Neuropsychiatric symptoms and brain morphology in patients with mild cognitive impairment and Alzheimer's disease with dementia

Neuroanatomical correlates and predictors of psychotic symptoms in Alzheimer's disease: A systematic review and meta-analysis

BACKGROUND

Psychotic symptoms (hallucinations and delusions) are a type of neuropsychiatric symptom found during Alzheimer's Disease (AD).

OBJECTIVE

This systematic review aims to comprehensively capture, analyse, and evaluate the body of evidence that has investigated associations between brain regions/networks and psychotic symptoms in AD.

METHODS

The protocol, created according to the PRISMA guidelines, was pre-registered on OSF (https://osf.io/tg8xp/). Searches were performed using PubMed, Web of Science and PsycInfo. A partial coordinate-based meta-analysis (CBMA) was performed based on data availability.

RESULTS

Eighty-two papers were selected: delusions were found to be associated mainly with right fronto-temporal brain regions and the insula; hallucinations mainly with fronto-occipital areas; both were frequently associated with the anterior cingulate cortex. The CBMA, performed on the findings of fourteen papers on delusions, identified a cluster in the frontal lobe, one in the putamen, and a smaller one in the insula.

CONCLUSIONS

The available evidence highlights that key brain regions, predominantly in the right frontal lobe, the anterior cingulate cortex, and temporo-occipital areas, appear to underpin the different manifestations of psychotic symptoms in AD and MCI. The fronto-temporal areas identified in relation to delusions may underpin a failure to assimilate correct information and consider alternative possibilities (which might generate and maintain the delusional belief), and dysfunction within the salience network (anterior cingulate cortex and insula) may suggest a contribution for how internal and external stimuli are identified; the fronto-occipital areas linked to hallucinations may indicate diminished sensory processing and non-optimal predictive processing, that together contribute to misinterpretation of stimuli and misperceptions; the fronto-temporal and occipital areas, as well as the anterior cingulate cortex were linked to the psychotic cluster.

Serum and urine metabolomics based on UPLC-QTOF/MS reveal the effect and potential mechanism of "schisandra-evodia" herb pair in the treatment of Alzheimer's disease

The "schisandra-evodia" herb pair (S-E) is a herbal preparation to treat Alzheimer's disease (AD). This study aims to investigate the therapeutic efficacy and potential mechanism of S-E in AD rats, utilizing pharmacodynamic assessments and serum- and urine-based metabolomic analyses. Pharmacodynamic assessments included Morris water maze test, hematoxylin-eosin staining and immunohistochemistry experiments. The results of the study showed that the AD model was successful; the S-E significantly enhanced long-term memory and spatial learning in AD rats. Meanwhile, S-E notably ameliorated Aβ25-35-induced cognitive impairment, improved hippocampal neuron morphology, decreased Aβ deposition in the hippocampus and mitigated inflammatory damage. We then analyzed serum and urine samples using UPLC-MS/MS to identify potential biomarkers and metabolic pathways. Metabolomic analysis revealed alterations in 40 serum metabolites and 38 urine metabolites following S-E treatment, predominantly affecting pathways related to taurine and hypotaurine metabolism, linoleic acid metabolism, α-linolenic acid metabolism, glycerophospholipid metabolism and arachidonic acid metabolism. This study elucidates the biochemical mechanism underlying AD and the metabolic pathway influenced by S-E, laying the groundwork for future clinical applications.

Role of fronto-limbic circuit in neuropsychiatric symptoms of dementia: clinical evidence from an exploratory study

Background

Neuropsychiatric symptoms (NPSs) are a distressful aspect of dementia and the knowledge of structural correlates of NPSs is limited. We aimed to identify associations of fronto-limbic circuit with specific NPSs in patients with various types of cognitive impairment.

