Apathy associated with Alzheimer disease: use of dextroamphetamine challenge

Advances in Brain Stimulation, Nanomedicine and the Use of Magnetoelectric Nanoparticles: Dopaminergic Alterations and Their Role in Neurodegeneration and Drug Addiction

Recent advancements in brain stimulation and nanomedicine have ushered in a new era of therapeutic interventions for psychiatric and neurodegenerative disorders. This review explores the cutting-edge innovations in brain stimulation techniques, including their applications in alleviating symptoms of main neurodegenerative disorders and addiction. Deep Brain Stimulation (DBS) is an FDA-approved treatment for specific neurodegenerative disorders, including Parkinson's Disease (PD), and is currently under evaluation for other conditions, such as Alzheimer's Disease. This technique has facilitated significant advancements in understanding brain electrical circuitry by enabling targeted brain stimulation and providing insights into neural network function and dysfunction. In reviewing DBS studies, this review places particular emphasis on the underlying main neurotransmitter modifications and their specific brain area location, particularly focusing on the dopaminergic system, which plays a critical role in these conditions. Furthermore, this review delves into the groundbreaking developments in nanomedicine, highlighting how nanotechnology can be utilized to target aberrant signaling in neurodegenerative diseases, with a specific focus on the dopaminergic system. The discussion extends to emerging technologies such as magnetoelectric nanoparticles (MENPs), which represent a novel intersection between nanoformulation and brain stimulation approaches. These innovative technologies offer promising avenues for enhancing the precision and effectiveness of treatments by enabling the non-invasive, targeted delivery of therapeutic agents as well as on-site, on-demand stimulation. By integrating insights from recent research and technological advances, this review aims to provide a comprehensive understanding of how brain stimulation and nanomedicine can be synergistically applied to address complex neuropsychiatric and neurodegenerative disorders, paving the way for future therapeutic strategies.

An Update on Apathy in Alzheimer's Disease

Apathy is a complex multi-dimensional syndrome that affects up to 70% of individuals with Alzheimer's disease (AD). Whilst many frameworks to define apathy in AD exist, most include loss of motivation or goal-directed behaviour as the central feature. Apathy is associated with significant impact on persons living with AD and their caregivers and is also associated with accelerated cognitive decline across the AD spectrum. Neuroimaging studies have highlighted a key role of fronto-striatial circuitry including the anterior cingulate cortex (ACC), orbito-frontal cortex (OFC) and associated subcortical structures. Importantly, the presence and severity of apathy strongly correlates with AD stage and neuropathological biomarkers of amyloid and tau pathology. Following from neurochemistry studies demonstrating a central role of biogenic amine neurotransmission in apathy syndrome in AD, recent clinical trial data suggest that apathy symptoms may improve following treatment with agents such as methylphenidate-which may have an important role alongside emerging non-pharmacological treatment strategies. Here, we review the diagnostic criteria, rating scales, prevalence, and risk factors for apathy in AD. The underlying neurobiology, neuropsychology and associated neuroimaging findings are reviewed in detail. Finally, we discuss current treatment approaches and strategies aimed at targeting apathy syndrome in AD, highlighting areas for future research and clinical trials in patient cohorts.

Biomedical knowledge graph learning for drug repurposing by extending guilt-by-association to multiple layers

Computational drug repurposing aims to identify new indications for existing drugs by utilizing high-throughput data, often in the form of biomedical knowledge graphs. However, learning on biomedical knowledge graphs can be challenging due to the dominance of genes and a small number of drug and disease entities, resulting in less effective representations. To overcome this challenge, we propose a "semantic multi-layer guilt-by-association" approach that leverages the principle of guilt-by-association - "similar genes share similar functions", at the drug-gene-disease level. Using this approach, our model DREAMwalk: Drug Repurposing through Exploring Associations using Multi-layer random walk uses our semantic information-guided random walk to generate drug and disease-populated node sequences, allowing for effective mapping of both drugs and diseases in a unified embedding space. Compared to state-of-the-art link prediction models, our approach improves drug-disease association prediction accuracy by up to 16.8%. Moreover, exploration of the embedding space reveals a well-aligned harmony between biological and semantic contexts. We demonstrate the effectiveness of our approach through repurposing case studies for breast carcinoma and Alzheimer's disease, highlighting the potential of multi-layer guilt-by-association perspective for drug repurposing on biomedical knowledge graphs.

Apathy in Parkinson's Disease: Defining the Park Apathy Subtype

Apathy is a neurobehavioural symptom affecting Parkinson's disease patients of all disease stages. Apathy seems to be associated with a specific underlying non-motor disease subtype and reflects dysfunction of separate neural networks with distinct neurotransmitter systems. Due to the complicated neuropsychiatric aetiology of apathy, clinical assessment of this invalidating non-motor symptom remains challenging. We aim to summarize the current findings on apathy in Parkinson's disease and highlight knowledge gaps. We will discuss the prevalence rates across the different disease stages and suggest screening tools for clinically relevant apathetic symptoms. We will approach the fundamental knowledge on the neural networks implicated in apathy in a practical manner and formulate recommendations on patient-tailored treatment. We will discuss the Park apathy phenotype in detail, shedding light on different clinical manifestations and implications for prognosis. With this review, we strive to distil the vast available theoretical knowledge into a clinical and patient-oriented perspective.

