Association between physical activity and conversion from mild cognitive impairment to dementia

Background: Physical activity has been suggested to prevent the conversion of mild cognitive impairment (MCI) to dementia in patients. We investigated the association between the continuance and regularity of physical activity and the risk of developing dementia in patients with MCI. Methods: We analyzed 6-year followed up data for 247,149 individuals in the National Health Insurance Service (NHIS) cohort of Korea who were enrolled between January 1, 2009, and December 31, 2015. The patients were divided into four groups: those who did not engage in physical activity consistently (Never-PA group), those who initiated physical activity (Initiation-PA group), those who ceased physical activity (Withdrawal-PA group), and those who performed physical activity consistently (Maintenance-PA group). We also divided the patients into two groups: those who engaged in physical activity irregularly (Irregular-PA) and those who undertook physical activity regularly (Regular-PA). Results: When the risk for the Never-PA group was set as the benchmark (ref = 1), the Maintenance-PA group had the lowest incidence of dementia of the Alzheimer type (DAT) compared to the other groups (HR = 0.82, 95% CI 0.79-0.86). The DAT risk of the Initiation-PA group (HR = 0.89, 95% CI 0.85-0.93) was lower than the Never-PA group. In addition, compared to the Irregular-PA group, the Regular-PA group had a 15% reduced risk for developing DAT. Conclusions: Although no causal inference could be made, continued regular physical activity in patients with MCI is associated with a protective effect against developing DAT. Moreover, ceasing physical activity could halt this protective effect.ope

A Patient with Recurrent Dyskinesia and Hyperpyrexia Syndrome

Dyskinesia hyperpyrexia syndrome is a rare medical emergency in Parkinson's disease. It is characterized by continuous dyskinesia associated with hyperthermia, rhabdomyolysis, and alteration of the mental state. We present the case of a 74-year-old woman who presented with recurrent dyskinesia hyperpyrexia syndrome. Although some provocation factors and clinical manifestations seem to be shared with parkinsonism hyperpyrexia syndrome, a clear distinction in management should be considered.ope

Temporal trajectory of biofluid markers in Parkinson's disease

Full dynamics of biofluid biomarkers have been unknown in patients with Parkinson's disease (PD). Using data from 396 PD patients and 182 controls in the Parkinson's Progression Markers Initiative (PPMI) database, we estimated long-term temporal trajectories of CSF α-synuclein (α-syn), amyloid-β (Aβ), total tau (t-tau), phosphorylated tau (p-tau) and serum neurofilament light chain (NfL) by integrating function between the baseline levels and annual changes. At baseline, PD patients showed lower CSF α-syn, Aβ, t-tau and p-tau levels than those of the controls. In all PD patients, CSF α-syn and Aβ decreased in a negative exponential pattern before the onset of motor symptoms, whereas CSF t-tau and p-tau, and serum NfL increased. Patients with cognitive impairment exhibited faster decline of Aβ and α-syn and faster rise of t-tau, p-tau and NfL, when compared to those without. Similarly, low Aβ group showed earlier decline of α-syn, faster rise of t-tau, p-tau and NfL, and faster decline of cognitive performances, when compared to high Aβ group. Our results suggest that longitudinal changes in biomarkers can be influenced by cognitive impairment and Aβ burden at baseline. PD patients with Aβ pathology may be associated with early appearance of α-synuclein pathology, rapid progression of axonal degeneration and neurodegeneration, and consequently greater cognitive decline.ope

Two cases of Superior Mesenteric Artery Occlusion in Acute Cerebral Infarction patients with Atrial Fibrillation

Background : Acute superior mesenteric artery occlusion is a life-threatening disease that often has nonspecific symptoms. However, it should be suspected in those with known risk factors such as atrial fibrillation, cardiac thrombus or cardiac valvular disease. Case Report : We reported two cases of acute thromboembolic occlusions of superior mesenteric artery that developed in acute cerebral infarction patients with confirmed atrial fibrillation. Conclusions : Nonspecific symptoms of acute superior mesenteric artery occlusion should be closely monitored in acute cerebral infarction patients with atrial fibrillation, considering significance of early management of both vascular disease entities.ope

Principal components of tau positron emission tomography and longitudinal tau accumulation in Alzheimer's disease

Background: We aimed to investigate the clinical correlates of principal components (PCs) of tau positron emission tomography (PET) and their predictability for longitudinal changes in tau accumulation in Alzheimer's disease (AD). Methods: We enrolled 272 participants who underwent two PET scans [18F-flortaucipir for tau and 18F-florbetaben for amyloid-β (Aβ)], brain magnetic resonance imaging, and neuropsychological tests as baseline assessments. Among them, 187 participants underwent the same follow-up assessments after an average of 2 years. Using Aβ-positive AD dementia-specific PCs obtained from the baseline scans of 56 Aβ-positive patients with AD dementia, we determined the expression of the first two PCs (PC1 and PC2) in all participants. We assessed the correlation of PC expression with baseline clinical characteristics and tau accumulation rates. Moreover, we investigated the predictability of PCs for the longitudinal tau accumulation in training and test sets. Results: PC1 corresponded to the tau distribution pattern in AD, while the two PC2 extremes reflected the parietal or temporal predominance of tau distribution. PC1 expression increased with tau burden and decreased with cognitive impairment, while PC2 expression decreased with advanced age and visuospatial and attention function deterioration. The tau accumulation rate was positively correlated with PC1 expression (greater tau burden) and negatively correlated with PC2 expression (temporal predominance). A regression model using both PCs could predict longitudinal changes in the tau burden (intraclass correlation coefficient = 0.775, R2 = 0.456 in test set). Conclusions: PC analysis of tau PET could be useful for evaluating disease progression, characterizing the tau distribution pattern, and predicting longitudinal tau accumulation.ope

