Nutritional supplementation for Alzheimer's disease?

Associations between dietary one-carbon metabolism nutrients, genetic risk, with Alzheimer's disease: a prospective cohort study

BACKGROUND

The associations between one-carbon metabolism (OCM) nutrients (methionine, folate, vitamin B6, and vitamin B12) and Alzheimer's disease (AD) remains inconclusive.

OBJECTIVES

This study aims to investigate the association of dietary OCM nutrients with the subsequent risk of AD, and further assessed whether participants with a high genetic risk for AD might benefit from dietary OCM nutrients.

METHODS

We analyzed data from 192,214 participants who completed at least one 24-hour dietary questionnaire and had no previous history of AD based on the UK Biobank. Nutrients intake was calculated using McCance and Widdowson's The Composition of Food and USDA's Food and Nutrient Database for Dietary Studies. Cox proportional models with restricted cubic splines were applied to explore the associations.

RESULTS

Over a median follow-up of 13.35 years, 959 cases of AD (41 early-onset cases and 918 late-onset cases) were identified. Compared to those in the low-intake OCM group (quartile 1), participants in the high-intake OCM group (quartile 4) had a reduced risk of developing AD. The corresponding hazard ratios (HRs) and 95% CI for methionine, folate, vitamin B6, and vitamin B12 intake were 0.66 (0.54, 0.80), 0.71 (0.58, 0.87), 0.71 (0.59, 0.87), and 0.77 (0.64, 0.93), respectively. Similar associations were observed in late-onset AD. In early-onset AD, high methionine and vitamin B12 intake were associated with a 70% (HR = 0.30, 95% CI: 0.10, 0.86) and 71% (HR = 0.29, 95% CI: 0.09, 0.96) reduction in risk, respectively. Participants with low genetic risk and high OCM nutrients intake had a >75% reduced AD risk compared to high-risk, low-intake participants.

CONCLUSIONS

In this prospective cohort study, we found that higher intake of OCM nutrients is associated with a reduced risk of AD. Participants with a high genetic risk of AD are more likely to benefit from dietary OCM nutrients intake.

Effects of intensive lifestyle changes on the progression of mild cognitive impairment or early dementia due to Alzheimer's disease: a randomized, controlled clinical trial

BACKGROUND

Evidence links lifestyle factors with Alzheimer's disease (AD). We report the first randomized, controlled clinical trial to determine if intensive lifestyle changes may beneficially affect the progression of mild cognitive impairment (MCI) or early dementia due to AD.

METHODS

A 1:1 multicenter randomized controlled phase 2 trial, ages 45-90 with MCI or early dementia due to AD and a Montreal Cognitive Assessment (MoCA) score of 18 or higher. The primary outcome measures were changes in cognition and function tests: Clinical Global Impression of Change (CGIC), Alzheimer's Disease Assessment Scale (ADAS-Cog), Clinical Dementia Rating-Sum of Boxes (CDR-SB), and Clinical Dementia Rating Global (CDR-G) after 20 weeks of an intensive multidomain lifestyle intervention compared to a wait-list usual care control group. ADAS-Cog, CDR-SB, and CDR-Global scales were compared using a Mann-Whitney-Wilcoxon rank-sum test, and CGIC was compared using Fisher's exact test. Secondary outcomes included plasma Aβ42/40 ratio, other biomarkers, and correlating lifestyle with the degree of change in these measures.

RESULTS

Fifty-one AD patients enrolled, mean age 73.5. No significant differences in any measures at baseline. Only two patients withdrew. All patients had plasma Aβ42/40 ratios <0.0672 at baseline, strongly supporting AD diagnosis. After 20 weeks, significant between-group differences in the CGIC (p= 0.001), CDR-SB (p= 0.032), and CDR Global (p= 0.037) tests and borderline significance in the ADAS-Cog test (p= 0.053). CGIC, CDR Global, and ADAS-Cog showed improvement in cognition and function and CDR-SB showed significantly less progression, compared to the control group which worsened in all four measures. Aβ42/40 ratio increased in the intervention group and decreased in the control group (p = 0.003). There was a significant correlation between lifestyle and both cognitive function and the plasma Aβ42/40 ratio. The microbiome improved only in the intervention group (p <0.0001).

CONCLUSIONS

Comprehensive lifestyle changes may significantly improve cognition and function after 20 weeks in many patients with MCI or early dementia due to AD.

