Neurobiological basis of behavioral and psychological symptoms in dementia of the Alzheimer type

Atypical instantaneous spatio-temporal patterns of neural dynamics in Alzheimer's disease

Cognitive functions produced by large-scale neural integrations are the most representative 'emergence phenomena' in complex systems. A novel approach focusing on the instantaneous phase difference of brain oscillations across brain regions has succeeded in detecting moment-to-moment dynamic functional connectivity. However, it is restricted to pairwise observations of two brain regions, contrary to large-scale spatial neural integration in the whole-brain. In this study, we introduce a microstate analysis to capture whole-brain instantaneous phase distributions instead of pairwise differences. Upon applying this method to electroencephalography signals of Alzheimer's disease (AD), which is characterised by progressive cognitive decline, the AD-specific state transition among the four states defined as the leading phase location due to the loss of brain regional interactions could be promptly characterised. In conclusion, our synthetic analysis approach, focusing on the microstate and instantaneous phase, enables the capture of the instantaneous spatiotemporal neural dynamics of brain activity and characterises its pathological conditions.

Neurodegenerative pathologies associated with behavioral and psychological symptoms of dementia in a community-based autopsy cohort

In addition to the memory disorders and global cognitive impairment that accompany neurodegenerative diseases, behavioral and psychological symptoms of dementia (BPSD) commonly impair quality of life and complicate clinical management. To investigate clinical-pathological correlations of BPSD, we analyzed data from autopsied participants from the community-based University of Kentucky Alzheimer's Disease Research Center longitudinal cohort (n = 368 research volunteers met inclusion criteria, average age at death 85.4 years). Data assessing BPSD were obtained approximately annually, including parameters for agitation, anxiety, apathy, appetite problems, delusions, depression, disinhibition, hallucinations, motor disturbance, and irritability. Each BPSD was scored on a severity scale (0-3) via the Neuropsychiatric Inventory Questionnaire (NPI-Q). Further, Clinical Dementia Rating (CDR)-Global and -Language evaluations (also scored on 0-3 scales) were used to indicate the degree of global cognitive and language impairment. The NPI-Q and CDR ratings were correlated with neuropathology findings at autopsy: Alzheimer's disease neuropathological changes (ADNC), neocortical and amygdala-only Lewy bodies (LBs), limbic predominant age-related TDP-43 encephalopathy neuropathologic changes (LATE-NC), primary age-related tauopathy (PART), hippocampal sclerosis, and cerebrovascular pathologies. Combinations of pathologies included the quadruple misfolding proteinopathy (QMP) phenotype with co-occurring ADNC, neocortical LBs, and LATE-NC. Statistical models were used to estimate the associations between BPSD subtypes and pathologic patterns. Individuals with severe ADNC (particularly those with Braak NFT stage VI) had more BPSD, and the QMP phenotype was associated with the highest mean number of BPSD symptoms: > 8 different BPSD subtypes per individual. Disinhibition and language problems were common in persons with severe ADNC but were not specific to any pathology. "Pure" LATE-NC was associated with global cognitive impairment, apathy, and motor disturbance, but again, these were not specific associations. In summary, Braak NFT stage VI ADNC was strongly associated with BPSD, but no tested BPSD subtype was a robust indicator of any particular "pure" or mixed pathological combination.

Cognitive Decline and BPSD Are Concomitant with Autophagic and Synaptic Deficits Associated with G9a Alterations in Aged SAMP8 Mice

Behavioural and psychological symptoms of dementia (BPSD) are presented in 95% of Alzheimer’s Disease (AD) patients and are also associated with neurotrophin deficits. The molecular mechanisms leading to age-related diseases are still unclear; however, emerging evidence has suggested that epigenetic modulation is a key pathophysiological basis of ageing and neurodegeneration. In particular, it has been suggested that G9a methyltransferase and its repressive histone mark (H3K9me2) are important in shaping learning and memory by modulating autophagic activity and synaptic plasticity. This work deepens our understanding of the epigenetic mechanisms underlying the loss of cognitive function and BPSD in AD. For this purpose, several tasks were performed to evaluate the parameters of sociability (three-chamber test), aggressiveness (resident intruder), anxiety (elevated plus maze and open field) and memory (novel object recognition test) in mice, followed by the evaluation of epigenetic, autophagy and synaptic plasticity markers at the molecular level. The behavioural alterations presented by senescence-accelerated mice prone 8 (SAMP8) of 12 months of age compared with their senescence-accelerated mouse resistant mice (SAMR1), the healthy control strain was accompanied by age-related cognitive deficits and alterations in epigenetic markers. Increased levels of G9a are concomitant to the dysregulation of the JNK pathway in aged SAMP8, driving a failure in autophagosome formation. Furthermore, lower expression of the genes involved in the memory-consolidation process modulated by ERK was observed in the aged male SAMP8 model, suggesting the implication of G9a. In any case, two of the most important neurotrophins, namely brain-derived neurotrophic factor (Bdnf) and neurotrophin-3 (NT3), were found to be reduced, along with a decrease in the levels of dendritic branching and spine density presented by SAMP8 mice. Thus, the present study characterizes and provides information regarding the non-cognitive and cognitive states, as well as molecular alterations, in aged SAMP8, demonstrating the AD-like symptoms presented by this model. In any case, our results indicate that higher levels of G9a are associated with autophagic deficits and alterations in synaptic plasticity, which could further explain the BPSD and cognitive decline exhibited by the model.