Methods

Of 84 participants, 27 were diagnosed with mild cognitive impairment (MCI), 41 with Alzheimer's disease (AD) dementia and 16 with non-AD dementia. In all patients we assessed regional brain morphometry using a region of interest (ROI)-based analysis. The mean cortical thickness (CT) of 20 cortical regions and the volume (V) of 4 subcortical areas of the fronto-limbic system were extracted. NPSs were rated with the Neuropsychiatric Inventory (NPI). We used multiple linear regression models adjusted for age and disease duration to identify significant associations between scores of NPI sub-domains and MRI measures of brain morphometry.

Results

All significant associations found were negative, except those between irritability and the fronto-opercular regions in MCI patients (corresponding to a 40-50% increase in CT) and between delusions and hippocampus and anterior cingulate gyrus (with a 40-60% increase). Apathy showed predominant involvement of the inferior frontal regions in AD group (a 30% decrease in CT) and of the cingulate cortex in non-AD group (a 50-60% decrease in CT). Anxiety correlated in MCI patients with the cingulate gyrus and caudate, with a CT and V decrease of about 40%, while hallucinations were associated with left enthorinal gyrus and right amygdala and temporal pole. Agitation showed associations in the AD group with the frontal regions and the temporal pole, corresponding to a 30-40% decrease in CT. Euphoria, disinhibition and eating abnormalities were associated in the MCI group with the entorhinal, para-hippocampal and fusiform gyri, the temporal pole and the amygdala (with a 40-70% decrease in CT and V). Finally, aberrant motor behavior reported a significant association with frontal and cingulate regions with a 50% decrease in CT.

Conclusion

Our findings indicate that specific NPSs are associated with the structural involvement of the fronto-limbic circuit across different types of neurocognitive disorders. Factors, such as age and disease duration, can partly account for the variability of the associations observed.

Neuroanatomical and neurocognitive correlates of delusion in Alzheimer's disease and mild cognitive impairment

BACKGROUND

Neuropsychiatric symptoms and delusions are highly prevalent among people with dementia. However, multiple roots of neurobiological bases and shared neural basis of delusion and cognitive function remain to be characterized. By utilizing a fine-grained multivariable approach, we investigated distinct neuroanatomical correlates of delusion symptoms across a large population of dementing illnesses.

METHODS

In this study, 750 older adults with mild cognitive impairment and Alzheimer's disease completed brain structural imaging and neuropsychological assessment. We utilized principal component analysis followed by varimax rotation to identify the distinct multivariate correlates of cortical thinning patterns. Five of the cognitive domains were assessed whether the general cognitive abilities mediate the association between cortical thickness and delusion.

RESULTS

The result showed that distributed thickness patterns of temporal and ventral insular cortex (component 2), inferior and lateral prefrontal cortex (component 1), and somatosensory-visual cortex (component 5) showed negative correlations with delusions. Subsequent mediation analysis showed that component 1 and 2, which comprises inferior frontal, anterior insula, and superior temporal regional thickness accounted for delusion largely through lower cognitive functions. Specifically, executive control function assessed with the Trail Making Test mediated the relationship between two cortical thickness patterns and delusions.

DISCUSSION

Our findings suggest that multiple distinct subsets of brain regions underlie the delusions among older adults with cognitive impairment. Moreover, a neural loss may affect the occurrence of delusion in dementia largely due to impaired general cognitive abilities.

Neuropsychiatric symptoms and brain morphology in patients with mild cognitive impairment, cerebrovascular disease and Parkinson disease: A cross sectional and longitudinal study

OBJECTIVES

Neuropsychiatric symptoms (NPS) increase risk of developing dementia and are linked to various neurodegenerative conditions, including mild cognitive impairment (MCI due to Alzheimer's disease [AD]), cerebrovascular disease (CVD), and Parkinson's disease (PD). We explored the structural neural correlates of NPS cross-sectionally and longitudinally across various neurodegenerative diagnoses.