TRIAL REGISTRATION

Approved by Western Institutional Review Board on 12/31/2017 (#20172897) and by Institutional Review Boards of all sites. This study was registered retrospectively with clinicaltrials.gov on October 8, 2020 (NCT04606420, ID: 20172897).

Impact of multivitamin-mineral and cocoa extract on incidence of mild cognitive impairment and dementia: Results from the COcoa Supplement and Multivitamin Outcomes Study for the Mind (COSMOS-Mind)

INTRODUCTION

We assessed the effects of multivitamin-mineral and cocoa extract supplementation on incident mild cognitive impairment (MCI) and all-cause probable dementia.

METHODS

COSMOS-Mind (N = 2262), a 2 × 2 factorial, randomized-controlled clinical trial administered a telephone-based cognitive battery at baseline and annually for 3 years. Incidence rates of MCI, and separately dementia, were compared among treatment arms with proportional hazards regression.

RESULTS

Over 3 years, 110 incident MCI and 14 incident dementia cases were adjudicated. Incidence rates did not vary by assignment to multivitamin-mineral or cocoa extract (all p's ≥ 0.05); however, statistical power was low. When participants assigned to multivitamin-mineral versus placebo converted to MCI, their scores for global cognition (p = 0.03) and executive function (p < 0.001) were higher and had declined less relative to the previous year (p = 0.03 for global cognition; p = 0.004 for executive function).

DISCUSSION

Multivitamin-mineral therapy may provide cognitive resilience, countering conversion to MCI, but not significantly reduce its incidence over 3 years.

HIGHLIGHTS

Multivitamin-mineral supplementation did not reduce risks for cognitive impairment. Cocoa extract supplementation did not reduce risks for cognitive impairment. Multivitamin-mineral supplementation slowed cognitive declines for incident mild cognitive impairment.

Turning Back the Clock: A Retrospective Single-Blind Study on Brain Age Change in Response to Nutraceuticals Supplementation vs. Lifestyle Modifications

BACKGROUND

There is a growing consensus that chronological age (CA) is not an accurate indicator of the aging process and that biological age (BA) instead is a better measure of an individual's risk of age-related outcomes and a more accurate predictor of mortality than actual CA. In this context, BA measures the "true" age, which is an integrated result of an individual's level of damage accumulation across all levels of biological organization, along with preserved resources. The BA is plastic and depends upon epigenetics. Brain state is an important factor contributing to health- and lifespan.

METHODS AND OBJECTIVE

Quantitative electroencephalography (qEEG)-derived brain BA (BBA) is a suitable and promising measure of brain aging. In the present study, we aimed to show that BBA can be decelerated or even reversed in humans (N = 89) by using customized programs of nutraceutical compounds or lifestyle changes (mean duration = 13 months).

RESULTS

We observed that BBA was younger than CA in both groups at the end of the intervention. Furthermore, the BBA of the participants in the nutraceuticals group was 2.83 years younger at the endpoint of the intervention compared with their BBA score at the beginning of the intervention, while the BBA of the participants in the lifestyle group was only 0.02 years younger at the end of the intervention. These results were accompanied by improvements in mental-physical health comorbidities in both groups. The pre-intervention BBA score and the sex of the participants were considered confounding factors and analyzed separately.

CONCLUSIONS

Overall, the obtained results support the feasibility of the goal of this study and also provide the first robust evidence that halting and reversal of brain aging are possible in humans within a reasonable (practical) timeframe of approximately one year.

Longitudinal White and Gray Matter Response to Precision Medicine-Guided Intervention for Alzheimer's Disease

BACKGROUND

Alzheimer's disease (AD) is a debilitating condition that is widely known to adversely affect gray matter (GM) and white matter (WM) tracts within the brain. Recently, precision medicine has shown promise in alleviating the clinical and gross morphological trajectories of patients with AD. However, regional morphological changes have not yet been adequately characterized.

OBJECTIVE

Investigate regional morphological responses to a precision medicine-guided intervention with regards to white and gray matter in AD and mild cognitive impairment (MCI).

METHODS

Clinical and neuroimaging data were compiled over a 9-month period from 25 individuals who were diagnosed with AD or MCI receiving individualized treatment plans. Structural T1-weighted MRI scans underwent segmentation and volumetric quantifications via Neuroreader. Longitudinal changes were calculated via annualized percent change of WM or GM ratios.