Therapeutic effect of palmitoylethanolamide in cognitive decline: A systematic review and preliminary meta-analysis of preclinical and clinical evidence

Cognitive decline is believed to be associated with neurodegenerative processes involving excitotoxicity, oxidative damage, inflammation, and microvascular and blood-brain barrier dysfunction. Interestingly, research evidence suggests upregulated synthesis of lipid signaling molecules as an endogenous attempt to contrast such neurodegeneration-related pathophysiological mechanisms, restore homeostatic balance, and prevent further damage. Among these naturally occurring molecules, palmitoylethanolamide (PEA) has been independently associated with neuroprotective and anti-inflammatory properties, raising interest into the possibility that its supplementation might represent a novel therapeutic approach in supporting the body-own regulation of many pathophysiological processes potentially contributing to neurocognitive disorders. Here, we systematically reviewed all human and animal studies examining PEA and its biobehavioral correlates in neurocognitive disorders, finding 33 eligible outputs. Studies conducted in animal models of neurodegeneration indicate that PEA improves neurobehavioral functions, including memory and learning, by reducing oxidative stress and pro-inflammatory and astrocyte marker expression as well as rebalancing glutamatergic transmission. PEA was found to promote neurogenesis, especially in the hippocampus, neuronal viability and survival, and microtubule-associated protein 2 and brain-derived neurotrophic factor expression, while inhibiting mast cell infiltration/degranulation and astrocyte activation. It also demonstrated to mitigate β-amyloid-induced astrogliosis, by modulating lipid peroxidation, protein nytrosylation, inducible nitric oxide synthase induction, reactive oxygen species production, caspase3 activation, amyloidogenesis, and tau protein hyperphosphorylation. Such effects were related to PEA ability to indirectly activate cannabinoid receptors and modulate proliferator-activated receptor-α (PPAR-α) activity. Importantly, preclinical evidence suggests that PEA may act as a disease-modifying-drug in the early stage of a neurocognitive disorder, while its protective effect in the frank disorder may be less relevant. Limited human research suggests that PEA supplementation reduces fatigue and cognitive impairment, the latter being also meta-analytically confirmed in 3 eligible studies. PEA improved global executive function, working memory, language deficits, daily living activities, possibly by modulating cortical oscillatory activity and GABAergic transmission. There is currently no established cure for neurocognitive disorders but only treatments to temporarily reduce symptom severity. In the search for compounds able to protect against the pathophysiological mechanisms leading to neurocognitive disorders, PEA may represent a valid therapeutic option to prevent neurodegeneration and support endogenous repair processes against disease progression.

Gut Microbiota Changes and Their Correlation with Cognitive and Neuropsychiatric Symptoms in Alzheimer's Disease

BACKGROUND

Gut microbiota can influence human brain function and behavior. Recent studies showed that gut microbiota might play an important role in the pathogenesis of Alzheimer's disease (AD).

OBJECTIVE

To investigate the composition of gut microbiota in AD patients and their association with cognitive function and neuropsychiatric symptoms (NPS).

METHODS

The fecal samples from 60 AD patients (30 with NPS and 30 without NPS) and 32 healthy control subjects (HC) were collected and analyzed by 16S ribosomal RNA sequencing. The functional variations of gut microbiota were predicted using Phylogenetic Investigation of Communities by Reconstruction of Unobserved States. The correlation between different bacterial taxa and cognitive (Mini-Mental State Examination (MMSE), Clinical Dementia Rating (CDR)), and NPS measures were analyzed.

RESULTS

The fecal microbial composition of AD patients was quite distinct from HC. Bifidobacterium, Sphingomonas, Lactobacillus, and Blautia were enriched, while Odoribacter, Anaerobacterium, and Papillibacter were reduced. AD patients with NPS showed decreased Chitinophagaceae, Taibaiella, and Anaerobacterium compared with those without NPS. Functional pathways were different between AD and HC, and between AD patients with and without NPS. Correlation analysis showed that Sphingomonas correlated negatively with MMSE; Anaerobacterium and Papillibacter correlated positively with MMSE and negatively with CDR. Cytophagia, Rhodospirillaceae, and Cellvibrio correlated positively with NPS, while Chitinophagaceae, Taibaiella, and Anaerobacterium correlated negatively with NPS.