METHODS

The study included individuals with MCI due to AD, (n = 74), CVD (n = 143), and PD (n = 137) at baseline, and at 2-years follow-up (MCI due to AD, n = 37, CVD n = 103, and PD n = 84). We assessed the severity of NPS using the Neuropsychiatric Inventory Questionnaire. For brain structure we included cortical thickness and subcortical volume of predefined regions of interest associated with corticolimbic and frontal-executive circuits.

RESULTS

Cross-sectional analysis revealed significant negative correlations between appetite with both circuits in the MCI and CVD groups, while apathy was associated with these circuits in both the MCI and PD groups. Longitudinally, changes in apathy scores in the MCI group were negatively linked to the changes of the frontal-executive circuit. In the CVD group, changes in agitation and nighttime behavior were negatively associated with the corticolimbic and frontal-executive circuits, respectively. In the PD group, changes in disinhibition and apathy were positively associated with the corticolimbic and frontal-executive circuits, respectively.

CONCLUSIONS

The observed correlations suggest that underlying pathological changes in the brain may contribute to alterations in neural activity associated with MBI. Notably, the difference between cross-sectional and longitudinal results indicates the necessity of conducting longitudinal studies for reproducible findings and drawing robust inferences.

Associations of hearing loss and structural changes in specific cortical regions: a Mendelian randomization study

INTRODUCTION

Previous studies have suggested a correlation between hearing loss (HL) and cortical alterations, but the specific brain regions that may be affected are unknown.

METHODS

Genome-wide association study (GWAS) data for 3 subtypes of HL phenotypes, sensorineural hearing loss (SNHL), conductive hearing loss, and mixed hearing loss, were selected as exposures, and GWAS data for brain structure-related traits were selected as outcomes. The inverse variance weighted method was used as the main estimation method.

RESULTS

Negative associations were identified between genetically predicted SNHL and brain morphometric indicators (cortical surface area, cortical thickness, or volume of subcortical structures) in specific brain regions, including the bankssts (β = -0.006 mm, P = 0.016), entorhinal cortex (β = -4.856 mm2, P = 0.029), and hippocampus (β = -24.819 cm3, P = 0.045), as well as in brain regions functionally associated with visual perception, including the pericalcarine (β = -10.009 cm3, P = 0.013).

CONCLUSION

Adaptive changes and functional remodeling of brain structures occur in patients with genetically predicted HL. Brain regions functionally associated with auditory perception, visual perception, and memory function are the main brain regions vulnerable in HL.

Post-stroke aggressive behavior in patients wıth first-ever ischemic stroke: underlying clinical and imaging factors

BACKGROUND

Aggression is defined as a complex behavior consisting of a combination of sensory, emotional, cognitive and motor elements. We aimed to examine the relationships between post-stroke aggressive behavior (PSAB) and neuropsychological and neuroimaging findings.

METHODS

380 patients in the stroke unit were classified as aggressive or non-aggressive based on symptoms elicited by the Neuropsychiatric Inventory (NPI) and aggression screening questionnaire.

RESULTS

Aggressive behavior was detected in 42 (11.1%) of 380 patients who had a first ischemic stroke. Patients with PSAB were older than those without (338 patients) (66.98 + 13.68 vs. 62.61 + 13.06, P = 0.043). Hamilton depression and anxiety scales showed significantly higher rates of depression and anxiety in the PSAB group compared to the non-PSAB group (47.6% vs. 16.3% and 57.1% vs. 15.4%, respectively; P = 0.001). Lesion mapping analysis showed that lesions in patients with PSAB mostly included the lower parietal lobe and lateral frontal gyrus. Multiple regression analysis showed that gender (OR, 2.81; CI%, 1.24-6.39), lateral prefrontal infarction (OR, 6.43; CI%, 1.51-27.44), parietal infarction (OR, 2.98; CI%, 1.15-7.76), occipital infarction (OR, 2.84; CI%, 1.00-8.06), multiple infarcts (OR, 5.62; CI%, 2.27-13.93), anxiety (OR, 2.06; CI%, 0.89-4.81) and verbal memory deficit (OR, 4.21; CI%, 1.37-12.93) were significant independent predictors of PSAB.

