Long-term donepezil treatment in 565 patients with Alzheimer's disease (AD2000): randomised double-blind trial

Exploring the Mechanisms and Therapeutic Approaches of Mitochondrial Dysfunction in Alzheimer's Disease: An Educational Literature Review

Alzheimer's disease (AD) presents a significant challenge to global health. It is characterized by progressive cognitive deterioration and increased rates of morbidity and mortality among older adults. Among the various pathophysiologies of AD, mitochondrial dysfunction, encompassing conditions such as increased reactive oxygen production, dysregulated calcium homeostasis, and impaired mitochondrial dynamics, plays a pivotal role. This review comprehensively investigates the mechanisms of mitochondrial dysfunction in AD, focusing on aspects such as glucose metabolism impairment, mitochondrial bioenergetics, calcium signaling, protein tau and amyloid-beta-associated synapse dysfunction, mitophagy, aging, inflammation, mitochondrial DNA, mitochondria-localized microRNAs, genetics, hormones, and the electron transport chain and Krebs cycle. While lecanemab is the only FDA-approved medication to treat AD, we explore various therapeutic modalities for mitigating mitochondrial dysfunction in AD, including antioxidant drugs, antidiabetic agents, acetylcholinesterase inhibitors (FDA-approved to manage symptoms), nutritional supplements, natural products, phenylpropanoids, vaccines, exercise, and other potential treatments.

Cortical acetylcholine response to deep brain stimulation of the basal forebrain in mice

Deep brain stimulation (DBS) using electrical stimulation of neuronal tissue in the basal forebrain to enhance release of the neurotransmitter acetylcholine is under consideration to improve executive function in patients with dementia. Although some small studies indicate a positive response in the clinical setting, the relationship between DBS and acetylcholine pharmacokinetics is incompletely understood. We examined the cortical acetylcholine response to different stimulation parameters of the basal forebrain. Two-photon in vivo imaging was combined with deep brain stimulation in C57BL/6J mice. Stimulating electrodes were implanted in the subpallidal basal forebrain, and the ipsilateral somatosensory cortex was imaged. Acetylcholine activity was determined using the GRABACh-3.0 acetylcholine receptor sensor, and blood vessels were visualized with Texas red. Experiments manipulating stimulation frequency demonstrated that integrated acetylcholine-induced fluorescence was insensitive to frequency with the same number of pulses, and that maximum peak levels were achieved with frequencies from 60 to 130 Hz. Altering pulse train length indicated that longer stimulation resulted in higher peaks and more activation with sublinear summation. The acetylcholinesterase inhibitor, donepezil, increased the peak response to 600 pulses of stimulation at 60 Hz, and the integrated response increased by 57% with the 2 mg/kg dose and 126% with the 4 mg/kg dose. Acetylcholine levels returned to baseline with a time constant of 14-18 s. Donepezil increases total acetylcholine receptor activation associated with DBS but does not change temporal kinetics. The long time constants observed in the cerebral cortex add to the evidence supporting volume and synaptic neurotransmission.NEW & NOTEWORTHY Peak acetylcholine responses to deep brain stimulation of the subpallidal basal forebrain increases with increased frequency and number of pulses. Long recovery periods in the 10s of seconds support "volume" versus "phasic" transmission of acetylcholine. Donepezil administration enhances the effect of stimulation on cortical acetylcholine release.

Antidepressant use and cognitive decline in patients with dementia: a national cohort study

BACKGROUND

Dementia is associated with psychiatric symptoms but the effects of antidepressants on cognitive function in dementia are understudied. We aimed to investigate the association between antidepressants and cognitive decline in patients with dementia, and the risk of severe dementia, fractures and death, depending on antidepressant class, drug, and dose.

METHODS

This is a national cohort study. Patients with dementia registered in the Swedish Registry for Cognitive/Dementia Disorders-SveDem from May 1, 2007, until October 16, 2018, with at least one follow-up after dementia diagnosis, and who were new users of antidepressants, were included. Antidepressant use as a time varying exposure defined during the 6 months leading up to dementia diagnosis or each subsequent follow-up. We used linear mixed models to examine the association between antidepressant use and cognitive trajectories assessed by Mini-Mental State Examination (MMSE) scores. We used Cox proportional hazards models to calculate the hazard ratios for severe dementia (MMSE score < 10), fracture, and death. We compared antidepressant classes and drugs, and analyzed dose-response.

RESULTS

We included 18740 patients (10 205 women [54.5%]; mean [SD] age, 78.2[7.4] years), of which 4271 (22.8%) received at least one prescription for an antidepressant. During follow-up, a total of 11912 prescriptions for antidepressants were issued, with selective serotonin reuptake inhibitors (SSRI) being the most common (64.8%). Antidepressant use was associated with faster cognitive decline (β (95% CI) = - 0.30(- 0.39, - 0.21) points/year), in particular sertraline (- 0.25(- 0.43, - 0.06) points/year), citalopram (- 0.41(- 0.55, - 0.27) points/year), escitalopram (- 0.76(- 1.09, - 0.44) points/year), and mirtazapine (- 0.19(- 0.34, - 0.04) points/year) compared with non-use. The association was stronger in patients with severe dementia (initial MMSE scores 0-9). Escitalopram showed a greater decline rate than sertraline. Compared with non-use, dose response of SSRIs on greater cognitive decline and higher risks of severe dementia, all-cause mortality, and fracture were observed.

CONCLUSIONS

In this cohort study, current antidepressant use was associated with faster cognitive decline; furthermore, higher dispensed doses of SSRIs were associated with higher risk for severe dementia, fractures, and all-cause mortality. These findings highlight the significance of careful and regular monitoring to assess the risks and benefits of different antidepressants use in patients with dementia.

Pivotal trial of low-intensity pulsed ultrasound therapy for early Alzheimer's disease: Rationale and design

Background

There are lines of evidence suggesting that cerebral microcirculatory dysfunction is involved in the pathogenesis of Alzheimer's disease (AD). We have developed a low-intensity pulsed ultrasound (LIPUS) therapy that upregulates endothelial NO synthase with therapeutic angiogenesis. We demonstrated that the LIPUS therapy ameliorates cognitive declines in mouse models of AD and tended to do so in patients with early AD (mild AD and mild cognitive impairment due to AD) in the pilot trial. Thus, the Japanese government has designated our LIPUS device as the first breakthrough medical device in Japan.

Objective

We are performing a pivotal clinical trial (LIPUS-AD) to finally address the efficacy and safety of our LIPUS therapy in patients with early AD in Japan.

Methods

LIPUS-AD is a randomized, double-blind, placebo-controlled trial, in which a total of 220 patients with early AD, who are positive for amyloid-β (Aβ) PET, will be randomized in a 1:1 fashion. The LIPUS therapy is performed for the whole brain for one hour 3 times a week as one session under the special conditions (32 cycles, 0.5 MHz, 0.25 W/cm2). It is performed for 6 sessions with 3-month intervals in the LIPUS group for 72 weeks, while the placebo group receives placebo therapy. Before and at 72 weeks of the trial, all subjects undergo brain Aβ PET and MRI and 9 cognitive functions tests. The primary efficacy endpoint is the changes in ADAS-J-cog-14 scores from baseline to 72 weeks.

Conclusions

LIPUS-AD addresses efficacy and safety of the LIPUS therapy in patients with early AD.Clinical Trial Gov. No.: NCT05983575.

Treatment of Alzheimer Disease

OBJECTIVE

Symptom-oriented treatment has been the mainstay of Alzheimer disease (AD) pharmacotherapy for decades. This article reviews the evidence basis for symptomatic treatments for AD and the emerging data on amyloid-lowering therapies with possible disease-slowing effects.

LATEST DEVELOPMENT

Amyloid-lowering monoclonal antibody therapies entered clinical use in 2021. In July 2023, lecanemab became the first of these to gain full US Food and Drug Administration (FDA) approval and limited Medicare payment coverage. Donanemab gained similar approval status in July 2024. The approved agents remove amyloid plaque from the brain and appear to slow clinical disease progression but can produce significant adverse events known as amyloid-related imaging abnormalities with cerebral edema or effusion and with cerebral hemorrhages. Extensive safety monitoring is therefore required, including scheduled MRI scans. Also in 2023, brexpiprazole became the first agent specifically approved by the FDA for agitation associated with AD. Suvorexant, an orexin receptor antagonist, previously was approved for the treatment of insomnia in people with mild and moderate AD.

ESSENTIAL POINTS

There is robust evidence for the use of acetylcholinesterase inhibitors for patients with mild, moderate, and severe dementia due to AD, including outcomes beyond changes in cognitive screening test scores. More limited studies support the use of memantine in moderate and severe stages. These agents have a primary effect of delaying decline in cognition and function and postponing the emergence of adverse behaviors. Pharmacotherapy for behavioral and psychological symptoms is less predictable, and most clinical trials have had negative results. Anti-amyloid therapies provide the first FDA-approved option to alter AD pathology, but an understanding of overall utility and value to patients remains in its infancy.

Discontinuation of Cholinesterase Inhibitors Following Initiation of Memantine and Admission to Long-Term Care Among Older Adults

Importance

Discontinuing cholinesterase inhibitors when initiating memantine in patients with dementia may be reasonable to reduce treatment burden, costs, and the risk of adverse drug events.

Objective

To assess the association of cholinesterase inhibitor discontinuation on long-term care institutionalization among older adults with dementia who initiate memantine.

Design, Setting, and Participants

This retrospective propensity score-matched cohort study used Medicare claims data from January 2014 to December 2019. Participants included fee-for-service Medicare beneficiaries with dementia. Data were analyzed from September 2021 to August 2024.

