Effective pharmaceutical treatments for age-related cognitive decline have proved elusive. There is, however, compelling evidence that nutritional status and supplementation could play crucial roles in modifying the expression of cognitive change through the lifespan. Subjective memory impairment and mild cognitive impairment can be harbingers of dementia but this is by no means inevitable. Neurocognitive change is influenced by a variety of processes, many of which are involved in other aspects of systemic health, including cardiovascular function. Importantly, many of these processes are governed by mechanisms which may be modified by specific classes of bioactive nutrients. There is increasing, converging evidence from controlled trials that nutritional interventions can improve mood and cognitive function in both clinical and healthy populations. Specific examples include selected botanical extracts such as the flavonoids. Some nutritional supplements (e.g. broad-spectrum micronutrient supplementation) appear to support improved cognitive function, possibly through redressing insufficient nutrient status (i.e. suboptimal but above the threshold for frank deficiency). Recent mechanistic research has unveiled physiologically plausible, modifiable, cognition-relevant targets for nutrition and nutraceuticals. These include processes involved in both systemic and central vascular function, inflammation, metabolism, central activation, improved neural efficiency and angiogenesis. The advent and development of human neuroimaging methodology have greatly aided our understanding of the core central mechanisms of cognitive change. Different imaging modalities can provide insights into modifiable central mechanisms which may be targeted by bioactive nutrients. The latter may contribute to slowing age-related decline through supporting neurocognitive scaffolding mechanisms.

Background: The AIBL study, which commenced in November 2006, is a two-center prospective study of a cohort of 1112 volunteers aged 60+. The cohort includes 211 patients meeting NINCDS-ADRDA criteria for Alzheimer's disease (AD) (180 probable and 31 possible). We aimed to identify factors associated with rapid cognitive decline over 18 months in this cohort of AD patients.

Methods: We defined rapid cognitive decline as a drop of 6 points or more on the Mini-Mental State Examination (MMSE) between baseline and 18-month follow-up. Analyses were also conducted with a threshold of 4, 5, 7 and 8 points, as well as with and without subjects who had died or were too severely affected to be interviewed at 18 months and after, both including and excluding subjects whose AD diagnosis was “possible” AD. We sought correlations between rapid cognitive decline and demographic, clinical and biological variables.

Results: Of the 211 AD patients recruited at baseline, we had available data for 156 (73.9%) patients at 18 months. Fifty-one patients were considered rapid cognitive decliners (32.7%). A higher Clinical Dementia Rating scale (CDR) and higher CDR “sum of boxes” score at baseline were the major predictors of rapid cognitive decline in this population. Furthermore, using logistic regression model analysis, patients treated with a cholinesterase inhibitor (CheI) had a higher risk of being rapid cognitive decliners, as did males and those of younger age.

Conclusions: Almost one third of patients satisfying established research criteria for AD experienced rapid cognitive decline. Worse baseline functional and cognitive status and treatment with a CheI were the major factors associated with rapid cognitive decline over 18 months in this population.

Background: Maintaining continuous pharmacological treatment of patients with dementia is often difficult. In the current study we surveyed the discontinuation of donepezil, a cholinesterase inhibitor, for the treatment of Alzheimer's disease in a Japanese geriatric outpatient clinic in a university hospital.

Methods: Using a retrospective chart review from 1 July 2003 to 30 June 2005, prescriptions of donepezil and the reasons for discontinuing the prescription in a university hospital were determined. The severity of dementia was evaluated by the clinical dementia rating (CDR).

Results: Out of 264 patients, 140 (53.1%) discontinued taking donepezil during the two-year observation period. The mean age of the continued group and the discontinued group did not differ significantly (79.5 ± 6.7, 79.8 ± 6.4, respectively). Kaplan-Meier analysis showed that the patients with more severe cognitive impairment (CDR score = 3) discontinued donepezil earlier and more frequently. The reasons for discontinuation were a change in the doctors treating the patients (n = 71), ineffectiveness (n = 16), gastrointestinal side-effects (n = 11), and others (n = 41). In patients with CDR = 1 or 2, changes of doctors were the most frequent reason for discontinuation. However, in patients with CDR = 3, ineffectiveness of the medication was the major reason for discontinuation.

Conclusion: Donepezil was frequently discontinued, and the rate of discontinuation was higher in patients with advanced dementia.

