Response to rivastigmine or donepezil in Alzheimer's patients with symptoms suggestive of concomitant Lewy body pathology

An Examination of the Motives for Attributing and Interpreting Deception in People with Amnestic Mild Cognitive Impairment

The aim of the present study was to examine how a person with amnestic mild cognitive impairment perceives the phenomenon of deception. Amnestic mild cognitive impairment (aMCI) usually represents the prodromal phase of Alzheimer's disease (AD), with patients showing memory impairment but with normal activities of daily living. It was expected that aMCI patients would face difficulties in the attribution and interpretation of deceptive behavior due to deficits regarding their diagnosis. The main sample of the study consisted of 76 older adults who were patients of a daycare center diagnosed with aMCI. A sample of 55 highly educated young adults was also examined in the same experiment to qualitatively compare their performance with that of aMCI patients. Participants were assigned a scenario where a hypothetical partner (either a friend or a stranger) was engaged in a task in which the partner could lie to boost their earnings at the expense of the participant. The results showed that aMCI patients, even if they understood that something was going wrong, did not invest in interpretations of potential deception and tended to avoid searching for confirmative information related to the hypothetical lie of their partner compared to highly educated young adults. It seems that aMCI patients become somehow "innocent", and this is discussed in terms of cognitive impairment and/or socioemotional selectivity.

Drugs to Treat Neuroinflammation in Neurodegenerative Disorders

Neuroinflammation is associated with disorders of the nervous system, and it is induced in response to many factors, including pathogen infection, brain injury, toxic substances, and autoimmune diseases. Astrocytes and microglia have critical roles in neuroinflammation. Microglia are innate immune cells in the central nervous system (CNS), which are activated in reaction to neuroinflammation-inducing factors. Astrocytes can have pro- or anti-inflammatory responses, which depend on the type of stimuli presented by the inflamed milieu. Microglia respond and propagate peripheral inflammatory signals within the CNS that cause low-grade inflammation in the brain. The resulting alteration in neuronal activities leads to physiological and behavioral impairment. Consequently, activation, synthesis, and discharge of various pro-inflammatory cytokines and growth factors occur. These events lead to many neurodegenerative conditions, such as Alzheimer's disease, Parkinson's disease, and multiple sclerosis discussed in this study. After understanding neuroinflammation mechanisms and the involvement of neurotransmitters, this study covers various drugs used to treat and manage these neurodegenerative illnesses. The study can be helpful in discovering new drug molecules for treating neurodegenerative disorders.

Predictors of response to acetylcholinesterase inhibitors in dementia: A systematic review

Background

The mainstay of therapy for many neurodegenerative dementias still relies on acetylcholinesterase inhibitors (AChEI); however, there is debate on various aspects of such treatment. A huge body of literature exists on possible predictors of response, but a comprehensive review is lacking. Therefore, our aim is to perform a systematic review of the predictors of response to AChEI in neurodegenerative dementias, providing a categorization and interpretation of the results.

Methods

We conducted a systematic review of the literature up to December 31st, 2021, searching five different databases and registers, including studies on rivastigmine, donepezil, and galantamine, with clearly defined criteria for the diagnosis of dementia and the response to AChEI therapy. Records were identified through the string: predict * AND respon * AND (acetylcholinesterase inhibitors OR donepezil OR rivastigmine OR galantamine). The results were presented narratively.

Results

We identified 1,994 records in five different databases; after exclusion of duplicates, title and abstract screening, and full-text retrieval, 122 studies were finally included.

Discussion

The studies show high heterogeneity in duration, response definition, drug dosage, and diagnostic criteria. Response to AChEI seems associated with correlates of cholinergic deficit (hallucinations, fluctuating cognition, substantia innominate atrophy) and preserved cholinergic neurons (faster alpha on REM sleep EEG, increased anterior frontal and parietal lobe perfusion after donepezil); white matter hyperintensities in the cholinergic pathways have shown inconsistent results. The K-variant of butyrylcholinesterase may correlate with better response in late stages of disease, while the role of polymorphisms in other genes involved in the cholinergic system is controversial. Factors related to drug availability may influence response; in particular, low serum albumin (for donepezil), CYP2D6 variants associated with reduced enzymatic activity and higher drug doses are the most consistent predictors, while AChEI concentration influence on clinical outcomes is debatable. Other predictors of response include faster disease progression, lower serum cholesterol, preserved medial temporal lobes, apathy, absence of concomitant diseases, and absence of antipsychotics. Short-term response may predict subsequent cognitive response, while higher education might correlate with short-term good response (months), and long-term poor response (years). Age, gender, baseline cognitive and functional levels, and APOE relationship with treatment outcome is controversial.

Design and Synthesis of Novel Dual Cholinesterase Inhibitors: In Vitro Inhibition Studies Supported with Molecular Docking

The major cholinesterase enzymes, acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), are important in the therapy of Alzheimer's disease (AD) based on the cholinergic hypothesis. As a result, in recent years, the investigation of dual cholinesterase inhibition methods has become important among scientists. In this study, novel N-(4-chlorobenzyl)-3,4-dimethoxy-N-(m-substituted)benzamide derivatives were synthesized. Then, inhibitory properties of these derivatives were examined in human AChE and BuChE in vitro and possible interactions were determined by molecular docking studies. All benzamide derivatives were exhibited dual inhibitory character and high BBB permeability. The most effective inhibitor was found as N7 for both AChE and BuChE with IC₅₀ values of 1.57 and 2.85 μM, respectively. Besides the most potent inhibitor was predicted as N7 in terms of binding energies with -12.18 kcal/mol and -9.92 kcal/mol, respectively. The reason for these results is that bromine (N7) is the bulkiest molecule among the other substituted groups. These derivatives could be exploited to develop new medications for the treatment of central nervous system-related diseases as AD by acting as dual inhibitors of AChE and BChE.

Caring for patients with cognitive dysfunction, fluctuations and dementia caused by Parkinson's disease

Cognitive dysfunction is one of the most prevalent non-motor symptoms in patients with Parkinson's disease (PD). While it tends to worsen in the later stages of disease, it can occur at any time, with 15-20% of patients exhibiting cognitive deficits at diagnosis (Aarsland et al., 2010; Goldman and Sieg, 2020). The characteristic features of cognitive dysfunction include impairment in executive function, visuospatial abilities, and attention, which vary in severity from subtle impairment to overt dementia (Martinez-Horta and Kulisevsky, 2019). To complicate matters, cognitive dysfunction is prone to fluctuate in PD patients, impacting diagnosis and the ability to assess progression and decision-making capacity. The diagnosis of cognitive impairment or dementia has a huge impact on patient independence, quality of life, life expectancy and caregiver burden (Corallo et al., 2017; Lawson et al., 2016; Leroi et al., 2012). It is therefore essential that physicians caring for patients with PD provide education, screening and treatment for this aspect of the disease. In this chapter, we provide a practical guide for the assessment and management of various degrees of cognitive dysfunction in patients with PD by approaching the disease at different stages. We address risk factors for cognitive dysfunction, prevention strategies prior to making the diagnosis, available tools for screening. Lastly, we review aspects of care, management and considerations, including decision-making capacity, that occur after the patient has been diagnosed with cognitive dysfunction or dementia.

Neuropsychiatric aspects of Parkinson disease psychopharmacology: Insights from circuit dynamics

Parkinson disease (PD) is a neurodegenerative disorder with a complex pathophysiology characterized by the progressive loss of dopaminergic neurons within the substantia nigra. Persons with PD experience several motoric and neuropsychiatric symptoms. Neuropsychiatric features of PD include depression, anxiety, psychosis, impulse control disorders, and apathy. In this chapter, we will utilize the National Institutes of Mental Health Research Domain Criteria (RDoC) to frame and integrate observations from two prevailing disease constructions: neurotransmitter anomalies and circuit physiology. When there is available evidence, we posit how unified translational observations may have clinical relevance and postulate importance outside of PD. Finally, we review the limited evidence available for pharmacologic management of these symptoms.