RESULTS

Montreal Cognitive Assessment scores (p < 0.001) and various domains of the Computerized Neurocognitive Screening Vital Signs significantly improved from baseline to 9-month follow-up. There was regional variability in WM and GM atrophy or hypertrophy, but none of these observed changes were statistically significant after correction for multiple comparisons.

Supplementation With Carotenoids, Omega-3 Fatty Acids, and Vitamin E Has a Positive Effect on the Symptoms and Progression of Alzheimer’s Disease

Background: Preliminary work by our center has reported behavior and functional benefits in patients with Alzheimer’s disease (AD) following targeted micronutritional supplementation. Objective: To build on the existing exploratory research and investigate the impact of these micronutrients on the natural progression of AD in a randomized controlled trial. Methods: Patients with mild-moderate AD consumed daily 1 g fish oil (of which 500 mg DHA, 150 mg EPA), 22 mg carotenoids (10 mg lutein, 10 mg meso-zeaxanthin, 2 mg zeaxanthin), and 15 mg vitamin E or placebo for 12 months in a double-blind, placebo-controlled, randomized clinical trial. Carotenoids, ω-3FAs, and vitamin E were quantified in blood. Carotenoids were also measured in skin. AD severity was measured using the mini-mental state examination and dementia severity rating scale tools. Behavior, mood, and memory were measured using an informant-based questionnaire. Results: Following 12 months of supplementation, the active group (n = 50) compared to the placebo group (n = 27), demonstrated statistically significant improvements in skin carotenoid measurements, blood carotenoids, ω-3FAs, and vitamin E concentrations (p <  0.05, for all). The active group also performed better in objective measures of AD severity (i.e., memory and mood), with a statistically significant difference reported in the clinical collateral for memory (p <  0.001). Conclusion: Exponential increases in the prevalence of AD and its relentless progressive nature is driving the need for interventions that help to ameliorate symptoms and improve quality of life in AD patients. Given the positive outcomes demonstrated in this trial, this combined micronutrient dietary supplement should be considered in the overall management of AD.

Improvement of cognitive performance by a nutraceutical formulation: Underlying mechanisms revealed by laboratory studies

Cognitive decline, decrease in neuronal function and neuronal loss that accompany normal aging and dementia are the result of multiple mechanisms, many of which involve oxidative stress. Herein, we review these various mechanisms and identify pharmacological and non-pharmacological approaches, including modification of diet, that may reduce the risk and progression of cognitive decline. The optimal degree of neuronal protection is derived by combinations of, rather than individual, compounds. Compounds that provide antioxidant protection are particularly effective at delaying or improving cognitive performance in the early stages of Mild Cognitive Impairment and Alzheimer's disease. Laboratory studies confirm alleviation of oxidative damage in brain tissue. Lifestyle modifications show a degree of efficacy and may augment pharmacological approaches. Unfortunately, oxidative damage and resultant accumulation of biomarkers of neuronal damage can precede cognitive decline by years to decades. This underscores the importance of optimization of dietary enrichment, antioxidant supplementation and other lifestyle modifications during aging even for individuals who are cognitively intact.

[Effects of the use of 17 β-estradiol and genistein in Alzheimer's disease in women with menopause]

The use of 17 β-estradiol and genistein in women with menopause helps in the reduction of vasomotor symptoms and cognitive improvement. There is evidence on the use of certain flavonoids such as genistein, which has a potentially neuroprotective role in neurodegenerative diseases such as Alzheimer's. Scientific evidence on the effects of phytoestrogens and genistein during menopause and their effect on cognition are scarce, however, in the present review it was found that the intervention with 17 β-estradiol has positive effects on cognition in women with Alzheimer's disease. In addition, the use of genistein, daidzein or any supplement based on isoflavones may influence vasomotor symptoms. 17 β-estradiol supplements in women in early menopause and with some degree of cognitive impairment may have beneficial effects.