Behavioral and psychological symptoms of dementia (BPSD) are a common manifestation of Alzheimer's disease (AD) and other dementia syndromes. Patients experience prominent and multiple symptoms, which are both distressing and a source of considerable social, health, and economic cost. Development of symptoms is in part related to progressive neurodegeneration and cholinergic deficiency in brain regions important in the regulation of behavioral and emotional responses including the cortex, hippocampus, and limbic system. Cholinesterase (ChE) inhibitors offer a mechanism-based approach to therapy to enhance endogenous cholinergic neurotransmission. Studies using ChE inhibitors have demonstrated their clear potential to improve or stabilize existing BPSD. Differences have been noted between selective acetylcholinesterase (AChE) inhibitors (donepezil and galantamine) and dual ChE inhibitors (rivastigmine) in terms of treatment response. While donepezil has shown efficacy in moderate to severe noninstitutionalized AD patients, conflicting results have been obtained in mild to moderate patients and in nursing home patients. Galantamine has been shown to delay the onset of BPSD during a five-month study but has been otherwise poorly studied to-date. Both donepezil and galantamine have not as yet demonstrated efficacy in reducing psychotic symptoms or in reducing levels of concomitant psychotropic medication use. Studies with the dual ChE inhibitor rivastigmine in mild to moderately severe AD and in Lewy body dementia (LBD) have shown improvements in behavioral symptoms including psychosis. Improvements have been maintained over a period of up to two years. In addition, institutionalized patients with severe AD have shown symptomatic benefits with a reduction in the requirement for additional psychotropic drugs following treatment with rivastigmine. The psychotropic properties associated with rivastigmine may in part be mediated through effects on butyrylcholinesterase. Current treatment options are limited for patients with dementia syndromes other than AD. However, data concerning rivastigmine in patients with LBD and preliminary studies in Parkinson's disease dementia and vascular dementia suggest a role for ChE inhibitors across the spectrum of dementia syndromes. Finally, studies that incorporated a delayed start design demonstrate that ChE inhibitors may delay the progression of BPSD.

Alzheimer's disease (AD) is characterized by deterioration in the ability to perform activities of daily living (ADL) in addition to loss of cognitive function and behavioral changes. This decline in day-to-day functioning is increasingly recognized as a source of considerable social, health, and economic costs. Inability to perform ADL results in growing caregiver burden and may lead to the eventual need for alternative care or nursing home placement. The measurement of ADL, which enables monitoring of the effectiveness of therapeutic interventions, can be performed using a number of inventories including the Progressive Deterioration Scale (PDS), the Disability Assessment for Dementia (DAD), and the Alzheimer Disease Cooperative Study ADL (ADCS/ADL) assessment scale. Clinical studies using these and other scales have indicated that cholinesterase (ChE) inhibitors offer an effective approach to treating the functional decline of AD. Donepezil, rivastigmine, and galantamine have been shown in some studies to prevent or slow decline in ADL over treatment periods of one to two years. For instance, in a 24-week study in subjects with moderate to severe AD, donepezil-treated patients remained stable compared with the placebo-treated patients. Rivastigmine has shown improvement or stabilization of PDS scores in patients with mild to moderate disease following 26 weeks of treatment and slowed deterioration in patients with more severe disease. Evidence to date suggests that these agents may not be equally effective at slowing or stabilizing loss in ADL over time and that these differences may reflect differences in pharmacology. In addition to inhibition of acetylcholinesterase (AChE), these compounds have other putative differences in mechanisms of action. Galantamine allosterically modulates the nicotinic receptor and may prevent the loss of ADL. Rivastigmine robustly inhibits butyrylcholinesterase in addition to AChE and therefore acts as a dual ChE inhibitor. Comparative studies evaluating the differential effects of these ChE inhibitors on ADL are awaited.

Cognitive decline, commonly first recognized as memory impairment, is a typical feature of Alzheimer's disease (AD). Neuropathological changes in the cerebral cortex and limbic system lead to deficits in learning, memory, language, and visuospatial skills. The precise nature of cognitive dysfunction reflects the distribution of pathological changes in AD. These will vary along the disease severity continuum and may also depend on where the disease sits in the spectrum of dementia. For example, AD-related disorders such as Lewy body dementia (LBD) and Parkinson's disease dementia (PDD) also show symptoms of cognitive decline and share several pathological features, including degeneration of cortical cholinergic and striatal dopaminergic neurons. In vascular dementia (VaD), there is often an unequal distribution of cognitive deficit, with severe impairment in some functions and relative sparing of others. Cholinesterase (ChE) inhibitors, which help restore acetylcholine levels in the brain, are licensed for the symptomatic treatment of AD and have shown additional benefit in related dementias. Physiological correlates of cholinergic function/dysfunction in the brain include regional cerebral blood flow, glucose metabolism, and cerebrospinal fluid levels of ChE enzymes. These variables represent valuable markers of the clinical efficacy of ChE inhibitors. However, direct assessment of cognitive improvement, stabilization or decline is usually considered the key efficacy parameter in clinical studies of ChE inhibitors in AD and related dementias. Large-scale, placebo-controlled clinical studies of ChE inhibitors have demonstrated efficacy in treating the cognitive impairments associated with AD. Randomized comparative studies of ChE inhibitors are now under way to directly compare symptomatic efficacy and effects on disease progression. Clinical trial data of the cognitive effects of ChE inhibitors in AD, LBD, PDD, and VaD are discussed in detail in this article. The benefits of long-term treatment on symptomatic improvement in cognition and further potential disease-modifying effects are highlighted.