Norepinephrine May Oppose Other Neuromodulators to Impact Alzheimer's Disease

While much of biomedical research since the middle of the twentieth century has focused on molecular pathways inside the cell, there is increasing evidence that extracellular signaling pathways are also critically important in health and disease. The neuromodulators norepinephrine (NE), serotonin (5-hydroxytryptamine, 5HT), dopamine (DA), acetylcholine (ACH), and melatonin (MT) are extracellular signaling molecules that are distributed throughout the brain and modulate many disease processes. The effects of these five neuromodulators on Alzheimer's disease (AD) are briefly examined in this paper, and it is hypothesized that each of the five molecules has a u-shaped (or Janus-faced) dose-response curve, wherein too little or too much signaling is pathological in AD and possibly other diseases. In particular it is suggested that NE is largely functionally opposed to 5HT, ACH, MT, and possibly DA in AD. In this scenario, physiological "balance" between the noradrenergic tone and that of the other three or four modulators is most healthy. If NE is largely functionally opposed to other prominent neuromodulators in AD, this may suggest novel combinations of pharmacological agents to counteract this disease. It is also suggested that the majority of cases of AD and possibly other diseases involve an excess of noradrenergic tone and a collective deficit of the other four modulators.

Diagnostic criteria for apathy in neurocognitive disorders

INTRODUCTION

Apathy is common in neurocognitive disorders (NCD) but NCD-specific diagnostic criteria are needed.

METHODS

The International Society for CNS Clinical Trials Methodology Apathy Work Group convened an expert group and sought input from academia, health-care, industry, and regulatory bodies. A modified Delphi methodology was followed, and included an extensive literature review, two surveys, and two meetings at international conferences, culminating in a consensus meeting in 2019.

RESULTS

The final criteria reached consensus with more than 80% agreement on all parts and included: limited to people with NCD; symptoms persistent or frequently recurrent over at least 4 weeks, a change from the patient's usual behavior, and including one of the following: diminished initiative, diminished interest, or diminished emotional expression/responsiveness; causing significant functional impairment and not exclusively explained by other etiologies.

DISCUSSION

These criteria provide a framework for defining apathy as a unique clinical construct in NCD for diagnosis and further research.

Selective serotonin reuptake inhibitors-associated apathy syndrome: A cross sectional study

Selective serotonin reuptake inhibitors (SSRIs), commonly used to treat depression, are associated with loss of motivation, anergy, and lack of curiosity often referred collectively as apathy. However, this association has not been systematically assessed using a specific rating scale for measuring apathy syndrome. Our objective was to study the association between SSRI use and apathy syndrome.We conducted a retrospective chart review of 125 patients enrolled in an outpatient psychiatry clinic. The prevalence of apathy syndrome and its clinical significance (based on standardized assessment) were compared between patients treated and not treated with SSRIs. Apathy was assessed using the Apathy Evaluation Scale-clinician version with a score ranging 18-72 with higher score for worse apathy. A score of greater than 30 is considered clinically significant apathy.Among 119 patients, the mean apathy scores were significantly higher in those treated with SSRIs compared to those not treated with SSRIs (42.5 ± 9.2 vs 31.3 ± 6, P < .0001). The SSRI group also had a significantly higher percentage of patients with clinically significant apathy (92% vs 61%, P < .0001). Use of all SSRIs was associated with the presence of apathy. Apathy was seen in all mental health diagnostic categories with highest Apathy evaluation scale-clinician version scores in those with dementia.SSRI use may be associated with higher rates of apathy syndrome. Clinicians should specifically inquire about iatrogenic apathy syndrome when evaluating patients on an SSRI if there is suspicion of loss of motivation. Limitations of this study included retrospective nature of this study, and that majority of the sample was males. Prospective studies are needed to elucidate information regarding the prevalence, etiology, and treatment response for SSRI-associated apathy syndrome.

The Roles of Apathy and Depression in Predicting Alzheimer Disease: A Longitudinal Analysis in Older Adults With Mild Cognitive Impairment

OBJECTIVE

Apathy and depression have each been associated with an increased risk of conversion from mild cognitive impairment (MCI) to Alzheimer disease (AD).These symptoms often co-occur and the contribution of each to risk of AD is not clear.

METHODS

National Alzheimer's Coordinating Center participants diagnosed with MCI at baseline and followed until development of AD or loss to follow-up (n = 4,932) were included. The risks of developing AD in MCI patients with neuropsychiatric symptoms (NPS) (apathy only, depression only, or both) were compared to that in those without NPS in a multivariate Cox regression survival analysis adjusting for baseline cognitive impairment, years of smoking, antidepressant use, and AD medication use.