Donepezil for dementia due to Alzheimer's disease

BACKGROUND

Alzheimer's disease is the most common cause of dementia in older people. One approach to symptomatic treatment of Alzheimer's disease is to enhance cholinergic neurotransmission in the brain by blocking the action of the enzyme responsible for the breakdown of the neurotransmitter acetylcholine. This can be done by a group of drugs known as cholinesterase inhibitors. Donepezil is a cholinesterase inhibitor.This review is an updated version of a review first published in 1998.

OBJECTIVES

To assess the clinical efficacy and safety of donepezil in people with mild, moderate or severe dementia due to Alzheimer's disease; to compare the efficacy and safety of different doses of donepezil; and to assess the effect of donepezil on healthcare resource use and costs.

SEARCH METHODS

We searched Cochrane Dementia and Cognitive Improvement's Specialized Register, MEDLINE, Embase, PsycINFO and a number of other sources on 20 May 2017 to ensure that the search was as comprehensive and up-to-date as possible. In addition, we contacted members of the Donepezil Study Group and Eisai Inc.

SELECTION CRITERIA

We included all double-blind, randomised controlled trials in which treatment with donepezil was administered to people with mild, moderate or severe dementia due to Alzheimer's disease for 12 weeks or more and its effects compared with those of placebo in a parallel group of patients, or where two different doses of donepezil were compared.

DATA COLLECTION AND ANALYSIS

One reviewer (JSB) extracted data on cognitive function, activities of daily living, behavioural symptoms, global clinical state, quality of life, adverse events, deaths and healthcare resource costs. Where appropriate and possible, we estimated pooled treatment effects. We used GRADE methods to assess the quality of the evidence for each outcome.

MAIN RESULTS

Thirty studies involving 8257 participants met the inclusion criteria of the review, of which 28 studies reported results in sufficient detail for the meta-analyses. Most studies were of six months' duration or less. Only one small trial lasted 52 weeks. The studies tested mainly donepezil capsules at a dose of 5 mg/day or 10 mg/day. Two studies tested a slow-release oral formulation that delivered 23 mg/day. Participants in 21 studies had mild to moderate disease, in five studies moderate to severe, and in four severe disease. Seventeen studies were industry funded or sponsored, four studies were funded independently of industry and for nine studies there was no information on source of funding.Our main analysis compared the safety and efficacy of donepezil 10 mg/day with placebo at 24 to 26 weeks of treatment. Thirteen studies contributed data from 3396 participants to this analysis. Eleven of these studies were multicentre studies. Seven studies recruited patients with mild to moderate Alzheimer's disease, two with moderate to severe, and four with severe Alzheimer's disease, with a mean age of about 75 years. Almost all evidence was of moderate quality, downgraded due to study limitations.After 26 weeks of treatment, donepezil compared with placebo was associated with better outcomes for cognitive function measured with the Alzheimer's Disease Assessment Scale-Cognitive (ADAS-Cog, range 0 to 70) (mean difference (MD) -2.67, 95% confidence interval (CI) -3.31 to -2.02, 1130 participants, 5 studies), the Mini-Mental State Examination (MMSE) score (MD 1.05, 95% CI 0.73 to 1.37, 1757 participants, 7 studies) and the Severe Impairment Battery (SIB, range 0 to 100) (MD 5.92, 95% CI 4.53 to 7.31, 1348 participants, 5 studies). Donepezil was also associated with better function measured with the Alzheimer's Disease Cooperative Study activities of daily living score for severe Alzheimer's disease (ADCS-ADL-sev) (MD 1.03, 95% CI 0.21 to 1.85, 733 participants, 3 studies). A higher proportion of participants treated with donepezil experienced improvement on the clinician-rated global impression of change scale (odds ratio (OR) 1.92, 95% CI 1.54 to 2.39, 1674 participants, 6 studies). There was no difference between donepezil and placebo for behavioural symptoms measured by the Neuropsychiatric Inventory (NPI) (MD -1.62, 95% CI -3.43 to 0.19, 1035 participants, 4 studies) or by the Behavioural Pathology in Alzheimer's Disease (BEHAVE-AD) scale (MD 0.4, 95% CI -1.28 to 2.08, 194 participants, 1 study). There was also no difference between donepezil and placebo for Quality of Life (QoL) (MD -2.79, 95% CI -8.15 to 2.56, 815 participants, 2 studies).Participants receiving donepezil were more likely to withdraw from the studies before the end of treatment (24% versus 20%, OR 1.25, 95% CI 1.05 to 1.50, 2846 participants, 12 studies) or to experience an adverse event during the studies (72% vs 65%, OR 1.59, 95% 1.31 to 1.95, 2500 participants, 10 studies).There was no evidence of a difference between donepezil and placebo for patient total healthcare resource utilisation.Three studies compared donepezil 10 mg/day to donepezil 5 mg/day over 26 weeks. The 5 mg dose was associated with slightly worse cognitive function on the ADAS-Cog, but not on the MMSE or SIB, with slightly better QoL and with fewer adverse events and withdrawals from treatment. Two studies compared donepezil 10 mg/day to donepezil 23 mg/day. There were no differences on efficacy outcomes, but fewer participants on 10 mg/day experienced adverse events or withdrew from treatment.

AUTHORS' CONCLUSIONS

There is moderate-quality evidence that people with mild, moderate or severe dementia due to Alzheimer's disease treated for periods of 12 or 24 weeks with donepezil experience small benefits in cognitive function, activities of daily living and clinician-rated global clinical state. There is some evidence that use of donepezil is neither more nor less expensive compared with placebo when assessing total healthcare resource costs. Benefits on 23 mg/day were no greater than on 10 mg/day, and benefits on the 10 mg/day dose were marginally larger than on the 5 mg/day dose, but the rates of withdrawal and of adverse events before end of treatment were higher the higher the dose.

Cholinesterase Inhibitory Activities of Adamantyl-Based Derivatives and Their Molecular Docking Studies

Adamantyl-based compounds are clinically important for the treatments of type 2 diabetes and for their antiviral abilities, while many more are under development for other pharmaceutical uses. This study focused on the acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitory activities of adamantyl-based ester derivatives with various substituents on the phenyl ring using Ellman's colorimetric method. Compound 2e with a 2,4-dichloro electron-withdrawing substituent on the phenyl ring exhibited the strongest inhibition effect against AChE, with an IC₅₀ value of 77.15 µM. Overall, the adamantyl-based ester with the mono-substituent at position 3 of the phenyl ring exhibited good AChE inhibition effects with an ascending order for the substituents: Cl < NO₂ < CH₃ < OCH₃. Furthermore, compounds with electron-withdrawing groups (Cl and NO₂) substituted at position 3 on their phenyl rings demonstrated stronger AChE inhibition effects, in comparison to their respective positional isomers. On the other hand, compound 2j with a 3-methoxyphenyl ring showed the highest inhibition effect against BChE, with an IC₅₀ value of 223.30 µM. Molecular docking analyses were conducted for potential AChE and BChE inhibitors, and the results demonstrated that the peripheral anionic sites of target proteins were predominant binding sites for these compounds through hydrogen bonds and halogen interactions instead of hydrophobic interactions in the catalytic active site.

