitates the development of cutting-edge therapeutic approaches that can either stop or change the course of the diseases. Many studies have shown that α-synuclein is a significant therapeutic target and that inhibiting α-synuclein aggregation, oligomerization, and fibrillation is an important disease-modifying strategy. Since α-syn is a defining feature of Parkinson's disease, the current review provides an overview of plant phytochemicals and synthetic heterocyclic compounds that target α-syn in Parkinson's disease in order to develop new drugs for Dementia with Lewy Bodies.

Long-term outcomes with pimavanserin for psychosis in clinical practice

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Psychosis in PD is a common problem, with limited treatment options.

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Pimavanserin is FDA approved for PDP, but long-term outcomes in clinical practice are lacking.

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While it has been proven to be effective in short-duration clinical trials, our clinical experiences, however, demonstrate less promising results in the long term.

Introduction

Pimavanserin is the only medication FDA-approved for the treatment of Parkinson disease (PD) psychosis (PDP), but reports of long-term, real-world clinical experience are lacking.

Methods

A retrospective chart review of all patients treated with pimavanserin was conducted at our large Movement Disorders practice in Providence, Rhode Island, USA. Demographic and clinical data for each patient were collected and descriptive analyses were performed.

Results

We identified 54 patients (23 female) who initiated pimavanserin, whose median age was 70 years (range 44–87 years) and the median duration of pimavanserin therapy was 26 weeks. Initial improvement was seen in 47% of the entire group, and 50% of the DLB patients. Additional antipsychotic medication was needed concomitantly with pimavanserin to maintain a positive response for 40% of patients. Only 15% of the entire group had effective treatment of their condition with pimavanserin monotherapy over a median of 52 weeks. Among the initial responders, 32% continued on pimavanserin monotherapy. Among the non-responders, the mean trial period for patients who did not improve was 27 weeks, for patients who worsened was 16 weeks, and for those who experienced adverse effects was 1–2 weeks. Reported sex was similar across responders (60%), non-responders (56%), and the overall cohort (57%).

Conclusion

Our real-world experience shows that pimavanserin is safe and tolerable, with a lower response rate than reported in other publications. While it has been proven to be effective in short-duration clinical trials, our clinical experiences, however, demonstrate less promising results in the long term.

Complicity of α-synuclein oligomer and calcium dyshomeostasis in selective neuronal vulnerability in Lewy body disease

α-Synuclein oligomers and Ca²⁺ dyshomeostasis have been thoroughly investigated with respect to the pathogenesis of Lewy body disease (LBD). In LBD, α-synuclein oligomers exhibit a neuron-specific cytoplasmic distribution. Highly active neurons and neurons with a high Ca²⁺ burden are prone to damage in LBD. The neuronal vulnerability may be determined by transneuronal axonal transmission of the pathological processes; however, this hypothesis seems inconsistent with pathological findings that neurons anatomically connected to LBD-vulnerable neurons, such as neurons in the ventral tegmentum, are spared in LBD. This review focuses on and discusses the crucial roles played by α-synuclein oligomers and Ca²⁺ dyshomeostasis in early intraneural pathophysiology in LBD-vulnerable neurons. A challenging view is proposed on the synergy between retrograde transport of α-synuclein and vesicular Ca release, whereby neuronal vulnerability is propagated backward along repeatedly activated signaling pathway.

ACR Appropriateness Criteria® Dementia

Degenerative disease of the central nervous system is a growing public health concern. The primary role of neuroimaging in the workup of patients with probable or possible Alzheimer disease has typically been to exclude other significant intracranial abnormalities. In general, the imaging findings in structural studies, such as MRI, are nonspecific and have limited potential in differentiating different types of dementia. Advanced imaging methods are not routinely used in community or general practices for the diagnosis or differentiation of forms of dementia. Nonetheless, in patients who have been evaluated by a dementia expert, FDG-PET helps to distinguish Alzheimer disease from frontotemporal dementia. In patients with suspected dementia with Lewy bodies, functional imaging of the dopamine transporter (ioflupane) using SPECT may be helpful. In patients with suspected normal-pressure hydrocephalus, DTPA cisternography and HMPAO SPECT/CT brain may provide assessment. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Impact of a Clinical Decision Support Tool on Dementia Diagnostics in Memory Clinics: The PredictND Validation Study

BACKGROUND

Determining the underlying etiology of dementia can be challenging. Computer- based Clinical Decision Support Systems (CDSS) have the potential to provide an objective comparison of data and assist clinicians.

OBJECTIVES

To assess the diagnostic impact of a CDSS, the PredictND tool, for differential diagnosis of dementia in memory clinics.

METHODS

In this prospective multicenter study, we recruited 779 patients with either subjective cognitive decline (n=252), mild cognitive impairment (n=219) or any type of dementia (n=274) and followed them for minimum 12 months. Based on all available patient baseline data (demographics, neuropsychological tests, cerebrospinal fluid biomarkers, and MRI visual and computed ratings), the PredictND tool provides a comprehensive overview and analysis of the data with a likelihood index for five diagnostic groups; Alzheimer´s disease, vascular dementia, dementia with Lewy bodies, frontotemporal dementia and subjective cognitive decline. At baseline, a clinician defined an etiological diagnosis and confidence in the diagnosis, first without and subsequently with the PredictND tool. The follow-up diagnosis was used as the reference diagnosis.