RESULTS

Thirty-seven percent (N = 1713) of MCI patients developed AD (median follow-up 23 months). MCI patients with both apathy and depression had the greatest risk (hazard ratio [HR] = 1.37; 95% confidence interval [CI]: 1.17-1.61; p < 0.0001; Wald χ2 = 14.70; df = 1). Those with apathy only also had a greater risk (HR = 1.24; 95% CI: 1.05-1.47; p = 0.01; Wald χ2 = 6.22; df = 1), but not those with depression only (HR = 1.08; 95% CI: 0.95-1.22; p=0.25; Wald χ2 = 1.30; df = 1). Post-hoc analyses suggested depression may exacerbate cognitive decline in MCI patients with apathy (odds ratio = 0.70; 95% CI 0.52-0.95; p = 0.02; Wald χ2 = 5.28; df = 1), compared to those without apathy.

CONCLUSION

MCI patients with apathy alone or both apathy and depression are at a greater risk of developing AD compared to those with no NPS. Interventions targeting apathy and depression may reduce risk of AD.

Dopamine and Dopamine Receptors in Alzheimer's Disease: A Systematic Review and Network Meta-Analysis

Background: The dopaminergic system has been associated with the progression of Alzheimer's disease. But previous studies found inconsistent results regarding the relationship between Alzheimer's disease and dopamine when looking at dopamine receptor concentrations. Objective: The aim of this review was to synthesize, using a random-effects model of meta-analysis, the link between the dopaminergic system and Alzheimer's disease. Methods: A detailed analysis protocol was registered at the PROSPERO database prior to data extraction (CRD42018110798). Electronic databases of PubMed, Embase, Web of Science, and Psyc-ARTICLES were searched up to December 2018 for studies that examined dopamine and dopamine receptors in relation to Alzheimer's disease. Standardized mean differences (SMD) were calculated to assess group differences in the levels of dopaminergic neurometabolites. Results: Seventeen studies met the eligibility criteria. Collectively, they included 512 patients and 500 healthy controls. There were significantly lower levels of dopamine in patients with Alzheimer's disease compared with controls (SMD = -1.56, 95% CI: -2.64 to -0.49). In addition, dopamine 1 receptor (SMD = -5.05, 95% CI: -6.14 to -3.97) and dopamine 2 receptor (SMD = -1.13, 95% CI: -1.52 to -0.74) levels were decreased in patients with Alzheimer's disease compared with controls. The results of network meta-analysis indicated that the rank of correlation with Alzheimer's disease from highest to lowest was dopamine (0.74), dopamine 2 receptor (0.49), dopamine 3 receptor (0.46), dopamine 4 receptor (0.33), dopamine 5 receptor (0.31), and dopamine 1 receptor (0.64). Conclusions: Overall, decreased levels of dopaminergic neurotransmitters were linked with the pathophysiology of Alzheimer's disease. Nonetheless, there is a clear need for more prospective studies to validate these hypotheses.

Exposure to ambient fine particles and neuropsychiatric symptoms in cognitive disorder: A repeated measure analysis from the CREDOS (Clinical Research Center for Dementia of South Korea) study

There is a growing concern that air pollution, especially those particles <2.5 μm (PM_2.5), could increase the risk of cognitive impairment and mental disorders. However, the relationship between ambient PM_2.5 and neuropsychiatric symptoms in people with cognitive impairment is still undetermined. This longitudinal study included 645 pairs of cognitively impaired subjects, who had not changed residence within Seoul, and their caregivers from the Clinical Research Center for Dementia of South Korea study cohort between September 2005 and June 2010 (1763 days). Neuropsychiatric symptoms were measured by the Korean version of the Neuropsychiatry Inventory, and caregiver burden was examined by the Neuropsychiatry Inventory Caregiver Distress Scale at the first and second visits at the outpatient clinic. District-specific PM_2.5 concentrations were constructed over 1 month to 1 year prior to each visit. A log-linear regression using generalized estimating equations to account for repeated measures was used to assess the relationship between PM_2.5 exposure and neuropsychiatric symptoms or caregiver burden. Aggravated neuropsychiatric symptoms were associated with exposure to high PM_2.5 levels (adjusted percent change: 16.7% [95% confidence interval (CI), 5.0-29.7] per 8.3 μg/m³ increase in 1-month moving averages). Increased caregiver burden was associated with high PM_2.5 exposures only in caregivers for patients with Alzheimer's disease (adjusted percent change: 29.0% [95% CI, 8.1-53.9] per 8.3 μg/m³ increase in 1-month moving averages). The present results indicate that PM_2.5 exposure is associated with aggravated neuropsychiatric symptoms and increased caregiver burden in subjects with cognitive impairment. The findings in this study suggest that the role of air pollution deserves great consideration in the aging population with cognitive impairment.

