Binaural processing deficit and cognitive impairment in Alzheimer's disease.

Speech comprehension in noisy environments depends on central auditory functions, which are vulnerable in Alzheimer's disease (AD). Binaural processing exploits two ear sounds to optimally process degraded sound information; its characteristics are poorly understood in AD. We studied behavioral and electrophysiological alterations in binaural processing among 121 participants (AD = 27; amnestic mild cognitive impairment [aMCI] = 33; subjective cognitive decline [SCD] = 30; cognitively normal [CN] = 31). We observed impairment of binaural processing in AD and aMCI, and detected a U-shaped curve change in phase synchrony (declining from CN to SCD and to aMCI, but increasing from aMCI to AD). This improvement in phase synchrony accompanying more severe cognitive stages could reflect neural adaptation for binaural processing. Moreover, increased phase synchrony is associated with worse memory during the stages when neural adaptation apparently occurs. These findings support a hypothesis that neural adaptation for binaural processing deficit may exacerbate cognitive impairment, which could help identify biomarkers and therapeutic targets in AD.

Acanthocytes Identified in Huntington's Disease.

Background: Neuroacanthocytosis (NA) and Huntington's disease (HD) are neurodegenerative conditions that share clinical symptoms and imaging findings, despite their distinct genetic etiologies. Usually, the presence of acanthocytes can help narrow the differential diagnosis of a familial choreiform disorder, as the diagnosis of NA syndrome is supported by the presence of acanthocytes in peripheral blood. In this study, we demonstrate four patients who present with HD and acanthocytosis. Methods: We retrieved the data of 40 HD patients with fresh peripheral blood screened for erythrocytes in our hospital from 2014 to 2022. Of these 40 patients, four patients with acanthocytes were recruited for this study. Patients' investigations included clinical and laboratory studies, HTT gene sequencing, and whole-exome sequencing. Fresh peripheral blood was screened for erythrocytes by scanning electron microscopy. Results: The four adult patients were Han Chinese and unrelated. The age ranged from 45 to 61 years, with a disease duration of 4-10 years. The main neurological features at diagnosis included progressive involuntary movements, psychiatric changes, and dementia. Genetic analysis showed an expansion at the HTT gene. The mean proportion of acanthocytes was mild (6-10%) elevated in patient one and high (>20%) elevated in patients 2-4 by scanning electron microscopy examination. Conclusion: Our study illustrates that HD can combine with acanthocytosis, which may expand the clinical phenotype. Even though the primary gene defect appears to be predominately directed at the brain, a peripheral defect can be seen in HD. Our study highlights the complexity and diversity of HD.

Association between atherosclerosis and Alzheimer's disease: A systematic review and meta-analysis.

BACKGROUND: To evaluate the relationship between atherosclerosis and Alzheimer's disease (AD), we conducted a systematic review and meta-analysis to study the difference of carotid intima-media thickness (CIMT) and the prevalence of atherosclerosis between AD patients and non-AD controls. METHODS: The studies on the association between atherosclerosis and AD were manually searched in PubMed, Embase, Cochrane Library, and CNKI (China National Knowledge Infrastructure) spanned to September 2018 according to PRISMA (the Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. RESULTS: Thirteen studies were included in the final analysis, seven studies with data on the mean CIMT (610 cases and 417 controls) and ten studies reporting on the prevalence of atherosclerosis (1,698 cases and 6,452 controls). Compared with controls, AD group showed a significantly higher CIMT (overall standard mean difference = 0.94; 95% CI, 0.48-1.40; p < .0001) and an increased prevalence of atherosclerosis (OR = 1.46; 95% CI, 1.26-1.68; p < .0001). CONCLUSIONS: Atherosclerosis is significantly associated with AD. CIMT might be a useful marker to predict the risk of AD and assess the vascular burden. The finding is also important for possible prevention and treatment of AD in the future.

TRanscranial AlterNating current Stimulation FOR patients with Mild Alzheimer's Disease (TRANSFORM-AD study): Protocol for a randomized controlled clinical trial.