Multi-Target Directed Donepezil-Like Ligands for Alzheimer's Disease

HIGHLIGHTS ASS234 is a MTDL compound containing a moiety from Donepezil and the propargyl group from the PF 9601N, a potent and selective MAO B inhibitor. This compound is the most advanced anti-Alzheimer agent for preclinical studies identified in our laboratory.Derived from ASS234 both multipotent donepezil-indolyl (MTDL-1) and donepezil-pyridyl hybrids (MTDL-2) were designed and evaluated as inhibitors of AChE/BuChE and both MAO isoforms. MTDL-2 showed more high affinity toward the four enzymes than MTDL-1.MTDL-3 and MTDL-4, were designed containing the N-benzylpiperidinium moiety from Donepezil, a metal- chelating 8-hydroxyquinoline group and linked to a N-propargyl core and they were pharmacologically evaluated.The presence of the cyano group in MTDL-3, enhanced binding to AChE, BuChE and MAO A. It showed antioxidant behavior and it was able to strongly complex Cu(II), Zn(II) and Fe(III).MTDL-4 showed higher affinity toward AChE, BuChE.MTDL-3 exhibited good brain penetration capacity (ADMET) and less toxicity than Donepezil. Memory deficits in scopolamine-lesioned animals were restored by MTDL-3.MTDL-3 particularly emerged as a ligand showing remarkable potential benefits for its use in AD therapy. Alzheimer's disease (AD), the most common form of adult onset dementia, is an age-related neurodegenerative disorder characterized by progressive memory loss, decline in language skills, and other cognitive impairments. Although its etiology is not completely known, several factors including deficits of acetylcholine, β-amyloid deposits, τ-protein phosphorylation, oxidative stress, and neuroinflammation are considered to play significant roles in the pathophysiology of this disease. For a long time, AD patients have been treated with acetylcholinesterase inhibitors such as donepezil (Aricept®) but with limited therapeutic success. This might be due to the complex multifactorial nature of AD, a fact that has prompted the design of new Multi-Target-Directed Ligands (MTDL) based on the "one molecule, multiple targets" paradigm. Thus, in this context, different series of novel multifunctional molecules with antioxidant, anti-amyloid, anti-inflammatory, and metal-chelating properties able to interact with multiple enzymes of therapeutic interest in AD pathology including acetylcholinesterase, butyrylcholinesterase, and monoamine oxidases A and B have been designed and assessed biologically. This review describes the multiple targets, the design rationale and an in-house MTDL library, bearing the N-benzylpiperidine motif present in donepezil, linked to different heterocyclic ring systems (indole, pyridine, or 8-hydroxyquinoline) with special emphasis on compound ASS234, an N-propargylindole derivative. The description of the in vitro biological properties of the compounds and discussion of the corresponding structure-activity-relationships allows us to highlight new issues for the identification of more efficient MTDL for use in AD therapy.

Rivastigmine: Dementia with Lewy Bodies

This Hospital Pharmacy feature is extracted from Off-Label Drug Facts, a publication available from Wolters Kluwer Health. Off-Label Drug Facts is a practitioner-oriented resource for information about specific drug uses that are unapproved by the US Food and Drug Administration. This new guide to the literature enables the health care professional or clinician to quickly identify published studies on off-label uses and determine if a specific use is rational in a patient care scenario. References direct the reader to the full literature for more comprehensive information before patient care decisions are made. Direct questions or comments regarding Off-Label Drug Uses to jgeneral@ku.edu .

Dementia With Lew Body: Impacts of Surgery

Patients who have dementia with Lewy bodies (DLB) and undergo surgery may develop aggravated postoperative cognitive dysfunction or postoperative delirium. Many patients with DLB respond poorly to surgery and anesthesia, and their conditions may worsen if they have other medical complications along with dementia. They may also face high risk of prolonged hospital stay, increased medical problems and/or mortality, causing significant physical, psychosocial, and financial burdens on individuals, family members, and society. Anesthesia, pain medications, old age, and surgery-related stresses are usually held responsible for the complications; however, the exact causes are still not fully understood. Literature on surgery-related complications for patients with DLB appears to be inadequate, and hence the topic merits detailed and systematic research. This article reviews postoperative complications and various surgery-related risk factors for DLB in light of other dementias such as Alzheimer's disease, as their neuropathologic features overlap with those of DLB.

Rivastigmine for Alzheimer's disease

BACKGROUND

Alzheimer's disease is the commonest cause of dementia affecting older people. One of the therapeutic strategies aimed at ameliorating the clinical manifestations of Alzheimer's disease is to enhance cholinergic neurotransmission in the brain by the use of cholinesterase inhibitors to delay the breakdown of acetylcholine released into synaptic clefts. Tacrine, the first of the cholinesterase inhibitors to undergo extensive trials for this purpose, was associated with significant adverse effects including hepatotoxicity. Other cholinesterase inhibitors, including rivastigmine, with superior properties in terms of specificity of action and lower risk of adverse effects have since been introduced. Rivastigmine has received approval for use in 60 countries including all member states of the European Union and the USA.

OBJECTIVES

To determine the clinical efficacy and safety of rivastigmine for patients with dementia of Alzheimer's type.

SEARCH METHODS

We searched ALOIS, the Cochrane Dementia and Cognitive Improvement Group Specialized Register, on 2 March 2015 using the terms: Rivastigmine OR  exelon OR ENA OR "SDZ ENA 713". ALOIS contains records of clinical trials identified from monthly searches of a number of major healthcare databases (Cochrane Library, MEDLINE, EMBASE, PsycINFO, CINAHL, LILACS), numerous trial registries and grey literature sources.

SELECTION CRITERIA

We included all unconfounded, double-blind, randomised, controlled trials in which treatment with rivastigmine was administered to patients with dementia of the Alzheimer's type for 12 weeks or more and its effects compared with those of placebo in a parallel group of patients, or where two formulations of rivastigmine were compared.

DATA COLLECTION AND ANALYSIS

One review author (JSB) applied the study selection criteria, assessed the quality of studies and extracted data.

MAIN RESULTS

A total of 13 trials met the inclusion criteria of the review. The trials had a duration of between 12 and 52 weeks. The older trials tested a capsule form with a dose of up to 12 mg/day. Trials reported since 2007 have tested continuous dose transdermal patch formulations delivering 4.6, 9.5 and 17.7 mg/day.Our main analysis compared the safety and efficacy of rivastigmine 6 to 12 mg/day orally or 9.5 mg/day transdermally with placebo.Seven trials contributed data from 3450 patients to this analysis. Data from another two studies were not included because of a lack of information and methodological concerns. All the included trials were multicentre trials and recruited patients with mild to moderate Alzheimer's disease with a mean age of about 75 years. All had low risk of bias for randomisation and allocation but the risk of bias due to attrition was unclear in four studies, low in one study and high in two studies.After 26 weeks of treatment rivastigmine compared to placebo was associated with better outcomes for cognitive function measured with the Alzheimer's Disease Assessment Scale-Cognitive (ADAS-Cog) score (mean difference (MD) -1.79; 95% confidence interval (CI) -2.21 to -1.37, n = 3232, 6 studies) and the Mini-Mental State Examination (MMSE) score (MD 0.74; 95% CI 0.52 to 0.97, n = 3205, 6 studies), activities of daily living (SMD 0.20; 95% CI 0.13 to 0.27, n = 3230, 6 studies) and clinician rated global impression of changes, with a smaller proportion of patients treated with rivastigmine experiencing no change or a deterioration (OR 0.68; 95% CI 0.58 to 0.80, n = 3338, 7 studies).Three studies reported behavioural change, and there were no differences compared to placebo (standardised mean difference (SMD) -0.04; 95% CI -0.14 to 0.06, n = 1529, 3 studies). Only one study measured the impact on caregivers using the Neuropsychiatric Inventory-Caregiver Distress (NPI-D) scale and this found no difference between the groups (MD 0.10; 95% CI -0.91 to 1.11, n = 529, 1 study). Overall, participants who received rivastigmine were about twice as likely to withdraw from the trials (odds ratio (OR) 2.01, 95% CI 1.71 to 2.37, n = 3569, 7 studies) or to experience an adverse event during the trials (OR 2.16, 95% CI 1.82 to 2.57, n = 3587, 7 studies).

AUTHORS' CONCLUSIONS

Rivastigmine (6 to 12 mg daily orally or 9.5 mg daily transdermally) appears to be beneficial for people with mild to moderate Alzheimer's disease. In comparisons with placebo, better outcomes were observed for rate of decline of cognitive function and activities of daily living, although the effects were small and of uncertain clinical importance. There was also a benefit from rivastigmine on the outcome of clinician's global assessment. There were no differences between the rivastigmine group and placebo group in behavioural change or impact on carers. At these doses the transdermal patch may have fewer side effects than the capsules but has comparable efficacy. The quality of evidence is only moderate for all of the outcomes reviewed because of a risk of bias due to dropouts. All the studies with usable data were industry funded or sponsored. This review has not examined economic data.