Behavioral and psychological symptoms in Alzheimer's dementia and vascular dementia

Behavioral and psychological symptoms of dementia (BPSD) are highly prevalent and represent a significant burden for patients and their caregivers. Early recognition and management of these symptoms is crucial as they are associated with increased risk of institutionalization, impairments in daily functioning, reduced quality of life, and more rapid progression to severe dementia. This chapter will discuss the pathophysiology, proposed diagnostic criteria, clinical features, and management of BPSD, including apathy, depression, agitation/aggression, psychosis, and sleep disturbances. Apathy and depression are the most common overall, and apathy is associated with high symptom severity likely because of its greater persistence. Symptoms such as agitation, aggression, hallucinations, and delusions may be especially distressing and dangerous to patients and caregivers. Nonpharmacologic management should be considered first-line therapy in most cases due to the modest and inconsistent evidence base for pharmacologic agents and greater risk of harm. However, the judicious use of pharmacologic agents may be warranted when symptoms are dangerous and/or severely distressing.

The Apathy in Dementia Methylphenidate Trial 2 (ADMET 2): study protocol for a randomized controlled trial

BACKGROUND

Alzheimer's disease (AD) is characterized not only by cognitive and functional decline, but also often by the presence of neuropsychiatric symptoms. Apathy, which can be defined as a lack of motivation, is one of the most prevalent neuropsychiatric symptoms in AD and typically leads to a worse quality of life and greater burden for caregivers. Treatment options for apathy in AD are limited, but studies have examined the use of the amphetamine, methylphenidate. The Apathy in Dementia Methylphenidate Trial (ADMET) found that treatment of apathy in AD with methylphenidate was associated with significant improvement in apathy in two of three outcome measures, some evidence of improvement in global cognition, and minimal adverse events. However, the trial only enrolled 60 participants who were followed for only 6 weeks. A larger, longer-lasting trial is required to confirm these promising findings.

METHODS

The Apathy in Dementia Methylphenidate Trial 2 (ADMET 2) is a phase III, placebo-controlled, masked, 6-month, multi-center, randomized clinical trial targeted to enroll 200 participants with AD and apathy. Participants are randomly assigned 1:1 to 20 mg methylphenidate per day prepared as four over-encapsulated tablets or to matching placebo. The primary outcomes include (1) the mean difference in the Neuropsychiatric Inventory Apathy subscale scores measured as change from baseline to 6 months, and (2) the odds of having a given rating or better on the modified AD Cooperative Study Clinical Global Impression of Change ratings at month 6 compared with the baseline rating. Other outcomes include change in cognition, safety, and cost-effectiveness measured at monthly follow-up visits up to 6 months.

DISCUSSION

Given the prevalence of apathy in AD and its impact on both patients and caregivers, an intervention to alleviate apathy would be of great benefit to society. ADMET 2 follows on the promising results from the original ADMET to evaluate the efficacy of methylphenidate as a treatment for apathy in AD. With a larger sample size and longer follow up, ADMET 2 is poised to confirm or refute the original ADMET findings.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT02346201 . Registered on 26 January 2015.

Pharmacological Therapy for Apathy in Alzheimer’s Disease: A Systematic Review and Meta-Analysis

Introduction:Apathy is highly prevalent in Alzheimer’s disease (AD), but whether pharmacotherapy is effective in managing apathy is unclear.Methods:To assess the efficacy of pharmacotherapy for apathy in AD we searched for randomized controlled trials (RCT) and aggregate data reporting on apathy in several search engines, reference lists of articles, and reviews. Demographic characteristics and relevant data were extracted to assess apathy.Results:Fifteen RCTs’ were examined, and 11 were used in aggregate meta-analytic statistics. Drugs included were cholinesterase inhibitors, memantine, and psycho-stimulants. We found no significant treatment effect in favour of any of the drugs, and the effect-size estimates under a random effect model were heterogeneous. Most RCTs had a high attrition rate and used the NPI apathy subscale to measure apathy.Conclusion:The lack of an effect could be explained by methodological limitations, publication bias, and heterogeneity.

Classification of Neuropsychiatric Symptoms Requiring Antipsychotic Treatment in Patients with Alzheimer's Disease: Analysis of the CATIE-AD Study

BACKGROUND

The Neuropsychiatric Inventory (NPI) comprises 12 items, which were conventionally determined by psychopathological symptoms of patients with dementia. The clinical rating scales with structured questionnaires have been useful to evaluate neuropsychiatric symptoms (NPSs) of patients with dementia over the past twenty year.

OBJECTIVE

The aim of this study was to classify the conventional NPSs in patients with Alzheimer's disease (AD) requiring antipsychotic treatment for their NPSs into distinct clusters to simplify assessment of these numerous symptoms.