CONCLUSION

The presence of PSAB may be related to neuropsychiatric symptoms such as high anxiety and verbal memory impairment, and neuroanatomical location of the lesions.

Early depressive manifestations in patients with dementia caused by Alzheimer's disease

Previous studies on the complex interplay between depression and dementia in patients with Alzheimer's disease revealed that early-life depression is a risk factor for dementia. Both depression and dementia appear to share common etiopathological mechanisms. In the present study, a comprehensive retrospective analysis was performed on a study group of patients with dementia suffering from previously diagnosed depression. The aim was to assess potentially relevant clinical and imaging parameters that can be used to characterize depression as a risk factor for dementia in later life. Statistically significant data correlating cognitive scores with the moment of depression onset and the length of time period to the diagnosis of dementia were identified. Furthermore, at the moment of depression diagnosis, structural cerebral alterations tended to appear more frequently in women compared with men. However, this sex-associated difference is not maintained after the moment of dementia diagnosis. Results from the present study contributed additional data to the evidence supporting a relationship between a history of depression and the occurrence of Alzheimer's disease, discussing relevant clinical and imaging parameters featured in patients with dementia and their inter-relations.

Alzheimer's disease heterogeneity revealed by neuroanatomical normative modeling

INTRODUCTION

Overlooking the heterogeneity in Alzheimer's disease (AD) may lead to diagnostic delays and failures. Neuroanatomical normative modeling captures individual brain variation and may inform our understanding of individual differences in AD-related atrophy.

METHODS

We applied neuroanatomical normative modeling to magnetic resonance imaging from a real-world clinical cohort with confirmed AD (n = 86). Regional cortical thickness was compared to a healthy reference cohort (n = 33,072) and the number of outlying regions was summed (total outlier count) and mapped at individual- and group-levels.

RESULTS

The superior temporal sulcus contained the highest proportion of outliers (60%). Elsewhere, overlap between patient atrophy patterns was low. Mean total outlier count was higher in patients who were non-amnestic, at more advanced disease stages, and without depressive symptoms. Amyloid burden was negatively associated with outlier count.

DISCUSSION

Brain atrophy in AD is highly heterogeneous and neuroanatomical normative modeling can be used to explore anatomo-clinical correlations in individual patients.

Depression and Agitation Factors Are Related to Regional Brain Atrophy and Faster Longitudinal Cognitive Decline in Mild Cognitive Impairment

BACKGROUND

Neuropsychiatric symptoms (NPS) are a common aspect of Alzheimer's disease (AD). Multiple studies have investigated its brain correlates, but it still remains unclear how they relate with brain atrophy in mild cognitive impairment (MCI).

OBJECTIVE

Our objective was to investigate brain volume in MCI patients as a function of NPS.

METHODS

We measured grey matter volume, neuropsychological status and NPS (Neuropsychiatric Inventory, NPI), in a sample of 81 MCI patients (43 females). Participants were divided in groups depending on presence (NPS+) or absence (NPS-) of NPS and on type of NPS.

RESULTS

We found lower volume of left temporal pole in patients with depression compared to NPS- (p = 0.012), and in patients with agitation compared to NPS- in the right middle occipital gyrus (p = 0.003). We also found a significant correlation between volume of left temporal pole and MMSE (r (78)  = 0.232, p = 0.019). Finally, NPS+ presented lower cross-sectional cognitive level than NPS- (t (79)  = 1.79, p = 0.038), and faster cognitive decline (t (48)  = -1.74, p = 0.044).

CONCLUSIONS

Our results support the colocalization of structural damage as a possible mechanism underlying the relationship between MCI and depression and provide novel evidence regarding agitation. Moreover, our longitudinal evidence highlights the relevance of an adequate identification of NPS in MCI patients to identify those at risk of faster cognitive decline.

