Imaging of neurodegenerative cognitive and behavioral disorders: practical considerations for dementia clinical practice

Explore the correlation between cerebral vessel characteristics with cognitive impairment among elder individuals: a community study from China

Background

Brain Magnetic Resonance Imaging (MRI) examination of cerebral small vessel disease (CSVD) may help screen vascular cognitive impairment. A recently estimated CSVD score system was suggested to capture the overall CSVD burden. The study aimed to detect the association between systemic evaluation score of cerebral vascular imaging parameters with cognitive functions.

Methods

This was a cross-sectional study in community settings. From October 2017 to September 2018, elder (≧60) residents were recruited through on-site visit in 6 communities from Shanghai, China. The participants underwent brain MRI, carotid ultrasound, laboratory tests of blood and urine samples. Cognitive function was evaluated using Mini-Mental State Examination (MMSE). MRI score of CSVD was calculated according to the 2012 standard for the evaluation of statistical changes in imaging.

Results

Total 171 subjects completed survey and examinations. There were 55 participants diagnosed with cognitive impairment, with a total percentage of 32.2%. Participants with and without cognitive impairment showed significant differences in age, BMI and education level. Cognitive impaired participant had more disease history/comorbidity of hypertension and chronic renal insufficiency, higher level of creatinine, as well as lower level of full blood count (FBC) and alanine aminotransferase (ALT). A significant difference was detected in CSVD score between participants with and without cognitive impairment. Results of linear regression analysis showed significant negative correlations between MMSE score and both left and right carotid artery peak systolic velocity (PSV), however the CSVD score was only borderline (P = 0.0566) positively correlated with MMSE. Multivariate linear correlation analysis including all collected risk factor data showed that left carotid artery PSV score was among the independent negative correlated factors of MMSE. Multivariate binary logistic analysis showed that age, education and history of hypertension were the only statistically associated factors of cognitive impairment.

Conclusions

The current study identified high prevalence of cognitive impairment in a Chinese community. In addition, correlations between cerebral vascular disease imaging status and cognitive functions were confirmed although the sample size limited the possibility of screening cognitive impairment with imaging technique.

Plasma lipidome is dysregulated in Alzheimer's disease and is associated with disease risk genes

Lipidomics research could provide insights of pathobiological mechanisms in Alzheimer's disease. This study explores a battery of plasma lipids that can differentiate Alzheimer's disease (AD) patients from healthy controls and determines whether lipid profiles correlate with genetic risk for AD. AD plasma samples were collected from the Sydney Memory and Ageing Study (MAS) Sydney, Australia (aged range 75-97 years; 51.2% male). Untargeted lipidomics analysis was performed by liquid chromatography coupled-mass spectrometry (LC-MS/MS). We found that several lipid species from nine lipid classes, particularly sphingomyelins (SMs), cholesterol esters (ChEs), phosphatidylcholines (PCs), phosphatidylethanolamines (PIs), phosphatidylinositols (PIs), and triglycerides (TGs) are dysregulated in AD patients and may help discriminate them from healthy controls. However, when the lipid species were grouped together into lipid subgroups, only the DG group was significantly higher in AD. ChEs, SMs, and TGs resulted in good classification accuracy using the Glmnet algorithm (elastic net penalization for the generalized linear model [glm]) with more than 80% AUC. In general, group lipids and the lipid subclasses LPC and PE had less classification accuracy compared to the other subclasses. We also found significant increases in SMs, PIs, and the LPE/PE ratio in human U251 astroglioma cell lines exposed to pathophysiological concentrations of oligomeric Aβ₄₂. This suggests that oligomeric Aβ₄₂ plays a contributory, if not causal role, in mediating changes in lipid profiles in AD that can be detected in the periphery. In addition, we evaluated the association of plasma lipid profiles with AD-related single nucleotide polymorphisms (SNPs) and polygenic risk scores (PRS) of AD. We found that FERMT2 and MS4A6A showed a significantly differential association with lipids in all lipid classes across disease and control groups. ABCA7 had a differential association with more than half of the DG lipids (52.63%) and PI lipids (57.14%), respectively. Additionally, 43.4% of lipids in the SM class were differentially associated with CLU. More than 30% of lipids in ChE, PE, and TG classes had differential associations with separate genes (ChE-PICALM, SLC24A4, and SORL1; PE-CLU and CR1; TG-BINI) between AD and control group. These data may provide renewed insights into the pathobiology of AD and the feasibility of identifying individuals with greater AD risk.