Exposures

Discontinuation vs continuation of cholinesterase inhibitor.

Main Outcomes and Measures

The primary outcome was 1-year long-term care institutionalization-free days. Secondary outcomes include all-cause death and adverse drug events over 1 year. We performed subgroup analyses based on age, sex, dementia type (Alzheimer disease vs other), frailty, and dementia severity (mild vs moderate or severe) based on claims-based algorithms. The primary outcome was analyzed using nonparametric restricted mean survival time analysis.

Results

Among 16 292 beneficiaries who initiated memantine, 1820 (11.2%) discontinued cholinesterase inhibitors. In the propensity score-matched cohort of 3612 beneficiaries, the mean (SD) age was 80.7 (6.7) years, 2261 (62.6%) were female, and 1989 (55.0%) had a diagnosis of Alzheimer disease. Over 1 year, long-term care institutionalization occurred in 51 of 1806 beneficiaries (2.8%) who discontinued cholinesterase inhibitors (3.4 per 100 person-years) and 62 of 1806 beneficiaries (3.4%) who continued (4.1 per 100 person-years). There was no statistically significant difference in the 1-year mean institutionalization-free days between discontinuation and continuation groups (360.6 [95% CI, 359.3 to 362.0] days vs 359.1 [95% CI, 357.5 to 360.6] days; mean difference, 1.5 [95% CI,-0.5 to 3.6] days). The mean difference in the long-term care institutionalization-free days did not differ by age category, sex, dementia type, frailty, or dementia stage. Individuals who discontinued had a lower rate of fall-related injury (0.9 vs 2.0 per 100 person-years; hazard ratio [HR], 0.47 [95% CI, 0.25 to 0.88]). There was no difference between the discontinuation and continuation groups in all-cause death (10.4 vs 11.6 per 100 person-years; HR, 0.89 [95% CI, 0.72 to 1.10]).

Conclusions and Relevance

In this study, discontinuing cholinesterase inhibitors upon memantine initiation was not associated with an increased risk of long-term care institutionalization but with a lower risk of fall-related injury among older adults with dementia. These findings offer valuable insights for clinicians aiming to reduce treatment burden in this population.

On the Therapeutic Use of Monoclonal Antibodies Against Amyloid Plaques in Older Adults with Down Syndrome: A Narrative Review and Perspective

Down syndrome (DS) is a genetic disorder caused by an extra copy of chromosome 21 (trisomy 21 or T21) and is associated with an increased risk of early-onset Alzheimer's disease (AD), also known as DS-associated AD (DSAD). Individuals with DS typically develop amyloid neuropathology in their late-thirties to early-forties and the mean age of onset of clinical dementia is approximately 55 years. Recent advances in AD clinical research have focused on monoclonal antibodies (mAbs) targeting amyloid-β (Aβ) plaques as a potential therapeutic approach. Therefore, there has been guarded enthusiasm about using anti-amyloid mAbs in the prevention/treatment of DSAD. This narrative review and perspective explores the current understanding of amyloid pathology in AD and DSAD, the rationale for using anti-amyloid mAbs in the treatment of DSAD, and the challenges and opportunities for research toward the application of this therapeutic strategy to older adults with DS.

Somatostatin: Linking Cognition and Alzheimer Disease to Therapeutic Targeting

Over 4 decades of research support the link between Alzheimer disease (AD) and somatostatin [somatotropin-releasing inhibitory factor (SRIF)]. SRIF and SRIF-expressing neurons play an essential role in brain function, modulating hippocampal activity and memory formation. Loss of SRIF and SRIF-expressing neurons in the brain rests at the center of a series of interdependent pathological events driven by amyloid-β peptide (Aβ), culminating in cognitive decline and dementia. The connection between the SRIF and AD further extends to the neuropsychiatric symptoms, seizure activity, and inflammation, whereas preclinical AD investigations show SRIF or SRIF receptor agonist administration capable of enhancing cognition. SRIF receptor subtype-4 activation in particular presents unique attributes, with the potential to mitigate learning and memory decline, reduce comorbid symptoms, and enhance enzymatic degradation of Aβ in the brain. Here, we review the links between SRIF and AD along with the therapeutic implications. SIGNIFICANCE STATEMENT: Somatostatin and somatostatin-expressing neurons in the brain are extensively involved in cognition. Loss of somatostatin and somatostatin-expressing neurons in Alzheimer disease rests at the center of a series of interdependent pathological events contributing to cognitive decline and dementia. Targeting somatostatin-mediated processes has significant therapeutic potential for the treatment of Alzheimer disease.

Effects of traditional Chinese medicine on outcomes and costs of dementia care: results from a retrospective real-world study

OBJECTIVES

This study aims to assess the impact of Traditional Chinese Medicine (TCM) on dementia patients, utilizing real-world data. Specifically, it seeks to evaluate how TCM influences clinical outcomes by examining changes in the Clinical Dementia Rating (CDR) and Mini-Mental State Examination (MMSE) scores, as well as its effect on medical expenses over a two-year period. Data from a multi-center research database spanning from 2004 to 2021 will be used to achieve these objectives, addressing the current gap in empirical data concerning intuitive outcomes and cognitive function assessments.

METHODS

Propensity score matching was adopted to improve comparability among the intervention and control groups. Due to repeated dependent variable measurements, the generalized estimating equation was used to control for socio-demographic characteristics, regional characteristics, and Western medicine treatments for dementia.

RESULTS

After propensity score matching, a total of 441 research subjects were included: 90 in the TCM intervention group and 351 in the non-TCM intervention group. The results of multivariate regression analysis showed that compared with the non-TCM intervention group, the MMSE scores in the TCM intervention group increased by 0.608 points each year. The annual change in CDR scores in the TCM intervention group was 0.702 times that of the non-TCM utilization group. After TCM intervention, annual outpatient expenses increased by US$492.2, hospitalization expenses increased by US$324.3, and total medical expenses increased by US$815.9, compared with the non-intervention group.

CONCLUSIONS

TCM interventions significantly decelerate cognitive decline in dementia patients, evidenced by slower reductions in MMSE scores and mitigated increases in CDR scores. However, these benefits are accompanied by increased medical expenses, particularly for outpatient care. Future healthcare strategies should balance the cognitive benefits of TCM with its economic impact, advocating for its inclusion in dementia care protocols.

A golden age of muscarinic acetylcholine receptor modulation in neurological diseases

Over the past 40 years, the muscarinic acetylcholine receptor family, particularly the M1-receptor and M4-receptor subtypes, have emerged as validated targets for the symptomatic treatment of neurological diseases such as schizophrenia and Alzheimer disease. However, despite considerable effort and investment, no drugs have yet gained clinical approval. This is largely attributable to cholinergic adverse effects that have halted the majority of programmes and resulted in a waning of interest in these G-protein-coupled receptor targets. Recently, this trend has been reversed. Driven by advances in structure-based drug design and an appreciation of the optimal pharmacological properties necessary to deliver clinical efficacy while minimizing adverse effects, a new generation of M1-receptor and M4-receptor orthosteric agonists and positive allosteric modulators are now entering the clinic. These agents offer the prospect of novel therapeutic solutions for 'hard to treat' neurological diseases, heralding a new era of muscarinic drug discovery.

Efficacy of Acetylcholinesterase Inhibitors in the Logopenic Variant of Primary Progressive Aphasia

INTRODUCTION

For over 25 years, cholinesterase inhibitors (ChEIs) have been the main symptomatic treatment for Alzheimer's disease (AD). Several meta-analyses have supported their effectiveness in various neurocognitive, functional, and behavioral aspects of amnestic AD. Over 86% of cases of the logopenic variant of primary progressive aphasia (lvPPA), also named language variant AD, are caused by a similar pathologic process than AD, yet no study has examined the efficacy of ChEIs in this AD variant. We aimed to explore the efficacy of ChEIs in the treatment of lvPPA by comparing their evolution on the MMSE, and other functional and behavioral parameters, to that of treated amnestic AD patients.

METHODS

A retrospective chart review was performed in 45 patients with lvPPA and 52 patients with amnestic AD. Both groups were similar in terms of age, level of education, and onset of symptoms. Drug history and MMSE scores, as well as functional (activities of daily living [ADLs] and instrumental activities of daily living [IADLs]), neurocognitive and neuropsychiatric symptoms were collected on several time points before and after the introduction of ChEIs. Data were analyzed using ANOVA and a generalized linear mixed model.

RESULTS

Patients with lvPPA showed a similar trajectory of decline than amnestic AD patients on serial MMSEs up to 12-24 months after the introduction of ChEIs. There was a significant impact on ADLs but not IADLs and neuropsychiatric symptoms remained stable over time.

CONCLUSION

This study provides preliminary evidence for efficacy of ChEIs in patients with lvPPA and suggests similar benefits to those seen in amnestic AD patients, hence reassuring patients and their physicians.

INTRODUCTION

For over 25 years, cholinesterase inhibitors (ChEIs) have been the main symptomatic treatment for Alzheimer's disease (AD). Several meta-analyses have supported their effectiveness in various neurocognitive, functional, and behavioral aspects of amnestic AD. Over 86% of cases of the logopenic variant of primary progressive aphasia (lvPPA), also named language variant AD, are caused by a similar pathologic process than AD, yet no study has examined the efficacy of ChEIs in this AD variant. We aimed to explore the efficacy of ChEIs in the treatment of lvPPA by comparing their evolution on the MMSE, and other functional and behavioral parameters, to that of treated amnestic AD patients.

