A double-blind, placebo-controlled trial of memantine in age-associated memory impairment (memantine in AAMI)

A phase II single-arm trial of memantine for prevention of cognitive decline during chemotherapy in patients with early breast cancer: Feasibility, tolerability, acceptability, and preliminary effects

BACKGROUND

Cognitive difficulties have been described after chemotherapy for breast cancer, but there is no standard of care to improve cognitive outcomes in these patients. This trial examined the feasibility, tolerability, acceptability, and preliminary effects of memantine to prevent cognitive decline during chemotherapy for breast cancer.

METHODS

Patients with stage I-III breast cancer, scheduled for neo/adjuvant chemotherapy, completed a cognitive battery prior to and 4 weeks after completing chemotherapy. Memantine (10 mg BID) was administered concurrent with chemotherapy. Our primary cognitive outcome was visual working memory assessed by the Delayed Matching to Sample test. We used the Brief Medication Questionnaire to assess acceptability.

RESULTS

Of 126 patients approached, 56 (44%) enrolled. Forty-five (80%) received ≥1 dose of memantine and completed pre-post assessments. Seventy-six percent reported taking ≥90% of scheduled doses. Participants were mean age of 56, 77% White, and 57% had stage I disease. Sixty-four percent had stable or improved Delayed Matching to Sample test scores. Stable or improved cognition was observed in 87%-91% across objective cognitive domain composite measures. Sixty-six percent self-reported stable or improved cognitive symptoms. There were seven greater than or equal to grade 3 adverse events; two were possibly related to memantine. Only 5% reported that taking memantine was a disruption to their lives.

CONCLUSIONS

Memantine was well-tolerated and consistently taken by a large majority of patients receiving breast cancer chemotherapy. The majority demonstrated stable or improved cognition from pre- to post-assessment. Randomized trials are needed to determine memantine's efficacy to ameliorate cognitive loss.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04033419.

Therapeutic approaches for improving cognitive function in the aging brain

The rapid aging of populations around the world has become an unprecedented challenge. Aging is associated with cognitive impairment, including dementia and mild cognitive impairment. Successful drug development for improving or maintaining cognition in the elderly is critically important. Although 4 drugs for improving cognition in Alzheimer's disease have been approved, a variety of potential drugs targeting age-related cognitive impairment are still in development. In addition, non-pharmacological interventions, including cognition-oriented treatments, non-invasive brain stimulation physical exercise, and lifestyle-related interventions, have also been suggested as cognitive enhancers in the last decade. In this paper, we reviewed the recent evidence of pharmacological and non-pharmacological interventions aimed at improving or maintaining cognition in the elderly.

Memantine for the patients with mild cognitive impairment in Parkinson's disease: a pharmacological fMRI study

BACKGROUND

Mild cognitive impairment in Parkinson's disease (PD-MCI) is associated with an increased risk of cognitive decline. PD-MCI is characterized by impairments in executive function and visuospatial recognition. The visuospatial n-back test is useful for assessing both domains. The 0-back test reflects visuospatial recognition, while the 1-back and 2-back tests reflect working memory. Cholinesterase inhibitors are effective in the treatment of PD-MCI and dementia in PD (PDD). Although some studies have reported the efficacy of memantine for PDD, the therapeutic efficacy of memantine in patients with PD-MCI remains uncertain.

METHODS

This study aimed to investigate the effects of memantine on brain function in patients with PD-MCI, using a randomized double-blinded crossover protocol and functional MRI (fMRI). Ten patients who completed 16 weeks of follow-up were included. They were randomly assigned to either the memantine or placebo. Patients in the memantine group received 5 mg/day of memantine in the first week. The memantine dose was increased by 5 mg/day per week, until a final dose of 20 mg/day. Patients in the placebo group received the placebo following the same regimen as memantine. After the intervention, they underwent a 4 weeks washout period. Following the crossover protocol, a second intervention was conducted after the washout period. In each intervention, fMRI and neuropsychological tests were performed at the maximum dose period. Comparing the memantine and placebo groups, we investigated difference in the brain regions using the visuospatial n-back test.

RESULTS

There were no significant regions enhanced by memantine comparing with placebo at any load of n-back tests. In contrast, exploring regions reduced by memantine, we found significant reduction of activations within right lingual gyrus and left superior frontal gyrus in comparison between 2-back and 0-back test. A number of correct answers of the 2-back test and time to complete Trail Making Test-A were worse during memantine intervention.