CONCLUSION

AD patients have gut microbiota alterations related to cognition, and differential taxa between AD patients with and without NPS associated differently with NPS domains, which helps further understand the pathogenesis of AD and explore potential therapeutic targets.

Benedet A, Thomas EM, Parsons M, Nasreddine Z, Rosa‐Neto P, Gauthier S. Association between regional tau pathology and neuropsychiatric symptoms in aging and dementia due to Alzheimer's disease

BACKGROUND

Neuropsychiatric symptoms (NPS) are frequent in aging and Alzheimer's disease (AD). Here we study the relationship between NPS and AD pathologies in vivo.

METHOD

Two hundred and twenty-one individuals from the TRIAD cohort (143 cognitively unimpaired, 52 mild cognitive impairment, and 26 AD) underwent [18F]MK6240-tau-positron emission tomography (PET), [18F]AZD4694-amyloid-PET, magnetic resonance imaging, and neuropsychological evaluations. Spearman correlations and voxel-based regression models evaluated the relationship between Neuropsychiatric Inventory Questionnaire (NPI-Q) scores, and tau-PET, amyloid-PET, and voxel-based morphometry.

RESULTS

Fifty percent of individuals presented NPS; these correlated with tau, not amyloid beta or neurodegeneration. Associations between NPI-Q score and tau-PET were stronger in the parietal association area, superior frontal, temporal, and medial occipital lobes. NPI-Q domains associated with distinct patterns of tau uptake.

CONCLUSIONS

NPS are predominantly related to tau in aging and dementia. Regions affected are part of the behavioral circuits, and vulnerable to early AD pathology. Domain-specific analyses showed NPS are related to the AD pathophysiological processes in a symptom-specific manner.

Use of Antipsychotics in Patients with Behavioral and Psychological Symptoms of Dementia: Results of a Spanish Delphi Consensus

BACKGROUND

Behavioral and psychological symptoms of dementia (BPSD) are difficult to manage and associated with poor outcome.

OBJECTIVES

The aim of this study was to reach consensus on the use of antipsychotics in patients with BPSD in Spain.

METHODS

A qualitative, multicenter, two-round Delphi study was carried out, with the participation of specialists involved in the care of dementia patients throughout Spain. They completed a 76-item questionnaire related to the identification of BPSD, treatment with antipsychotics, follow-up of patients, barriers for the use of atypical antipsychotics, and effects of antipsychotics on quality of life.

RESULTS

A total of 162 specialists in neurology, psychiatry, and geriatrics (61% men) with a mean (SD) age of 45.9 (10) years participated in the study. Almost all participants (96.9%) strongly agreed that atypical antipsychotics are safer and better tolerated than typical antipsychotics. There was agreement on the importance to review the indication and dose of the antipsychotic drug at least every 3 months. There was consistent high rate of agreement on the beneficial impact of atypical antipsychotics on the quality of life of patients with dementia and their caregivers. A consensus was also reached on the need of detecting BPSD in patients with dementia as it decreases the quality of life of both patients and caregivers, and the need to routinely screen for dementia in elderly patients with no previous psychiatric history in the presence of suggestive symptoms of BPSD. Finally, the participants in the study agreed that administrative barriers for the prescription of atypical antipsychotics in Spain hinder the access to this drug group and favor the prescription of typical antipsychotics.

CONCLUSIONS

The participants in the study agreed that atypical antipsychotics should be preferred to typical antipsychotics in the management of BPSD. Wide consensus was reached about the importance of early identification of BPSD in persons with cognitive impairment, the use and management of atypical antipsychotic drugs and their favorable impact on patients and caregiver's quality of life.

Caregiver-Reported Sleep Disturbances Are Associated With Behavioral and Psychological Symptoms in an Asian Elderly Cohort With Cognitive Impairment-No Dementia

OBJECTIVE

Sleep disturbances were found to be associated with more behavioral and psychological symptoms (BPS) in early patients with Alzheimer's disease (AD). However, data on preclinical stages of dementia are lacking. Hence, the present study sought to investigate the association between sleep disturbances and BPS in dementia-free elderly with varying severity of cognitive impairment in an Asian sample.

METHODS

Community-living elderly were recruited and administered a comprehensive cognitive battery (vascular dementia battery [VDB]) and the Neuropsychiatric Inventory to assess symptoms of sleep disturbances and BPS. Severity of cognitive impairment was diagnosed and classified as no cognitive impairment (NCI), cognitive impairment-no dementia (CIND) -mild (1-2 impaired domains on the VDB), and CIND-moderate (≥3 impaired domains on the VDB). Analysis of variance was conducted to assess the associations between the presence of sleep disturbances and BPS scores in each diagnostic group. Logistic regression was used to examine whether the coexistence of sleep disturbances and other BPS was associated with CIND-moderate, which is known to carry a higher risk of progression to AD.