The pleiotropic neuroprotective effects of resveratrol in cognitive decline and Alzheimer's disease pathology: From antioxidant to epigenetic therapy

While the elderly segment of the population continues growing in importance, neurodegenerative diseases increase exponentially. Lifestyle factors such as nutrition, exercise, and education, among others, influence ageing progression, throughout life. Notably, the Central Nervous System (CNS) can benefit from nutritional strategies and dietary interventions that prevent signs of senescence, such as cognitive decline or neurodegenerative diseases such as Alzheimer's disease and Parkinson's Disease. The dietary polyphenol Resveratrol (RV) possesses antioxidant and cytoprotective effects, producing neuroprotection in several organisms. The oxidative stress (OS) occurs because of Reactive oxygen species (ROS) accumulation that has been proposed to explain the cause of the ageing. One of the most harmful effects of ROS in the cell is DNA damage. Nevertheless, there is also evidence demonstrating that OS can produce other molecular changes such as mitochondrial dysfunction, inflammation, apoptosis, and epigenetic modifications, among others. Interestingly, the dietary polyphenol RV is a potent antioxidant and possesses pleiotropic actions, exerting its activity through various molecular pathways. In addition, recent evidence has shown that RV mediates epigenetic changes involved in ageing and the function of the CNS that persists across generations. Furthermore, it has been demonstrated that RV interacts with gut microbiota, showing modifications in bacterial composition associated with beneficial effects. In this review, we give a comprehensive overview of the main mechanisms of action of RV in different experimental models, including clinical trials and discuss how the interconnection of these molecular events could explain the neuroprotective effects induced by RV.

Effects of oral nutrition supplements in persons with dementia: A systematic review

OBJECTIVE

Persons with dementia are at risk of malnutrition, evidenced by low dietary intake, which has consequences for nutritional status, activity of daily living and disease progression. The effects of oral nutrition supplements (ONS) on nutritional intake, nutritional status, and cognitive and physical outcomes in older persons with dementia were evaluated.

METHODS

PubMed, Medline, Embase, CINAHL and the Cochrane Central Register of Controlled Trials were searched in December 2017, and this was repeated in May 2019. The Preferred Reporting Items for Systematic Reviews and Analysis (PRISMA) checklist was used. Papers were considered if they presented experimental clinical trials using oral nutritional supplements to persons diagnosed with dementia, including Alzheimer's disease and mild cognitive impairment, and conducted in hospitals, nursing homes or homes.

RESULTS

We included ten articles reporting nine clinical trials. A total of 407 persons with dementia were included, of whom 228 used ONS for 7 to 180 days. Nutritional intake improved by 201 to 600 kcal/day. Energy intake from ordinary foods was not affected, thus ONS improved the persons daily intake of energy and protein. Body weight, muscle mass, and nutritional biomarkers in blood improved in the intervention groups compared with the control groups. No effects on cognition or physical outcomes were observed.

CONCLUSION

ONS increases the intake of energy and protein and improves nutritional status in persons with dementia; however, RCTs with longer intervention periods are needed to investigate the impact on cognitive and functional outcomes.

Bioactive Food Abates Metabolic and Synaptic Alterations by Modulation of Gut Microbiota in a Mouse Model of Alzheimer's Disease

Recent investigations have demonstrated an important role of gut microbiota (GM) in the pathogenesis of Alzheimer's disease (AD). GM modulates a host's health and disease by production of several substances, including lipopolysaccharides (LPS) and short-chain fatty acids (SCFAs), among others. Diet can modify the composition and diversity of GM, and ingestion of a healthy diet has been suggested to lower the risk to develop AD. We have previously shown that bioactive food (BF) ingestion can abate neuroinflammation and oxidative stress and improve cognition in obese rats, effects associated with GM composition. Therefore, BF can impact the gut-brain axis and improved behavior. In this study, we aim to explore if inclusion of BF in the diet may impact central pathological markers of AD by modulation of the GM. Triple transgenic 3xTg-AD (TG) female mice were fed a combination of dried nopal, soy, chia oil, and turmeric for 7 months. We found that BF ingestion improved cognition and reduced Aβ aggregates and tau hyperphosphorylation. In addition, BF decreased MDA levels, astrocyte and microglial activation, PSD-95, synaptophysin, GluR1 and ARC protein levels in TG mice. Furthermore, TG mice fed BF showed increased levels of pGSK-3β. GM analysis revealed that pro-inflammatory bacteria were more abundant in TG mice compared to wild-type, while BF ingestion was able to restore the GM's composition, LPS, and propionate levels to control values. Therefore, the neuroprotective effects of BF may be mediated, in part, by modulation of GM and the release of neurotoxic substances that alter brain function.