METHODS

Twelve items scores (product of severity and frequency of each symptom) in the NPI taken from the baseline visit were classified into subgroups by principle component analysis using data from 421 outpatients with AD enrolled in the Clinical Antipsychotic Trials of Intervention Effectiveness-Alzheimer's Disease (CATIE-AD) Phase 1. Chi square tests were conducted to examine the co-occurrence of the subgroups.

RESULTS

We found four distinct clusters: aggressiveness (agitation and irritabilities), apathy and eating problems (apathy and appetite/eating disturbance), psychosis (delusions and hallucinations), and emotion and disinhibition (depression, euphoria, and disinhibition). Anxiety, aberrant motor behavior, and sleep disturbance were not included by these clusters. Apathy and eating problems, and emotion and disinhibition co-occurred (p = 0.002), whereas aggressiveness and psychosis occurred independent of the other clusters.

CONCLUSIONS

Four distinct category clusters were identified from NPSs in patients with AD requiring antipsychotic treatment. Future studies should investigate psychosocial backgrounds or risk factors of each distinct cluster, in addition to their longitudinal course over treatment intervention.

Apathy associated with neurocognitive disorders: Recent progress and future directions

INTRODUCTION

Apathy is common in neurocognitive disorders (NCDs) such as Alzheimer's disease and mild cognitive impairment. Although the definition of apathy is inconsistent in the literature, apathy is primarily defined as a loss of motivation and decreased interest in daily activities.

METHODS

The Alzheimer's Association International Society to Advance Alzheimer's Research and Treatment (ISTAART) Neuropsychiatric Syndromes Professional Interest Area (NPS-PIA) Apathy workgroup reviewed the latest research regarding apathy in NCDs.

RESULTS

Progress has recently been made in three areas relevant to apathy: (1) phenomenology, including the use of diagnostic criteria and novel instruments for measurement, (2) neurobiology, including neuroimaging, neuropathological and biomarker correlates, and (3) interventions, including pharmacologic, nonpharmacologic, and noninvasive neuromodulatory approaches.

DISCUSSION

Recent progress confirms that apathy has a significant impact on those with major NCD and those with mild NCDs. As such, it is an important target for research and intervention.

Drug Development in Alzheimer's Disease: The Contribution of PET and SPECT

Clinical trials aiming to develop disease-altering drugs for Alzheimer’s disease (AD), a neurodegenerative disorder with devastating consequences, are failing at an alarming rate. Poorly defined inclusion-and outcome criteria, due to a limited amount of objective biomarkers, is one of the major concerns. Non-invasive molecular imaging techniques, positron emission tomography and single photon emission (computed) tomography (PET and SPE(C)T), allow visualization and quantification of a wide variety of (patho)physiological processes and allow early (differential) diagnosis in many disorders. PET and SPECT have the ability to provide biomarkers that permit spatial assessment of pathophysiological molecular changes and therefore objectively evaluate and follow up therapeutic response, especially in the brain. A number of specific PET/SPECT biomarkers used in support of emerging clinical therapies in AD are discussed in this review.

Reward processing in neurodegenerative disease

Representation of reward value involves a distributed network including cortical and subcortical structures. Because neurodegenerative illnesses target specific anatomic networks that partially overlap with the reward circuit, they would be predicted to have distinct impairments in reward processing. This review presents the existing evidence of reward processing changes in neurodegenerative diseases including mild cognitive impairment (MCI), Alzheimer's disease, frontotemporal dementia, amyotrophic lateral sclerosis (ALS), Parkinson's disease, and Huntington's disease, as well as in healthy aging. Carefully distinguishing the different aspects of reward processing (primary rewards, secondary rewards, reward-based learning, and reward-based decision-making) and using tasks that differentiate the stages of processing reward will lead to improved understanding of this fundamental process and clarify a contributing cause of behavioral change in these illnesses.

Principles and management of neuropsychiatric symptoms in Alzheimer's dementia

Neuropsychiatric symptoms of Alzheimer's disease (NPS-AD) are highly prevalent and lead to poor medical and functional outcomes. In spite of the burdensome nature of NPS-AD, we are continuing to refine the nosology and only beginning to understand the underlying pathophysiology. Cluster analyses have frequently identified three to five subsyndromes of NPS-AD: behavioral dysfunction (for example, agitation/aggressiveness), psychosis (for example, delusions and hallucinations), and mood disturbance (for example, depression or apathy). Recent neurobiological studies have used new neuroimaging techniques to elucidate behaviorally relevant circuits and networks associated with these subsyndromes. Several fronto-subcortical circuits, cortico-cortical networks, and neurotransmitter systems have been proposed as regions and mechanisms underlying NPS-AD. Common to most of these subsyndromes is the broad overlap of regions associated with the salience network (anterior cingulate and insula), mood regulation (amygdala), and motivated behavior (frontal cortex). Treatment strategies for dysregulated mood syndromes (depression and apathy) have primarily targeted serotonergic mechanisms with antidepressants or dopaminergic mechanisms with psychostimulants. Psychotic symptoms have largely been targeted with anti-psychotic medications despite controversial risk/benefit tradeoffs. Management of behavioral dyscontrol, including agitation and aggression in AD, has encompassed a wide range of psychoactive medications as well as non-pharmacological approaches. Developing rational therapeutic approaches for NPS-AD will require a firmer understanding of the underlying etiology in order to improve nosology as well as provide the empirical evidence necessary to overcome regulatory and funding challenges to further study these debilitating symptoms.