Rivastigmine for Alzheimer's disease

BACKGROUND

Alzheimer's disease is the commonest cause of dementia affecting older people. One of the therapeutic strategies aimed at ameliorating the clinical manifestations of Alzheimer's disease is to enhance cholinergic neurotransmission in the brain by the use of cholinesterase inhibitors to delay the breakdown of acetylcholine released into synaptic clefts. Tacrine, the first of the cholinesterase inhibitors to undergo extensive trials for this purpose, was associated with significant adverse effects including hepatotoxicity. Other cholinesterase inhibitors, including rivastigmine, with superior properties in terms of specificity of action and lower risk of adverse effects have since been introduced. Rivastigmine has received approval for use in 60 countries including all member states of the European Union and the USA.

OBJECTIVES

To determine the clinical efficacy and safety of rivastigmine for patients with dementia of Alzheimer's type.

SEARCH METHODS

We searched ALOIS, the Cochrane Dementia and Cognitive Improvement Group Specialized Register, on 2 March 2015 using the terms: Rivastigmine OR  exelon OR ENA OR "SDZ ENA 713". ALOIS contains records of clinical trials identified from monthly searches of a number of major healthcare databases (Cochrane Library, MEDLINE, EMBASE, PsycINFO, CINAHL, LILACS), numerous trial registries and grey literature sources.

SELECTION CRITERIA

We included all unconfounded, double-blind, randomised, controlled trials in which treatment with rivastigmine was administered to patients with dementia of the Alzheimer's type for 12 weeks or more and its effects compared with those of placebo in a parallel group of patients, or where two formulations of rivastigmine were compared.

DATA COLLECTION AND ANALYSIS

One review author (JSB) applied the study selection criteria, assessed the quality of studies and extracted data.

MAIN RESULTS

A total of 13 trials met the inclusion criteria of the review. The trials had a duration of between 12 and 52 weeks. The older trials tested a capsule form with a dose of up to 12 mg/day. Trials reported since 2007 have tested continuous dose transdermal patch formulations delivering 4.6, 9.5 and 17.7 mg/day.Our main analysis compared the safety and efficacy of rivastigmine 6 to 12 mg/day orally or 9.5 mg/day transdermally with placebo.Seven trials contributed data from 3450 patients to this analysis. Data from another two studies were not included because of a lack of information and methodological concerns. All the included trials were multicentre trials and recruited patients with mild to moderate Alzheimer's disease with a mean age of about 75 years. All had low risk of bias for randomisation and allocation but the risk of bias due to attrition was unclear in four studies, low in one study and high in two studies.After 26 weeks of treatment rivastigmine compared to placebo was associated with better outcomes for cognitive function measured with the Alzheimer's Disease Assessment Scale-Cognitive (ADAS-Cog) score (mean difference (MD) -1.79; 95% confidence interval (CI) -2.21 to -1.37, n = 3232, 6 studies) and the Mini-Mental State Examination (MMSE) score (MD 0.74; 95% CI 0.52 to 0.97, n = 3205, 6 studies), activities of daily living (SMD 0.20; 95% CI 0.13 to 0.27, n = 3230, 6 studies) and clinician rated global impression of changes, with a smaller proportion of patients treated with rivastigmine experiencing no change or a deterioration (OR 0.68; 95% CI 0.58 to 0.80, n = 3338, 7 studies).Three studies reported behavioural change, and there were no differences compared to placebo (standardised mean difference (SMD) -0.04; 95% CI -0.14 to 0.06, n = 1529, 3 studies). Only one study measured the impact on caregivers using the Neuropsychiatric Inventory-Caregiver Distress (NPI-D) scale and this found no difference between the groups (MD 0.10; 95% CI -0.91 to 1.11, n = 529, 1 study). Overall, participants who received rivastigmine were about twice as likely to withdraw from the trials (odds ratio (OR) 2.01, 95% CI 1.71 to 2.37, n = 3569, 7 studies) or to experience an adverse event during the trials (OR 2.16, 95% CI 1.82 to 2.57, n = 3587, 7 studies).

AUTHORS' CONCLUSIONS

Rivastigmine (6 to 12 mg daily orally or 9.5 mg daily transdermally) appears to be beneficial for people with mild to moderate Alzheimer's disease. In comparisons with placebo, better outcomes were observed for rate of decline of cognitive function and activities of daily living, although the effects were small and of uncertain clinical importance. There was also a benefit from rivastigmine on the outcome of clinician's global assessment. There were no differences between the rivastigmine group and placebo group in behavioural change or impact on carers. At these doses the transdermal patch may have fewer side effects than the capsules but has comparable efficacy. The quality of evidence is only moderate for all of the outcomes reviewed because of a risk of bias due to dropouts. All the studies with usable data were industry funded or sponsored. This review has not examined economic data.

Drug therapies in older adults (part 1)

Prescribing for older adults represents a significant challenge as the UK population ages. Physiological decline and the rising prevalence of frailty increase the likelihood of altered pharmacodynamics and pharmacokinetics, suboptimal prescribing and adverse effects among this growing cohort of the population. In the first of two articles, we begin by considering these issues and posit four key questions which should be considered when prescribing for older adults. Does this agent reflect the priorities of the patient? Are there alternatives - with greater efficacy, effectiveness or tolerability - that might be considered? Are the dose, frequency and formulation appropriate? How does this prescription relate to concurrent medication? We also describe current drug therapies in two disease states with a predilection for older adults: Alzheimer's disease (AD) and osteoporosis. Using these examples we highlight the limitations of evidence-based medicine and guidelines in this cohort of the population, illustrating the reliance on sub-group analysis to demonstrate the efficacy of drug therapies for older adults in osteoporosis and the underutilisation of appropriate treatments for patients with AD as a result of flawed guidelines.

The spectrum of cognitive impairment in Lewy body diseases

Cognitive impairment represents an important and often defining component of the clinical syndromes of Lewy body disorders: Parkinson's disease and dementia with Lewy bodies. The spectrum of cognitive deficits in these Lewy body diseases encompasses a broad range of clinical features, severity of impairment, and timing of presentation. It is now recognized that cognitive dysfunction occurs not only in more advanced Parkinson's disease but also in early, untreated patients and even in those patients with pre-motor syndromes, such as rapid eye movement behavior disorder and hyposmia. In recent years, the concept of mild cognitive impairment as a transitional or pre-dementia state in Parkinson's disease has emerged. This has led to much research regarding the diagnosis, prognosis, and underlying neurobiology of mild cognitive impairment in Parkinson's disease, but has also raised questions regarding the usefulness of this concept and its application in clinical and research settings. In addition, the conundrum of whether Parkinson's disease dementia and dementia with Lewy bodies represent the same or different entities remains unresolved. Although these disorders overlap in many aspects of their presentations and pathophysiology, they differ in other elements, such as timing of cognitive, behavioral, and motor symptoms; medication responses; and neuropathological contributions. This article examines the spectrum and evolution of cognitive impairment in Lewy body disorders and debates these controversial issues in the field using point-counterpoint approaches.

[Dementia: Where are the Lewy bodies?]

Dementia with Lewy bodies (DLB) is the second cause of degenerative dementia in autopsy studies. In clinical pratice however, the prevalence of DLB is much lower with important intercenter variations. Among the reasons for this low sensitivity of DLB diagnosis are (1) the imprecision and subjectivity of the diagnostic criteria; (2) the underestimation of non-motor symptoms (REM-sleep behavior disorder, dysautonomia, anosmia); mostly (3) the nearly constant association of Lewy bodies with Alzheimer's disease pathology, which dominates the clinical phenotype. With the avenue of targeted therapies against the protein agregates, new clinical scales able to apprehend the coexistence of Lewy pathology in Alzheimer's disease are expected.

UPDATE ON DEMENTIA WITH LEWY BODIES

Dementia with Lewy bodies (DLB) is the second most common form of dementia after Alzheimer disease (AD). DLB is characterized pathologically by Lewy body and Lewy neuritic pathology, often with variable levels of Alzheimer-type pathology. Core clinical features include fluctuating cognition, visual hallucinations, and parkinsonism resulting in greater impairments of quality of life, more caregiver burden, and higher health-related costs compared with AD. These issues, together with a high sensitivity to adverse events with treatment with antipsychotic agents, make the need for an early and accurate diagnosis of DLB essential. Unfortunately, current consensus criteria are highly specific but lack sufficient sensitivity. Use of composite risk scores may improve accuracy of clinical diagnosis. Imaging findings, particularly targeting dopaminergic systems have shown promise as potential markers to differentiate DLB from AD. A combination of non-pharmacologic treatments and pharmacotherapy interventions may maximize cognitive function and overall quality of life in DLB patients.