Relative Efficacy of a Nutritional Intervention on Cognitive Performance Across the Adult Lifespan and During Early Cognitive Decline

A nutritional supplement has maintained or improved cognitive performance for healthy adults and individuals with mild cognitive impairment (MCI). Performance varied between 93 healthy adults aged 18-73 years versus 43 aged 75-85 years and among individuals with MCI. Healthy adult performance was stratified by age and for MCI as "intact" or "impaired" (Dementia Rating Scale guidelines). Some older individuals performed as well as younger individuals. All intact individuals with MCI maintained baseline performance; only impaired individuals receiving the supplement maintained baseline performance. Variation among elderly individuals can preclude observation of efficacy. Supplementation may maintain rather than improve performance for some individuals.

Reversibility of Age-related Oxidized Free NADH Redox States in Alzheimer's Disease Neurons by Imposed External Cys/CySS Redox Shifts

Redox systems including extracellular cysteine/cystine (Cys/CySS), intracellular glutathione/oxidized glutathione (GSH/GSSG) and nicotinamide adenine dinucleotide reduced/oxidized forms (NADH/NAD⁺) are critical for maintaining redox homeostasis. Aging as a major risk factor for Alzheimer’s disease (AD) is associated with oxidative shifts, decreases in anti-oxidant protection and dysfunction of mitochondria. Here, we examined the flexibility of mitochondrial-specific free NADH in live neurons from non-transgenic (NTg) or triple transgenic AD-like mice (3xTg-AD) of different ages under an imposed extracellular Cys/CySS oxidative or reductive condition. We used phasor fluorescence lifetime imaging microscopy (FLIM) to distinguish free and bound NADH in mitochondria, nuclei and cytoplasm. Under an external oxidative stress, a lower capacity for maintaining mitochondrial free NADH levels was found in old compared to young neurons and a further decline with genetic load. Remarkably, an imposed Cys/CySS reductive state rejuvenated the mitochondrial free NADH levels of old NTg neurons by 71% and old 3xTg-AD neurons by 89% to levels corresponding to the young neurons. Using FLIM as a non-invasive approach, we were able to measure the reversibility of aging subcellular free NADH levels in live neurons. Our results suggest a potential reductive treatment to reverse the loss of free NADH in old and Alzheimer’s neurons.

Cognitive Improvement in Healthy Older Adults Can Parallel That of Younger Adults Following Lifestyle Modification: Support for Cognitive Reserve During Aging

Executive function was assayed following a nutritional supplementation in healthy adults using the Trail Making Test. Comparison with published normative scores demonstrated that cohorts from 35-74 years of age displayed similar relative improvement compared to their own baseline performance. These findings support early, pro-active lifestyle modifications to maintain cognitive performance during aging and further demonstrate the persistence of cognitive reserve in healthy older adults.

While I Still Remember: 30 Years of Alzheimer's Disease Research

Turns out I have been a major contributor to the Journal of Alzheimer's Disease over its 20-year history. As such, I was invited to provide a review of my work over the years. What follows is a retrospective of how the Alzheimer-related research of a Ph.D. (i.e., not an M.D.) transitioned from basic to clinical, and moved from bench to bedside and back again.I have included some of the more humorous and poignant twists along the way that some older players may find familiar and I hope might inspire some younger players to hang in there.

Investigation of thymol effect on learning and memory impairment induced by intrahippocampal injection of amyloid beta peptide in high fat diet- fed rats

Obesity and consumption of a high fat diet (HFD) are known to increase the risk of Alzheimer's disease (AD). In the present study, we have examined the protective and therapeutic effects of thymol (main monoterpene phenol found in thyme essential oil) on a HFD-fed rat model of AD. Fourty adult male Wistar rats were randomly assigned to 5 groups:(n = 8 rats/group): group 1, control, consumed an ordinary diet, group 2 consumed a HFD for 8 weeks, then received phosphate-buffered saline (PBS) via intrahippocampal (IHP) injection, group 3 consumed HFD for 8 weeks, then received beta-amyloid (Aβ)1-42 via IHP injections to induce AD, group 4 consumed HFD for 8 weeks, then received Aβ1-42, and was treated by thymol (30 mg/kg in sunflower oil) daily for 4 weeks, and group 5 consumed HFD for 8 week, then received Aβ1-42 after what sunflower oil was administered by oral gavage daily for 4 weeks. Biochemical tests showed an impaired lipid profile and higher glucose levels upon consumption of HFD, which was ameliorated by thymol treatment. In behavioral results, spatial memory in group 3 was significantly impaired, but groups treated with thymol showed better spatial memory compared to group 3 (p ≤ 0.01). In histological results, formation of Aβ plaque in hippocampus of group 3 increased significantly compared to group 1 and group 2 (p ≤ 0.05), but group 4 showed decreased Aβ plaques compared to group 3 (p ≤ 0.01). In conclusion, thymol decreased the effects of Aβ on memory and could be considered as neuroprotective.