CONCLUSIONS

Memantine did not improve visuospatial working memory of the patients with PD-MCI. Treatment for PD should be planned carefully considering the impact on cognitive function. Further study is needed to establish new therapeutic strategy.

TRIAL REGISTRATION

UMIN000046104. Retrospectively registered. First registration date: 28 Sept 2017.

Cancer and Alzheimer's disease inverse relationship: an age-associated diverging derailment of shared pathways

Several epidemiological studies show an inverse association between cancer and Alzheimer's disease (AD). It is debated whether this association is the consequence of biological mechanisms shared by both these conditions or may be related to the pharmacological treatments carried out on the patients. The latter hypothesis, however, is not sustained by the available evidence. Hence, the focus of this review is to analyze common biological mechanisms for both cancer and AD and to build up a biological theory useful to explain the inverse correlation between AD and cancer. The review proposes a hypothesis, according to which several molecular players, prominently PIN1 and p53, have been investigated and considered involved in complex molecular interactions putatively associated with the inverse correlation. On the other hand, p53 involvement in both diseases seems to be a consequence of the aberrant activation of other proteins. Instead, PIN1 may be identified as a novel key regulator at the crossroad between cancer and AD. PIN1 is a peptidyl-prolyl cis-trans isomerase that catalyzes the cis-trans isomerization, thus regulating the conformation of different protein substrates after phosphorylation and modulating protein function. In particular, trans-conformations of Amyloid Precursor Protein (APP) and tau are functional and "healthy", while cis-conformations, triggered after phosphorylation, are pathogenic. As an example, PIN1 accelerates APP cis-to-trans isomerization thus favoring the non-amyloidogenic pathway, while, in the absence of PIN1, APP is processed through the amyloidogenic pathway, thus predisposing to neurodegeneration. Furthermore, a link between PIN1 and tau regulation has been found, since when PIN1 function is inhibited, tau is hyperphosphorylated. Data from brain specimens of subjects affected by mild cognitive impairment and AD have revealed a very low PIN1 expression. Moreover, polymorphisms in PIN1 promoter correlated with an increased PIN1 expression are associated with a delay of sporadic AD age of onset, while a polymorphism related to a reduced PIN1 expression is associated with a decreased risk of multiple cancers. In the case of dementias, in particular of Alzheimer's disease, new biological markers and targets based on the discussed players can be developed based on a theoretical approach relying on different grounds compared to the past. An unbiased expansion of the rationale and of the targets may help to achieve in the field of neurodegenerative dementias similar advances to those attained in the case of cancer treatment.

Memantine for dementia

BACKGROUND

Memantine is a moderate affinity uncompetitive antagonist of glutamate NMDA receptors. It is licensed for use in moderate and severe Alzheimer's disease (AD); in the USA, it is also widely used off-label for mild AD.

OBJECTIVES

To determine efficacy and safety of memantine for people with dementia. To assess whether memantine adds benefit for people already taking cholinesterase inhibitors (ChEIs).

SEARCH METHODS

We searched ALOIS, the Cochrane Dementia and Cognitive Improvement Group's register of trials (http://www.medicine.ox.ac.uk/alois/) up to 25 March 2018. We examined clinical trials registries, press releases and posters of memantine manufacturers; and the web sites of the FDA, EMEA and NICE. We contacted authors and companies for missing information.

SELECTION CRITERIA

Double-blind, parallel group, placebo-controlled, randomised trials of memantine in people with dementia.

DATA COLLECTION AND ANALYSIS

We pooled and analysed data from four clinical domains across different aetiologies and severities of dementia and for AD with agitation. We assessed the impact of study duration, severity and concomitant use of ChEIs. Consequently, we restricted analyses to the licensed dose (20 mg/day or 28 mg extended release) and data at six to seven months duration of follow-up, and analysed separately results for mild and moderate-to-severe AD.We transformed results for efficacy outcomes into the difference in points on particular outcome scales.

