Neurological Surgery最新文献

In Japan, dementia-related medical services are covered by the universal health insurance system, with patient co-payments based on age and income. The reimbursement system includes specific fees for dementia care such as early diagnosis, cognitive assessments, and multidisciplinary consultations. These fee structures aim to promote timely and efficient diagnosis and treatment of dementia. Ongoing challenges include balancing quality of care with healthcare sustainability.

The Japan Brain Dock Society, established in 1992, embodies two primary objectives: the detection of unruptured cerebral aneurysms and white matter lesions. In 2018, in response to the needs of an increasingly aging society, the Society broadened its mission to include dementia prevention, adopting the subtitle "A Medical Society for the Prevention of Stroke and Dementia." Although brain dock examinations are not covered by public health insurance and are offered as self-funded services, they have become widely accepted as a form of preventive medicine in Japan. This acceptance is supported by high public health awareness and proactive participation from municipalities and corporations. Among OECD countries, Japan has the highest number of MRI units per capita, ensuring easy access to neuroimaging and facilitating the detection of asymptomatic brain diseases. Consequently, Japan has already amassed a substantial volume of brain dock data. Recent rapid advances in artificial intelligence (AI) are now being applied to the brain dock field, particularly for the early diagnosis of dementia. This article explores how brain dock programs are integrating AI technologies and how they are expected to contribute to the early detection and prevention of dementia.

Community-based surveys conducted in Japan investigating the prevalence of dementia and its underlying causes revealed that dementia of Alzheimer's type (DAT) is the most common, followed by vascular dementia (VaD), dementia with Lewy bodies (DLB), mixed dementia, and other conditions including frontotemporal lobar degeneration (FTLD). Accurate differential diagnosis of these disorders requires clarification of their clinical characteristics. The initial symptoms of DAT typically include recent memory loss, episodic memory impairment, and temporal disorientation. Behavioral and psychological symptoms often observed in DAT include delusions of theft, "saving appearance" responses, and head-turning signs. Vascular dementia develops in association with cerebrovascular disease and frequently exhibits a stepwise progression. DLB is characterized by core clinical features such as cognitive fluctuations, visual hallucinations, parkinsonism, and REM sleep behavior disorder. Diagnostic tools such as ¹²³Iodine-metaiodobenzylguanidine (MIBG) myocardial scintigraphy and dopamine transporter (DAT) imaging may aid in diagnosis. In Parkinson's disease with dementia (PDD), cognitive impairment appears more than one year after the onset of parkinsonism. FTLD involves degeneration of the frontal and temporal lobes, leading to prominent changes in personality, behavior, and language function. Several subtypes of FTLD exist depending on the affected brain region, including the behavioral variant of frontotemporal dementia, semantic dementia, and progressive non-fluent aphasia. Idiopathic normal-pressure hydrocephalus (iNPH) is characterized by gait disturbance, urinary incontinence, and dementia, resulting from an abnormal accumulation of cerebrospinal fluid. Pathologically confirmed cases of DLB and progressive supranuclear palsy (PSP) may occasionally present with symptoms resembling iNPH.

Alzheimer's disease (AD) is the most common cause of dementia, characterized by the pathological accumulation of amyloid-β (Aβ) and phosphorylated tau in the brain. Recent advances in biomarker technology have significantly improved AD diagnosis and treatment. Cerebrospinal fluid biomarkers and amyloid positron emission tomography imaging are now available in clinical settings and serve as key tools in identifying early-stage AD, especially when considering anti-Aβ monoclonal antibody therapies. In 2024, the Alzheimer's Association proposed revised diagnostic criteria that integrate both biomarker-based and clinical staging systems. This framework introduces a classification of "core biomarkers" that reflect AD-specific pathology and defines biological and clinical symptom stages. Furthermore, blood-based biomarkers, such as plasma p-tau217 and MTBR-tau243, are gaining attention as minimally invasive tools for early diagnosis and disease staging. As these biomarkers become more accessible, proper interpretation within a clinical context remains essential. In Japan, biomarker testing is currently recommended only for symptomatic individuals, and its use requires careful judgment regarding indications and relevance to the clinical setting. This review outlines the evolution of diagnostic criteria, current and emerging biomarkers, and their implications for personalized AD care while emphasizing the need for expert clinical interpretation to ensure responsible and patient-centric use.

Pharmacological interventions for dementia include medications aimed at alleviating its core symptom: cognitive dysfunction. These medicines are known as anti-dementia drugs. As our understanding of Alzheimer's disease (AD) has advanced, the amyloid hypothesis stating that amyloid proteins are involved in the pathogenesis of AD has been proposed. To date, anti-dementia drugs such as cholinesterase inhibitors and N-methyl-D-aspartate receptor antagonists have focused on symptomatic treatment. In recent years, based on the amyloid hypothesis, the development of medicines that target either (1) the enzyme that produces amyloid beta (Aβ) or (2) Aβ itself, has been promoted as a treatment strategy for AD. In 2021, the first drug targeting Aβ, aducanumab, was launched in the USA. In Japan, lecanemab and donanemab are now available as monoclonal antibodies targeting Aβ. Additionally, medications have been used to manage the behavioral and psychological symptoms of dementia (BPSD), Parkinsonism, and rapid eye movement sleep behavior disorder. Furthermore, dementia is a major risk factor for delirium, which often occurs during the course of dementia. In this study, we introduce pharmacotherapy with anti-dementia drugs, BPSD treatment, and delirium.