Efficacy of lifestyle interventions on clinical and neuroimaging outcomes in elderly

The prevalence of Alzheimer's disease (AD) is constantly growing worldwide in absence of any effective treatment. Methodology and technique advancements facilitated the early diagnosis of AD leading to a shift toward preclinical AD stages investigation in order to delay the disease onset in individuals at risk for AD. Recent evidence demonstrating the aging related multifactorial nature of AD supported the hypothesis that modifiable environmental factors can accelerate or delay the disease onset. In particular, healthy dietary habits, constant physical and cognitive activities are associated with reduced brain atrophy, amyloid load and incidence of AD cases. Due to these promising results, an emerging field of studies is currently investigating the efficacy of interventions addressing different lifestyle habits in cognitive intact elderly individuals as a potential preventive strategy against AD onset. We provide a critical overview of the current evidence on nonpharmacologic treatments in elderly individuals, discussing their efficacy on clinical and neuroimaging outcomes and identifying current methodological issues. Future perspectives, relevant for the scientific community and the worldwide public health institutes will be further discussed.

Combined omega-3 fatty acids, aerobic exercise and cognitive stimulation prevents decline in gray matter volume of the frontal, parietal and cingulate cortex in patients with mild cognitive impairment

Previous studies in older adults suggested beneficial effects of omega-3 fatty acid (FA) supplementation, aerobic exercise, or cognitive stimulation on brain structure and function. However, combined effects of these interventions in patients suffering from mild cognitive impairment (MCI) are unknown. Using a randomized interventional design, we evaluated the effect of combined omega-3 FA supplementation, aerobic exercise and cognitive stimulation (target intervention) versus omega-3 FA supplementation and non-aerobic exercise (control intervention) on cognitive function and gray matter volume in patients with MCI. Moreover, we analyzed potential vascular, metabolic or inflammatory mechanisms underlying these effects. Twenty-two MCI patients (8 females; 60-80years) successfully completed six months of omega-3 FA intake, aerobic cycling training and cognitive stimulation (n=13) or omega-3 FA intake and non-aerobic stretching and toning (n=9). Before and after the interventions, cognitive performance, magnetic resonance imaging of the brain at 3T (n=20), intima-media thickness of the internal carotid artery and serum markers of glucose control, lipid and B-vitamin metabolism, and inflammation were assessed. Intervention-related changes in gray matter volume of Alzheimer's disease (AD)-related brain regions, i.e., frontal, parietal, temporal and cingulate cortex were examined using voxel-based morphometry of high resolution T1-weighted images. After the intervention period, significant differences emerged in brain structure between groups: Gray matter volume decreased in the frontal, parietal and cingulate cortex of patients in the control intervention, while gray matter volume in these areas was preserved or even increased after the target intervention. Decreases in homocysteine levels in the target intervention group were associated with increases in gray matter volume in the middle frontal cortex (p=0.010). No significant differences in cognitive performance or other vascular, metabolic and inflammatory parameters were observed between groups. This pilot study provides preliminary evidence that omega-3 FA intake combined with aerobic exercise and cognitive stimulation prevents atrophy in AD-related brain regions in MCI patients, compared to omega-3 FA intake plus the control condition of stretching and toning. These promising findings should now be validated in a larger interventional trial.

Benefits and risks of add-on therapies for Alzheimer's disease

Despite three decades of intensive research, the efforts of scientific society and industry and the expenditures, numerous attempts to develop effective treatments for Alzheimer's disease have failed. Currently, approved and widely used medications to treat cognitive deficits in Alzheimer's disease are symptomatic only and show at best modest efficacy. In this context, the need to develop a successful, disease-modifying treatment is loudly expressed. One way to achieve this goal is the use of add-on therapies or various combinations of existing ‘conventional’ drugs. Results of several clinical studies and post hoc analyses of combination therapy with all cholinesterase inhibitors and memantine are published. Moreover, there is a need for studies on long-term efficacy of combination therapy in Alzheimer's.