METHODS

A retrospective chart review was performed in 45 patients with lvPPA and 52 patients with amnestic AD. Both groups were similar in terms of age, level of education, and onset of symptoms. Drug history and MMSE scores, as well as functional (activities of daily living [ADLs] and instrumental activities of daily living [IADLs]), neurocognitive and neuropsychiatric symptoms were collected on several time points before and after the introduction of ChEIs. Data were analyzed using ANOVA and a generalized linear mixed model.

RESULTS

Patients with lvPPA showed a similar trajectory of decline than amnestic AD patients on serial MMSEs up to 12-24 months after the introduction of ChEIs. There was a significant impact on ADLs but not IADLs and neuropsychiatric symptoms remained stable over time.

CONCLUSION

This study provides preliminary evidence for efficacy of ChEIs in patients with lvPPA and suggests similar benefits to those seen in amnestic AD patients, hence reassuring patients and their physicians.

Cortical Acetylcholine Response to Deep Brain Stimulation of the Basal Forebrain

Background

Deep brain stimulation (DBS), the direct electrical stimulation of neuronal tissue in the basal forebrain to enhance release of the neurotransmitter acetylcholine, is under consideration as a method to improve executive function in patients with dementia. While some small studies indicate a positive response in the clinical setting, the relationship between DBS and acetylcholine pharmacokinetics is incompletely understood.

Objective

We examined the cortical acetylcholine response to different stimulation parameters of the basal forebrain.

Methods

2-photon imaging was combined with deep brain stimulation. Stimulating electrodes were implanted in the subpallidal basal forebrain, and the ipsilateral somatosensory cortex was imaged. Acetylcholine activity was determined using the GRABACh-3.0 muscarinic acetylcholine receptor sensor, and blood vessels were imaged with Texas red.

Results

Experiments manipulating pulse train frequency demonstrated that integrated acetylcholine induced fluorescence was insensitive to frequency, and that peak levels were achieved with frequencies from 60 to 130 Hz. Altering pulse train length indicated that longer stimulation resulted in higher peaks and more activation with sublinear summation. The acetylcholinesterase inhibitor donepezil increased the peak response to 10s of stimulation at 60Hz, and the integrated response increased 57% with the 2 mg/kg dose, and 126% with the 4 mg/kg dose. Acetylcholine levels returned to baseline with a time constant of 14 to 18 seconds in all experiments.

Conclusions

These data demonstrate that acetylcholine receptor activation is insensitive to frequency between 60 and 130 Hz. High peak responses are achieved with up to 900 pulses. Donepezil increases total acetylcholine receptor activation associated with DBS but did not change temporal kinetics. The long time constants observed in the cerebral cortex add to the evidence supporting volume in addition to synaptic transmission.

Pongamol Alleviates Neuroinflammation and Promotes Autophagy in Alzheimer's Disease by Regulating the Akt/mTOR Signaling Pathway

Alzheimer's disease (AD), one of the neurodegenerative disorders, is highly correlated with the abnormal hyperphosphorylation of Tau and aggregation of β-amyloid (Aβ). Oxidative stress, neuroinflammation, and abnormal autophagy are key drivers of AD and how they contribute to neuropathology remains largely unknown. The flavonoid compound pongamol is reported to possess a variety of pharmacological activities, such as antioxidant, antibacterial, and anti-inflammatory. This study investigated the neuroprotective effect and its mechanisms of pongamol in lipopolysaccharide (LPS)-induced BV2 cells, d-galactose/sodium nitrite/aluminum chloride (d-gal/NaNO2/AlCl3)-induced AD mice, and Caenorhabditis elegans models. Our research revealed that pongamol reduced the release of inflammatory factors IL-1β, TNF-α, COX-2, and iNOS in LPS-induced BV2 cells. Pongamol also protected neurons and significantly restored memory function, inhibited Tau phosphorylation, downregulated Aβ aggregation, and increased oxidoreductase activity in the hippocampus of AD mice. In addition, pongamol reversed the nuclear transfer of NF-κB and increased the levels of Beclin 1 and LC3 II/LC3 I. Most importantly, the anti-inflammatory and promoter autophagy effects of pongamol may be related to the regulation of the Akt/mTOR signaling pathway. In summary, these results showed that pongamol has a potential neuroprotective effect, which greatly enriched the research on the pharmacological activity of pongamol for improving AD.

Aducanumab in Alzheimer's Disease: A Critical Update

Alzheimer's disease (AD) is a complex neurological disorder that results in cognitive decline. The incidence rates of AD have been increasing, particularly among individuals 60 years of age or older. In June 2021, the US FDA approved aducanumab, the first humanized monoclonal antibody, as a potential therapeutic option for AD. Clinical trials have shown this drug to effectively target the accumulation of Aβ (beta-amyloid) plaques in the brain, and its effectiveness is dependent on the dosage and duration of treatment. Additionally, aducanumab has been associated with improvements in cognitive function. Biogen, the pharmaceutical company responsible for developing and marketing aducanumab, has positioned it as a potential breakthrough for treating cerebral damage in AD. However, the drug has raised concerns due to its high cost, limitations, and potential side effects. AD is a progressive neurological condition that affects memory, cognitive function, and behaviour. It significantly impacts the quality of life of patients and caregivers and strains healthcare systems. Ongoing research focuses on developing disease-modifying therapies that can halt or slow down AD progression. The pathogenesis of AD involves various molecular cascades and signaling pathways. However, the formation of extracellular amyloid plaques is considered a critical mechanism driving the development and progression of the disease. Aducanumab, as a monoclonal antibody, has shown promising results in inhibiting amyloid plaque formation, which is the primary pathological feature of AD. This review explores the signaling pathways and molecular mechanisms through which aducanumab effectively prevents disease pathogenesis in AD.

Study on the Pharmacological Mechanism of Icariin for the Treatment of Alzheimer's Disease Based on Network Pharmacology and Molecular Docking Techniques

The purpose of this study is to explore the pharmacological mechanism of icariin (ICA) in the treatment of Alzheimer's disease (AD) based on network pharmacology and network molecular docking technology. In order to investigate the regulatory effect of ICA on the expression level of AD pathological phosphorylation regulatory proteins, this study further explored the possible molecular mechanism of ICA regulating AD autophagy through network pharmacology. Macromolecular docking network was verified by Autodock Vina 1.1.2 software. The main active ingredients of ICA, the physicochemical properties, and pharmacokinetic information of ICA were predicted using online databases and relevant information. The results showed that the targets of MAPK3, AKT1, HSP90AA1, ESR1, and HSP90AA1 were more critical in the treatment of AD. Autophagy, apoptosis, senescence factors, phosphatidylinositide 3-kinase/protein kinase B (P13K/AKT) signaling pathway, MAKP, mTOR, and other pathways were significantly associated with AD. Docking of ICA with HIF-1, BNIP3, PINK1, and Parkin pathway molecules showed that the key targets of the signaling pathway were more stably bound to ICA, which may provide a better pathway for ICA to regulate autophagy by providing a better pathway. ICA can improve AD, and its mechanism may be related to the P13K/AKT, MAKP, and mTOR signaling pathways, thereby regulating autophagy-related proteins.

Early start of anti-dementia medication is associated with lower health and social care costs in Alzheimer´s patients: a Finnish nationwide register study

OBJECTIVES

To evaluate the association between health and social care costs and early start of anti-dementia medication in a nationwide cohort of Finnish Alzheimer's disease (AD) patients.

METHODS

The cohort included 7454 Finnish AD patients who had their first AD diagnosis in 2012 and lived at home at the time of diagnosis. Data were collected retrospectively from the Finnish national health and social care registers. The primary outcome was 2-year cumulative direct costs after the incident AD diagnosis. The exploratory variable was early anti-dementia medication start (anti-dementia medication started within 3 months of the incident AD diagnosis). Sociodemographic variables, admission to 24-h care and care intensity level, as well as comorbidities were considered as adjusting variables.

RESULTS

Of all patients, 88.9% started AD medication within 3 months of diagnosis. The 2-year cumulative costs were €30,787 and €40,484 per patient for early and late starters, respectively. When adjusted for possible confounders, early start of anti-dementia medication was associated with 26.5% lower 2-year cumulative costs compared to late starters (relative cost 0.735; p < 0.001).

CONCLUSIONS

Early diagnosis and start of anti-dementia medication is important for managing the costs of increasing number of AD patients.

Potentially Inappropriate Medication Dispensing in Outpatients: Comparison of Different Measurement Approaches

Purpose of the Research

This paper aims at comparing different approaches to measure potentially inappropriate medication (PIM) with routinely collected data on prescriptions, patient age institutionalization status (ie in nursing home or in the community). A secondary objective is to measure the rate and prevalence of PIM dispensing and to identify problematic practices in Switzerland.

Material and Methods

The studied population includes about 90,000 insured over 17 years old from a Swiss health maintenance organization in 2019 and 2020. We computed and compared the number of PIM per patient for Beers criteria, Priscus list, Laroche, NORGEP and Prescrire approaches. We also created a composite indicator that accounts for the specificities of the Swiss context (adaptation to the Swiss drugs' market, recommendations in force related to sleeping pills, anxiolytics and NSAIDs). We also stratified the analysis per physician, including initiation and cessation of PIM prescription.

Results

Our comparison revealed similarities between the approaches, but also that each of them had specific gaps that provides further motivation for the development of a composite approach. PIM rate was particularly high for sleeping pills, anxiolytics, NSAIDs, even when analyses were limited to chronic use. Drugs with anticholinergic effect were also frequently prescribed. Based on our composite indicator, 27% of insured over 64 years old received at least one PIM in 2020, and 8% received more than one. Our analyses also reveal that for sleeping pills and anxiolytics, half of the volume (or prevalence?) occurs in the <65 population. We observed strong variations between physicians and a significant proportion of new users among patients with PIM.