Underrecognition and undertreatment of dementia in Italian nursing homes

OBJECTIVE

To determine the prevalence of dementia diagnoses and the use of antidementia drugs in a cohort of Italian older nursing home (NH) residents.

DESIGN

Cross-sectional study.

SETTING

The NH residents participating in 2 studies: the U.L.I.S.S.E. study and the Umbria Region survey.

PARTICIPANTS

A total of 2215 nursing home residents.

MEASUREMENT

Each resident underwent a comprehensive geriatric assessment at baseline by means of the RAI MDS 2.0. Dementia diagnosis was based on ICD-9 codes.

RESULTS

The prevalence of dementia diagnosis according to ICD-9 codes was 50.7% (n = 1123), whereas 312 subjects had cognitive impairment with a cognitive performance scale score ≥3 without a diagnosis of dementia. Only 56 NH residents were treated (5% of the sample) and the main drugs used were cholinesterase inhibitor, whereas only 1 subject was treated with memantine. Limiting our analysis to patients with mild to moderate Alzheimer's disease, who are those reimbursed by the public health care system for receiving antidementia drugs, the percentage rose to 11.3%.

CONCLUSION

These findings demonstrate a high rate of underdiagnosis and undertreatment of dementia in Italian NH residents. Potential explanations include the lack of systematic assessment of cognitive functions, the limitations to antidementia drug reimbursement, the complexity of the reimbursement procedure itself, and the high prevalence of patients with severe dementia. Older NH residents still lack proper access to state-of-the-art diagnosis and treatment for a devastating condition such as dementia.

Cholinesterase inhibitors for dementia with Lewy bodies, Parkinson's disease dementia and cognitive impairment in Parkinson's disease

BACKGROUND

Previous Cochrane reviews have considered the use of cholinesterase inhibitors in both Parkinson's disease with dementia (PDD) and dementia with Lewy bodies (DLB). The clinical features of DLB and PDD have much in common and are distinguished primarily on the basis of whether or not parkinsonism precedes dementia by more than a year. Patients with both conditions have particularly severe deficits in cortical levels of the neurotransmitter acetylcholine. Therefore, blocking its breakdown using cholinesterase inhibitors may lead to clinical improvement.

OBJECTIVES

To assess the efficacy, safety and tolerability of cholinesterase inhibitors in dementia with Lewy bodies (DLB), Parkinson's disease with dementia (PDD), and cognitive impairment in Parkinson's disease falling short of dementia (CIND-PD) (considered as separate phenomena and also grouped together as Lewy body disease).

SEARCH METHODS

The trials were identified from a search of ALOIS, the Specialised Register of the Cochrane Dementia and Cognitive Improvement Group (on 30 August 2011) using the search terms Lewy, Parkinson, PDD, DLB, LBD. This register consists of records from major healthcare databases (MEDLINE, EMBASE, PsycINFO, CINAHL) and many ongoing trial databases and is updated regularly.Reference lists of relevant studies were searched for additional trials.

SELECTION CRITERIA

Randomised, double-blind, placebo-controlled trials assessing the efficacy of treatment with cholinesterase inhibitors in DLB, PDD and cognitive impairment in Parkinson's disease (CIND-PD).

DATA COLLECTION AND ANALYSIS

Data were extracted from published reports by one review author (MR). The data for each 'condition' (that is DLB, PDD or CIND-PD) were considered separately and, where possible, also pooled together. Statistical analysis was conducted using Review Manager version 5.0.

MAIN RESULTS

Six trials met the inclusion criteria for this review, in which a total of 1236 participants were randomised. Four of the trials were of a parallel group design and two cross-over trials were included. Four of the trials included participants with a diagnosis of Parkinson's disease with dementia (Aarsland 2002a; Dubois 2007; Emre 2004; Ravina 2005), of which Dubois 2007 remains unpublished. Leroi 2004 included patients with cognitive impairment and Parkinson's disease (both with and without dementia). Patients with dementia with Lewy bodies (DLB) were included in only one of the trials (McKeith 2000).For global assessment, three trials comparing cholinesterase inhibitor treatment to placebo in PDD (Aarsland 2002a; Emre 2004; Ravina 2005) reported a difference in the Alzheimer's Disease Cooperative Study-Clinical Global Impression of Change (ADCS-CGIC) score of -0.38, favouring the cholinesterase inhibitors (95% CI -0.56 to -0.24, P < 0.0001).For cognitive function, a pooled estimate of the effect of cholinesterase inhibitors on cognitive function measures was consistent with the presence of a therapeutic benefit (standardised mean difference (SMD) -0.34, 95% CI -0.46 to -0.23, P < 0.00001). There was evidence of a positive effect of cholinesterase inhibitors on the Mini-Mental State Examination (MMSE) in patients with PDD (WMD 1.09, 95% CI 0.45 to 1.73, P = 0.0008) and in the single PDD and CIND-PD trial (WMD 1.05, 95% CI 0.42 to 1.68, P = 0.01) but not in the single DLB trial.For behavioural disturbance, analysis of the pooled continuous data relating to behavioural disturbance rating scales favoured treatment with cholinesterase inhibitors (SMD -0.20, 95% CI -0.36 to -0.04, P = 0.01).For activities of daily living, combined data for the ADCS and the Unified Parkinson's Disease Rating Scale (UPDRS) activities of daily living rating scales favoured treatment with cholinesterase inhibitors (SMD -0.20, 95% CI -0.38 to -0.02, P = 0.03).For safety and tolerability, those taking a cholinesterase inhibitor were more likely to experience an adverse event (318/452 versus 668/842; odds ratio (OR) 1.64, 95% CI 1.26 to 2.15, P = 0.0003) and to drop out (128/465 versus 45/279; OR 1.94, 95% CI 1.33 to 2.84, P = 0.0006). Adverse events were more common amongst those taking rivastigmine (357/421 versus 173/240; OR 2.28, 95% CI 1.53 to 3.38, P < 0.0001) but not those taking donepezil (311/421 versus 145/212; OR 1.24, 95% CI 0.86 to 1.80, P = 0.25). Parkinsonian symptoms in particular tremor (64/739 versus 12/352; OR 2.71, 95% CI 1.44 to 5.09, P = 0.002), but not falls (P = 0.39), were reported more commonly in the treatment group but this did not have a significant impact on the UPDRS (total and motor) scores (P = 0.71). Fewer deaths occurred in the treatment group than in the placebo group (4/465 versus 9/279; OR 0.28, 95% CI 0.09 to 0.84, P = 0.03).

AUTHORS' CONCLUSIONS

The currently available evidence supports the use of cholinesterase inhibitors in patients with PDD, with a positive impact on global assessment, cognitive function, behavioural disturbance and activities of daily living rating scales. The effect in DLB remains unclear. There is no current disaggregated evidence to support their use in CIND-PD.

Butyrylcholinesterase inhibitors ameliorate cognitive dysfunction induced by amyloid-β peptide in mice

The cholinesterase inhibitor, rivastigmine, ameliorates cognitive dysfunction and is approved for the treatment of Alzheimer's disease (AD). Rivastigmine is a dual inhibitor of acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE); however, the impact of BuChE inhibition on cognitive dysfunction remains to be determined. We compared the effects of a selective BuChE inhibitor, N1-phenethyl-norcymserine (PEC), rivastigmine and donepezil (an AChE-selective inhibitor) on cognitive dysfunction induced by amyloid-β peptide (Aβ(1-40)) in mice. Five-week-old imprinting control region (ICR) mice were injected intracerebroventricularly (i.c.v.) with either Aβ(1-40) or the control peptide Aβ(40-1) on Day 0, and their recognition memory was analyzed by a novel object recognition test. Treatment with donepezil (1.0mg/kg), rivastigmine (0.03, 0.1, 0.3mg/kg) or PEC (1.0, 3.0mg/kg) 20min prior to, or immediately after the acquisition session (Day 4) ameliorated the Aβ(1-40) induced memory impairment, indicating a beneficial effect on memory acquisition and consolidation. In contrast, none of the investigated drugs proved effective when administrated before the retention session (Day 5). Repeated daily administration of donepezil, rivastigmine or PEC, on Days 0-3 inclusively, ameliorated the cognitive dysfunction in Aβ(1-40) challenged mice. Consistent with the reversal of memory impairments, donepezil, rivastigmine or PEC treatment significantly reduced Aβ(1-40) induced tyrosine nitration of hippocampal proteins, a marker of oxidative damage. These results indicate that BuChE inhibition, as well as AChE inhibition, is a viable therapeutic strategy for cognitive dysfunction in AD.