Effect of methylphenidate on attention in apathetic AD patients in a randomized, placebo-controlled trial

BACKGROUND

Little is known about the effect of methylphenidate (MPH) on attention in Alzheimer's disease (AD). MPH has shown to improve apathy in AD, and both apathy and attention have been related to dopaminergic function. The goal was to investigate MPH effects on attention in AD and assess the relationship between attention and apathy responses.

METHODS

MPH (10 mg PO twice daily) or placebo was administered for six weeks in a randomized, double-blind trial in mild-to-moderate AD outpatients with apathy (Neuropsychiatric Inventory (NPI) Apathy ≥ 4). Attention was measured with the Wechsler Adult Intelligence Scale--Digit Span (DS) subtest (DS forward, selective attention) and apathy with the Apathy Evaluation Scale (AES). A mixed effects linear regression estimated the difference in change from baseline between treatment groups, defined as δ (MPH (DS week 6-DS baseline)) - (placebo (DS week 6-DS baseline)).

RESULTS

In 60 patients (37 females, age = 76 ± 8, Mini-Mental State Examination (MMSE) = 20 ± 5, NPI Apathy = 7 ± 2), the change in DS forward (δ = 0.87 (95% CI: 0.06-1.68), p = 0.03) and DS total (δ = 1.01 (95% CI: 0.09-1.93), p = 0.03) favored MPH over placebo. Of 57 completers, 17 patients had improved apathy (≥3.3 points on the AES from baseline to end point) and 40 did not. There were no significant associations between AES and NPI Apathy with DS change scores in the MPH, placebo, AES responder, or non-responder groups. DS scores did not predict apathy response to MPH treatment.

CONCLUSION

These results suggest MPH can improve attention and apathy in AD; however, the effects appear independent in this population.

Serum homocysteine levels are correlated with behavioral and psychological symptoms of Alzheimer's disease

PURPOSE

Homocysteine has been associated with cognitive impairment and various psychiatric symptoms. This study was designed to clarify whether a relationship exists between the serum levels of homocysteine and the behavioral and psychological symptoms of dementia.

METHODS

Patients with Alzheimer's disease (n=77) and control subjects (n=37) were included in this study. History taking, physical examination, and cognitive assessment were carried out as part of the investigation for the diagnosis of Alzheimer's disease based on the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition. The Mini-Mental State Examination, Global Deterioration Scale, Clinical Dementia Rating, and the Korean version of the Neuropsychiatric Inventory were applied to all patients. The patients' serum homocysteine, folate, and vitamin B12 levels were measured.

RESULTS

Patients with Alzheimer's disease had statistically significantly lower Mini-Mental State Examination scores and higher serum homocysteine levels compared to the control subjects. Mean serum folate and vitamin B12 concentration were significantly lower in patients with Alzheimer's disease compared to control subjects. A statistically significant positive correlation was found between the serum homocysteine levels and the Neuropsychiatric Inventory subdomains, including delusion, agitation/aggression, depression/dysphoria, elation/euphoria, apathy/indifference, and disinhibition. No statistically significant correlation was found between the serum homocysteine concentration and the Mini-Mental State Examination, Global Deterioration Scale, or Clinical Dementia Rating.

CONCLUSION

Associations between the serum homocysteine levels and behavioral and psychological symptoms of dementia were observed, raising the possibility of an etiological role. However, the correlations between the folate or vitamin B12 levels and the Neuropsychiatric Inventory scores were not significant. The pathophysiological mechanisms underlying these findings remain to be elucidated. This was a cross-sectional study and the findings should be confirmed by repetitive, prospective longitudinal studies in a larger group of patients with neurodegenerative disorders.

Safety and efficacy of methylphenidate for apathy in Alzheimer's disease: a randomized, placebo-controlled trial

OBJECTIVE

In a recent crossover trial, methylphenidate treatment decreased apathy in Alzheimer's disease. We further assessed this finding in the Apathy in Dementia Methylphenidate Trial (ADMET).

METHOD

Six-week, randomized, double-blind, placebo-controlled multicenter trial enrolling Alzheimer's disease participants (NINCDS-ADRDA criteria) with apathy assigned to methylphenidate 20 mg daily or placebo, conducted from June 2010 to December 2011. Primary outcomes were change in Apathy Evaluation Scale (AES) score and modified Alzheimer's Disease Cooperative Study-Clinical Global Impression of Change (ADCS-CGI-C). Secondary outcomes included change in Neuropsychiatric Inventory (NPI) apathy score, Mini-Mental State Examination (MMSE) score, and safety.