Conclusion

Our results show that PIMs prescribing is very frequent in Switzerland and is driven mostly by a few drug categories. There is important physician variation in PIM prescribing that warrants the development of intervention targeted at high PIM-prescribers.

Psychiatric Adverse Events of Acetylcholinesterase Inhibitors in Alzheimer's Disease and Parkinson's Dementia: Systematic Review and Meta-Analysis

BACKGROUND

The acetylcholinesterase inhibitors (AChEIs) donepezil, galantamine, and rivastigmine are commonly used in the management of various forms of dementia.

OBJECTIVES

While these drugs are known to induce classic cholinergic adverse events such as diarrhea, their potential to cause psychiatric adverse events has yet to be thoroughly examined.

METHODS

We sought to determine the risk of psychiatric adverse events associated with the use of AChEIs through a systematic review and meta-analysis of double-blind randomized controlled trials involving patients with Alzheimer's dementia and Parkinson's dementia.

RESULTS

A total of 48 trials encompassing 22,845 patients were included in our analysis. Anorexia was the most commonly reported psychiatric adverse event, followed by agitation, insomnia, and depression. Individuals exposed to AChEIs had a greater risk of experiencing appetite disorders, insomnia, or depression compared with those who received placebo (anorexia: odds ratio [OR] 2.93, 95% confidence interval [CI] 2.29-3.75; p < 0.00001; decreased appetite: OR 1.93, 95% CI 1.33-2.82; p = 0.0006; insomnia: OR 1.55, 95% CI 1.25-1.93; p < 0.0001; and depression: OR 1.59, 95% CI 1.23-2.06, p = 0.0004). Appetite disorders were also more frequent with high-dose versus low-dose therapy. A subgroup analysis revealed that the risk of insomnia was higher for donepezil than for galantamine.

CONCLUSIONS

Our findings suggest that AChEI therapy may negatively impact psychological health, and careful monitoring of new psychiatric symptoms is warranted. Lowering the dose may resolve some psychiatric adverse events, as may switching to galantamine in the case of insomnia.

CLINICAL TRIAL REGISTRATION

The study was pre-registered on PROSPERO (CRD42021258376).

Evaluation of clinical benefits of treatments for Alzheimer's disease

The need for regulatory approval of new therapies for the treatment of Alzheimer's disease-a progressive neurodegenerative condition-has made the assessment of treatment efficacy an urgent priority for discussion and investigation in the field. In the first part of this Personal View, we summarise current views on what constitutes a clinically meaningful benefit from treatment for Alzheimer's disease, including the concept of a minimum treatment effect against which to compare trial outcomes and its limitations. Considering existing and divergent definitions of clinically meaningful change, we define this concept in the second part of the Personal View by proposing a new approach that consecutively considers whether a treatment benefit for Alzheimer's disease is noticeable, valuable, and worthwhile in the context of costs and risks. This approach could be a useful foundation from which the field can move forwards on this issue and address existing gaps in understanding.

Turning the Spotlight to Cholinergic Pharmacotherapy of the Human Language System

Even though language is essential in human communication, research on pharmacological therapies for language deficits in highly prevalent neurodegenerative and vascular brain diseases has received little attention. Emerging scientific evidence suggests that disruption of the cholinergic system may play an essential role in language deficits associated with Alzheimer's disease and vascular cognitive impairment, including post-stroke aphasia. Therefore, current models of cognitive processing are beginning to appraise the implications of the brain modulator acetylcholine in human language functions. Future work should be directed further to analyze the interplay between the cholinergic system and language, focusing on identifying brain regions receiving cholinergic innervation susceptible to modulation with pharmacotherapy to improve affected language domains. The evaluation of language deficits in pharmacological cholinergic trials for Alzheimer's disease and vascular cognitive impairment has thus far been limited to coarse-grained methods. More precise, fine-grained language testing is needed to refine patient selection for pharmacotherapy to detect subtle deficits in the initial phases of cognitive decline. Additionally, noninvasive biomarkers can help identify cholinergic depletion. However, despite the investigation of cholinergic treatment for language deficits in Alzheimer's disease and vascular cognitive impairment, data on its effectiveness are insufficient and controversial. In the case of post-stroke aphasia, cholinergic agents are showing promise, particularly when combined with speech-language therapy to promote trained-dependent neural plasticity. Future research should explore the potential benefits of cholinergic pharmacotherapy in language deficits and investigate optimal strategies for combining these agents with other therapeutic approaches.

Improving Visual Working Memory with Cholinergic Deep Brain Stimulation

Acetylcholine is a critical modulatory neurotransmitter for cognitive function. Cholinergic drugs improve cognitive performance and enhance neuronal activity in the sensory and association cortices. An alternative means of improving cognitive function is through the use of deep brain stimulation. Prior animal studies have demonstrated that stimulation of the nucleus basalis of Meynert through DBS improves cognitive performance on a visual working memory task to the same degree as cholinesterase inhibitors. Additionally, unlike current pharmacological treatments for neurocognitive disorders, DBS does not lose efficacy over time and adverse effects are rare. These findings suggest that DBS may be a promising alternative for treating cognitive impairments in neurodegenerative disorders such as Alzheimer's disease. Thus, further research and human trials should be considered to assess the potential of DBS as a therapeutic treatment for these disorders.

Review of Alzheimer's disease drugs and their relationship with neuron-glia interaction

Alzheimer's disease (AD) is the most common cause of dementia worldwide. Because Alzheimer's disease has no known treatment, sufferers and their caregivers must concentrate on symptom management. Astrocytes and microglia are now known to play distinct physiological roles in synaptic function, the blood-brain barrier, and neurovascular coupling. Consequently, the search for drugs that can slow the degenerative process in dementia sufferers continues because existing drugs are designed to alleviate the symptoms of Alzheimer's disease. Drugs that address pathological changes without interfering with the normal function of glia, such as eliminating amyloid-beta deposits, are prospective treatments for neuroinflammatory illnesses. Because neuron-astrocytes-microglia interactions are so complex, developing effective, preventive, and therapeutic medications for AD will necessitate novel methodologies and strategic targets. This review focused on existing medications used in treating AD amongst which include Donepezil, Choline Alphoscerate, Galantamine, Dextromethorphan, palmitoylethanolamide, citalopram, resveratrol, and solanezumab. This review summarizes the effects of these drugs on neurons, astrocytes, and microglia interactions based on their pharmacokinetic properties, mechanism of action, dosing, and clinical presentations.

The effects of herbal medicine (Jujadokseo-hwan) on quality of life in patients with mild cognitive impairment: Cost-effectiveness analysis alongside randomized controlled trial

Background

Mild cognitive impairment (MCI), the early stage of dementia, requires effective intervention for symptom management and improving patients' quality of life (QoL). Jujadokseo-hwan (JDH) is a Korean herbal medicine prescription used to improve MCI symptoms, such as memory deficit. This study evaluates the improvement in QoL through JDH. Alongside a clinical trial, it estimates the cost-effectiveness of JDH, compared to placebo, for MCI over 24 weeks.

Methods

Changes in QoL were measured using the EuroQol-5 Dimensions (EQ-5D) and Korean version QoL-Alzheimer's Disease (KQOL-AD). Direct medical and non-medical costs were surveyed and incremental cost-effectiveness ratios (ICER) per QALY for JDH were produced.

Results

In total, 64 patients were included in the economic evaluation (n = 35 in JDH, n = 29 in placebo). In the JDH group, EQ-5D and KQOL-AD improved by 0.020 (p = .318) and 3.40 (p = .011) over 24 weeks, respectively. In the placebo group, they increased by 0.001 (p=.920) and 1.07 (p=.130), respectively. The ICER was KRW 76,400,000 per QALY and KRW 108,000 per KQOL-AD for JDH, compared to the placebo group.

Conclusion

JDH is not considered a cost-effective treatment option compared with placebo; however, it positively affects QoL improvement in patients with MCI.

Treatment of Vascular and Neurodegenerative Forms of Cognitive Impairment and Dementias

Ideally, dementia care should be provided by a collaborative team. Eligible patients should be treated with the cognitive-enhancing medications, the cholinesterase inhibitors and memantine. For most of the common causes of dementia, there are no disease-modifying medications, with the exception that vascular dementia can be prevented by treating vascular risk factors to prevent stroke. There is hope that Alzheimer disease can be treated by using monoclonal antibodies that target amyloid beta, although more trials are needed. Holistic, patient-centered care can enhance quality and extend the time that the patient can live safely in the community.

Results and insights from a phase I clinical trial of Lomecel-B for Alzheimer's disease

HYPOTHESIS

We hypothesized that Lomecel-B, an allogeneic medicinal signaling cell (MSC) therapeutic candidate for Alzheimer's disease (AD), is safe and potentially disease-modifying via pleiotropic mechanisms of action.

KEY PREDICTIONS

We prospectively tested the predictions that Lomecel-B administration to mild AD patients is safe (primary endpoint) and would provide multiple exploratory indications of potential efficacy in clinical and biomarker domains (prespecified secondary/exploratory endpoints).

STRATEGY AND KEY RESULTS

Mild AD patient received a single infusion of low- or high-dose Lomecel-B, or placebo, in a double-blind, randomized, phase I trial. The primary safety endpoint was met. Fluid-based and imaging biomarkers indicated significant improvement in the Lomecel-B arms versus placebo. The low-dose Lomecel-B arm showed significant improvements versus placebo on neurocognitive and other assessments.

INTERPRETATION

Our results support the safety of Lomecel-B for AD, suggest clinical potential, and provide mechanistic insights. This early-stage study provides important exploratory information for larger efficacy-powered clinical trials.