Cholinesterase inhibitors in Alzheimer's disease and Lewy body spectrum disorders: the emerging pharmacogenetic story

This review provides an update on the current state of pharmacogenetic research in the treatment of Alzheimer's disease (AD) and Lewy body disease (LBD) as it pertains to the use of cholinesterase inhibitors (ChEI). AD and LBD are first reviewed from clinical and pathophysiological perspectives. This is followed by a discussion of ChEIs used in the symptomatic treatment of these conditions, focusing on their unique and overlapping pharmacokinetic and pharmacodynamic profiles, which can be used to identify candidate genes for pharmacogenetics studies. The literature published to date is then reviewed and limitations are discussed. This is followed by a discussion of potential endophenotypes which may help to refine future pharmacogenetic studies of response and adverse effects to ChEIs.

Conceptual and methodological issues in designing a randomized, controlled treatment trial for geriatric bipolar disorder: GERI-BD

AIM

This report considers the conceptual and methodological concerns confronting clinical investigators seeking to generate knowledge regarding the tolerability and benefits of pharmacotherapy in geriatric bipolar disorder (BD) patients.

METHOD

There is continuing need for evidence-based guidelines derived from randomized controlled trials that will enhance drug treatment of geriatric BD patients. Therefore, we present the complex conceptual and methodological choices encountered in designing a multisite clinical trial and the decisions reached by the investigators with the intention that study findings be pertinent to, and can facilitate, routine treatment decisions.

RESULTS

Guided by a literature review and input from peers, the tolerability and antimanic effects of lithium and valproate were judged to be the key mood stabilizers to investigate with regard to treating bipolar I disorder manic, mixed, and hypomanic states. The patient selection criteria are intended to generate a sample that not only experiences common treatment needs but also represents the variety of older patients seen in university-based clinical settings. The clinical protocol guides titration of lithium and valproate to target serum concentrations, with lower levels allowed when necessitated by limited tolerability. The protocol emphasizes initial monotherapy. However, augmentation with risperidone is permitted after three weeks when indicated by operational criteria.

CONCLUSIONS

A randomized, controlled trial that both investigates commonly prescribed mood stabilizers and maximizes patient participation can meaningfully address high-priority clinical concerns directly relevant to the routine pharmacologic treatment of geriatric BD patients.

Aggressive course of disease in dementia

The rate of disease progression in Alzheimer's disease (AD) patients is variable. A significant proportion of AD patients appear to experience an aggressive course of disease, and this has a major impact on prognosis, the patients, and their caregivers and society in general. Here we review the current literature on an aggressive course of disease in dementia and how it can be recognized in clinical practice. We also discuss the options available for treating patients with this condition.

A novel effect of rivastigmine on pre-synaptic proteins and neuronal viability in a neurodegeneration model of fetal rat primary cortical cultures and its implication in Alzheimer's disease

Alzheimer's disease (AD) is characterized by deposition of amyloid-beta peptide plaque, disrupted amyloid-beta-precursor protein (APP) metabolism, hyperphosphorylation of Tau leading to neurofibrillary tangles and associated neurotoxicity. Moreover, there is synaptic loss in AD, which occurs early and may precede frank amyloidosis. The central cholinergic system is especially vulnerable to the toxic events associated with AD, and reduced acetylcholine levels in specific brain regions is thought to be central to memory deficits in AD. First-generation cholinesterase inhibitors have provided only symptomatic relief to patients with AD by prolonging the action of remaining acetylcholine with little or no change in the course of the disease. Some second-generation cholinesterase inhibitors are multifunctional drugs that may provide more than purely palliative results. To evaluate the effects of the dual acetylcholinesterase and butyrylcholinesterase inhibitor rivastigmine on key aspects of AD, embryonic day 16 rat primary cortical cultures were treated with rivastigmine under media conditions observed to induce time-dependent neurodegeneration. Samples were subjected to western blotting and immunocytochemistry techniques to determine what influence this drug may have on synaptic proteins and neuronal morphology. There was a strong increase in relative cell viability associated with rivastigmine treatment. Significant dose-dependent increases were observed in the levels of synaptic markers synaptosomal-associated protein of 25 kDa (SNAP-25) and synaptophysin, as well as the neuron-specific form of enolase. Together with an observed enhancement of neuronal morphology, our results suggest a rivastigmine-mediated novel neuroprotective and/or neurorestorative effects involving the synapse. Our observations may explain the potential for rivastigmine to alter the course of AD, and warrant further investigations into using butyrylcholinesterase inhibition as a therapeutic strategy for AD, especially with regard to restoration of synaptic function.

Cholinesterase inhibition: is there evidence for disease-modifying effects?

BACKGROUND

Cholinesterase inhibitors are broadly established as first-line symptomatic therapy for Alzheimer's disease (AD). Symptomatic effects are mediated by the inhibition of acetyl- and/or butyryl-cholinesterase (AChE and/or BuChE) - the enzymes that degrade acetylcholine (ACh) in the synapse. However, ACh is also found outside the synapse ('extracellular ACh') where, among other activities, it plays a role in controlling inflammation and might impact on pathological changes. OBJECTIVE/SCOPE: New data and clinical findings are reviewed and discussed to build a preliminary case for possible disease-modifying effects of cholinesterase inhibition.

FINDINGS

Trials seeking to demonstrate disease-modifying effects in subjects with mild cognitive impairment failed to reach their primary endpoints, but these failures might relate to aspects of trial methods and analyses. A re-analysis of one of these trials, using a more sensitive model controlling for factors that predict progression to AD, showed a significant delay in progression to AD with dual cholinesterase inhibition over 3 to 4 years. Taken with other evidence, it is plausible that cholinesterase inhibition might contribute to disease modification. The detection of putative disease-modifying effects may be most easily implemented in certain patient subpopulations, and genotyping studies suggest a particular role for BuChE.

CONCLUSION

Long-term inhibition of BuChE might be especially important when exploring any disease-modifying effects of cholinesterase inhibitors. Elucidation of the mechanisms involved could provide insights leading to the development of new treatments that modify the development and progression of AD.

Progression from mild cognitive impairment to Alzheimer's disease: effects of sex, butyrylcholinesterase genotype, and rivastigmine treatment

OBJECTIVE

Evaluate the effect of sex and butyrylcholinesterase (BuChE) genotype on the incidence of Alzheimer's disease (AD), cognitive and functional decline, brain volume changes, and response to rivastigmine treatment in individuals with mild cognitive impairment (MCI).

METHODS

This retrospective exploratory analysis from a 3-4 year, randomized, placebo-controlled study of rivastigmine in MCI patients included participants who consented to pharmacogenetic testing.

RESULTS

Of a total of 1018 patients, 490 [253 (52%) female] were successfully genotyped for BuChE. In patients receiving placebo, the BuChE wt/wt genotype was associated with a statistically significant higher incidence of progression to AD and functional decline in women, compared with men with the BuChE wt/wt genotype. In patients with a BuChE-K allele receiving placebo, incidence of progression to AD and rate of functional decline were not significantly different by sex; however, cognitive decline was significantly faster in men. Statistically significant benefits of rivastigmine treatment on incident AD, functional decline, ventricular volume expansion, whole-brain atrophy, and white matter loss were evident in female BuChE wt/wt.