INTRODUCTION: Recently, transcranial alternating current stimulation (tACS), which can interact with ongoing neuronal activity, has emerged as a potentially effective and promising treatment for Alzheimer's disease (AD), and the 40 Hz gamma frequency was suggested as a suitable stimulation frequency for AD. METHODS: The TRANSFORM-AD study is a double-blind, randomized-controlled trial that will include 40 individuals with mild AD. Eligible patients need to have amyloid ß (Aß) loads examined by Pittsburgh compound B (PiB) positron emission tomography (PET) or decreased Aß level in cerebrospinal fluid. Participants will be randomized into either a 40 Hz tACS group or a sham stimulation group. Both groups will undergo 30 one-hour sessions across 3 weeks (21 days). The outcome measures will be assessed at baseline, at the end of the intervention, and 3 months after the first session. The primary outcome is global cognitive function, assessed by the 11-item cognitive subscale of the Alzheimer's Disease Assessment Scale (ADAS-Cog), and the secondary outcomes include changes in other neuropsychological assessments and in PiB-PET, structural magnetic resonance imaging (MRI), resting electroencephalography (EEG), and simultaneous EEG-functional MRI (EEG-fMRI) results. RESULTS: The trial is currently ongoing, and it is anticipated that recruitment will be completed in June 2021. DISCUSSION: This trial will evaluate the efficacy and safety of 40 Hz tACS in patients with AD, and further explore the potential mechanisms by analyzing amyloid deposits using PiB-PET, brain volume and white matter integrity by structural MRI, and neural activity by EEG and EEG-fMRI.

The Efficacy of COGnitive tRaining in patiEnts with Amnestic mild coGnitive impairmENT (COG-REAGENT): Protocol for a Multi-Center Randomized Controlled Trial.

BACKGROUND: Amnestic mild cognitive impairment (aMCI) is often the prodromal stage of Alzheimer's disease (AD). Although previous studies have suggested that computerized cognitive training is an effective non-pharmacological intervention for aMCI, large-sample, randomized controlled studies are warranted to provide a high level of evidence. OBJECTIVE: To identify the efficacy of computerized cognitive training for aMCI. METHODS: This study will include 260 patients diagnosed with aMCI from 8 centers in China. A computerized multi-domain adaptive training program will be used in this study, and the targeted cognitive domains include memory, attention, language, and executive function. The patients will be randomized into either a cognitive-training group or an active-control group. The intervention is a 12-week internet-based cognitive training performed for 40 minutes per day, 4 days a week. Neuropsychological assessments and structural and functional MRI will be obtained at baseline, at the end of the intervention, and 6 months after randomization. The primary outcome will be the global cognitive function score assessed by Montreal Cognitive Assessment. The secondary outcomes include changes in other neuropsychological assessments and neuroplasticity changes measured by structural and functional MRI. RESULTS: The trial is currently ongoing, and it is anticipated that recruitment will be completed in December 2020. CONCLUSION: This multi-center, large-sample, randomized controlled trial will investigate the short and long-term effects of computerized cognitive training in patients with aMCI. Furthermore, the combination of functional and structural MRI results will also reveal the underlying mechanisms of the effect of intervention.

Plasma Clusterin as a Potential Biomarker for Alzheimer's Disease-A Systematic Review and Meta-analysis.

BACKGROUND: Plasma clusterin has been reported to be associated with the pathology, prevalence, severity, and rapid clinical progress of Alzheimer's Disease (AD). However, whether plasma clusterin can be used as a biomarker of AD is inconsistent and even conflicting. OBJECTIVE: We conducted this study to evaluate the potential of plasma clusterin as the biomarker of AD. METHOD: PubMed, Embase, and Cochrane databases were systematically searched for studies on the relationship between plasma clusterin levels and AD diagnosis, risk and disease severity. We also compared the difference in Cerebrospinal Fluid (CSF) clusterin levels between AD and control groups. We converted and pooled data using standardized mean difference, Pearson linear regression model and the Cox regression model. RESULTS: A total of 17 articles and 7228 individuals, including 1936 AD were included. The quality ranged from moderate to high. There was no difference in plasma clusterin between AD and control groups (SMD= 0.19 [-0.10, 0.48], p=0.20). Plasma clusterin levels were not correlated with the risk (RR=1.03 [0.97-1.09], p=0.31), the MMSE scores (R=0.33 [-0.06, 0.71], p= 0.09), and the integrated neuropsychological measurements (R=0.21 [-0.20, 0.63], p=0.31) of AD. Additionally, there was no difference in CSF clusterin between AD and control groups (SMD=1.94 [ -0.49, 4.37], p=0.12). CONCLUSION: Our meta-analysis suggested no relationship between plasma clusterin levels and the diagnosis, risk, and disease severity of AD and no difference in the CSF clusterin between AD and the control groups. Overall, there is no evidence to support plasma clusterin as a biomarker of AD based on the pooled results.