RESULTS

Among 839 elderly, 79 (9.4%) reported sleep disturbances. Participants with sleep disturbances had higher total BPS burden than those without among CIND participants but not in NCIs. Furthermore, CIND-moderate participants with sleep disturbances had more delusions, hallucinations, anxiety, depression, irritability, aberrant motor behavior, and appetite change ( P < .05). The presence of both sleep disturbances and other BPS was associated with CIND-moderate (odds ratio: 2.5, 95% confidence interval: 1.1-5.5).

CONCLUSIONS

Sleep disturbances are associated with higher total BPS burden and specific BPS among elderly patients with cognitive impairment, particularly those with CIND moderate, which carries higher risk of developing dementia.

Association of premorbid personality with behavioral and psychological symptoms in dementia with Lewy bodies: Comparison with Alzheimer's disease patients

AIM

The aim of this study was to elucidate the relation between premorbid personality traits and behavioral and psychological symptoms in dementia (BPSD) in dementia with Lewy bodies (DLB) and Alzheimer's disease (AD) patients.

METHODS

Forty-one DLB patients and 98 AD patients were assessed for BPSD using the Neuropsychiatric Inventory (NPI). Each patient's midlife personality traits were rated by a family member using the NEO Five-Factor Inventory (NEO-FFI) questionnaire.

RESULTS

In multiple regression analyses for DLB patients, NPI total score and anxiety were significantly associated with premorbid openness, delusion with premorbid agreeableness, and agitation with premorbid conscientiousness. In AD patients, depression was significantly associated with premorbid neuroticism, and agitation, apathy, and irritability with premorbid agreeableness.

CONCLUSION

Premorbid personalities affected BPSD differently in DLB and AD. Given the differences in the effects of premorbid personalities on BPSD, additional studies are needed to develop interventions to reduce these symptoms.

Association of neuropsychiatric symptoms and sub-syndromes with cognitive impairment in community-dwelling Asian elderly

OBJECTIVES

To investigate the presence of neuropsychiatric symptoms (NPS) and sub-syndromes in elderly community-dwelling Asians with varying severity of cognitive impairment.

METHODS

Chinese and Malay participants (n = 613) from the Epidemiology of Dementia in Singapore (EDIS) Study aged ≥ 60 years underwent clinical examination, neuropsychological testing, and NPS assessment using the Neuropsychiatric Inventory (NPI). Diagnosis of no cognitive impairment (NCI), cognitive impairment-no dementia (CIND), including CIND-mild and CIND-moderate, and dementia were made using established criteria.

RESULTS

A significant increase in the numbers of NPS was observed accompanying with increasing severity of cognitive impairment (p < 0.001). Compared to those with NCI/CIND-mild, participants with CIND-moderate [Odds ratio (OR): 4.2, 95% confidence interval (CI): 1.8-10.0] or dementia [OR: 9.2, 95% CI: 2.3-36.0] were more likely to have two or more neuropsychiatric sub-syndromes. Participants with CIND-moderate were more likely to have hyperactivity [OR: 2.0, 95% CI: 1.0-3.8] and apathy [OR: 2.9, 95% CI: 1.0-8.4] sub-syndromes, whereas patients with dementia were more likely to have psychosis [OR: 6.9, 95% CI: 2.4-20.1], affective (OR: 8.7, 95% CI: 1.8-42.9), and hyperactivity (OR: 5.4, 95% CI: 1.8-16.1). Furthermore, executive dysfunction and visual memory impairment were associated with the presence of three neuropsychiatric sub-syndromes; whist language and visuomotor speed impairment were related to the presence of two sub-syndromes. By contrast, impairment in attention, verbal memory, and visuoconstruction were not associated with any of the sub-syndromes.

CONCLUSIONS

The presence of NPS and sub-syndromes increase with increasing severities of cognitive impairment, and different neuropsychiatric syndromes are associated with specific impairment on cognitive domains in community-dwelling Asian elderly.

Temperature control can abolish anesthesia-induced tau hyperphosphorylation and partly reverse anesthesia-induced cognitive impairment in old mice

AIMS

Anesthesia is related to cognitive impairment and the risk for Alzheimer's disease. Hypothermia during anesthesia can lead to abnormal hyperphosphorylation of tau, which has been speculated to be involved in anesthesia-induced cognitive impairment. The aim of this study was to investigate whether maintenance of the tau phosphorylation level by body temperature control during anesthesia could reverse the cognitive dysfunction in C57BL/6 mice.

METHODS

Eighteen-month-old mice were repeatedly anesthetized during a 2-week period with or without maintenance of body temperature, control mice were treated with normal saline instead of anesthetics. Tau phosphorylation level in mice brain was detected on western blot, and cognitive performance was measured using the Morris water maze (MWM).