Effect of A/T/N imaging biomarkers on impaired odor identification in Alzheimer's disease

Odor identification ability may serve as an important diagnostic biomarker in Alzheimer's disease (AD). The aim of the study is to investigate the contribution of A/T/N neuroimaging biomarkers to impaired odor identification ability in the Alzheimer's disease spectrum. In 127 participants, we compared A/T/N neuroimaging biomarkers between normosmia and hyposmia groups, and performed correlation analysis between the biomarkers and Cross-Cultural Smell Identification Test (CCSIT) scores. Additionally, path analysis for odor identification ability was performed using cognitive function as a mediator. In between-group comparison, individuals with hyposmia showed higher frequency of amyloid-β (Aβ) positivity, and lower neuropsychological test performance than those with normosmia. After correction for covariates including total cognition scores, there was no difference in the Aβ or tau burden between the normosmia and hyposmia groups, and no correlation between CCSIT scores and Aβ or tau burden. Meanwhile, cortical volumes in the lateral and medial temporal cortices were smaller in the hyposmia group and decreased with the worsening of CCSIT scores. Path analysis showed that only neurodegeneration had a direct effect on odor identification, while Aβ and tau burden contributed to odor identification with the mediation of cognition. In the Alzheimer's disease spectrum, impaired odor identification ability may be attributable to neurodegeneration rather than the direct effect of Aβ or tau burden.ope

Effect of APOE ε4 genotype on amyloid-β and tau accumulation in Alzheimer's disease

Background: To assess the effects of apolipoprotein E (ApoE) ε4 genotype on amyloid-β (Aβ) and tau burden and their longitudinal changes in Alzheimer's disease (AD) spectrum. Methods: Among 272 individuals who underwent PET scans (18F-florbetaben for Aβ and 18F-flortaucipir for tau) and ApoE genotyping, 187 individuals completed 2-year follow-up PET scans. After correcting for the partial volume effect, we compared the standardized uptake value ratio (SUVR) for Aβ and tau burden between the ε4+ and ε4- groups. By using a linear mixed-effect model, we measured changes in SUVR in the ApoE ε4+ and ε4- groups. Results: The ε4+ group showed greater baseline Aβ burden in the diffuse cortical regions and greater tau burden in the lateral, and medial temporal, cingulate, and insula cortices. Tau accumulation rate was higher in the parietal, occipital, lateral, and medial temporal cortices in the ε4+ group. In Aβ+ individuals, baseline tau burden was greater in the medial temporal cortex, while Aβ burden was conversely greater in the ε4- group. Tau accumulation rate was higher in the ε4+ group in a small region in the lateral temporal cortex. The effect of ApoE ε4 on enhanced tau accumulation persisted even after adjusting for the global cortical Aβ burden. Conclusions: Progressive tau accumulation may be more prominent in ε4 carriers, particularly in the medial and lateral temporal cortices. ApoE ε4 allele has differential effects on the Aβ burden depending on the existing amyloidosis and may enhance vulnerability to progressive tau accumulation in the AD spectrum independent of Aβ.ope

Dural Arteriovenous Fistula Manifested as Rapid Progressive Dementia Successfully Treated by Endovascular Embolization Only

A 43-year-old male presented with daytime sleepiness at work and indifferent behavior like never before. Two weeks prior to hospital admission, he had episodic memory loss with well preserved remote memory. Brain MRI showed a dural arteriovenous fistula (DAVF) in the right lateral transverse sinus with a bilateral thalamic venous infarction. Cerebral angiography confirmed a right transverse sigmoid dural arteriovenous fistula with a feeding artery of the right occipital artery and left posterior meningeal artery. The DAVF was completely eliminated through multiple endovascular interventions. Recently, endovascular treatment has become one of the main therapeutic options to obliterate a fistulous site, which has led to a rapid diagnostic approach and management of DAVFs with high curative rates. We report a rare case of posterior fossa located at a dural arteriovenous fistula that caused rapid progressive dementia and was successfully eliminated through only endovascular treatment.ope

Isolated Leptomeningeal Neurosarcoidosis

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Paroxysmal Ataxia and Dysarthria in a Patient with Demyelinating Disease

Paroxysmal dysarthria and ataxia is characterized by abrupt onset of dysarthria and ataxia of unilateral limbs for seconds. We present a 45-year-old female patient with paroxysmal symptoms of dysarthria, right-sided ataxia, and a persistent symptom of upbeating nystagmus. Her brain fluid attenuated inversion recovery (FLAIR) magnetic resonance imaging indicated potential diagnosis of demyelinating disease. The paroxysmal and persistent symptoms have recovered after phenytoin administration. Sodium channel blocker may play a role in reducing the ephaptic transmission in a demyelinated or re-myelinated lesion.ope