Repetitive TMS applied to the precuneus stabilizes cognitive status in Alzheimer’s disease

This scientific commentary refers to ‘Precuneus magnetic stimulation for Alzheimer's disease: a randomized, sham-controlled trial’ by Koch et al. (https://doi.org/10.1093/brain/awac285).

M1 muscarinic receptor activation reduces the molecular pathology and slows the progression of prion-mediated neurodegenerative disease

Many dementias are propagated through the spread of "prion-like" misfolded proteins. This includes prion diseases themselves (such as Creutzfeldt-Jakob disease) and Alzheimer's disease (AD), for which no treatments are available to slow or stop progression. The M1 acetylcholine muscarinic receptor (M1 receptor) is abundant in the brain, and its activity promotes cognitive function in preclinical models and in patients with AD. Here, we investigated whether activation of the M1 receptor might slow the progression of neurodegeneration associated with prion-like misfolded protein in a mouse model of prion disease. Proteomic and transcriptomic analysis of the hippocampus revealed that this model had a molecular profile that was similar to that of human neurodegenerative diseases, including AD. Chronic enhancement of the activity of the M1 receptor with the positive allosteric modulator (PAM) VU0486846 reduced the abundance of prion-induced molecular markers of neuroinflammation and mitochondrial dysregulation in the hippocampus and normalized the abundance of those associated with neurotransmission, including synaptic and postsynaptic signaling components. PAM treatment of prion-infected mice prolonged survival and maintained cognitive function. Thus, allosteric activation of M1 receptors may reduce the severity of neurodegenerative diseases caused by the prion-like propagation of misfolded protein.

Informal dementia care: The carer's lived experience at the divides between policy and practice

Support for informal dementia care at a local community level is not working for most carers today. Carers looking after a person with dementia have long lamented the absence of an empowered named support and an effectively actioned care plan. Drawing on literary writing and social research, we argue in this article that these challenges have existed since dementia emerged as a major condition in the West during the 1980s. Based on this historical context, we ask: Why has this issue persisted over the last four decades? How have healthcare politics and policy initiatives responded to these requests? And what can we learn from this for the current, COVID-19 exacerbated crisis of care? This article focuses on the English context, to discuss these ongoing challenges in the light of a series of policy papers, and to ask what is hampering the implementation of such policy initiatives. In England, local authorities are responsible for dementia support. This article focuses on the situation in a county in the Midlands where one of us (AB) has been lobbying local government for over a decade. The discussion contextualises the lived experience of dementia care within the situation exacerbated by the COVID-19 pandemic, ensuing politics of crises and persistent emphasis on cure over care. We find that the absence on two points centrally challenges care: a joined-up approach between health and social care and adequate information on available care support services, accessible through an empowered named contact. To enhance the lived experience of dementia care, consistent provision of individual named support and professional care support, as and when required, should become essential to local implementation of the care policy.

The listed, delisted, and sustainability of therapeutic medicines for dementia patients: the study is specific to South Korea

The Dementia Management Act (DMA) came into effect on August 4, 2011, in South Korea. Diagnosis and medication were rapidly performed for dementia in a short time. We investigated the cardiac effects of increased drug prescription following DMA. We observed a correlation between Alzheimer’s disease (AD) and anti-AD drug (AAD) groups from 2010 to 2019 on the National Health Insurance System (NHIS) of South Korea. This study investigated the increase and decrease in deaths of AD patients with AAD. We analysed the mortality per 100,000 population with the R² Calculator. Moreover, we made the up or down datum line for the simple decision on the listed, delisted, and sustainable drug examined by a linear equation and R². We observed that life expectancy was diminished by AAD in Sorokdo National Hospital. In the NHIS, donepezil and rivastigmine increased the number of deaths decided on R² > 0.75. Memantine was sustainable. We could not decide on galantamine because it is one of the other groups. We made a straightforward decision-maker of delisted, listed, or sustainable criteria based on mortality and datum line.

Cost-effectiveness of pharmacological therapies for people with Alzheimer's disease and other dementias: a systematic review and meta-analysis

Objectives

This study aims to synthesize the empirical economic evidence of pharmaceutical therapies for people with dementia.

Study design

Systematic review and meta-analysis. Literature evaluating the costs and effects of drug therapies for dementia was indexed until December 2021. Quality of study was assessed using the Cochrane Risk of Bias Tool and Consensus on Health Economic Criteria list. Cost data were standardized to 2020 US dollars and analyzed from healthcare service and societal perspectives. Random-effects models were used to synthesize economic and clinical data, based on mean differences (MDs) and standardized MDs.

Results

Ten unique studies were identified from 11,771 records. Acetylcholinesterase inhibitors (AChEIs) and memantine improved dementia-related symptoms, alongside nonsignificant savings in societal cost (AChEIs: MD-2002 [− 4944 ~ 939]; memantine: MD-6322 [− 14355 ~ 1711]). Despite decreases in cost, antidepressants of mirtazapine and sertraline and second-generation antipsychotics were limited by their significant side effects on patients’ cognitive and activity functions. Subgroup analysis indicated that the impacts of AChEIs on cost were affected by different analytical perspectives, follow-up periods, and participant age.

Conclusions

AChEIs and memantine are cost-effective with improvements in dementia-related symptoms and trends of cost-savings. More empirical evidence with non-industrial sponsorships and rigorous design in different settings is warranted.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12962-022-00354-3.

Design, Synthesis, and Evaluation of Novel 2H-Benzo[b][1,4]thiazin-3(4H)-one Derivatives as New Acetylcholinesterase Inhibitors

Alzheimer’s disease (AD) is a slowly progressive neurodegenerative disease that causes dementia in people aged 65 and over. In the present study, a series of thiadiazole hybrid compounds with benzothiazine derivatives as acetylcholinesterase inhibitors were developed and evaluated for their biological activity. The AChE and BChE inhibition potentials of all compounds were evaluated by using the in vitro Ellman method. The biological evaluation showed that compounds 3i and 3j displayed significant inhibitory activity against AChE. Compounds 3i and 3j showed IC₅₀ values of 0.027 µM and 0.025 µM against AChE, respectively. The reference drug donepezil (IC₅₀ = 0.021 µM) also showed significant inhibition against AChE. Further docking simulation also revealed that these compounds (3i and 3j) interacted with the active site of the enzyme similarly to donepezil. The antioxidant study revealed that compounds 3i and 3j exhibited greater antioxidant effects. An in vitro blood–brain barrier permeability study showed that compounds 3i and 3j are promising compounds against AD. The cytotoxicity study of compounds 3i and 3j showed non-cytotoxic with an IC₅₀ value of 98.29 ± 3.98 µM and 159.68 ± 5.53 µM against NIH/3T3 cells, respectively.

Primary Palliative Care in Dementia

Primary palliative care is a fundamental aspect of high-quality care for patients with a serious illness such as dementia. The clinician caring for a patient and family suffering with dementia can provide primary palliative care in numerous ways. Perhaps the most important aspects are high quality communication while sharing a diagnosis, counseling the patient through progression of illness and prognostication, and referral to hospice when appropriate. COVID-19 presents additional risks of intensive care requirement and mortality which we must help patients and families navigate. Throughout all of these discussions, the astute clinician must monitor the patient's decision making capacity and balance respect for autonomy with protection against uninformed consent. Excellent primary palliative care also involves discussion of deprescribing medications of uncertain benefit such as long term use of cholinesterase inhibitors and memantine and being vigilant in the monitoring of pain with its relationship to behavioral disturbance in patients with dementia. Clinicians should follow a standardized approach to pain management in this vulnerable population. Caregiver burden is high for patients with dementia and comprehensive care should also address this burden and implement reduction strategies. When these aspects of care are particularly complex or initial managements strategies fall short, palliative care specialists can be an important additional resource not only for the patient and family, but for the care team struggling to guide the way through a disease with innumerable challenges.

Biased M1 muscarinic receptor mutant mice show accelerated progression of prion neurodegenerative disease

The M1 muscarinic acetylcholine receptor (M1-receptor) plays a crucial role in learning and memory and is a validated drug target for the treatment of Alzheimer’s disease (AD). Furthermore, M1-receptor ligands have been demonstrated to display disease-modifying effects in preclinical models of neurodegenerative disease. By employing a genetic mouse model expressing a G protein–biased M1-receptor in combination with a mouse model of terminal neurodegenerative disease, we demonstrate here that the M1-receptor exerts an inherent neuroprotective activity that is dependent on its phosphorylation status. Thus, in AD drug development programs, M1-receptor ligands that maintain the receptor phosphorylation status will be more likely to lead to beneficial neuroprotective outcomes.

There are currently no treatments that can slow the progression of neurodegenerative diseases, such as Alzheimer’s disease (AD). There is, however, a growing body of evidence that activation of the M1 muscarinic acetylcholine receptor (M1-receptor) can not only restore memory loss in AD patients but in preclinical animal models can also slow neurodegenerative disease progression. The generation of an effective medicine targeting the M1-receptor has however been severely hampered by associated cholinergic adverse responses. By using genetically engineered mouse models that express a G protein–biased M1-receptor, we recently established that M1-receptor mediated adverse responses can be minimized by ensuring activating ligands maintain receptor phosphorylation/arrestin-dependent signaling. Here, we use these same genetic models in concert with murine prion disease, a terminal neurodegenerative disease showing key hallmarks of AD, to establish that phosphorylation/arrestin-dependent signaling delivers neuroprotection that both extends normal animal behavior and prolongs the life span of prion-diseased mice. Our data point to an important neuroprotective property inherent to the M1-receptor and indicate that next generation M1-receptor ligands designed to drive receptor phosphorylation/arrestin-dependent signaling would potentially show low adverse responses while delivering neuroprotection that will slow disease progression.