Acetylcholinesterase (AChE) predominates in the healthy brain, with butyrylcholinesterase (BuChE) considered to play a minor role in regulating brain acetylcholine (ACh) levels. However, BuChE activity progressively increases in patients with Alzheimer's disease (AD), while AChE activity remains unchanged or declines. Both enzymes therefore represent legitimate therapeutic targets for ameliorating the cholinergic deficit considered to be responsible for the declines in cognitive, behavioral and global functioning characteristic of AD. The two enzymes differ in substrate specificity, kinetics and activity in different brain regions. Experimental evidence from the use of agents with enhanced selectivity for BuChE (cymserine analogues, MF-8622) and the dual inhibitor of both AChE and BuChE, rivastigmine, indicates potential therapeutic benefits of inhibiting both AChE and BuChE in AD and related dementias. Recent evidence suggests that both AChE and BuChE may have roles in the aetiology and progression of AD beyond regulation of synaptic ACh levels. The development of specific BuChE inhibitors and further experience with the dual enzyme inhibitor rivastigmine will improve understanding of the aetiology of AD and should lead to a wider variety of potent treatment options.

Background: There are difficulties in accurately defining patients with vascular dementia (VaD) and, therefore, little is known about the characteristics of this population. Objective: To examine the population characteristics in patients with VaD enrolled in two randomized, double-blind, placebo-controlled, 24-week clinical trials of the efficacy and tolerability of the acetylcholinesterase inhibitor donepezil. Methods: Enrolled patients had probable or possible VaD, classified according to NINDS-AIREN criteria. Patients were excluded if they had a diagnosis of Alzheimer's disease or dementia caused by other conditions not associated with the cardiovascular system. Results: A total of 1,219 patients, 73% with probable VaD and 27% with possible VaD, were enrolled. Patients had a mean Hachinski score of 9.7, with memory impairment the most prominent feature of their dementia. Sixty-eight percent of patients had a history of at least one stroke and 28% of patients had a history of transient ischemic attack before dementia. In the 99% of patients who had abnormal computer-assisted tomography or magnetic resonance imaging scans, cortical and subcortical infarcts were among the lesions observed, with significant white-matter lesions also present in some patients. Seventy-three percent of patients had experienced an abrupt onset of cognitive symptoms. Vascular risk factors were prominent and included hypertension (70%), smoking (62%), and hypercholesterolemia (39%). Conclusions: The patients enrolled in these trials had probable or possible VaD; these patients exhibited a history of cerebrovascular disease and a broad range of comorbid cardiovascular conditions. The large number of patients enrolled will permit a thorough examination of the efficacy and tolerability of donepezil in VaD.

Vascular dementia (VaD) is a disorder with no cure and limited treatment options. Similarities between VaD and Alzheimer's disease (AD) arise on a number of levels. Both involve progressive decline in cognition, functional ability, and behavior, and there is evidence for a central role of reduced cholinergic neurotransmission in the two illnesses. Treatment strategies in VaD have historically focused on prevention, although evidence of cognitive benefits with preventative treatment is scarce. Acetylcholinesterase inhibitors represent a rational treatment possibility for symptomatic therapy of patients with VaD. A recent large-scale trial of galantamine in patients with VaD or AD with cerebrovascular disease (AD + CVD) represents the first placebo-controlled trial showing clinically relevant benefits in these important patient populations.

Vascular dementia (VaD), like Alzheimer's disease (AD), is associated with cholinergic deficits. Rivastigmine provides sustained, brain-selective inhibition of acetylcholinesterase and butyrylcholinesterase. Preliminary data suggest that rivastigmine may provide significant benefits in patients with AD and cerebrovascular disease (mixed dementia), and in patients with VaD. Open-label rivastigmine treatment has been associated with improved cognitive and functional abilities, behavioral symptoms, and reduced caregiver stress in a small pilot study in these patients. Larger, prospective, double-blind studies of rivastigmine in patients with VaD are under way. These studies will confirm whether rivastigmine is an efficacious treatment option for a range of patients for whom, until now, there have been few symptomatic therapies.