RESULTS

After anesthesia-induced hypothermia in old mice, tau was hyperphosphorylated and the cognitive performance, measured on MWM, was impaired. When body temperature was controlled during anesthesia, however, the tau hyperphosphorylation was completely avoided, and there was partial recovery in cognitive impairment measured on the MWM.

CONCLUSION

Hyperphosphorylation of tau in the brain after anesthesia is an important event, and it might be, although not solely, responsible for postoperative cognitive decline.

Neurobiology of neuropsychiatric symptoms in Alzheimer's disease: A critical review with a focus on neuroimaging

The objective of this critical review of the literature was to reveal the neural circuits involved in the occurrence of neuropsychiatric symptoms (NPS) in Alzheimer's disease (AD) patients through the association of these symptoms with neuroimaging findings. The search for articles was performed on PUBMED from January 2000 to May 2013, using the key words: Dementia AND BPSD; Dementia AND Neuropsychiatric Symptoms; and Dementia AND Psychosis, Delusions, Hallucinations, Agitation, Depression, Anxiety, Apathy, Euphoria, Disinhibition, Irritability, Aberrant Motor Behavior, Sleep or Eating Disorders. Forty-six articles were reviewed and important contributions, especially regarding the psychopathological concepts discussed, were also considered even if not included in this time period. The available evidence suggests the three most relevant neurobiological models for neuropsychiatric symptoms in Alzheimer's disease are the frontal-subcortical circuits, the cortico-cortical networks, and the monoaminergic system. We discussed the association of the individual symptoms or syndromes with these models.

The presence of behavioural and psychological symptoms and progression to dementia in the cognitively impaired older population

OBJECTIVE

Behavioural and psychological symptoms (BPS) are common in the older population and may be an indication of early dementia. We explored the predictive effect of the presence of BPS on the 2-year progression to dementia in a cognitively impaired population aged 65 years and over without dementia at baseline.

METHODS

Twelve symptoms were measured in 2024 participants without dementia at baseline as part of a population-based longitudinal study of ageing. The risk of progression to dementia was predicted in those with cognitive impairment for each individual BPS and using a BPS composite score.

RESULTS

Wandering and persecution were independently associated with progression to dementia after adjustment for socio-demographic factors, cognitive domains and other BPS. When stratifying by cognitive function, those with low cognition (MMSE 0-18) and 4 or more BPS were more likely to progress to dementia than those without BPS.

CONCLUSIONS

We have shown that some psychiatric symptoms are associated with increased short-term progression to dementia in those with low cognition. The predictive effect of BPS in dementia progression has implications for risk stratification of those at high risk of progression to dementia, along with memory impairment, other cognitive impairment and health variables.

Effect of age and severity of cognitive dysfunction on spontaneous activity in pet dogs - part 2: social responsiveness

Changes in social interactions with owners and other dogs are frequently observed in dogs with cognitive dysfunction syndrome (CDS). The aim of this work was to assess the effect of age and severity of CDS on social responsiveness. This is the second part of a 2-part report on spontaneous activity in pet dogs. A human interaction test and a mirror test were administered at baseline and 6 months later to assess social responses to humans and conspecifics, respectively, to four groups of privately-owned dogs: young (n=9), middle-aged (n=9), cognitively unimpaired aged (n=31), and cognitively impaired aged (n=36). The severity of cognitive impairment was considered in the last group and dogs were categorised as having either mild or severe CDS. The influence of the person and the mirror on locomotion and exploratory behaviour was also studied. Dogs were recorded in a testing room and the video recordings were subsequently analysed. Young dogs displayed more interactions involving physical contact with a person. Young and middle-aged dogs showed more vocalisations in response to social isolation. In contrast, aged animals spent more time in front of the mirror. Changes in social responsiveness associated with severe CDS included decreased response to social isolation and human interaction and increased time in front of the mirror, suggesting a deficit in habituation. Testing of spontaneous activity might help to characterise CDS in aged dogs, a condition increasingly diagnosed in veterinary clinics and a potentially useful natural model of Alzheimer's disease in humans.

