Elderly with neuro-cognitive disorders (NCDs) present with variable level of severity of cognitive deficits which may be related to some or more domains of cognitive abilities. These domains include memory, orientation, learning, comprehension, judgment, emotional control, inability to initiate/ perform an activity etc. NCDs are categorized as delirium, dementia, amnestic, and other cognitive disorders in Diagnostic and Statistical Manual of Mental Disorders, 4 ^th Edition, Text Revision (DSM-IV TR); further, given a new diagnostic category of NCDs in DSM-5 and the subsections incorporated delirium, major NCDs (which were earlier labeled as dementia), and a new category of mild NCD. Dementia is one of the most common NCD and its prevalence show a frightening statistics. As the illness progresses the condition of patients worsen and at times care givers experience significant burden. Early recognition and consultation generally leads to a better management and thus, familiarity with issues related to cognitive decline as well as its epidemiology, screening, and management in handling the catastrophe is very much needed. The present article provides a comprehensive overview on the issue.

As advancements are being made in the medical field, the average life span is increasing and more complaints related to the elderly are coming into notice. Of these, mild cognitive decline (MCD) or mild cognitive impairment (MCI) is recently becoming an increasingly recognized entity that is often considered a precursor of dementia but is found to have other outcomes as well. It also has variations in presentations; it does not present only as memory complaint but also in the form of other cognitive or behavioral manifestations and has always been a point of controversy regarding the objectivity of the diagnosis. It is considered as the appropriate stage for intervention to prevent its progression to dementia and therefore, requires early identification for which various diagnostic modalities such as neuroimaging, neuropsychological tests, and biological markers are considered. Currently, there are no specific treatment guidelines for MCD. Drugs used in Alzheimer's disease (AD), lifestyle modifications, and other nonpharmacological approaches have shown some benefit in MCI but the results are variable; hence, the need for further research is warranted for effective preventive therapy. In this article, we will be discussing MCD as a clinical construct, evaluation of a person suspected of having MCD, and management of the same.

Cognitive decline has a spectrum of presentations, which manifest from normality as part of senility to the established form of various neurodegenerative illnesses causing dementia. Understanding these various differential diagnoses is of great clinical significance as they have different management and interventional strategies. The neuropsychological deficits which are identified should follow known neuropathological disease patterns that helps in distinguishing different types of cognitive impairment to established dementia. It is important to look at different cognitive impairment in elderly with core diagnostic sense to define severity, type of cognitive impairments, identifying patients need for accommodation or adaptation, associated risks, effectiveness of therapies and predict mortality. This would help clinicians to identify and plan management based on individual needs in cases with variable cognitive impairment.

Cognitive impairment in elderly is a challenging issue which needs proper attention, care and management. Neuropsychological assessments (NA) are those authentic measures that help not only in narrowing down the differential diagnosis of cognitive dysfunction, but also assist in choosing treatment modalities, evaluating the efficacy of an intervention and to assess outcome. NA may also define the patient's functional limitations or cognitive strengths. Therefore, appropriate application of NA can improve the quality of care and management of an elderly with cognitive impairment. NA has many applications as it provides full understanding about the individual and his environment. However, in India there are many challenging issues regarding Na, which are discussed in the present article.

Age-associated cognitive decline or normal (nonpathological, normative, usual) cognitive aging has been found to be an inevitable part of increased age in humans and differs in extent among individuals. The determinants of the differences in age-related cognitive decline are not fully understood. Progress in the field is taking place across many areas of biomedical and psychosocial sciences. ^[1] The phenotype of normal cognitive aging is well-described. Some mental capabilities are well-maintained into old age. From early adulthood, there are declines in mental domains such as processing speed, reasoning, memory, and executive functions, some of which are underpinned by a decline in a general cognitive factor. There are contributions to understanding individual differences in normal cognitive aging from genetics, general health, and medical disorders such as atherosclerotic disease, biological processes such as inflammation, neurobiological changes, diet, and lifestyle. Many of the effect sizes are small; some are poorly replicated and in some cases, there is a possibility of reverse causation, with prior cognitive ability causing the supposed "cause" of cognitive ability in old age. ^[1] Genome-wide scans are a likely source to establish genetic contributions. The role of vascular factors in cognitive aging is increasingly studied and understood. The same applies to diet, biomarkers such as inflammation, and lifestyle factors such as exercise. There are marked advances in brain imaging, with better in vivo studies of brain correlates of cognitive changes. There is growing appreciation that factors affecting general bodily aging also influence cognitive functions in old age. ^[1]

Maintenance of cognitive function in old age has become increasingly desirable to a human society with an aging population. Various studies have shown that there is major variation in the clinical manifestations and severity of cognitive aging as a result of neurodegenerative changes that are similar in nature and extent. These mismatches led to the emergence of the concept of cognitive reserve (CR), which focuses on the adaptability and the flexible strategies of the brain that allow some people to cope better than others in the circumstance of age-related or Alzheimer's disease (AD)-related pathology. It is believed that CR is mainly influenced by an individual's education, intellect, mental stimulation, participation in leisure activities, dietary preferences, and social stimulation. These determinants of CR help in slowing the rate of memory decline in the normal aging process and also reduce the risk of developing AD. The role of functional neuroimaging has recently gained importance in the context of understanding the neural basis of CR and its relationship to aging-related behavior changes. Future research in this field may enable earlier detection and thus reduction in the prevalence of age-related cognitive changes and AD. This article is a review of the neurobiology of CR, the concept of CR, and the promotion of preserving CR by analyzing its determinants along with their implementation against its deterioration toward cognitive loss and disorders.