Diagnosing and Treating Depression in Patients with Alzheimer's Disease

Although cognitive and functional impairment are the hallmark features of Alzheimer's disease (AD), neuropsychiatric symptoms associated with AD account for increased rates of disability and profoundly impact the quality of life of both patients and their caregivers. This narrative review of current evidence provides practical guidance in diagnosing and managing depression in patients with AD using pharmacological and nonpharmacological interventions. After apathy, depression is the second most common neuropsychiatric symptom in AD. Diagnosing late-life depression (LLD), particularly in those affected by AD, is complicated because older patients may not meet the criteria for a major depressive disorder. Clinically, late-life depression and dementia can be indistinguishable. Although these two entities are now thought to be related, the pathologic mechanisms remain unclear. Evidence suggests that LLD may be a prodromal symptom of neurodegenerative disease. The various geropsychiatric measures currently used to diagnose, rate the severity of, and monitor the progress of treatment for depression are imperfect. Neuroimaging represents a promising avenue toward understanding the complex pathophysiologic relationships between dementia and LLD, and will support the pursuit of biomarker-driven diagnosis and treatment. Nonpharmacologic interventions to relieve depression in persons with cognitive impairment and dementia include emotion-oriented therapies, behavioral and cognitive-behavioral modification programs, and structured activity programs. Sensory-stimulation therapies and multisensory approaches show some promise for successfully treating depression in patients with dementia, but further rigorous research is needed to establish their validity. Clinical consensus and research appear to support selective serotonin reuptake inhibitors as a first choice for the pharmacological treatment of depression in patients with dementia. However, initial support for these therapies remains variable, and further investigation is needed. Extra care is required in prescribing to this population because of the generally high level of medical and psychiatric comorbidity and the potential difficulty in assessing the cognitively impaired patient's response.

Neuropsychological impact of white matter hyperintensities in older adults without dementia

The purpose of this study was to determine (a) if simple clinical judgements of white matter hyperintensities (WMH) on imaging are associated with measurable cognitive impacts in otherwise cognitively normal older adults, (b) if neuropsychological measures can predict those with WMH, and (c) the frequency of low cognitive scores in those with WMH on a battery of measures. Forty-four individuals judged free of other cognitive disorders despite moderate to extensive WMH were compared with 50 individuals matched on age (mean of 83), education (college educated), and gender (predominantly female). Data was obtained from the National Alzheimer's Coordinating Center database. The group with at least moderate WMH had lower scores on the Trail Making Test A, verbal fluency, and digit span. A component score derived from these measures was a significant predictor of the presence of WMH, though only correctly classified 68% of participants. Even in individuals free from other suspected conditions, clinically judged moderate to extensive WMH was associated with cognitive weaknesses for processing speed, working memory, and executive functioning. This shows that a relatively simple judgment of WMH burden is meaningfully associated with worse cognition. Implications and future directions for are discussed.

The Alzheimer's Disease Clinical Spectrum: Diagnosis and Management

Alzheimer's disease (AD) care requires timely diagnosis and multidisciplinary management. Evaluation involves structured patient and caregiver history and symptom-function reviews, examination, and testing (laboratory and neuroimaging) to delineate impairment level, determine the cognitive-behavioral syndrome, and diagnose cause. Clinical biomarkers are available to aid high confidence in etiologic diagnosis. Management uses psychoeducation, shared goal setting, and patient-caregiver dyad decision making. When combined, pharmacologic and nonpharmacologic therapies mitigate symptoms and reduce clinical progression and care burden. AD biopathologic processes develop over decades before symptoms manifest; this period is increasingly targeted in research as an opportunity to best delay or prevent AD dementia.

Diagnosis and Management of Neuropsychiatric Symptoms in Alzheimer's Disease

PURPOSE OF REVIEW

To explore the most recent developments in the effective diagnosis and treatment of neuropsychiatric symptoms (NPS) in Alzheimer's disease (AD).