Apolipoprotein E genotypes and neuropsychiatric symptoms and syndromes in late-onset Alzheimer's disease

Neuropsychiatric symptoms (NPS) in dementia, previously denominated as behavioural and psychological symptoms of dementia, are often more distressing, impairing, and costly than cognitive symptoms, representing a major health burden for older adults. These symptoms are common features of Alzheimer's disease (AD), and are one of the major risk factors for institutionalization. There is a high prevalence of neuropsychiatric disturbances in patients with AD, including depression, anxiety, apathy, psychosis, aggression, and agitation. At present, the role of the apolipoprotein E (APOE) genotypes in the development of NPS or neuropsychiatric syndromes/endophenotypes in AD patients is unclear. In this article, we summarized the findings of the studies of NPS and neuropsychiatric syndromes in AD in relation to APOE genotypes, with special attention to the possible underlying mechanisms. While some studies failed to find a significant association between the APOE polymorphism and NPS in late-onset AD, other studies reported a significant association between the APOE ɛ4 allele and an increase in agitation/aggression, hallucinations, delusions, and late-life depression or anxiety. However, current cumulative evidence coming from the few existing longitudinal studies shows no association of APOE genotypes with NPS as a whole in AD. Some negative studies that focused on the distribution of APOE genotypes between AD patients with or without NPS further emphasized the importance of sub-grouping NPS in distinct neuropsychiatric syndromes. Explanations for the variable findings in the existing studies included differences in patient populations, differences in the assessment of neuropsychiatric symptomatology, possible lack of statistical power to detect associations in the negative studies, and small sample sizes generating false positives that cannot be consistently replicated. Finally, many reviewed studies were cross-sectional, whereas it would be of paramount importance to evaluate the risk for incident NPS in relation to the APOE genotype in prospectively followed cohorts of AD patients. In fact, identifying predisposing genetic risk factors may allow us to understand the pathophysiological features of neuropsychiatric syndromes or symptoms in AD, so optimizing possible therapeutic options.

The APOE polymorphism in Alzheimer's disease patients with neuropsychiatric symptoms and syndromes

BACKGROUND

Neuropsychiatric symptoms (NPS) are a common feature of Alzheimer's disease (AD), resulting in particular AD endophenotypes. The common AD genetic risk factor apolipoprotein E (APOE) has been suggested underlying these AD endophenotypes.

METHODS

APOE genotyping, a comprehensive geriatric assessment (CGA), and Neuropsychiatric Inventory were performed on 322 consecutive older patients. Patients were divided into three groups: AD with NPS (N = 93), AD without NPS (N = 108), and, as a control group, patients with no cognitive impairment (NoCI: N = 121). Patients with NPS were further sub-divided in four groups according to the European Alzheimer's Disease Consortium (EADC) classification of neuropsychiatric syndromes in AD: hyperactive, psychotic, affective, and apathetic.

RESULTS

AD patients with NPS showed a significantly higher grade of cognitive impairment, more severity stage of dementia, more disability in the activities of daily living (ADL), and the instrumental ADL than AD patients without NPS. As expected, an higher frequency of APOE ε3/ε4 genotype was observed in patients with AD, both with and without NPS, than patients with NoCI. No difference in the distribution of APOE genotypes was found between AD patients with vs. without NPS. However, in AD patients APOE ε4-carriers, there was an increased risk of affective [odds ratio (OR): 2.34, 95% confidence interval (CI): 1.19-4.58) and apathetic (OR: 2.24,95%CI: 1.19-4.22) syndromes.

CONCLUSIONS

These findings did not suggest a significant association between APOE polymorphism and presence of NPS in AD patients. In AD patients with NPS, however, APOE ε4-carrier status was associated with an increased risk of affective and apathetic syndromes.

Neuropsychiatric Symptoms, Endophenotypes, and Syndromes in Late-Onset Alzheimer's Disease: Focus on APOE Gene

Neuropsychiatric symptoms, previously denominated as behavioural and psychological symptoms of dementia, are common features of Alzheimer's disease (AD) and are one of the major risk factors for institutionalization. At present, the role of the apolipoprotein E (APOE) gene in the development of neuropsychiatric symptoms in AD patients is unclear. In this paper, we summarized the findings of the studies of neuropsychiatric symptoms and neuropsychiatric syndromes/endophenotypes in AD in relation to APOE genotypes, with special attention to the possible underlying mechanisms. While some studies failed to find a significant association between APOE and neuropsychiatric symptoms in late-onset AD, other studies reported a significant association between the APOE ε4 allele and an increase in agitation/aggression, hallucinations, delusions, and late-life depression or anxiety. Furthermore, some negative studies that focused on the distribution of APOE genotypes between AD patients with or without neuropsychiatric symptoms further emphasized the importance of subgrouping neuropsychiatric symptoms in distinct neuropsychiatric syndromes. Explanations for the variable findings in the existing studies included differences in patient populations, differences in the assessment of neuropsychiatric symptomatology, and possible lack of statistical power to detect associations in the negative studies.

Current concepts in Alzheimer's disease: a multidisciplinary review

This comprehensive, pedagogically-oriented review is aimed at a heterogeneous audience representative of the allied disciplines involved in research and patient care. After a foreword on epidemiology, genetics, and risk factors, the amyloid cascade model is introduced and the main neuropathological hallmarks are discussed. The progression of memory, language, visual processing, executive, attentional, and praxis deficits, and of behavioral symptoms is presented. After a summary on neuropsychological assessment, emerging biomarkers from cerebrospinal fluid assays, magnetic resonance imaging, nuclear medicine, and electrophysiology are discussed. Existing treatments are briefly reviewed, followed by an introduction to emerging disease-modifying therapies such as secretase modulators, inhibitors of Abeta aggregation, immunotherapy, inhibitors of tau protein phosphorylation, and delivery of nerve growth factor.

