Eye-tracking-based cognitive assessment efficiently detects mild cognitive decline in the predementia stage.

INTRODUCTION: The early detection of cognitive decline is key to maximizing the benefits of preventive and therapeutic interventions against dementia. Generally, dementia is first assessed by interview-based neuropsychological tests, but the lengthy interview and mental stress during the assessment process make screenings inefficient. We previously developed a rapid screening test for dementia using an eye-tracking technology (eye tracking-based cognitive assessment, ETCA) and reported its utility for clinically detecting cognitive impairment in dementia cases. However, the ETCA's performance in detecting people with mild cognitive decline, which is the major target population for dementia-prevention strategies, remains insufficiently examined. Therefore, this study aimed to evaluate the ETCA's performance in individuals aged 40 years and older (n = 94, mean age; 61.0 [SD 13.1] years) without being formally diagnosed with dementia. METHODS: All participants underwent both the ETCA and neuropsychological tests, including the Mini-Mental State Examination (MMSE), Rivermead Behavioral Memory Test (RBMT), and Addenbrooke's Cognitive Examination-III (ACE-III) on the same day. We examined the correlations in scores between the ETCA and each neuropsychological test. Furthermore, we selected participants who earned normal scores in each neuropsychological test and evaluated the ETCA's performance in this subgroup. RESULTS: Participants' ETCA scores correlated significantly with their scores on neuropsychological tests, including the MMSE, RBMT, and ACE-III. Notably, the ETCA scores correlated with the RBMT or ACE-III scores in individuals who showed normal scores in each neuropsychological test. CONCLUSION: The ETCA has the potential to screen mild cognitive decline efficiently at the predementia stage in nonclinical settings.

Antiepileptic Drugs Modulate Alzheimer-Related Tau Aggregation in a Neuronal Activity-Independent Manner.

INTRODUCTION: A rapidly increasing number of patients with dementia present a serious social problem. Recently, the incidence of epilepsy in patients with Alzheimer's disease (AD) is increasing, drawing attention to the pathological relationship between the two conditions. Clinical studies have suggested the protective action of antiepileptic agents on dementia; however, the underlying mechanism remains unknown. We evaluated the effects of multiple antiepileptic drugs using tau aggregation assay systems to determine the effects of antiepileptic agents on tau aggregation, a major neuropathological finding associated with AD. METHODS: We evaluated the effects of seven antiepileptic agents on intracellular tau aggregation using a tau-biosensor cell-based high-throughput assay. Next, we tested these agents in a cell-free tau aggregation assay using thioflavin T (ThT). RESULTS: The assay results revealed that phenobarbital inhibited tau aggregation, whereas sodium valproate, gabapentin, and piracetam promoted tau aggregation. In the cell-free tau aggregation assay using ThT, we confirmed that phenobarbital significantly inhibited tau aggregation. CONCLUSION: Antiepileptic drugs may modify the tau pathology in AD in a neural activity-independent manner. Our finding may provide an important insight into the optimization of antiepileptic drug therapy in older adults with dementia.

A novel chronic dural port platform for continuous collection of cerebrospinal fluid and intrathecal drug delivery in free-moving mice.

BACKGROUND: Cerebrospinal fluid (CSF) provides a close representation of pathophysiological changes occurring in the central nervous system (CNS); therefore, it has been employed in pathogenesis research and biomarker development for CNS disorders. CSF obtained from valid mouse models relevant to CNS disorders can be an important resource for successful biomarker and drug development. However, the limited volume of CSF that can be collected from tiny intrathecal spaces and the technical difficulties involved in CSF sampling has been a bottleneck that has hindered the detailed analysis of CSF in mouse models. METHODS: We developed a novel chronic dural port (CDP) method without cannulation for CSF collection of mice. This method enables easy and repeated access to the intrathecal space in a free-moving, unanesthetized mouse, thereby enabling continuous long-term CSF collection with minimal tissue damage and providing a large volume of high-quality CSF from a single mouse. When combined with chemical biosensors, the CDP method allows for real-time monitoring of the dynamic changes in neurochemicals in the CSF at a one-second temporal resolution in free-moving mice. Moreover, the CDP can serve as a direct access point for the intrathecal injection of CSF tracers and drugs. RESULTS: We established a CDP implantation and continuous CSF collection protocol. The CSF collected using CDP was not contaminated with blood and maintained physiological concentrations of basic electrolytes and proteins. The CDP method did not affect mouse's physiological behavior or induce tissue damage, thereby enabling a stable CSF collection for up to four weeks. The spatio-temporal distribution of CSF tracers delivered using CDP revealed that CSF metabolism in different brain areas is dynamic. The direct intrathecal delivery of centrally acting drugs using CDP enabled real-time behavioral assessments in free-moving mice. CONCLUSIONS: The CDP method enables the collection of a large volume of high-quality CSF and direct intrathecal drug administration with real-time behavioral assessment in free-moving mice. Combined with animal models relevant to CNS disorders, this method provides a unique and valuable platform for biomarker and therapeutic drug research.

Novel Method for Rapid Assessment of Cognitive Impairment Using High-Performance Eye-Tracking Technology.

A rapid increase in the number of patients with dementia has emerged as a global health challenge. Accumulating evidence suggests that early diagnosis and timely intervention can delay cognitive decline. The diagnosis of dementia is commonly performed using neuropsychological tests, such as the Mini-Mental State Examination (MMSE), administered by trained examiners. While these traditional neuropsychological tests are valid and reliable, they are neither simple nor sufficiently short as routine screening tools for dementia. Here, we developed a brief cognitive assessment utilizing an eye-tracking technology. The subject views a series of short (178 s) task movies and pictures displayed on a monitor while their gaze points are recorded by the eye-tracking device, and the cognitive scores are determined from the gaze plots data. The cognitive scores were measured by both an eye tracking-based assessment and neuropsychological tests in 80 participants, including 27 cognitively healthy controls (HC), 26 patients with mild cognitive impairment (MCI), and 27 patients with dementia. The eye tracking-based cognitive scores correlated well with the scores from the neuropsychological tests, and they showed a good diagnostic performance in detecting patients with MCI and dementia. Rapid cognitive assessment using eye-tracking technology can enable quantitative scoring and the sensitive detection of cognitive impairment.

Helicobacter cinaedi-associated Carotid Arteritis.

A 65-year-old Japanese man with bilateral carotid atherosclerosis presented with right neck pain and fever. Contrast-enhanced computed tomography suggested carotid arteritis, and carotid ultrasonography showed an unstable plaque. The patient developed a cerebral embolism, causing a transient ischemic attack. Helicobacter cinaedi was detected in blood culture, and H. cinaedi-associated carotid arteritis was diagnosed. Empirical antibiotic therapy was administered for 6 weeks. After readmission for recurrent fever, he was treated another 8 weeks. Although the relationship between H. cinaedi infection and atherosclerosis development remains unclear, the atherosclerotic changes in our patient's carotid artery might have been attributable to H. cinaedi infection.