[Non-cognitive psychopathological symptoms in mild cognitive impairment]

Noncognitive psychopathological symptoms (NPS) in elderly patients are increasingly attracting the attention of researchers in the field of neurodegenerative diseases. The question is raised whether these symptoms are risk factors or initial manifestations of the neurodegeneration process. This article provides information on the prevalence of late-onset NPS together with mild cognitive impairment (MCI), combination of which reflects the risk of developing dementia. The characteristic of mild behavioral impairment syndrome, which is currently used along with the concept of MCI, is given. The authors summarized data of the studies published over the past 10 years on the effect of NPS on the progression of cognitive impairment. Topics related to the differential diagnosis of these disorders, as well as existing approaches to treatment, are considered.

Impact of Donepezil and Memantine on Behavioral and Psychological Symptoms of Alzheimer Disease: Six-month Open-label Study

BACKGROUND

Behavioral and psychological symptoms of dementia (BPSD) are common in individuals with Alzheimer disease (AD). Donepezil and memantine are both widely used for the treatment of moderate AD.

OBJECTIVE

To evaluate the effects of donepezil and memantine in relieving BPSD in individuals with moderate AD.

METHOD

We conducted a prospective, randomized, 6-month clinical trial involving 85 individuals with moderate AD divided into two groups: group 1 (n = 42) was treated with donepezil; group 2 (n = 43) was treated with memantine. We used the Neuropsychiatric Inventory (NPI) to assess the prevalence and severity of BPSD at baseline and after 6 months of treatment with donepezil or memantine.

RESULTS

The two groups' baseline characteristics, including age, sex, mean length of education, and disease duration, were comparable, as were their baseline Mini-Mental State Examination scores. The NPI Total score improved from baseline to month 6 in both groups (P < 0.0001). Analyses of the NPI subdomains revealed that both donepezil treatment and memantine treatment produced statistically significant improvement in all of the NPI domains except euphoria and apathy, for which no improvement was observed after memantine treatment. Both treatments were well tolerated, with mostly mild and transient adverse effects.

CONCLUSION

Specific drugs for AD, including donepezil and memantine, may be effective in treating BPSD in individuals with moderate AD, with a favorable safety profile.

From structure to clinic: Design of a muscarinic M1 receptor agonist with potential to treatment of Alzheimer's disease

Current therapies for Alzheimer's disease seek to correct for defective cholinergic transmission by preventing the breakdown of acetylcholine through inhibition of acetylcholinesterase, these however have limited clinical efficacy. An alternative approach is to directly activate cholinergic receptors responsible for learning and memory. The M1-muscarinic acetylcholine (M1) receptor is the target of choice but has been hampered by adverse effects. Here we aimed to design the drug properties needed for a well-tolerated M1-agonist with the potential to alleviate cognitive loss by taking a stepwise translational approach from atomic structure, cell/tissue-based assays, evaluation in preclinical species, clinical safety testing, and finally establishing activity in memory centers in humans. Through this approach, we rationally designed the optimal properties, including selectivity and partial agonism, into HTL9936-a potential candidate for the treatment of memory loss in Alzheimer's disease. More broadly, this demonstrates a strategy for targeting difficult GPCR targets from structure to clinic.

Is Aducanumab for LMICs? Promises and Challenges

Aducanumab, a human monoclonal antibody, was approved in June of 2021 as the first disease-modifying treatment for Alzheimer's disease by the United States Food and Drug Administration (U.S. FDA). A substantial proportion of patients with Alzheimer's disease live in low- and middle-income countries (LMICs), and the debilitating effects of this disease exerts burdens on patients and caregivers in addition to the significant economic strains many nations bear. While the advantages of a disease-modifying therapy are clear in delaying the progression of disease to improve patient outcomes, aducanumab's approval by the U.S. FDA was met with controversy for a plethora of reasons. This paper will provide precursory insights into aducanumab's role, appropriateness, and cost-effectiveness in low- and middle-income countries. We extend some of the controversies associated with aducanumab, including the contradicting evidence from the two trials (EMERGE and ENGAGE) and the resources required to deliver the treatment safely and effectively to patients, among other key considerations.

Neuromodulation in the Treatment of Alzheimer's Disease: Current and Emerging Approaches

Neuromodulation as a treatment strategy for psychiatric and neurological diseases has grown in popularity in recent years, with the approval of repetitive transcranial magnetic stimulation (rTMS) for the treatment of depression being one such example. These approaches offer new hope in the treatment of diseases that have proven largely intractable to traditional pharmacological approaches. For this reason, neuromodulation is increasingly being explored for the treatment of Alzheimer's disease. However, such approaches have variable, and, in many cases, very limited evidence for safety and efficacy, with most human evidence obtained in small clinical trials. Here we review work in animal models and humans with Alzheimer's disease exploring emerging neuromodulation modalities. Approaches reviewed include deep brain stimulation, transcranial magnetic stimulation, transcranial electrical stimulation, ultrasound stimulation, photobiomodulation, and visual or auditory stimulation. In doing so, we clarify the current evidence for these approaches in treating Alzheimer's disease and identify specific areas where additional work is needed to facilitate their clinical translation.

Basal Forebrain Cholinergic Neurons: Linking Down Syndrome and Alzheimer's Disease

Down syndrome (DS, trisomy 21) is characterized by intellectual impairment at birth and Alzheimer's disease (AD) pathology in middle age. As individuals with DS age, their cognitive functions decline as they develop AD pathology. The susceptibility to degeneration of a subset of neurons, known as basal forebrain cholinergic neurons (BFCNs), in DS and AD is a critical link between cognitive impairment and neurodegeneration in both disorders. BFCNs are the primary source of cholinergic innervation to the cerebral cortex and hippocampus, as well as the amygdala. They play a critical role in the processing of information related to cognitive function and are directly engaged in regulating circuits of attention and memory throughout the lifespan. Given the importance of BFCNs in attention and memory, it is not surprising that these neurons contribute to dysfunctional neuronal circuitry in DS and are vulnerable in adults with DS and AD, where their degeneration leads to memory loss and disturbance in language. BFCNs are thus a relevant cell target for therapeutics for both DS and AD but, despite some success, efforts in this area have waned. There are gaps in our knowledge of BFCN vulnerability that preclude our ability to effectively design interventions. Here, we review the role of BFCN function and degeneration in AD and DS and identify under-studied aspects of BFCN biology. The current gaps in BFCN relevant imaging studies, therapeutics, and human models limit our insight into the mechanistic vulnerability of BFCNs in individuals with DS and AD.

Cholinesterase inhibitory activity of tinosporide and 8-hydroxytinosporide isolated from Tinospora cordifolia: In vitro and in silico studies targeting management of Alzheimer's disease

Tinosporide and 8-hydroxytinosporide isolated from Tinospora cordifolia were evaluated for acetylcholinesterase (AChE) and butylcholinesterase (BuChE) inhibitory activities. The structure of the compound was confirmed by spectroscopic analysis, whereas cholinesterase inhibition was investigated by Ellman method using donepezil as standard drug and the data were presented as IC50 (μg/ml ± SEM). Furthermore, donepezil, tinosporide and 8-hydroxytinosporide were executed for docking analysis. The results from the isolated compounds TC-16R confirmed as tinosporide promisingly inhibited AChE with IC50 value of 13.45 ± 0.144, whereas TC-19R confirmed as 8-hydroxytinosporide moderately inhibited AChE with IC50 value of 46.71 ± 0.511. In case of BuChE inhibition, the IC50 values were found to be 408.50 ± 17.197 and 317.26 ± 6.918 for tinosporide and 8-hydroxytinosporide, respectively. The in silico studies revealed that the ligand tinosporide fit with the binding sites and inhibited AChE. Overall, the study findings suggested that tinosporide would be a complementary noble molecule of donepezil which is correlated with its pharmacological activity through in vitro studies, while 8-hydroxytinosporide modestly inhibited BuChE and the results are very close to the standard donepezil.

Apamin Improves Prefrontal Nicotinic Impairment in Mouse Model of Alzheimer's Disease

Disruption of attention is an early and disabling symptom of Alzheimer's disease (AD). The underlying cellular mechanisms are poorly understood and treatment options for patients are limited. These early attention deficits are evident in the TgCRND8 mouse, a well-established murine model of AD that recapitulates several features of the disease. Here, we report severe impairment of the nicotinic receptor-mediated excitation of prefrontal attentional circuitry in TgCRND8 mice relative to wild-type littermate controls. We demonstrate that this impairment can be remedied by apamin, a bee venom neurotoxin peptide that acts as a selective antagonist to the SK family of calcium-sensitive potassium channels. We probe this seeming upregulation of calcium-sensitive inhibition and find that the attenuated nicotinic firing rates in TgCRND8 attention circuits are mediated neither by greater cellular calcium signals nor by elevated SK channel expression. Instead, we find that TgCRND8 mice show enhanced functional coupling of nicotinic calcium signals to inhibition. This SK-mediated inhibition exerts a powerful negative feedback on nicotinic excitation, dampening attention-relevant signaling in the TgCRND8 brain. These mechanistic findings identify a new cellular target involved in the modulation of attention and a novel therapeutic target for early attention deficits in AD.

Early Start of Anti-Dementia Medication Delays Transition to 24-Hour Care in Alzheimer's Disease Patients: A Finnish Nationwide Cohort Study

BACKGROUND

Dementia is one of the strongest predictors of admission to a 24-hour care facility among older people, and 24-hour care is the major cost of Alzheimer's disease (AD).

OBJECTIVE

The aim of this study was to evaluate the association of early start of anti-dementia medication and other predisposing factors with 2-year risk of transition to 24-hour care in the nationwide cohort of Finnish AD patients.