MAIN RESULTS

Across all types of dementia, data were available from almost 10,000 participants in 44 included trials, most of which were at low or unclear risk of bias. For nearly half the studies, relevant data were obtained from unpublished sources. The majority of trials (29 in 7885 participants) were conducted in people with AD.1. Moderate-to-severe AD (with or without concomitant ChEIs). High-certainty evidence from up to 14 studies in around 3700 participants consistently shows a small clinical benefit for memantine versus placebo: clinical global rating (CGR): 0.21 CIBIC+ points (95% confidence interval (CI) 0.14 to 0.30); cognitive function (CF): 3.11 Severe Impairment Battery (SIB) points (95% CI 2.42 to 3.92); performance on activities of daily living (ADL): 1.09 ADL19 points (95% CI 0.62 to 1.64); and behaviour and mood (BM): 1.84 Neuropsychiatric Inventory (NPI) points (95% CI 1.05 to 2.76). There may be no difference in the number of people discontinuing memantine compared to placebo: risk ratio (RR) 0.93 (95% CI 0.83 to 1.04) corresponding to 13 fewer people per 1000 (95% CI 31 fewer to 7 more). Although there is moderate-certainty evidence that fewer people taking memantine experience agitation as an adverse event: RR 0.81 (95% CI 0.66 to 0.99) (25 fewer people per 1000, 95% CI 1 to 44 fewer), there is also moderate-certainty evidence, from three additional studies, suggesting that memantine is not beneficial as a treatment for agitation (e.g. Cohen Mansfield Agitation Inventory: clinical benefit of 0.50 CMAI points, 95% CI -3.71 to 4.71) .The presence of concomitant ChEI does not impact on the difference between memantine and placebo, with the possible exceptions of the BM outcome (larger effect in people taking ChEIs) and the CF outcome (smaller effect).2. Mild AD (Mini Mental State Examination (MMSE) 20 to 23): mainly moderate-certainty evidence based on post-hoc subgroups from up to four studies in around 600 participants suggests there is probably no difference between memantine and placebo for CF: 0.21 ADAS-Cog points (95% CI -0.95 to 1.38); performance on ADL: -0.07 ADL 23 points (95% CI -1.80 to 1.66); and BM: -0.29 NPI points (95% CI -2.16 to 1.58). There is less certainty in the CGR evidence, which also suggests there may be no difference: 0.09 CIBIC+ points (95% CI -0.12 to 0.30). Memantine (compared with placebo) may increase the numbers of people discontinuing treatment because of adverse events (RR 2.12, 95% CI 1.03 to 4.39).3. Mild-to-moderate vascular dementia. Moderate- and low-certainty evidence from two studies in around 750 participants indicates there is probably a small clinical benefit for CF: 2.15 ADAS-Cog points (95% CI 1.05 to 3.25); there may be a small clinical benefit for BM: 0.47 NOSGER disturbing behaviour points (95% CI 0.07 to 0.87); there is probably no difference in CGR: 0.03 CIBIC+ points (95% CI -0.28 to 0.34); and there may be no difference in ADL: 0.11 NOSGER II self-care subscale points (95% CI -0.35 to 0.54) or in the numbers of people discontinuing treatment: RR 1.05 (95% CI 0.83 to 1.34).There is limited, mainly low- or very low-certainty efficacy evidence for other types of dementia (Parkinson's disease and dementia Lewy bodies (for which CGR may show a small clinical benefit; four studies in 319 people); frontotemporal dementia (two studies in 133 people); and AIDS-related Dementia Complex (one study in 140 people)).There is high-certainty evidence showing no difference between memantine and placebo in the proportion experiencing at least one adverse event: RR 1.03 (95% CI 1.00 to 1.06); the RR does not differ between aetiologies or severities of dementia. Combining available data from all trials, there is moderate-certainty evidence that memantine is 1.6 times more likely than placebo to result in dizziness (6.1% versus 3.9%), low-certainty evidence of a 1.3-fold increased risk of headache (5.5% versus 4.3%), but high-certainty evidence of no difference in falls.

AUTHORS' CONCLUSIONS

We found important differences in the efficacy of memantine in mild AD compared to that in moderate-to-severe AD. There is a small clinical benefit of memantine in people with moderate-to-severe AD, which occurs irrespective of whether they are also taking a ChEI, but no benefit in people with mild AD.Clinical heterogeneity in AD makes it unlikely that any single drug will have a large effect size, and means that the optimal drug treatment may involve multiple drugs, each having an effect size that may be less than the minimum clinically important difference.A definitive long-duration trial in mild AD is needed to establish whether starting memantine earlier would be beneficial over the long term and safe: at present the evidence is against this, despite it being common practice. A long-duration trial in moderate-to-severe AD is needed to establish whether the benefit persists beyond six months.