RESULTS

60 participants were randomly assigned (29 methylphenidate, 31 placebo). At baseline, mean (SD) age = 76 (8) years, MMSE score = 20 (5), AES score = 51 (12), NPI total score = 16 (8), and 62% of the participants (n = 37) were female. After 6 weeks' treatment, mean (SD) change in AES score was -1.9 (1.5) for methylphenidate and 0.6 (1.4) for placebo (P = .23). Odds ratio for improvement in ADCS-CGI-C was 3.7 (95% CI, 1.3 to 10.8) (P = .02), with 21% of methylphenidate versus 3% of placebo rated as moderately or markedly improved. NPI apathy score improvement was 1.8 points (95% CI, 0.3 to 3.4) greater on methylphenidate than on placebo (P = .02). MMSE trended toward improvement on methylphenidate (P = .06). There were trends toward greater anxiety and weight loss > 2% in the methylphenidate-treated group.

CONCLUSIONS

Methylphenidate treatment of apathy in Alzheimer's disease was associated with significant improvement in 2 of 3 efficacy outcomes and a trend toward improved global cognition with minimal adverse events, supporting the safety and efficacy of methylphenidate treatment for apathy in Alzheimer's disease.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT01117181.

Neuropsychiatric symptoms in Alzheimer's disease

Neuropsychiatric symptoms (NPS) are core features of Alzheimer's disease and related dementias. Once thought to emerge primarily in people with late-stage disease, these symptoms are currently known to manifest commonly in very early disease and in prodromal phases, such as mild cognitive impairment. Despite decades of research, reliable treatments for dementia-associated NPS have not been found, and those that are in widespread use present notable risks for people using these medications. An Alzheimer's Association Research Roundtable was convened in the spring of 2010 to review what is known about NPS in Alzheimer's disease, to discuss classification and underlying neuropathogenesis and vulnerabilities, and to formulate recommendations for new approaches to tailored therapeutics.

Neuropsychiatric symptoms in Alzheimer's disease

Neuropsychiatric symptoms (NPS) are core features of Alzheimer's disease and related dementias. Once thought to emerge primarily in people with late-stage disease, these symptoms are currently known to manifest commonly in very early disease and in prodromal phases, such as mild cognitive impairment. Despite decades of research, reliable treatments for dementia-associated NPS have not been found, and those that are in widespread use present notable risks for people using these medications. An Alzheimer's Association Research Roundtable was convened in the spring of 2010 to review what is known about NPS in Alzheimer's disease, to discuss classification and underlying neuropathogenesis and vulnerabilities, and to formulate recommendations for new approaches to tailored therapeutics.

Dissociating behavioral disorders in early dementia-An FDG-PET study

Behavioral impairments occur frequently in dementia. Studies with magnetic resonance imaging, measuring atrophy, have systematically investigated their neural correlates. Such a systematic approach has not yet been applied to imaging with [(18)F] fluorodeoxyglucose positron emission tomography (FDG-PET), although regional hypometabolism may precede and exceed atrophy in dementia. The present study related all behavioral disorders as assessed with the Neuropsychiatric Inventory to reductions in brain glucose utilization as measured by FDG-PET with Statistical Parametric Mapping (SPM5). It included 54 subjects mainly with early Alzheimer's disease, frontotemporal lobar degeneration, and subjective cognitive impairment. Apathy, disinhibition and eating disorders - most frequent in frontotemporal lobar degeneration - correlated significantly with regional brain hypometabolism. Whereas a single regressor analysis and conjunction analysis revealed largely overlapping frontomedian regions that were associated with all three behavioral domains, a disjunction analysis identified three specific neural networks for each behavioral disorder, independent of dementia severity. Apathy was related to the ventral tegmental area, a component of the motivational dopaminergic network; disinhibition to both anterior temporal lobes including the anterior hippocampi and left amygdala, caudate head, orbitofrontal cortex and insulae; and eating disorders to the right lateral (orbito) frontal cortex/insula. Our study contributes to the understanding of behavioral deficits in early dementia and suggests specific diagnostic and therapeutic approaches.

NF-κB knockdown can modulate amphetamine-mediated feeding response

This study determined if transcription factor NF-κB is involved in the effect of amphetamine (AMPH)-mediated feeding response. Moreover, possible roles of hypothalamic neuropeptide Y (NPY) and proopiomelanocortin (POMC) were also investigated. AMPH was administered daily to rats for four days. Changes in NF-κB, NPY and POMC expression were assessed and compared. The NPY gene was down-regulated with maximal response on Day 2 during AMPH treatment, which was consistent with the response to feeding behavior. In contrast, NF-κB and POMC genes were up-regulated, and their expression was increased by about 200% and 450%, respectively, with maximal response on Day 2. Moreover, NF-κB DNA binding ability and expression were increased similar to that of POMC. To examine further if NF-κB was involved, intracerebroventricular infusion of NF-κB antisense oligonucleotide was performed 1 h before the daily AMPH dosing in freely moving rats. Results showed that NF-κB knockdown could modify AMPH anorexia as well as NPY and POMC expression. The present findings prove that cerebral NF-κB participates in AMPH-mediated appetite suppression, possibly by modulating NPY and POMC expression. These results may aid in therapeutic research on AMPH and AMPH-like anti-obesity drugs.