RESULTS

In total, 747 patients completed the follow-up visits (53% female, 69±10 years). The etiological diagnosis changed in 13% of all cases when using the PredictND tool, but the diagnostic accuracy did not change significantly. Confidence in the diagnosis, measured by a visual analogue scale (VAS, 0-100%) increased (ΔVAS=3.0%, p<0.0001), especially in correctly changed diagnoses (ΔVAS=7.2%, p=0.0011).

CONCLUSION

Adding the PredictND tool to the diagnostic evaluation affected the diagnosis and increased clinicians' confidence in the diagnosis indicating that CDSSs could aid clinicians in the differential diagnosis of dementia.

Is Lewy pathology in the human nervous system chiefly an indicator of neuronal protection or of toxicity?

Misfolded α-synuclein accumulates in histological inclusions constituting "Lewy pathology" found in idiopathic Parkinson disease, Parkinson disease dementia and dementia with Lewy body. The mechanism inducing α-synuclein misfolding is still unknown. The misfolded molecules form oligomers that organize into fibrils. α-Synuclein fibrils, in vitro, are capable of initiating an auto-replicating process, transforming normal molecules into misfolded molecules that aggregate. Fibrils can cross the neuronal membrane and recruit α-synuclein molecules in connected neurons. Such properties of seeding and propagation, shared with prion proteins, belong to "tissular propagons". Lewy bodies isolate harmful species from the cytoplasm and have been thought to be protective. In PRKN gene mutations, however, the absence of Lewy bodies is not associated with a more aggressive course. In idiopathic Parkinson disease, the proportion of neurons with Lewy bodies in the substantia nigra remains stable despite the progression of neuronal loss. This stable proportion suggests that Lewy bodies are eliminated at the rate at which neurons are lost because Lewy bodies cause, or invariably accompany, neuronal loss. Experimentally, cellular death selectively occurs in inclusion-bearing neurons. This set of data indicates that α-synuclein misfolding is the essential mechanism causing the lesions of Parkinson disease and dementia with Lewy body. Lewy pathology is a direct and visible evidence of α-synuclein misfolding and, as such, is an accurate marker for assessing the presence of α-synuclein misfolding even if the inclusions themselves may not be as directly causative as the molecules they accumulate.

Distinct α-Synuclein strains and implications for heterogeneity among α-Synucleinopathies

The deposition of misfolded β-sheet enriched amyloid protein is a shared feature of many neurodegenerative diseases. Recent studies demonstrated the existence of conformationally diverse strains as a common property for multiple amyloidogenic proteins including α-Synuclein (α-Syn). α-Syn is misfolded and aggregated in a group of neurodegenerative diseases collectively known as α-Synucleinopathies, which include Parkinson's disease (PD), dementia with Lewy body, multiple system atrophy and also a subset of Alzheimer's disease patients with concomitant PD-like Lewy bodies and neurites. While sharing the same pathological protein, different α-Synucleinopathies demonstrate distinct clinical and pathological phenotypes, which could result from the existence of diverse pathological α-Syn strains in patients. In this review, we summarized the characteristics of different α-Synucleinopathies and α-Syn strains generated with recombinant α-Syn monomers. We also make predictions of α-Syn strains that could potentially exist in patients based on the knowledge from other amyloid proteins and the clinical and pathological features of different α-Synucleinopathies.

Altered Expression of Human Mitochondrial Branched Chain Aminotransferase in Dementia with Lewy Bodies and Vascular Dementia

Cytosolic and mitochondrial human branched chain aminotransferase (hBCATc and hBCATm, respectively) play an integral role in brain glutamate metabolism. Regional increased levels of hBCATc in the CA1 and CA4 region of Alzheimer’s disease (AD) brain together with increased levels of hBCATm in frontal and temporal cortex of AD brains, suggest a role for these proteins in glutamate excitotoxicity. Glutamate toxicity is a key pathogenic feature of several neurological disorders including epilepsy associated dementia, AD, vascular dementia (VaD) and dementia with Lewy bodies (DLB). To further understand if these increases are specific to AD, the expression profiles of hBCATc and hBCATm were examined in other forms of dementia including DLB and VaD. Similar to AD, levels of hBCATm were significantly increased in the frontal and temporal cortex of VaD cases and in frontal cortex of DLB cases compared to controls, however there were no observed differences in hBCATc between groups in these areas. Moreover, multiple forms of hBCATm were observed that were particular to the disease state relative to matched controls. Real-time PCR revealed similar expression of hBCATm mRNA in frontal and temporal cortex for all cohort comparisons, whereas hBCATc mRNA expression was significantly increased in VaD cases compared to controls. Collectively our results suggest that hBCATm protein expression is significantly increased in the brains of DLB and VaD cases, similar to those reported in AD brain. These findings indicate a more global response to altered glutamate metabolism and suggest common metabolic responses that might reflect shared neurodegenerative mechanisms across several forms of dementia.