Behavioral and psychological symptoms, neurocognitive performance, and functional independence in mild dementia

This research investigated the interrelationships between behavioral and psychological symptoms in dementia (BPSD; i.e. disturbance of perception, thought content, mood, or behavior), cognition, and functional independence among mildly demented outpatients (MMSE = 23). A comprehensive neuropsychological evaluation was administered to 48 outpatients diagnosed with Alzheimer's disease ( n = 32) and vascular dementia ( n = 16) in order to assess cognitive function. A neuropsychiatric symptom inventory assessed BPSD and an instrumental activities of daily living questionnaire assessed functional independence. Pearson correlational analyses found that BPSD were associated with dementia severity, but not with performance on tests of specific neurocognitive domains. In addition, functional independence was associated with BPSD, dementia severity, and executive control, but not with language or memory. Multiple regression analyses revealed that dementia severity alone best predicted BPSD, and that BPSD more so than dementia severity best predicted functional independence. None of the specific neurocognitive domains predicted either BPSD or functional independence.

Treatment Strategies for the Behavioral Symptoms of Alzheimer's Disease: Focus on Early Pharmacologic Intervention

The impact of behavioral symptoms associated with Alzheimer's disease is substantial. These symptoms contribute to diminished quality of life for patients and caregivers and increase the cost of care in nursing homes. Early recognition of behavioral symptoms and appropriate treatment are important for successful management. Nonpharmacologic strategies remain the cornerstone of the management of Alzheimer's disease-related behavioral symptoms. However, nonpharmacologic strategies may not be effective for problem behaviors, and pharmacologic intervention may be necessary. Relevant articles were identified through various MEDLINE searches with no date restrictions, with an emphasis on recent studies that used cholinesterase inhibitors and memantine. Additional reports of interest were identified from the reference lists of these articles. To facilitate cross-study analyses in the review of cholinesterase inhibitors and memantine, the database search was limited to randomized, placebo-controlled trials that used the Neuropsychiatric Inventory to assess behavioral symptoms of Alzheimer's disease. Overall, evidence from trials of cholinesterase inhibitors and memantine suggests that when these agents are optimized for the various stages of Alzheimer's disease, they can also prevent the emergence of neuropsychiatric symptoms. Although results from the literature are not uniformly positive, cholinesterase inhibitors have been shown to produce significant improvements in behavioral symptoms in patients with both mild- to-moderate and moderate-to-severe Alzheimer's disease. Evidence also indicates that memantine might be of benefit as an adjunct to long-term cholinesterase inhibitor treatment in patients with moderate-to-severe Alzheimer's disease and that memantine monotherapy may have some beneficial effects on behavior in patients with mild-to-moderate disease. Of importance, although no direct comparisons have been performed, these agents seem to have an improved safety and tolerability profile compared with the frequently used antipsychotic drugs. When nonpharmacologic strategies are deemed insufficient to ease problem behaviors in patients with Alzheimer's disease, treatment with cholinesterase inhibitors, alone or in combination with memantine as appropriate for the stage of disease, may be considered as a first-line option in the early pharmacologic management of Alzheimer's disease-related behavioral symptoms.

Cognitive neuroscience of delusions in aging

Assessments and clinical understanding of late-onset delusions in the elderly are inconsistent and often incomplete. In this review, we consider the prevalence, neurobehavioral features, and neuroanatomic correlations of delusions in elderly persons - those with documented cognitive decline and those with no evidence of cognitive decline. Both groups exhibit a common phenotype: delusions are either of persecution or of misidentification. Late-onset delusions show a nearly complete absence of the grandiose, mystical, or erotomanic content typical of early onset psychoses. Absent also from both elderly populations are formal thought disorders, thought insertions, and delusions of external control. Neuroimaging and behavioral studies suggest a frontotemporal localization of delusions in the elderly, with right hemispheric lateralization in delusional misidentification and left lateralization in delusions of persecution. We propose that delusions in the elderly reflect a common neuroanatomic and functional phenotype, and we discuss applications of our proposal to diagnosis and treatment.