CONCLUSION

Sex and BuChE genotype seem to differentially influence the type of decline in MCI patients, with more rapid progression of cognitive decline in male BuChE-K, and more incident AD and functional decline in female BuChE wt/wt. Cognitive decline in male BuChE-K and functional decline and incident AD in female BuChE wt/wt were significantly attenuated by rivastigmine. Rivastigmine treatment also significantly reduced ventricular expansion, whole-brain atrophy rate, and white matter loss in female BuChE wt/wt, suggesting a possible disease-modifying effect.

Different cholinesterase inhibitor effects on CSF cholinesterases in Alzheimer patients

BACKGROUND

The current study aimed to compare the effects of different cholinesterase inhibitors on acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) activities and protein levels, in the cerebrospinal fluid (CSF) of Alzheimer disease (AD) patients.

METHODS AND FINDINGS

AD patients aged 50-85 years were randomized to open-label treatment with oral rivastigmine, donepezil or galantamine for 13 weeks. AChE and BuChE activities were assayed by Ellman's colorimetric method. Protein levels were assessed by enzyme-linked immunosorbent assay (ELISA). Primary analyses were based on the Completer population (randomized patients who completed Week 13 assessments). 63 patients were randomized to treatment. Rivastigmine was associated with decreased AChE activity by 42.6% and decreased AChE protein levels by 9.3%, and decreased BuChE activity by 45.6% and decreased BuChE protein levels by 21.8%. Galantamine decreased AChE activity by 2.1% and BuChE activity by 0.5%, but increased AChE protein levels by 51.2% and BuChE protein levels by 10.5%. Donepezil increased AChE and BuChE activities by 11.8% and 2.8%, respectively. Donepezil caused a 215.2% increase in AChE and 0.4% increase in BuChE protein levels. Changes in mean AChE-Readthrough/Synaptic ratios, which might reflect underlying neurodegenerative processes, were 1.4, 0.6, and 0.4 for rivastigmine, donepezil and galantamine, respectively.

CONCLUSION

The findings suggest pharmacologically-induced differences between rivastigmine, donepezil and galantamine. Rivastigmine provides sustained inhibition of AChE and BuChE, while donepezil and galantamine do not inhibit BuChE and are associated with increases in CSF AChE protein levels. The clinical implications require evaluation.

Rivastigmine for Alzheimer's disease

BACKGROUND

Alzheimer's disease (AD) is the commonest cause of dementia affecting older people. One of the therapeutic strategies aimed at ameliorating the clinical manifestations of Alzheimer's disease is to enhance cholinergic neurotransmission in relevant parts of the brain by the use of cholinesterase inhibitors to delay the breakdown of acetylcholine released into synaptic clefts. Tacrine, the first of the cholinesterase inhibitors to undergo extensive trials for this purpose, was associated with significant adverse effects including hepatotoxicity. Other cholinesterase inhibitors, including rivastigmine, with superior properties in terms of specificity of action and low risk of adverse effects, have now been introduced. Rivastigmine has received approval for use in 60 countries including all member states of the European Union and the USA.

OBJECTIVES

To determine the clinical efficacy and safety of rivastigmine for patients with dementia of Alzheimer's type.

SEARCH STRATEGY

The Specialized Register of the Cochrane Dementia and Cognitive Improvement Group (CDCIG), The Cochrane Library, MEDLINE, EMBASE, PsycINFO, CINAHL and LILACS were searched on 27 March 2008 using the terms: Rivastigmine OR exelon OR ENA OR "SDZ ENA 713" . The CDCIG Specialized Register contains records from all major health care databases (The Cochrane Library, MEDLINE, EMBASE, PsycINFO, CINAHL, LILACS) as well as from many clinical trials registries and grey literature sources.

SELECTION CRITERIA

All unconfounded, double-blind, randomized trials in which treatment with rivastigmine was administered to patients with dementia of the Alzheimer's type for more than two weeks and its effects compared with those of placebo in a parallel group of patients.

DATA COLLECTION AND ANALYSIS

One reviewer (JSB) applied study selection criteria, assessed the quality of studies and extracted data.

MAIN RESULTS

Nine trials, involving 4775 participants, were included in the analyses. Use of rivastigmine in high doses was associated with statistically significant benefits on several measures. High-dose rivastigmine (6 to 12 mg daily) was associated with a two-point improvement in cognitive function on the ADAS-Cog score compared with placebo (weighted mean difference -1.99, 95% confidence interval -2.49 to -1.50, on an intention-to-treat basis) and a 2.2 point improvement in activities of daily living assessed on the Progressive Deterioration Scale (weighted mean difference -2.15, 95% confidence interval -3.16 to -1.13, on an intention-to-treat basis) at 26 weeks. At lower doses (4 mg daily or lower) differences were in the same direction but were statistically significant only for cognitive function. There were statistically significantly higher numbers of events of nausea, vomiting, diarrhoea, anorexia, headache, syncope, abdominal pain and dizziness among patients taking high-dose rivastigmine than among those taking placebo. There was some evidence that adverse events might be less common with more frequent, smaller doses of rivastigmine. The 2008 update includes a new study testing two types of rivastigmine transdermal patch, one delivering a higher dose than previously tested (17.4 mg/day) and a smaller patch delivering 9.6 mg/day. The efficacy of the smaller patch was not significantly different compared with the capsules of similar daily dose, but was associated with significantly fewer adverse events of nausea, vomiting, dizziness and asthenia. The efficacy of the larger patch was not significantly different compared with the smaller patch, but the smaller patch was associated with significantly fewer adverse events of nausea, vomiting, weight loss and dizziness. There appears to be advantages associated with the smaller patch compared with both the higher dose patch and the 6-12 mg/day capsules.

AUTHORS' CONCLUSIONS

Rivastigmine appears to be beneficial for people with mild to moderate Alzheimer's disease. In comparisons with placebo, improvements were seen in the rate of decline of cognitive function, activities of daily living, and severity of dementia with daily doses of 6 to 12 mg. Adverse events were consistent with the cholinergic actions of the drug. A transdermal patch has been tested in one trial, and there is evidence that the lower dose smaller patch is associated with fewer side effects than the capsules or the higher dose larger patch and has comparable efficacy to both. This review has not examined economic data.

Emerging hypotheses regarding the influences of butyrylcholinesterase-K variant, APOE epsilon 4, and hyperhomocysteinemia in neurodegenerative dementias

Non-enzymatic functions of butyrylcholinesterase (BuChE) include prevention of the aggregation of amyloid-beta peptide (A beta) in a concentration-dependent manner. This is mediated by the C-terminus of the protein, distal from the enzymatic site. The BuChE-K variant polymorphism lowers expression of BuChE protein and/or alters C-terminal activity. In combination with factors that increase production or reduce elimination of A beta, and/or increase susceptibility to A beta toxicity - such as the apolipoprotein E (APOE) epsilon 4 allele and/or hyperhomocysteinemia - BuChE-K may accelerate cholinergic synaptic and neuronal damage and cognitive decline. A beta-mediated damage to ascending cholinergic pathways may be further accentuated by Lewy body and/or cerebrovascular disease. As the disease advances and functioning cholinergic synapses disappear, both the rapid cognitive decline and response to cholinesterase inhibitor therapy in individuals with these factors may diminish. Non-enzymatic functions of the BuChE protein, APOE epsilon 4 status and hyperhomocysteinemia influence the progression of pathology, symptom expression, and response to cholinesterase inhibition in a stage-specific manner in neurodegenerative disorders associated with Alzheimer, Lewy body and vascular pathology.

Fluoro-deoxy-glucose positron emission tomography correlates of impaired activities of daily living in dementia with Lewy bodies: implications for cognitive reserve

OBJECTIVES

1) To investigate the neural substrate of impaired activities of daily living (ADL) in dementia with Lewy bodies (DLB) and 2) to explore, in the context of cognitive reserve, if hypometabolism was more pronounced in well-educated patients at the same level of everyday impairment.

METHODS

Twenty-one patients with DLB underwent an extensive clinical evaluation including cerebral positron emission tomography with F-fluoro-2-deoxy-glucose scanning. First, brain areas were identified, where ADL performance and glucose metabolism were significantly correlated, controlling for individual differences in cognitive and motor dysfunction. Second, it was tested if there was a significant negative association between metabolism and years of education in brain regions associated with ADL performance. Again, a correction for cognitive and motor impairment was deployed.