Ageing often leads to decline in cognitive abilities. Significant cognitive impairment leads to functional impairment and need for care. Prevention of cognitive decline and delaying its progression would help to reduce the need for long-term care. Both genetic and environmental factors are important determinants of cognitive health in late life. A better cognitive reserve helps to prevent cognitive decline. Cognitive reserve is now considered as a functional reserve rather than a structural reserve. Cognitive reserve can be enhanced through experience. People with higher level of education tend to have higher cognitive reserve. Better cognitive reserve can act as a buffer. Engagement in cognitively stimulating activities may prevent cognitive decline in late life. Physical exercise also improves cognitive health. Aerobic exercises, which improve cardiorespiratory fitness, improve cognitive functions like motor functions, cognitive speed, and auditory and visual attention. Beneficial effects on executive functions are also reported. Healthy diet, especially adherence to Mediterranean diet (MeDi), is considered to be useful in preserving cognitive health. Engagement in social activities might also reduce cognitive decline. Encouraging adherence to a healthy lifestyle and continuing to be physically, socially, and cognitively active seems to be a promising strategy to prevent cognitive decline.

There is a large body of research on cognitive interventions for older adults the review which suggests the following: (1) Cognition remediation therapy is indicated for healthy elderly, and in mild cognitive impairment (MCI), early dementia, brain disease and injury, and severe mental illness (SMI). (2) Studies on healthy elderly demonstrate that with cognitive training (CT), cognitive stimulation (CS), and/or cognitive rehabilitation (CR) age-related cognitive decline can be reversed, at least partially if not fully, even in advanced age, with improved social functioning and quality of life. Better results are obtained if cognitive remediation therapy (CRT) is combined with vocational/psychosocial rehabilitation. Generalization of training to activities of daily living (ADL) and to secondary outcome measures such as quality of life and self-esteem are issues that need to be addressed in older adults. (3) Research in MCI has indicated that CRT, especially memory training, has some role. Future studies should place focus on the assessment of dose-response relationship, training generalization, and ecologically relevant approaches. (4) Findings of earlier work in early-stage dementia were frustrating, more recent work, especially randomized controlled trials of high quality, has provided a ray of rope with respect to effectiveness of CT and CR. Further well-designed studies are required to provide more definitive evidence. (5) Significant therapeutic effects of CR have been observed on cognitive function and ADL in the elderly patients with stroke. Routine screening for stroke patients and those with brain injury for cognitive impairment is recommended. (6) Available research provides evidence that cognitive remediation benefits people with SMI, and when combined with psychiatric rehabilitation this benefit generalizes to functioning. Elderly with SMI need special focus. Further needs to be carried out on older people with SMI.

This review aims to evaluate the existing evidence for pharmacotherapy for management of dementia. Data search strategies included electronic databases of relevant publications or cross-references. The searches were limited to acetyl cholinesterase inhibitors (AChEIs), memantine, antipsychotics, antidepressants, mood stabilizers, and benzodiazepines. Data in the form of meta-analysis and systemic reviews for treatment in five main types of dementia (Alzheimer's, frontotemporal, Parkinson's, Lewy body disease, and vascular type) were extracted. If a meta-analysis or systemic review was not available, then the searches included evaluation of data in the form of double-blind, randomized controlled trials or open-label studies. Various studies suggest that compared to placebo, AChEIs and memantine are associated with better outcome in all domains of Alzheimer's disease. In addition, combination therapy of AChEIs and memantine is superior to monotherapy with AChEIs in terms of behavioral disturbances, activities of daily living, and global assessment. In patients with dementia associated with Parkinson's disease or Lewy body dementia, use of donepezil, rivastigmine, and memantine is associated with significant efficacy on the global outcome measures when compared with placebo. Compared to placebo, AChEIs, but not memantine, have also been shown to have better cognitive outcomes in patients with dementia associated with Parkinson's disease or Lewy body dementia. Data are limited for the role of pharmacotherapy in management of frontotemporal dementia. In patients of vascular dementia, all AChEIs and memantine show some beneficial effects on cognition. Antidepressants and antipsychotics have been shown to be beneficial in management of behavioral symptoms and agitation. However, it is important to remember that there is black box warning for use of antipsychotics among patients with dementia. One of the major limitations of the research is variability in assessment instruments used for rating various symptoms encountered in patients of dementia. However, it can be concluded that in recent times, quality of studies has improved and many studies have included adequate sample sizes.

The elderly population with cognitive decline is increasing at an alarming rate in developing countries such as India. There is a paucity of basic clinical research in the field of cognitive decline dealing with areas of prevalence, etiology, diagnosis, and management. In India, prioritization of research capabilities is obligatory to decrease the research gap, i.e., the difference between the information needed to plan services and that which is available. The information can be gathered and utilized to frame policies and early remedial measures to tackle the emerging disease burden on the community. This article highlights the research done on cognitive decline so far and the further need for priority research on various important areas such as epidemiology, assessment methods and diagnosis, psychobehavioral symptoms, mild cognitive impairment (MCI), and interventional studies to create an evidence base for our population.