METHODS

This was a retrospective, non-interventional study based on individual-level data from Finnish national health and social care registers. The incident cohort included 7,454 AD patients (ICD-10, G30) comprised of two subgroups: those living unassisted at home (n = 5,002), and those receiving professional home care (n = 2,452). The primary outcome was admission to a 24-hour care facility. Exploratory variables were early versus late anti-dementia medication start, sociodemographic variables, care intensity level, and comorbidities.

RESULTS

Early anti-dementia medication reduced the risk of admission to 24-hour care both in patients living unassisted at home, with a hazard ratio (HR) of 0.58 (p < 0.001), and those receiving professional home care (HR, 0.84; p = 0.039). Being unmarried (HR, 1.69; p < 0.001), having an informal caregiver (HR, 1.69; p = 0.003), or having a diagnosis of additional neurological disorder (HR, 1.68; p = 0.006) or hip fracture (HR, 1.61; p = 0.004) were associated with higher risk of admission to 24-hour care in patients living unassisted at home.

CONCLUSION

To support living at home, early start of anti-dementia medication should be a high priority in newly diagnosed AD patients.

Mechanisms of Anticholinesterase Interference with Tau Aggregation Inhibitor Activity in a Tau-Transgenic Mouse Model

Background

Symptomatic treatments of Alzheimer’s Disease (AD) with cholinesterase inhibitors and/or memantine are relatively ineffective and there is a need for new treatments targeting the underlying pathology of AD. In most of the failed disease-modifying trials, patients have been allowed to continue taking symptomatic treatments at stable doses, under the assumption that they do not impair efficacy. In recently completed Phase 3 trials testing the tau aggregation inhibitor leuco-methylthioninium bis (hydromethane-sulfonate) (LMTM), we found significant differences in treatment response according to whether patients were taking LMTM either as monotherapy or as an add-on to symptomatic treatments.

Methods

We have examined the effect of either LMTM alone or chronic rivastigmine prior to LMTM treatment of tau transgenic mice expressing the short tau fragment that constitutes the tangle filaments of AD. We have measured acetylcholine levels, synaptosomal glutamate release, synaptic proteins, mitochondrial complex IV activity, tau pathology and Choline Acetyltransferase (ChAT) immunoreactivity.

Results

LMTM given alone increased hippocampal Acetylcholine (ACh) levels, glutamate release from synaptosomal preparations, synaptophysin levels in multiple brain regions and mitochondrial complex IV activity, reduced tau pathology, partially restored ChAT immunoreactivity in the basal forebrain and reversed deficits in spatial learning. Chronic pretreatment with rivastigmine was found to reduce or eliminate almost all these effects, apart from a reduction in tau aggregation pathology. LMTM effects on hippocampal ACh and synaptophysin levels were also reduced in wild-type mice.

Conclusion

The interference with the pharmacological activity of LMTM by a cholinesterase inhibitor can be reproduced in a tau transgenic mouse model and, to a lesser extent, in wild-type mice. Long-term pretreatment with a symptomatic drug alters a broad range of brain responses to LMTM across different transmitter systems and cellular compartments at multiple levels of brain function. There is, therefore, no single locus for the negative interaction. Rather, the chronic neuronal activation induced by reducing cholinesterase function produces compensatory homeostatic downregulation in multiple neuronal systems. This reduces a broad range of treatment responses to LMTM associated with a reduction in tau aggregation pathology. Since the interference is dictated by homeostatic responses to prior symptomatic treatment, it is likely that there would be similar interference with other drugs tested as add-on to the existing symptomatic treatment, regardless of the intended therapeutic target or mode of action. The present findings outline key results that now provide a working model to explain interference by symptomatic treatment.

Efficacy of preclinical pharmacological interventions against alterations of neuronal network oscillations in Alzheimer's disease: A systematic review

Despite the development of multiple pharmacological approaches over the years aimed at treating Alzheimer's Disease (AD) only very few have been approved for clinical use in patients. To date there still exists no disease-modifying treatment that could prevent or rescue the cognitive impairment, particularly of memory aquisition, that is characteristic of AD. One of the possibilities for this state of affairs might be that the majority of drug discovery efforts focuses on outcome measures of decreased neuropathological biomarkers characteristic of AD, without taking into acount neuronal processes essential to the generation and maintenance of memory processes. Particularly, the capacity of the brain to generate theta (θ) and gamma (γ) oscillatory activity has been strongly correlated to memory performance. Using a systematic review approach, we synthesize the existing evidence in the literature on pharmacological interventions that enhance neuronal theta (θ) and/or gamma (γ) oscillations in non-pathological animal models and in AD animal models. Additionally, we synthesize the main outcomes and neurochemical systems targeted. We propose that functional biomarkers such as cognition-relevant neuronal network oscillations should be used as outcome measures during the process of research and development of novel drugs against cognitive impairment in AD.

The effectiveness and cost-effectiveness of assistive technology and telecare for independent living in dementia: a randomised controlled trial

Objectives

The use of assistive technology and telecare (ATT) has been promoted to manage risks associated with independent living in people with dementia but with little evidence for effectiveness.

Methods

Participants were randomly assigned to receive an ATT assessment followed by installation of all appropriate ATT devices or limited control of appropriate ATT. The primary outcomes were time to institutionalisation and cost-effectiveness. Key secondary outcomes were number of incidents involving risks to safety, burden and stress in family caregivers and quality of life.

Results

Participants were assigned to receive full ATT (248 participants) or the limited control (247 participants). After adjusting for baseline imbalance of activities of daily living score, HR for median pre-institutionalisation survival was 0.84; 95% CI, 0.63 to 1.12; P = 0.20. There were no significant differences between arms in health and social care (mean -£909; 95% CI, -£5,336 to £3,345, P = 0.678) and societal costs (mean -£3,545; 95% CI, -£13,914 to £6,581, P = 0.499). ATT group members had reduced participant-rated quality-adjusted life years (QALYs) at 104 weeks (mean − 0.105; 95% CI, −0.204 to −0.007, P = 0.037) but did not differ in QALYs derived from proxy-reported EQ-5D.

Discussion

Fidelity of the intervention was low in terms of matching ATT assessment, recommendations and installation. This, however, reflects current practice within adult social care in England.

Conclusions

Time living independently outside a care home was not significantly longer in participants who received full ATT and ATT was not cost-effective. Participants with full ATT attained fewer QALYs based on participant-reported EQ-5D than controls at 104 weeks.

Long-term Effects of Cholinesterase Inhibitors on Cognitive Decline and Mortality

Objective

To investigate whether cholinesterase inhibitors (ChEIs) are associated with slower cognitive decline in Alzheimer dementia and decreased risk of severe dementia or death.

Methods

Patients with Alzheimer dementia from the Swedish Dementia Registry starting on ChEIs within 3 months of the dementia diagnosis were included and compared to nontreated patients with Alzheimer dementia. In a propensity score–matched cohort, the association between ChEI use and cognitive trajectories assessed by Mini-Mental State Examination (MMSE) scores was examined with a mixed model, and severe dementia (MMSE score <10) or death as an outcome was assessed with Cox proportional hazards models.

Results

The matched cohort included 11,652 ChEI users and 5,826 nonusers. During an average of 5 years of follow-up, 255 cases developed severe dementia, and 6,055 (35%) died. ChEI use was associated with higher MMSE score at each visit (0.13 MMSE points per year; 95% confidence interval [CI] 0.06–0.20). ChEI users had a 27% lower risk of death (0.73, 95% CI 0.69–0.77) compared with nonusers. Galantamine was associated with lower risk of death (0.71, 95% CI 0.65–0.76) and lower risk of severe dementia (0.69, 95% CI 0.47–1.00) and had the strongest effect on cognitive decline of all the ChEIs (0.18 MMSE points per year, 95% CI 0.07–0.28).

Conclusions

ChEIs are associated with cognitive benefits that are modest but persist over time and with reduced mortality risk, which could be explained partly by their cognitive effects. Galantamine was the only ChEI demonstrating a significant reduction in the risk of developing severe dementia.

Classification of Evidence

This study provides Class III evidence that for patients with Alzheimer dementia ChEIs decrease long-term cognitive decline and risk of death and that galantamine decreases the risk of severe dementia.

Assistive technology and telecare to maintain independent living at home for people with dementia: the ATTILA RCT

BACKGROUND

Assistive technology and telecare have been promoted to manage the risks associated with independent living for people with dementia, but there is limited evidence of their effectiveness.

OBJECTIVES

This trial aimed to establish whether or not assistive technology and telecare assessments and interventions extend the time that people with dementia can continue to live independently at home and whether or not they are cost-effective. Caregiver burden, the quality of life of caregivers and of people with dementia and whether or not assistive technology and telecare reduce safety risks were also investigated.

DESIGN

This was a pragmatic, randomised controlled trial. Blinding was not undertaken as it was not feasible to do so. All consenting participants were included in an intention-to-treat analysis.

SETTING

This trial was set in 12 councils in England with adult social services responsibilities.

PARTICIPANTS

Participants were people with dementia living in the community who had an identified need that might benefit from assistive technology and telecare.

INTERVENTIONS

Participants were randomly assigned to receive either assistive technology and telecare recommended by a health or social care professional to meet their assessed needs (a full assistive technology and telecare package) or a pendant alarm, non-monitored smoke and carbon monoxide detectors and a key safe (a basic assistive technology and telecare package).

MAIN OUTCOME MEASURES

The primary outcomes were time to admission to care and cost-effectiveness. Secondary outcomes assessed caregivers using the 10-item Center for Epidemiological Studies Depression Scale, the State-Trait Anxiety Inventory 6-item scale and the Zarit Burden Interview.