Dementia and mild cognitive impairment (MCI) are common and increasingly encountered clinical syndromes in neurology and neurosurgery, especially in an aging society. With Japan undergoing a rapid demographic shift, addressing cognitive decline in older adults has become an urgent public health concern. This review provides an overview of dementia and MCI, focusing on the epidemiology, definition, etiology, disease progression, diagnosis, treatment, and post-diagnostic support. Through this discussion, we aim to offer practical insights for neurosurgeons and other specialists caring for patients with cognitive impairment.

With the clinical application of monoclonal antibody therapy for Alzheimer's disease (AD), diagnostic techniques are shifting toward molecular-targeted imaging. The development of tracers for positron emission tomography (PET) targeting abnormal proteins associated with the disease, such as amyloid-beta and tau, has enabled the detection of neuropathological changes in AD in vivo. This study will contribute to the clinical diagnosis, staging, and monitoring of potential therapeutic approaches for AD. In general outpatient care, imaging modalities that employ widely available techniques such as magnetic resonance imaging or single-photon emission computed tomography remain necessary. This article provides a synopsis of the American College of Radiology recommendations concerning the clinical utility of neuroimaging techniques and reviews the temporal progression of in vivo pathologies derived from amyloid and tau PETs. We investigated the methods for distinguishing between the AD continuum and SNAP in patients with mild cognitive impairment using the ADNI database. Accurate assessment of the "cortical signature" is essential for the diagnosis of AD. Voxel-based morphometry is a useful tool because cortical atrophy is associated with the extension of tau PET lesions. Confirmation of cortical atrophy in conjunction with hippocampal atrophy offers diagnostic insights that facilitate the identification of AD.

Alzheimer's disease (AD), the most common cause of dementia, is marked by the pathological accumulation of misfolded proteins in the brain. Its key pathological features include extracellular amyloid β (Aβ) plaques and intracellular tau neurofibrillary tangles, both of which contribute to synaptic dysfunction and neuronal death. Familial AD is linked to mutations in the APP, PSEN1, or PSEN2 genes, which promote increased Aβ production or aggregation. In contrast, frontotemporal dementia (FTD), including FTDP-17, is associated with MAPT mutations that lead to tau fibril accumulation independent of Aβ pathology. Recent advances in cryo-electron microscopy (cryo-EM) have revealed disease-specific conformations of Aβ and tau fibrils at atomic resolution, highlighting the role of structural polymorphism in disease progression. Aβ contributes to synaptic deficits and activates glial cells, thereby initiating neuroinflammatory responses. Genetic risk factors such as APOE and TREM2 influence these pathological processes. Transgenic mouse models carrying familial mutations have replicated certain aspects of AD pathology. However, most models fail to fully reproduce the human-like filament structures or the sequential progression from Aβ to tau pathology. Novel knock-in models, combined with cryo-EM-based validation, now provide a more accurate platform for studying disease mechanisms and developing targeted therapies.

Small-to-medium-sized vestibular schwannomas are frequently managed initially by otolaryngologists because hearing loss, tinnitus, and dizziness, the most common presenting symptoms, lead patients to seek otolaryngologic care. Surgical intervention is often considered for patients aged<50 years, whereas radiotherapy is recommended for those aged>70 years. Patient preferences are crucial in treatment decisions. For small-to-medium-sized tumors, complete facial nerve preservation is a primary surgery goal. Surgical approach selection depends on the tumor size and patient's hearing status, with options including the middle cranial fossa, translabyrinthine, and retrolabyrinthine approaches.

Medical images, including magnetic resonance imaging scans, are composed of numerical data, making them well-suited for machine learning and statistical approaches such as deep learning and radiomics. While qualitative analysis of neurological images may have been sufficient for research a decade ago, current standards increasingly demand some level of quantitative analysis. Although the term "radiomics" may imply complex mathematical processing or advanced programming, its foundational concepts are surprisingly accessible, with origins tracing back to 1973. The mathematical formulas used in radiomic feature are generally within the scope of high school-level mathematics. This paper provides a framework for individuals keen on integrating radiomics into their analytical methodologies, structured in the following manner: In Section II a detailed, methodical example of the procedures involved in conducting radiomic analysis is provided. Section III provides a brief overview of the historical development of radiomics. Sections IV and V explore the two image feature concepts that underpin radiomics: the gray level co-occurrence matrix and the gray level run length matrix, providing readers a deeper understanding of the significance of the calculated image features.