Study protocol for a randomised, double-blind, placebo-controlled 12-week pilot phase II trial of Sailuotong (SLT) for cognitive function in older adults with mild cognitive impairment

Background

Mild cognitive impairment (MCI) is a syndrome characterised by a decline in cognition but relatively intact activities of daily living. People with MCI have an increased risk of developing dementia, and MCI is often referred to as a transitional stage between healthy ageing and dementia. Currently, there are no pharmaceutical therapies approved by the US Federal Drug Administration for MCI. Randomised controlled trials on the two major classes of anti-dementia pharmaceuticals, cholinesterase inhibitors and glutamate receptor antagonists, have produced poor results in MCI cohorts. There is a need to test and evaluate new and promising treatments for MCI that target multiple aspects of the syndrome’s multi-faceted pathophysiology. The primary aim of this study is to evaluate the efficacy of 12 weeks of treatment with a standardised herbal formula, Sailuotong (SLT), compared to placebo, on cognition in older adults with MCI. Secondary aims are to assess SLT’s mechanisms of action via electroencephalography (EEG), autonomic function, brain blood flow, and inflammation, as well as its safety in this cohort.

Methods/design

The target cohort for this trial is community-dwelling older adults over the age of 60 years who meet the National Institute of Aging-Alzheimer’s Association working group core clinical criteria for MCI due to Alzheimer’s disease. Eighty participants will be recruited and randomly allocated via a permuted block strategy at a 1:1 ratio to either the treatment or placebo group. The co-primary cognitive outcome measures are Logical Memory Story A delayed recall (episodic memory), Letter Number Sequencing (perceptual processing speed), and both the Trail Making Test and Rey Complex Figure Test (executive function). Secondary outcome measures are EEG activity, autonomic function (via electrocardiogram, skin conductance, and peripheral pulse pressure), brain blood flow (via common carotid artery ultrasound), and serum concentrations of inflammatory cytokines. Analyses will be performed blind to group allocation.

Discussion

This study is a 12-week, randomised, double-blind, placebo-controlled trial. Primary and secondary outcome measures will be compared between treatment and placebo groups at baseline and endpoint. Data from this pilot study will inform a larger, more highly powered clinical trial if the findings are positive.

Trial registration

Australian New Zealand Clinical Trials Registry (ANZCTR), ACTRN12617000371392 Registered on 10 March 2017.

Electronic supplementary material

The online version of this article (10.1186/s13063-018-2912-0) contains supplementary material, which is available to authorized users.

Exercise Intervention Associated with Cognitive Improvement in Alzheimer's Disease

Alzheimer's disease (AD) is a progressive neurodegenerative disease with the syndrome of cognitive and functional decline. Pharmacotherapy has always been in a dominant position for the treatment of AD. However, in most cases, drug therapy is accompanied with clinical delays when older adults have suffered from cognitive decline in episodic memory, working memory, and executive function. On the other hand, accumulating evidence suggests that exercise intervention may ameliorate the progression of cognitive impairment in aging ones while the standard strategy is lacking based on different levels of cognitive decline especially in mild cognitive impairment (MCI) and AD. MCI is the preclinical stage of AD in which neurodegeneration may be reversed via neuroplasticity. Therefore, taking exercise intervention in the early stage of MCI and healthy aging at the risk of AD could slow down the process of cognitive impairment and provide a promising cost-effective nonpharmacological therapy to dementia.

Combined treatment with memantine/es-citalopram for older depressed patients with cognitive impairment: a pilot study

OBJECTIVE

The objective of the study is to assess combined antidepressant and memantine treatment in older patients presenting with depression and cognitive impairment.

METHODS

Thirty-five depressed patients with cognitive impairment participated in this open-label pilot study. We evaluated whether, over a 48-week period, combined antidepressant (primarily es-citalopram) and memantine treatment was effective in the treatment of cognitive impairment and depression. Neuropsychological testing was performed, and antidepressant response monitored at baseline and at the 12, 24, and 48-week time points.

RESULTS

Treatment with escitalopram (mean daily dose 18.62 mg, SD 5.15) and memantine (mean daily dose 13.62 mg, SD 6.67) was associated with improvement in Hamilton Depression Rating Scale scores over the 48-week study period. Patients demonstrated significant improvement in the primary outcome of cognitive performance (Selective Reminding Test total immediate recall; SRT-IR) over the 48-week treatment period (p = 0.0147). Significant improvement was also observed in measures of naming and verbal fluency but not in the other cognitive domains. One of the 35 patients (2.9%) converted to Alzheimer's disease over the 48-week treatment period. In the amnestic mild cognitive impairment subsample (n = 22), the conversion rate was 4.5%, a rate lower than in other reports of patients with DEP-CI.