First episodes of behavioral symptoms in Alzheimer's disease patients at age 90 and over, and early-onset Alzheimer's disease: comparison with senile dementia of Alzheimer's type

We evaluated dementia symptoms to clarify the character of dementia with Alzheimer's disease (AD) observed in the oldest old patients and that of dementia with early-onset AD. Subjects were consecutive AD inpatients admitted for the first time at age of 90 years and over because of behavioral symptoms (demented nonagenarian group: D90G; n=18) and those with 24 consecutive inpatients with AD with early-onset (EOG). The Gottfries, Brane and Steen's scale and the Dementia Behavior Disturbance scale were used to evaluate the symptoms and troublesome behaviors. The scores of these scales in D90G and in EOG were compared with those of 26 sex distribution-, severity of dementia-, and disease duration-matched inpatients with AD with late-onset (LOG). Compared with LOG, wakefulness was more impaired and waking up at night was more frequent in D90G, while memory, orientation and inappropriate behaviors were more severe in EOG. These results suggest that the clinical features of dementia in EOG were quantitatively different from those of LOG. In contrast, the clinical feature of dementia of D90G were sleep-wake pattern disturbance and were qualitatively different from those of LOG.

Donepezil–tacrine hybrid related derivatives as new dual binding site inhibitors of AChE

A new series of donepezil-tacrine hybrid related derivatives have been synthesised as dual acetylcholinesterase inhibitors that could bind simultaneously to the peripheral and catalytic sites of the enzyme. These new hybrids combined a tacrine, 6-chlorotacrine or acridine unit as catalytic binding site and indanone (the heterocycle present in donepezil) or phthalimide moiety as peripheral binding site of the enzyme, connected through a different linker tether length. One of the synthesised compounds emerged as a potent and selective AChE inhibitor, which is able to displace propidium in a competition assay. These results seem to confirm the ability of this inhibitor to bind simultaneously to both sites of the enzyme and make it a promising lead for developing disease-modifying drugs for the future treatment of Alzheimer's disease. To gain insight into the molecular determinants that modulate the inhibitory activity of these compounds, a molecular modelling study was performed to explore their binding to the enzyme.

APP23 mice as a model of Alzheimer's disease: an example of a transgenic approach to modeling a CNS disorder

Animal models are considered essential in research ensuing elucidation of human disease processes and subsequently, testing of potential therapeutic strategies. This is especially true for neurodegenerative disorders, in which the first steps in pathogenesis are often not accessible in human patients. Alzheimer's disease is vastly becoming a major medical and socioeconomic problem in our aging society. Valid animal models for this uniquely human condition should exhibit histopathological, biochemical, cognitive, and behavioral alterations observed in Alzheimer's disease patients. Major progress has been made since the understanding of the genetic basis of Alzheimer's disease and the development and improvement of transgenic mouse models. All present Alzheimer's disease models developed are partial but nevertheless essential in further unraveling the nature and spatial and temporal development of the complex molecular pathology underlying this condition. One of the more recent transgenic attempts to model Alzheimer's disease is the APP23 transgenic mouse. This article describes the development and assessment of this human amyloid precursor protein overexpression model. We summarize histopathological and biochemical, cognitive and behavioral observations made in heterozygous APP23 mice, thereby emphasizing the model's contribution to clarification of neurodegenerative disease mechanisms. In addition, the first therapeutic interventions in the APP23 model are included.

A metabolic imaging severity rating scale for the assessment of cognitive impairment

PURPOSE

This study was designed to validate a simple scoring system for evaluating fluorodeoxyglucose (FDG) positron emission tomographic (PET) scans that can be used routinely in patients undergoing the clinical assessment of cognitive impairment.

METHODS

The FDG-PET scans of 106 patients with cognitive impairment (65 with Alzheimer disease, 16 with frontal lobe dementia, and 25 atypical cases) were acquired using the PENN-PET scanner 40 minutes after the intravenous administration of 8 mCi FDG. Metabolic activity in various anatomic structures of the brain was scored using the following qualitative scale: 4 = normal; 3 = mildly decreased; 2 = moderately decreased; 1 = severely decreased; and 0 = no activity. Regions of interest were also placed over these regions to obtain a quantitative value. Two distinct scores were obtained. Values for visual and sensorimotor cortices, thalami, basal ganglia, and cerebellum comprised score I. Score II consisted of the values for the frontal, temporal, and parietal cortices. The qualitative metabolic imaging severity rating scale (MISRS) was compared with a quantitative MISRS (obtained from the region-of-interest analysis of the same structures). The MISRS was then compared with the results from the Mini-Mental Status Examination (MMSE) and the Dementia Severity Rating Score (DSRS).

RESULTS

In all patients, the qualitative MISRS scores correlated significantly with the quantitative MISRS (r = 0.73, P < 0.0001). In all patients with cognitive impairment, the qualitative and quantitative MISRS scores correlated significantly with the DSRS and the MMSE (P < 0.001). In patients with Alzheimer disease, the qualitative and quantitative MISRS significantly correlated with the DSRS and MMSE.

CONCLUSION

A simple and practical rating scale can be used to assess the severity of cognitive impairment in patients with different types of dementing illnesses.