RESULTS

Of 495 participants, 248 were randomised to receive full assistive technology and telecare and 247 received the limited control. Comparing the assistive technology and telecare group with the control group, the hazard ratio for institutionalisation was 0.76 (95% confidence interval 0.58 to 1.01; p = 0.054). After adjusting for an imbalance in the baseline activities of daily living score between trial arms, the hazard ratio was 0.84 (95% confidence interval 0.63 to 1.12; p = 0.20). At 104 weeks, there were no significant differences between groups in health and social care resource use costs (intervention group - control group difference: mean -£909, 95% confidence interval -£5336 to £3345) or in societal costs (intervention group - control group difference: mean -£3545; 95% confidence interval -£13,914 to £6581). At 104 weeks, based on quality-adjusted life-years derived from the participant-rated EuroQol-5 Dimensions questionnaire, the intervention group had 0.105 (95% confidence interval -0.204 to -0.007) fewer quality-adjusted life-years than the control group. The number of quality-adjusted life-years derived from the proxy-rated EuroQol-5 Dimensions questionnaire did not differ between groups. Caregiver outcomes did not differ between groups over 24 weeks.

LIMITATIONS

Compliance with the assigned trial arm was variable, as was the quality of assistive technology and telecare needs assessments. Attrition from assessments led to data loss additional to that attributable to care home admission and censoring events.

CONCLUSIONS

A full package of assistive technology and telecare did not increase the length of time that participants with dementia remained in the community, and nor did it decrease caregiver burden, depression or anxiety, relative to a basic package of assistive technology and telecare. Use of the full assistive technology and telecare package did not increase participants' health and social care or societal costs. Quality-adjusted life-years based on participants' EuroQol-5 Dimensions questionnaire responses were reduced in the intervention group compared with the control group; groups did not differ in the number of quality-adjusted life-years based on the proxy-rated EuroQol-5 Dimensions questionnaire.

FUTURE WORK

Future work could examine whether or not improved assessment that is more personalised to an individual is beneficial.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN86537017.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 25, No. 19. See the NIHR Journals Library website for further project information.

Different Cognitive Profiles Are Associated with Progression Rate and Age at Death in Probable Alzheimer's Disease

BACKGROUND

Cognitive profiles characterized by primarily language or visuospatial deficits have been documented in individuals meeting diagnostic criteria for probable Alzheimer's disease (AD), but their association with progression rate or overall survival is not well described.

OBJECTIVE

To compare time from diagnosis to severe disease stage and death in probable AD patients classified into three groups based on neuropsychological test performance: marked verbal impairment (Verb-PI) with relatively preserved visuospatial function, marked visuospatial impairment with preserved verbal function (Vis-PI), and balanced verbal and visuospatial impairments (Bal-PI).

METHODS

This prospective cohort study included 540 probable AD patients attending an academic memory clinic who were enrolled from 1995-2013 and followed annually. Eligible individuals had a Mini-Mental State Exam (MMSE) score ≥10 at baseline, and at least one annual follow up visit. We used Cox proportional hazards modeling to analyze the association of cognitive profiles with time to decline in MMSE and CDR Global Score.

RESULTS

Sixty-one (11.3%) individuals had a Verb-PI profile, 86 (16%) had a Vis-PI profile, and 393 (72.8%) a Bal-PI profile. MMSE decline to <10 was faster in Verb-PI than Vis-PI (HR 2.004, 95%CI, 1.062-3.780; p = 0.032). Progression to CDR-GS = 3 was faster in Verb-PI individuals compared to Bal-PI (HR 1.604, 95%CI, 1.022-2.515; p = 0.040) or Vis-PI (HR 2.388, 95%CI, 1.330-4.288; p = 0.004) individuals. Baseline cognitive profile did not affect mortality.

CONCLUSION

A recognition of different AD profiles may help to personalize care by providing a better understanding of pathogenesis and expected progression.

Withdrawal or continuation of cholinesterase inhibitors or memantine or both, in people with dementia

BACKGROUND

Dementia is a progressive syndrome characterised by deterioration in memory, thinking and behaviour, and by impaired ability to perform daily activities. Two classes of drug - cholinesterase inhibitors (donepezil, galantamine and rivastigmine) and memantine - are widely licensed for dementia due to Alzheimer's disease, and rivastigmine is also licensed for Parkinson's disease dementia. These drugs are prescribed to alleviate symptoms and delay disease progression in these and sometimes in other forms of dementia. There are uncertainties about the benefits and adverse effects of these drugs in the long term and in severe dementia, about effects of withdrawal, and about the most appropriate time to discontinue treatment.

OBJECTIVES

To evaluate the effects of withdrawal or continuation of cholinesterase inhibitors or memantine, or both, in people with dementia on: cognitive, neuropsychiatric and functional outcomes, rates of institutionalisation, adverse events, dropout from trials, mortality, quality of life and carer-related outcomes.

SEARCH METHODS

We searched the Cochrane Dementia and Cognitive Improvement Group's Specialised Register up to 17 October 2020 using terms appropriate for the retrieval of studies of cholinesterase inhibitors or memantine. The Specialised Register contains records of clinical trials identified from monthly searches of a number of major healthcare databases, numerous trial registries and grey literature sources.

SELECTION CRITERIA

We included all randomised, controlled clinical trials (RCTs) which compared withdrawal of cholinesterase inhibitors or memantine, or both, with continuation of the same drug or drugs.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed citations and full-text articles for inclusion, extracted data from included trials and assessed risk of bias using the Cochrane risk of bias tool. Where trials were sufficiently similar, we pooled data for outcomes in the short term (up to 2 months after randomisation), medium term (3-11 months) and long term (12 months or more). We assessed the overall certainty of the evidence for each outcome using GRADE methods.

MAIN RESULTS

We included six trials investigating cholinesterase inhibitor withdrawal, and one trial investigating withdrawal of either donepezil or memantine. No trials assessed withdrawal of memantine only. Drugs were withdrawn abruptly in five trials and stepwise in two trials. All participants had dementia due to Alzheimer's disease, with severities ranging from mild to very severe, and were taking cholinesterase inhibitors without known adverse effects at baseline. The included trials randomised 759 participants to treatment groups relevant to this review. Study duration ranged from 6 weeks to 12 months. There were too few included studies to allow planned subgroup analyses. We considered some studies to be at unclear or high risk of selection, performance, detection, attrition or reporting bias. Compared to continuing cholinesterase inhibitors, discontinuing treatment may be associated with worse cognitive function in the short term (standardised mean difference (SMD) -0.42, 95% confidence interval (CI) -0.64 to -0.21; 4 studies; low certainty), but the effect in the medium term is very uncertain (SMD -0.40, 95% CI -0.87 to 0.07; 3 studies; very low certainty). In a sensitivity analysis omitting data from a study which only included participants who had shown a relatively poor prior response to donepezil, inconsistency was reduced and we found that cognitive function may be worse in the discontinuation group in the medium term (SMD -0.62; 95% CI -0.94 to -0.31). Data from one longer-term study suggest that discontinuing a cholinesterase inhibitor is probably associated with worse cognitive function at 12 months (mean difference (MD) -2.09 Standardised Mini-Mental State Examination (SMMSE) points, 95% CI -3.43 to -0.75; moderate certainty). Discontinuation may make little or no difference to functional status in the short term (SMD -0.25, 95% CI -0.54 to 0.04; 2 studies; low certainty), and its effect in the medium term is uncertain (SMD -0.38, 95% CI -0.74 to -0.01; 2 studies; very low certainty). After 12 months, discontinuing a cholinesterase inhibitor probably results in greater functional impairment than continuing treatment (MD -3.38 Bristol Activities of Daily Living Scale (BADLS) points, 95% CI -6.67 to -0.10; one study; moderate certainty). Discontinuation may be associated with a worsening of neuropsychiatric symptoms over the short term and medium term, although we cannot exclude a minimal effect (SMD - 0.48, 95% CI -0.82 to -0.13; 2 studies; low certainty; and SMD -0.27, 95% CI -0.47 to -0.08; 3 studies; low certainty, respectively). Data from one study suggest that discontinuing a cholinesterase inhibitor may result in little to no change in neuropsychiatric status at 12 months (MD -0.87 Neuropsychiatric Inventory (NPI) points; 95% CI -8.42 to 6.68; moderate certainty). We found no clear evidence of an effect of discontinuation on dropout due to lack of medication efficacy or deterioration in overall medical condition (odds ratio (OR) 1.53, 95% CI 0.84 to 2.76; 4 studies; low certainty), on number of adverse events (OR 0.85, 95% CI 0.57 to 1.27; 4 studies; low certainty) or serious adverse events (OR 0.80, 95% CI 0.46 to 1.39; 4 studies; low certainty), and on mortality (OR 0.75, 95% CI 0.36 to 1.55; 5 studies; low certainty). Institutionalisation was reported in one trial, but it was not possible to extract data for the groups relevant to this review.

AUTHORS' CONCLUSIONS

This review suggests that discontinuing cholinesterase inhibitors may result in worse cognitive, neuropsychiatric and functional status than continuing treatment, although this is supported by limited evidence, almost all of low or very low certainty. As all participants had dementia due to Alzheimer's disease, our findings are not transferable to other dementia types. We were unable to determine whether the effects of discontinuing cholinesterase inhibitors differed with baseline dementia severity. There is currently no evidence to guide decisions about discontinuing memantine. There is a need for further well-designed RCTs, across a range of dementia severities and settings. We are aware of two ongoing registered trials. In making decisions about discontinuing these drugs, clinicians should exercise caution, considering the evidence from existing trials along with other factors important to patients and their carers.