RESULTS

There was a significant association between glucose hypometabolism and impaired ADL performance in an extensive brain cluster located in the right temporoparietal cortex. Furthermore, schooling and metabolic rate were inversely associated in the right Brodmann area 19, controlling for ADL performance.

CONCLUSIONS

The study suggests that 1) certain brain metabolic alterations are specifically associated with the loss of everyday competence, even if differences in cognition and motor function are taken into consideration and 2) well-educated patients can offset more brain damage until reaching the same degree of ADL impairment as their less educated counterparts. These results extend the literature on cognitive reserve to a region-specific effect on ADL performance.

Effects of rivastigmine on tremor and other motor symptoms in patients with Parkinson's disease dementia: a retrospective analysis of a double-blind trial and an open-label extension

BACKGROUND AND AIM

Rivastigmine is now widely approved for the treatment of mild to moderately severe dementia in Parkinson's disease (PDD). However, since anticholinergic drugs have a role in the management of tremor in patients with Parkinson's disease (PD), concerns have been raised that the use of cholinergic drugs might worsen PD. The current analyses were performed to examine the potential of rivastigmine to affect tremor and other motor symptoms in patients with PDD.

METHODS

The safety profile of rivastigmine was evaluated using a database from a 24-week, randomized, double-blind, placebo-controlled trial in 541 PDD patients (362 randomized to rivastigmine, 179 to placebo), and 334 PDD patients who subsequently entered an open-label 24-week extension on rivastigmine.

RESULTS

During the double-blind trial, the adverse event (AE) of emerging or worsening tremor was reported in 10.2% of patients in the rivastigmine group, compared with 3.9% in the placebo group (p = 0.012). Tremor was most frequently reported during the titration phase of rivastigmine treatment, although this was not reflected in total motor Unified Parkinson's Disease Rating Scale (UPDRS) part III scores. Dose dependence of this AE was not observed. At the end of the double-blind phase, six (1.7%) rivastigmine-treated patients had discontinued the study because of tremor. In the open-label extension in which all patients received rivastigmine, tremor was reported by 6.9% of patients: 3.8% and 12.2% of whom had previously received double-blind rivastigmine and placebo, respectively (p = 0.006), suggesting that first exposure to rivastigmine leads to a transient increase in tremor. Three (0.9%) of the 334 patients who entered the open-label extension phase discontinued because of tremor. Incidences of worsening parkinsonism, bradykinesia and rigidity were all <5% in both treatment groups (all p-values not statistically significant, rivastigmine vs placebo). In the 48-week observation of rivastigmine treatment, there was no evidence of adverse long-term motor outcomes. Post-hoc analysis showed that similar improvements in the symptoms of dementia, including the ability to perform activities of daily living, were seen regardless of whether exacerbation of tremor was reported during the study.

CONCLUSION

Rivastigmine did not induce clinically significant exacerbation of motor dysfunction in patients with PDD. Rest tremor incidence as an AE was a transient phenomenon during dose titration of rivastigmine. There was no indication that exposure to long-term rivastigmine was associated with a worsening of PD.

Distinguishing Lewy body dementias from Alzheimer's disease

Lewy body dementia (LBD) is the second most common dementia after Alzheimer's disease (AD). LBD is characterized clinically by visual hallucinations, extrapyramidal symptoms, cognitive fluctuations and neuroleptic sensitivity. LBD and AD share many common features in pathology, genetics and biochemical alterations; however, correct clinical distinction between these disorders has prognostic and therapeutic implications. There are currently no definitive radiological or biological markers for LBD, but studies suggest that premorbid differences in cognitive domains and personality traits, differences in clinical presentation, and alterations in autonomic function and sleep may improve diagnosis. Cholinergic dysfunction plays a major role in both AD and LBD; however, dysfunction is greater in LBD. This may account for the more prominent hallucinations, and offers the possibility of a greater response to cholinesterase inhibitors in LBD. The treatment of LBD is symptomatic and is based on a limited number of clinical trials and extension of results from trials in AD. Current research is focused on the role of synuclein aggregation with possible roles for synuclein-derived peptides as aggregation inhibitors. Other approaches target amyloid, neuroinflammation, oxidative injury, proteolysis, lipid peroxidation and immunotherapies with variable results. Improved understanding of disease mechanisms may open new therapeutic avenues for LBD in the future.

Donepezil: an update

Donepezil hydrochloride is the most widely prescribed drug for Alzheimer's disease (AD). The main mechanism of action through which it influences cognition and function is presumed to be the inhibition of acetylcholinesterase enzyme in the brain; however, donepezil may also impact the pathophysiology of AD at several other points. Officially approved for mild-to-moderate and severe AD, donepezil has also been shown to be effective in early-stage AD, vascular dementia, Parkinson's disease dementia/Lewy body disease and cognitive symptoms associated with multiple sclerosis. In addition, one study suggested that donepezil may delay the onset of AD in subjects with mild cognitive impairment, a prodrome to AD. The pharmacokinetics, pharmacodynamics, safety/tolerability profile and drug interaction properties of donepezil make it an easy and safe agent to use. However, in general, the efficacy of donepezil is limited, and ongoing studies are investigating other agents that may ultimately overtake its present position as the mainstay of anti-AD therapy.

Effects of donepezil on central processing speed and attentional measures in Parkinson's disease with dementia and dementia with Lewy bodies

BACKGROUND

We examined attention-enhancing effects of the cholinesterase inhibitor donepezil in Dementia with Lewy bodies (DLB) and Parkinson's disease with dementia (PDD) by means of open label study.

METHODS

22 DLBs and 23 PDDs were assessed over 20 weeks using the Cognitive Drug Research Computerized Attentional Tasks. We examined how much closer our patients moved towards being normal for their age by comparing them to a non-demented elderly control sample (n = 183, aged 71-75 years).

RESULTS

Donepezil treatment improved power of attention, continuity of attention and reaction time variability. The deficit in responses was moved towards normal by 38 and 56% for power of attention and 22 and 10% for continuity of attention in PDD and DLB, respectively.

CONCLUSIONS

Improvements in attention were found with donepezil in PDD and DLB.

Prise en charge médicale des patients atteints de syndromes parkinsoniens atypiques dégénératifs

Atypical degenerative parkinsonian syndromes (progressive supranuclar palsy, multiple system atrophy, corticobasal degeneration, Lewy body dementia) are an important differential diagnosis to idiopathic Parkinson's disease. However, because these disorders are characterized by the degeneration of multiple neuronal populations, treatment approaches are much less specific than in Parkinson's disease, where dopamimetic drugs represent the mainstay of therapy. Thus, and because the progression of these disorders is usually more aggressive than Parkinson's disease, many physicians face a form of therapeutic resignation when confronted with patients suffering from atypical degenerative parkinsonian syndromes. However, in the present article, we wish to show that a symptom-by-symptom approach can substantially relieve the patients and their caregivers by providing an overview of pharmacologic and non-pharmacologic treatment options.

'I think therefore I am': improving cognition

PURPOSE OF REVIEW

In the absence of a specific treatment for dementia, the effective management of cognitive symptoms is a clinical priority.

RECENT FINDINGS

Although some differences have been observed in the profile of cognitive complaints observed in subtypes of dementia, there is increasing recognition of common, interacting neurobiological causes suggesting the need to seek a common treatment applicable to all causes of cognitive deterioration. There also exists increasing interest in intervening at the level of minor cognitive dysfunction by reducing risk factors for subclinical states.

SUMMARY

Pharmacological treatment of cognitive disorder is beneficial but has only temporary benefit for a subgroup of patients. Pharmacogenetics may have an important future role to play in deciding which patients may best benefit from the treatment. Low side effect therapies such as cognitive therapy and acupuncture show some benefits but their utility in combination with pharmacotherapies remains to be demonstrated. Prevention of milder forms of cognitive disorder by controlling risk factors such as hypertension and diabetes may reduce rates of more severe cognitive degeneration. Persons with cognitive dysfunction are commonly excluded from making decisions about the implementation of cognition-enhancing treatments although they wish to do so.