CONCLUSIONS

In this open-label trial, combined antidepressant and memantine treatment in patients with DEP-CI was associated with improved cognition and a low rate of conversion to dementia compared with published studies in patients with DEP-CI. Although limited by the open-label study design that incorporates practice effects that can improve cognitive test performance, the findings suggest the need for a larger randomized placebo-controlled trial.

Contribution of N-methyl-D-aspartate receptors to attention and episodic spatial memory during senescence

A decrease in N-methyl-D-aspartate receptor (NMDAR) function is associated with age-related cognitive impairments. However, NMDAR antagonists are prescribed for cognitive decline associated with age-related neurodegenerative disease, raising questions as to the role of NMDAR activity in cognitive function during aging. The current studies examined effects of NMDAR blockade on cognitive task that are sensitive to aging. Young and middle-age rats were trained on the five-choice serial reaction time task (5-CSRTT) and challenged with MK-801 (0.025, 0.05, and 0.1mg/kg or vehicle). Attention deficits were apparent in middle-age and performance of young and middle-age rats was enhanced for low doses of MK-801 (0.025 and 0.05). The beneficial effects on attention were reversed by the highest dose of MK-801. Older animals exhibited a delay-dependent impairment of episodic spatial memory examined on a delayed-matching to place water maze task. Similarly, a low dose of MK-801 (0.05mg/kg) impaired performance with increasing delay and aged animals were more susceptible to disruption by NMDAR blockade. Despite MK-801 impairment of episodic spatial memory, MK-801 had minimal effects on spatial reference memory. Our results confirm that NMDARs contribute to rapidly acquired and flexible spatial memory and support the idea that a decline in NMDAR function contributes to the age-related impairments in cognition.

Current management decisions in mild cognitive impairment

Efforts toward early detection of Alzheimer disease (AD) have focused on refinement and identification of diagnostic markers, with the goal of preventing or delaying disease progression. Mild cognitive impairment (MCI) has emerged as a potential precursor to dementia. Though not without controversy, MCI has been associated with an increased risk for conversion to AD. In this article, with emphasis on meta-analyses, randomized controlled trials, and extant literature reviews, considerations and recommendations for optimal clinical management of MCI are offered. Given the substantial heterogeneity of this patient population and inconsistent research methodologies, the need for informed, clinical judgment is critical.

The Testosterone Trials: Seven coordinated trials of testosterone treatment in elderly men

Background The prevalence of low testosterone levels in men increases with age, as does the prevalence of decreased mobility, sexual function, self-perceived vitality, cognitive abilities, bone mineral density, and glucose tolerance, and of increased anemia and coronary artery disease. Similar changes occur in men who have low serum testosterone concentrations due to known pituitary or testicular disease, and testosterone treatment improves the abnormalities. Prior studies of the effect of testosterone treatment in elderly men, however, have produced equivocal results. Purpose To describe a coordinated set of clinical trials designed to avoid the pitfalls of prior studies and to determine definitively whether testosterone treatment of elderly men with low testosterone is efficacious in improving symptoms and objective measures of age-associated conditions. Methods We present the scientific and clinical rationale for the decisions made in the design of this set of trials. Results We designed The Testosterone Trials as a coordinated set of seven trials to determine if testosterone treatment of elderly men with low serum testosterone concentrations and symptoms and objective evidence of impaired mobility and/or diminished libido and/or reduced vitality would be efficacious in improving mobility (Physical Function Trial), sexual function (Sexual Function Trial), fatigue (Vitality Trial), cognitive function (Cognitive Function Trial), hemoglobin (Anemia Trial), bone density (Bone Trial), and coronary artery plaque volume (Cardiovascular Trial). The scientific advantages of this coordination were common eligibility criteria, common approaches to treatment and monitoring, and the ability to pool safety data. The logistical advantages were a single steering committee, data coordinating center and data and safety monitoring board, the same clinical trial sites, and the possibility of men participating in multiple trials. The major consideration in participant selection was setting the eligibility criterion for serum testosterone low enough to ensure that the men were unequivocally testosterone deficient, but not so low as to preclude sufficient enrollment or eventual generalizability of the results. The major considerations in choosing primary outcomes for each trial were identifying those of the highest clinical importance and identifying the minimum clinically important differences between treatment arms for sample size estimation. Potential limitations Setting the serum testosterone concentration sufficiently low to ensure that most men would be unequivocally testosterone deficient, as well as many other entry criteria, resulted in screening approximately 30 men in person to randomize one participant. Conclusion Designing The Testosterone Trials as a coordinated set of seven trials afforded many important scientific and logistical advantages but required an intensive recruitment and screening effort.