Correlation transfer function analysis as a biomarker for Alzheimer brain plasticity using longitudinal resting-state fMRI data

Neural plasticity is the ability of the brain to alter itself functionally and structurally as a result of its experience. However, longitudinal changes in functional connectivity of the brain are still unrevealed in Alzheimer's disease (AD). This study aims to discover the significant connections (SCs) between brain regions for AD stages longitudinally using correlation transfer function (CorrTF) as a new biomarker for the disease progression. The dataset consists of: 29 normal controls (NC), and 23, 24, and 23 for early, late mild cognitive impairments (EMCI, LMCI), and ADs, respectively, along three distant visits. The brain was divided into 116 regions using the automated anatomical labeling atlas, where the intensity time series is calculated, and the CorrTF connections are extracted for each region. Finally, the standard t-test and ANOVA test were employed to investigate the SCs for each subject's visit. No SCs, along three visits, were found For NC subjects. The most SCs were mainly directed from cerebellum in case of EMCI and LMCI. Furthermore, the hippocampus connectivity increased in LMCI compared to EMCI whereas missed in AD. Additionally, the patterns of longitudinal changes among the different AD stages compared to Pearson Correlation were similar, for SMC, VC, DMN, and Cereb networks, while differed for EAN and SN networks. Our findings define how brain changes over time, which could help detect functional changes linked to each AD stage and better understand the disease behavior.

Neuropsychiatric disturbances in mild cognitive impairment: A scientometric analysis

Behavioral and psychological symptoms of dementia (BPSD) have been extensively studied in dementia than its prodromal stage, known as mild cognitive impairment (MCI). A scientometric study on BPSD in MCI would be valuable in synthesizing the existing body of research and providing insights into the trends, networks, and influencers within this area. We searched for related literature in the Web of Science database and extracted complete text and citation records of each publication. The primary objective was to map the research evolution of BPSD in MCI and highlight dominant research themes. The secondary objective was to identify research network characteristics (authors, journals, countries, and institutions) and abundances. A total of 12,369 studies published between 1980 and 2022 were included in the analysis. We found 51 distinct clusters from the co-cited reference network that were highly credible with significant modularity (Q = 0.856) and silhouette scores (S = 0.932). Five major research domains were identified: symptoms, diagnosis, brain substrates, biochemical pathways, and interventions. In recent years, the research focus in this area has been on gut microbiota, e-health, COVID-19, cognition, and delirium. Collectively, findings from this scientometric analysis can help clarify the scope and direction of future research and clinical practices.

Neuropsychiatric symptoms and their neural correlates in individuals with mild cognitive impairment

OBJECTIVES

Neuropsychiatric symptoms are common in subjects with MCI and associated with higher risk of progression to AD. The cognitive and neuroanatomical correlates of neuropsychiatric symptoms in MCI have not been fully elucidated. In this study, we sought to evaluate the association between neuropsychiatric symptoms, cognitive function, regional tau deposition, and brain volumes in MCI subjects.

METHODS

A total of 233 MCI and 305 healthy comparisons were selected from the ADNI-3 cohort. All the subjects underwent a comprehensive neuropsychological assessment, volumetric MR brain scan, and Flortaucipir PET for in vivo assessment of regional tau deposition. Prevalence of neuropsychiatric symptoms was evaluated by means of the NPI questionnaire. Multivariate analyses of variance were used to detect differences in cognitive and imaging markers in MCI subjects with and without neuropsychiatric symptoms.

RESULTS

61.4% MCI subjects showed at least one neuropsychiatric symptom, with the most prevalent ones being depression (26.1%), irritability (23.6%), and sleep disturbances (23.6%). There was a significant effect of neuropsychiatric symptoms on cognitive tests of frontal and executive functions. MCI subjects with neuropsychiatric symptoms showed reduced brain volumes in the orbitofrontal and posterior cingulate cortices, while no effects were detected on regional tau deposition. Posterior cingulate cortex volume was the only predictor of global neuropsychiatric burden in this MCI population.