RECENT FINDINGS

The clinical diagnosis of NPS in AD is facilitated by the use of the Neuropsychiatric Inventory (NPI). CT and MRI scans can be useful for detecting structural changes indicating AD. Other promising diagnostic methodologies that are less frequently used in the clinical setting include positron emission tomography (PET) scans for detecting amyloid and blood tests for detecting serum biomarkers. Numerous pharmaceutical agents have been studied for their use in managing NPS, with antipsychotics being popular for managing agitation but also having significant side effects. Non-pharmacological interventions, such as reminiscence therapy and the Describe, Investigate, Create, Evaluate (DICE) approach may be able to provide treatment without such adverse effects. Diagnosing AD and the comorbid NPS remains primarily a clinical endeavor with CT and MRI scans sometimes used, but evidence is amassing for the use of other imaging modalities and different lab tests for convenient and empiric diagnosis of AD to distinguish it from other psychiatric illnesses. The number of pharmacologic treatments for NPS that are safe as well as efficacious remains limited, yet non-pharmacologic interventions have clear clinical utility. In addition to searching for more successful pharmacological treatments, further research should focus on novel diagnostic tests and non-pharmacologic therapies.

In Vivo Imaging of Microglia With Multiphoton Microscopy

Neuroimaging has become an unparalleled tool to understand the central nervous system (CNS) anatomy, physiology and neurological diseases. While an altered immune function and microglia hyperactivation are common neuropathological features for many CNS disorders and neurodegenerative diseases, direct assessment of the role of microglial cells remains a challenging task. Non-invasive neuroimaging techniques, including magnetic resonance imaging (MRI), positron emission tomography (PET) and single positron emission computed tomography (SPECT) are widely used for human clinical applications, and a variety of ligands are available to detect neuroinflammation. In animal models, intravital imaging has been largely used, and minimally invasive multiphoton microcopy (MPM) provides high resolution detection of single microglia cells, longitudinally, in living brain. In this study, we review in vivo real-time MPM approaches to assess microglia in preclinical studies, including individual cell responses in surveillance, support, protection and restoration of brain tissue integrity, synapse formation, homeostasis, as well as in different pathological situations. We focus on in vivo studies that assess the role of microglia in mouse models of Alzheimer’s disease (AD), analyzing microglial motility and recruitment, as well as the role of microglia in anti-amyloid-β treatment, as a key therapeutic approach to treat AD. Altogether, MPM provides a high contrast and high spatial resolution approach to follow microglia chronically in vivo in complex models, supporting MPM as a powerful tool for deep intravital tissue imaging.

Development and validation of a priori risk model for extensive white matter lesions in people age 65 years or older: the Dijon MRI study

OBJECTIVES

The objective was to develop and validate a risk model for the likelihood of extensive white matter lesions (extWML) to inform clinicians on whether to proceed with or forgo diagnostic MRI.

DESIGN

Population-based cohort study and multivariable prediction model.

SETTING

Two representative samples from France.

PARTICIPANTS

Persons aged 60-80 years without dementia or stroke. Derivation sample n=1714; validation sample n=789.

PRIMARY AND SECONDARY OUTCOME MEASURES

Volume of extWML (log cm³) was obtained from T2-weighted images in a 1.5 T scanner. 20 candidate risk factors for extWML were evaluated with the C-statistic. Secondary outcomes in validation included incident stroke over 12 years follow-up.

RESULTS

The multivariable prediction model included six clinical risk factors (C-statistic=0.61). A cut-off of 7 points on the multivariable prediction model yielded the optimum balance in sensitivity 63.7% and specificity 54.0% and the negative predictive value was high (81.8%), but the positive predictive value was low (31.5%). In further validation, incident stroke risk was associated with continuous scores on the multivariable prediction model (HR 1.02; 95% CI 1.01 to 1.04, P=0.02) and dichotomised scores from the multivariable prediction model (HR 1.28; 95% CI 1.02 to 1.60, P=0.03).

CONCLUSIONS

A simple clinical risk equation for WML constituted by six variables can inform decisions whether to proceed with or forgo brain MRI. The high-negative predictive value demonstrates potential to reduce unnecessary MRI in the population aged 60-80 years.

Frontotemporal Degeneration in a Child

BACKGROUND

There is a predilection for the frontal and temporal lobes in certain cases of dementia in the adult, leading to the syndrome of frontotemporal dementia. However, this syndrome has seemed to elude the developing brain until now.

METHODS AND RESULTS

We describe an example of apparently selective neurodegeneration of the frontal and temporal regions during development associated with some of the clinical, magnetic resonance imaging, and fludeoxyglucose positron emission tomography (FDG PET) scan features of canonical frontotemporal dementia in the adult. This patient does not have any of the common frontotemporal dementia-causing mutations or known progressive brain disorders of children.

CONCLUSION

This patient illustrates that symptomatic, selective, and progressive vulnerability of the frontal and temporal lobes is not restricted to adulthood, expanding the phenotype of frontotemporal degeneration.