Use of computerized tests to assess the cognitive impact of interventions in the elderly

With the aging of the population, the possibility of the occurrence of cognitive decline rises. A number of types of intervention seek to attenuate or reverse this impairment. The use of computerized tests helps quantify the effects of interventions on cognitive function in the elderly. The objective of the present review was to analyze studies that have utilized computerized cognitive tests to determine the effects of interventions in the elderly population, describing the batteries and tests employed, the populations studied and reports by authors on the limitations or benefits of employing these tests in older adults. The review was performed on the PubMed database using the descriptors: cognitive computerized test and elderly. We retrieved 530 studies and, following analysis of their abstracts, selected 32 relevant to the subject. The studies utilized 19 different types of computerized tests and batteries to assess the interventions, which were predominantly drug trials. There were no reports on limitations in the use of the computerized tests, suggesting this type of intervention had good applicability, sensitivity, and little or no practice effects in this population.

Efficacy and safety of cognitive enhancers for patients with mild cognitive impairment: a systematic review and meta-analysis

BACKGROUND

Cognitive enhancers, including cholinesterase inhibitors and memantine, are used to treat dementia, but their effectiveness for mild cognitive impairment is unclear. We conducted a systematic review to examine the efficacy and safety of cognitive enhancers for mild cognitive impairment.

METHODS

Our eligibility criteria were studies of the effects of donepezil, rivastigmine, galantamine or memantine on mild cognitive impairment reporting cognition, function, behaviour, global status, and mortality or harms. We identified relevant material by searching electronic databases (e.g., MEDLINE, Embase), the references of included studies, trial registries and conference proceedings, and by contacting experts. Two reviewers independently screened the results of the literature search, abstracted data and appraised risk of bias using the Cochrane risk-of-bias tool.

RESULTS

We screened 15,554 titles and abstracts and 1384 full-text articles. Eight randomized clinical trials and 3 companion reports met our inclusion criteria. We found no significant effects of cognitive enhancers on cognition (Mini-Mental State Examination: 3 randomized clinical trials [RCTs], mean difference [MD] 0.14, 95% confidence interval [CI] -0.22 to 0.50; Alzheimer's Disease Assessment Scale - cognition subscale: 3 RCTs, standardized MD -0.07, 95% CI-0.16 to 0.01]) or function (Alzheimer's Disease Cooperative Study activities of daily living inventory: 2 RCTs, MD 0.30, 95% CI -0.26 to 0.86). Cognitive enhancers were associated with higher risks of nausea, diarrhea and vomiting than placebo.

INTERPRETATION

Cognitive enhancers did not improve cognition or function among patients with mild cognitive impairment and were associated with a greater risk of gastrointestinal harms. Our findings do not support the use of cognitive enhancers for mild cognitive impairment.

Treatment for mild cognitive impairment: systematic review

BACKGROUND

More people are presenting with mild cognitive impairment (MCI), frequently a precursor to dementia, but we do not know how to reduce deterioration.

AIMS

To systematically review randomised controlled trials (RCTs) evaluating the effects of any intervention for MCI on cognitive, neuropsychiatric, functional, global outcomes, life quality or incident dementia.

METHOD

We reviewed 41 studies fitting predetermined criteria, assessed validity using a checklist, calculated standardised outcomes and prioritised primary outcome findings in placebo-controlled studies.

RESULTS

The strongest evidence was that cholinesterase inhibitors did not reduce incident dementia. Cognition improved in single trials of: a heterogeneous psychological group intervention over 6 months; piribedil, a dopamine agonist over 3 months; and donepezil over 48 weeks. Nicotine improved attention over 6 months. There was equivocal evidence that Huannao Yicong improved cognition and social functioning.

CONCLUSIONS

There was no replicated evidence that any intervention was effective. Cholinesterase inhibitors and rofecoxib are ineffective in preventing dementia. Further good-quality RCTs are needed and preliminary evidence suggests these should include trials of psychological group interventions and piribedil.