CONCLUSIONS

Neuropsychiatric symptoms occur early in the AD trajectory and are mainly related to defects of control executive abilities and to the reduction of gray matter volume in the orbitofrontal and posterior cingulate cortices. A better understanding of the cognitive and neuroanatomical mechanisms of neuropsychiatric symptoms in MCI could help develop more targeted and efficacious treatment alternatives.

Dissecting the Relationship Between Neuropsychiatric and Neurodegenerative Disorders

Neurodegenerative diseases (NDDs) and neuropsychiatric disorders (NPDs) are two common causes of death in elderly people, which includes progressive neuronal cell death and behavioral changes. NDDs include Alzheimer's disease, Parkinson's disease, Huntington's disease, amyotrophic lateral sclerosis, multiple sclerosis, and motor neuron disease, characterized by cognitive defects and memory impairment, whereas NPDs include depression, seizures, migraine headaches, eating disorders, addictions, palsies, major depressive disorders, anxiety, and schizophrenia, characterized by behavioral changes. Mounting evidence demonstrated that NDDs and NPDs share an overlapping mechanism, which includes post-translational modifications, the microbiota-gut-brain axis, and signaling events. Mounting evidence demonstrated that various drug molecules, namely, natural compounds, repurposed drugs, multitarget directed ligands, and RNAs, have been potentially implemented as therapeutic agents against NDDs and NPDs. Herein, we highlighted the overlapping mechanism, the role of anxiety/stress-releasing factors, cytosol-to-nucleus signaling, and the microbiota-gut-brain axis in the pathophysiology of NDDs and NPDs. We summarize the therapeutic application of natural compounds, repurposed drugs, and multitarget-directed ligands as therapeutic agents. Lastly, we briefly described the application of RNA interferences as therapeutic agents in the pathogenesis of NDDs and NPDs. Neurodegenerative diseases and neuropsychiatric diseases both share a common signaling molecule and molecular phenomenon, namely, pro-inflammatory cytokines, γCaMKII and MAPK/ERK, chemokine receptors, BBB permeability, and the gut-microbiota-brain axis. Studies have demonstrated that any alterations in the signaling mentioned above molecules and molecular phenomena lead to the pathophysiology of neurodegenerative diseases, namely, Alzheimer's disease, Parkinson's disease, Huntington's disease, and amyotrophic lateral sclerosis, and neuropsychiatric disorders, such as bipolar disorder, schizophrenia, depression, anxiety, autism spectrum disorder, and post-traumatic stress disorder.

Brain Donation Decisions as Disease Specific Behaviors: An Elucidation of the Donation Process in the Context of Essential Tremor

Brain donation is a challenging process, comprising four sequential stages: (1) the brain donation decision, (2) pre-mortem arrangements and follow up, (3) specimen collection and (4) tissue processing. It is important to understand the factors that are pertinent to each stage. Currently, there is extensive information on factors that involve donor’s personal and cultural backgrounds and how these could affect the process. However, little is known about disease-specific factors that influence the process. The Essential Tremor Centralized Brain Repository was established in 2003, and after nearly 20 years of collecting essential tremor (ET) brain tissue, we are well-positioned to discuss the brain donation process from a disease-specific standpoint. In the current manuscript, we discuss ET disease-specific factors that influence the first two stages of the brain donation process. We center our discussion around three points: (1) factors that influence the patient’s decision to donate, (2) the involvement of next of kin in the donation, and (3) the rationale for enrolling patients prospectively and evaluating them longitudinally before the anatomical gift takes place. This discussion shares our understanding of the background from which our repository operates and may be of value for other brain banks that study similar neurodegenerative diseases.