Knocking down the transcript of protein kinase C-lambda modulates hypothalamic glutathione peroxidase, melanocortin receptor and neuropeptide Y gene expression in amphetamine-treated rats

It has been reported that neuropeptide Y (NPY) contributes to the behavioral response of amphetamine (AMPH), a psychostimulant. The present study examined whether protein kinase C (PKC)-λ signaling was involved in this action. Moreover, possible roles of glutathione peroxidase (GP) and melanocortin receptor 4 (MC4R) were also examined. Rats were given AMPH daily for 4 days. Hypothalamic NPY, PKCλ, GP and MC4R were determined and compared. Pretreatment with α-methyl-para-tyrosine could block AMPH-induced anorexia, revealing that endogenous catecholamine was involved in regulating AMPH anorexia. PKCλ, GP and MC4R were increased with maximal response on Day 2 during AMPH treatment, which were concomitant with the decreases in NPY. cAMP response element binding protein (CREB) DNA binding activity was increased during AMPH treatment, revealing the involvement of CREB-dependent gene transcription. An interruption of cerebral PKCλ transcript could partly block AMPH-induced anorexia and partly reverse NPY, MC4R and GP mRNA levels to normal. These results suggest that PKCλ participates in regulating AMPH-induced anorexia via a modulation of hypothalamic NPY gene expression and that increases of GP and MC4R may contribute to this modulation. Our results provided molecular evidence for the regulation of AMPH-induced behavioral response.

Use of psychostimulants in patients with dementia

OBJECTIVE

To review the efficacy and safety of psychostimulants for negative behavioral symptoms (ie, apathy, excessive daytime sedation) and cognition in patients with dementia.

DATA SOURCES

Literature was accessed through PubMed and MEDLINE (1966-June 2010), using the terms stimulant, psychostimulant, methylphenidate, dexmethylphenidate, amphetamine, dextroamphetamine, lisdexamfetamine, atomoxetine, modafinil, armodafinil, dementia, Alzheimer disease, vascular dementia, Lewy body dementia, mixed dementia, frontotemporal dementia, therapy, treatment, and therapeutic. Additional references identified from the initial search were reviewed.

STUDY SELECTION AND DATA EXTRACTION

All relevant clinical trials published in English and involving primarily older adults with dementia were included. Case reports, review articles, and other preclinical literature were included as appropriate.

DATA SYNTHESIS

Psychostimulants have been employed as a treatment for cognitive and behavioral symptoms in dementia for decades, but the literature has lagged behind this practice. Eight reports on use of psychostimulants as a treatment of apathy in dementia were reviewed. Methylphenidate was the most frequently studied medication and improvements in apathy were consistently noted; however, the magnitude and duration of effect remain unclear. Six studies examining the cognitive effects of a variety of psychostimulants in patients with dementia were reviewed; psychostimulants had little to no effect on cognition. A lack of studies exists to draw conclusions about the use of psychostimulants for the treatment of excessive daytime sedation in dementia. The possibility of psychostimulants to increase blood pressure; elevate heart rate; and lead to irritability, agitation, and psychosis makes careful patient selection critical, especially in older adults with severe cardiovascular disease or other underlying cardiac abnormalities.

CONCLUSIONS

Based on limited studies, methylphenidate is a possible treatment for apathy in patients with dementia. Psychostimulants, as a group, do not appear to be broadly effective treatments for behavioral or cognitive symptoms of dementia. The potential utility of psychostimulants must be balanced with careful patient selection.

The role of dopamine in symptoms and treatment of apathy in Alzheimer's disease

BACKGROUND

Alzheimer's disease (AD) is characterized by a number of serious and debilitating behavioral and psychological symptoms of dementia (BPSD). The most common of these BPSD is apathy, which represents a major source of morbidity and premature institutionalization in the AD population. Many studies have identified discrete changes to the dopaminergic (DAergic) system in patients with AD. The DAergic system is closely related to the brain reward system (BRS) and some studies have suggested that dysfunction in the DAergic system may account for symptoms of apathy in the AD population.

METHOD

Changes to the dopamine (DA) system in AD will be reviewed, and evidence supporting the involvement of the DAergic system in the development of apathy will be examined. Additionally, some pharmacological interventions with DA activity have been identified. The utility of these treatments in the AD population will be reviewed, with a focus on apathy as an outcome.

RESULTS

Evidence presented in this review suggests that DA dysfunction in discrete brain areas is an important correlate of apathy in AD and that the DAergic system may be a rational target for pharmacological treatment of apathy.