Effects of memantine and galantamine on cognitive performance in aged rhesus macaques

Current pharmacotherapies for Alzheimer's disease (AD) are focused on improving performance of daily activities, personal care, and management of problematic behaviors. Both memantine, a noncompetitive N-methyl-D-aspartate channel blocker and galantamine, a selective acetylcholinesterase inhibitor, are currently prescribed as symptomatic therapies for AD. However, drugs that progressed directly from testing in rodent models to testing in AD patients in clinical trials failed to demonstrate consistent effects on cognitive symptoms. Considering the lack of nonhuman primate data on the effects of memantine and galantamine alone or in combination on cognitive dysfunction in aged nonhuman primates, the present study examined how closely data derived from aged nonhuman primates reflects data obtained in humans. Mild beneficial effects on aspects of cognitive performance in aged primates were found, in general agreement with the human clinical experience with these drugs but in contrast to the more positive effects reported in the rodent literature. These data suggest that the nonhuman primate might have more predictive validity for drug development in this area than comparable rodent assays.

Prevalence of dementia in Al Kharga District, New Valley Governorate, Egypt

BACKGROUND

With aging, there is a parallel increase in the prevalence of dementia worldwide. The aim of this work is to determine the prevalence of dementia among the population of Al Kharga District, New Valley, Egypt.

METHODS

Screening of all subjects aged ≥50 years (n = 8,173 out of 62,583 inhabitants) was done through a door-to-door survey by 3 neurologists, using a short standardized Arabic screening test and a modified Mini-Mental State Examination. Suspected cases were subjected to full clinical examination, psychometric assessment using the Cognitive Abilities Screening Instrument, Instrumental Activities of Daily Living Scale, Geriatric Depression Scale, Hachinski Ischemic Score, DSM-IV-TR diagnostic criteria, neuroimaging, and laboratory investigations, when indicated.

RESULTS

The prevalence rate of dementia was 2.26% for the population aged ≥50 years. It increased steeply with age to a maximum of 18.48% for those aged ≥80 years. Alzheimer's disease (51.2%) was the most common subtype, followed by vascular dementia (28.7%), dementia due to general medical conditions (12.8%), and lastly dementia due to multiple etiologies (7.3%). Mild dementia was the commonest (53.7%).

CONCLUSION

Dementia is prevalent in Egypt as elsewhere. Detection through a door-to-door survey is the best method in developing countries for early detection of mild cases.

Paying more attention to attention: towards more comprehensive cognitive translation using mouse models of Alzheimer's disease

The cognitive phenotyping of mouse models of Alzheimer's disease (AD) currently focuses on impairments in learning and memory. However, AD is not simply a memory disorder, but other cognitive domains, and in particular attention, can also be impaired even at very early stages of the disease. In this review we argue for the benefits of including other constructs, and in particular attention, in preclinical studies to identify drug targets and disease mechanisms of AD in mouse models. First we give a brief account of the evidence for attentional deficits in AD; we then summarise methods to assess equivalent aspects of attention in mice, followed by a review of recent evidence for attentional impairments in widely used mouse models of AD. We conclude by suggesting that a multidimensional approach to cognitive assessment in preclinical models, in which a number of aspects of cognition are investigated while confounding factors are minimized, is becoming increasingly feasible and may contribute significantly towards the development of more targeted therapeutic interventions.

Effects of memantine on latent inhibition of active avoidance in wistar rats

Latent inhibition of active avoidance reaction was acquired by mature Wistar rats. It manifested in marked delay of habit acquisition after preexposure to the conditional stimulus in the first experimental session. Single dose of NMDA-receptor antagonist memantine (10 and 14 mg/kg) was applied 60 min before training in the second session. Failure of latent inhibition formation was registered after administration of the higher memantine dose; it manifested in accelerated attaining of the criterion (7 successive conditioned avoidance reactions) compared to training results after administration of the lower dose or physiological saline. The effects of memantine on attention were found to depend on the presence of pathology. It was hypothesized that the preparation can produce a positive effect on memory in Alzheimer-type dementia due to primary recovery of the inhibitory aspect of attention.

Memantine: a review of studies into its safety and efficacy in treating Alzheimer's disease and other dementias

Memantine is an uncompetitive N-methyl-D-aspartate receptor antagonist with moderate affinity. Its mechanism of action is neuroprotective and potentially therapeutic in several neuropsychiatric diseases. It has been approved by the FDA for the treatment of moderate to severe Alzheimer's disease (AD) either as a monotherapy or in combination with cholinesterase inhibitors. This review covers key studies of memantine's safety and efficacy in treating moderate to severe AD. It also covers current research into other dementias including but not exclusively mild AD and vascular dementia. Other studies on the efficacy of memantine for other neuropsychiatric diseases are discussed. Memantine is a safe and effective drug that merits further research on several topics. Clinicians should be aware of new studies and potential uses of memantine because of its safety and efficacy.

Randomized double-blind placebo-controlled donepezil augmentation in antidepressant-treated elderly patients with depression and cognitive impairment: a pilot study

OBJECTIVE

To assess combined antidepressant and cognitive enhancer treatment in elderly patients presenting with depression plus cognitive impairment.

METHODS

Twenty-three elderly (>50 years old) depressed, cognitively impaired (DEP-CI) patients participated in a pilot study. We evaluated whether, after 8 weeks of open antidepressant treatment, donepezil HCl (Aricept) would afford added cognitive benefit compared to placebo in a randomized 12-week trial. A subsample continued in an 8-month extension phase of open treatment with donepezil. Neuropsychological testing (NPT) was performed and antidepressant response monitored at baseline and the 8, 20, and 52-week time points.

RESULTS

At 8-weeks, the antidepressant response rate was 61% (14/23). Improvement in SRT immediate recall (SRT-IR; e.g. episodic verbal memory) was observed in responders compared to non-responders. During the 12-week, placebo-controlled, donepezil add-on trial, patients on donepezil showed further improvement in SRT-IR versus patients on placebo. In the open extension phase, patients who continued open donepezil treatment (n = 6) maintained improvement in memory and tended to show an advantage over patients who never received donepezil and were evaluated at the 52-week time point (n = 6). There were no observed significant donepezil effects on non-memory cognitive domains.

CONCLUSION

These preliminary findings suggest that addition of a cholinesterase inhibitor (AChEI) following antidepressant medication treatment in elderly Dep-CI patients may improve cognition, and support the need for a confirmatory, larger randomized placebo-controlled trial.

The uncompetitive N-methyl-D-aspartate (NMDA) receptor antagonist memantine prolongs spatial memory in a rat delayed radial-arm maze memory task

In the present study, we evaluated the effects of memantine in a delayed radial-arm maze rat task, consisting of an acquisition phase followed 18 h later by a win-shift retrieval test. When administered 20 min before acquisition, memantine elicited an inverted U-shape dose-response relationship, with low doses (0.3 and 0.56 mg/kg) reducing the number of errors committed during the retrieval test, while high doses (3 and 10 mg/kg) disrupted maze running. Memantine given immediately after acquisition or 20 min before retrieval failed to affect performance. Co-administration of subthreshold doses of memantine with either the CB(1) receptor antagonist rimonabant or the acetylcholine esterase inhibitor donepezil failed to enhance performance. Thus, low doses of memantine enhance acquisition processes that lead to prolonged spatial memory.

Memantine reduces oxidative damage and enhances long-term recognition memory in aged rats

Many neurodegenerative diseases, including Alzheimer's (AD), Parkinson's (PD) and Huntington's diseases (HD), are caused by different mechanisms but may share a common pathway to neuronal injury as a result of the overstimulation of glutamate receptors. It has been suggested that this pathway can be involved in generation of cognitive deficits associated with normal aging. Previous studies performed in our laboratory have demonstrated that aged rats presented recognition memory deficits. The aim of the present study was to evaluate the effect of memantine, a low-affinity N-methyl-D-aspartate (NMDA) receptor antagonist, on age-induced recognition memory deficits. Additionally, parameters of oxidative damage in cerebral regions related to memory formation were evaluated. In order to do that, male Wistar rats (24 months old) received daily injections of saline solution or memantine (20 mg/kg i.p.) during 21 days. The animals were submitted to a novel object recognition task 1 week after the last injection. Memantine-treated rats showed normal recognition memory while the saline group showed long-term recognition memory deficits. The results show that memantine is able to reverse age-induced recognition memory deficits. We also demonstrated that memantine reduced the oxidative damage to proteins in cortex and hippocampus, two important brain regions involved in memory formation. Thus, the present findings suggest that, at least in part, age-induced cognitive deficits are related to oxidative damage promoted by NMDA receptor overactivation.