See also
- Menopause-related cognitive impairment – similar symptoms, appears shortly after menopause, and can be treated with hormone replacement therapy
| Mild cognitive impairment | |
|---|---|
| Other names | Incipient dementia, isolated memory impairment |
| Specialty | Neurology |
| Symptoms | Can include memory impairments (amnestic) or cognitive problems like impaired decision making, language, or visuospatial skills (non-amnestic) |
| Usual onset | Typically appears in adults 65 or older |
| Types | Amnestic, non-amnestic |
| Risk factors | Age, family history, cardiovascular disease |
| Diagnostic method | Based on symptoms assessed by a clinical neuropsychologist through observations, neuroimaging, and blood tests |
Mild cognitive impairment (MCI) is a neurocognitive disorder which involves cognitive impairments beyond those expected based on an individual's age and education but which are not significant enough to interfere with instrumental activities of daily living. [1] MCI may occur as a transitional stage between normal aging and dementia, especially Alzheimer's disease. [2] It includes both memory and non-memory impairments. [3] The cause of the disorder remains unclear, as well as both its prevention and treatment, with some 50 percent of people diagnosed with it going on to develop Alzheimer's disease within five years. The diagnosis can also serve as an early indicator for other types of dementia, although MCI may remain stable or even remit. [4]
Mild cognitive impairment has been relisted as mild neurocognitive disorder in DSM-5, and in ICD-11, [5] the latter effective on 1 January 2022. [6]
MCI can present with a variety of symptoms, but is divided generally into two types. [4]
Amnestic MCI (aMCI) is mild cognitive impairment with memory loss as the predominant symptom; aMCI is frequently seen as a prodromal stage of Alzheimer's disease. [4] [3] [7] Studies suggest that these individuals tend to progress to probable Alzheimer's disease at a rate of approximately 10% to 15% per year.[ needs update ] [8] It is possible that being diagnosed with cognitive decline may serve as an indicator of MCI. [9]
Nonamnestic MCI (naMCI) is mild cognitive impairment in which impairments in domains other than memory (for example, language, visuospatial, executive) are more prominent. [4] [10] It may be further divided as nonamnestic single- or multiple-domain MCI, and these individuals are believed to be more likely to convert to other dementias (for example, dementia with Lewy bodies). [11]
The International Classification of Diseases classifies MCI as a "mental and behavioural disorder." [12]
Mild cognitive impairment (MCI) may be caused due to alteration in the brain triggered during early stages of Alzheimer's disease or other forms of dementia.[ better source needed ] [13] Exact causes of MCI are unknown. It is controversial whether MCI even should be identified as a disorder. [14]
Risk factors of both dementia and MCI are considered to be the same: these are aging, genetic (heredity) cause of Alzheimer's or other dementia, and cardiovascular disease. [15]
Individuals with MCI have increased oxidative damage in their nuclear and mitochondrial brain DNA. [16]
The diagnosis of MCI requires considerable clinical judgement, [8] and as such a comprehensive clinical assessment including clinical observation, neuroimaging, [17] blood tests and neuropsychological testing are best in order to rule out an alternate diagnosis. MCI is diagnosed when there is: [18]
Although amnestic MCI patients may not meet criteria for Alzheimer's disease, patients may be in a transitional stage of evolving Alzheimer's disease. [3]
Magnetic resonance imaging can observe deterioration, including progressive loss of gray matter in the brain, from mild cognitive impairment to full-blown Alzheimer disease. [19] A technique known as PiB PET imaging is used to show the sites and shapes of beta amyloid deposits in living subjects using a 11C tracer that binds selectively to such deposits. [20]
As of January 2018, [update] there are no USFDA-approved medications for the treatment of mild cognitive impairment. [4] Moreover, as of January 2018, there is no high-quality evidence that supports the efficacy of any pharmaceutical drugs or dietary supplements for improving cognitive symptoms in individuals with mild cognitive impairment. [4] A moderate amount of high-quality evidence supports the efficacy of regular physical exercise for improving cognitive symptoms in individuals with MCI. [4] The clinical trials that established the efficacy of exercise therapy for MCI involved twice weekly exercise over a period of six months. [4] A small amount of high-quality evidence supports the efficacy of cognitive training for improving some measures of cognitive function in individuals with mild cognitive impairment. [4] Due to the heterogeneity among studies which assessed the effect of cognitive training in individuals with MCI, there are no particular cognitive training interventions that have been found to provide greater symptomatic benefits for MCI relative to other forms of cognitive training. [4]
The American Academy of Neurology's (AAN) clinical practice guideline on mild cognitive impairment from January 2018 stated that clinicians should identify modifiable risk factors in individuals with MCI, assess functional impairments, provide treatment for any behavioral or neuropsychiatric symptoms, and monitor the individual's cognitive status over time. [4] It also stated that medications which cause cognitive impairment should be discontinued or avoided if possible. [4] Due to the lack of evidence supporting the efficacy of cholinesterase inhibitors in individuals with MCI, the AAN guideline stated that clinicians who choose to prescribe them for the treatment of MCI must inform patients about the lack of evidence supporting this therapy. [4] The guideline also indicated that clinicians should recommend that individuals with MCI engage in regular physical exercise for cognitive symptomatic benefits; [4] clinicians may also recommend cognitive training, which appears to provide some symptomatic benefit in certain cognitive measures. [4]
According to research conducted in England, people with MCI often do not receive adequate care and support in healthcare settings. This leaves them and their families in a limbo with uncertainty regarding their futures and the fear of possibly developing dementia. The lack of services also fails to point them to effective ways to prevent dementia such as exercise and social contact. Successful dementia prevention services would have to be tailored to people's preferences and backgrounds. [21] [22]
As MCI may represent a prodromal state to clinical Alzheimer's disease, treatments proposed for Alzheimer's disease, such as antioxidants and cholinesterase inhibitors, could potentially be useful; [23] however, as of January 2018, there is no evidence to support the efficacy of cholinesterase inhibitors for the treatment of mild cognitive impairment. [4] Two drugs used to treat Alzheimer's disease have been assessed for their ability to treat MCI or prevent progression to full Alzheimer's disease. Rivastigmine failed to stop or slow progression to Alzheimer's disease or to improve cognitive function for individuals with mild cognitive impairment; [24] donepezil showed only minor, short-term benefits and was associated with significant side effects. [25]
Current evidence suggests that cognition-based interventions do improve mental performance (i.e. memory, executive function, attention, and speed) in older adults and people with mild cognitive impairment. [26] Especially, immediate and delayed verbal recall resulted in higher performance gains from memory training.
There is currently limited evidence to form a strong conclusion to recommend the use of any form of carbohydrate in preventing or reducing cognitive decline in older adults with normal cognition or mild cognitive impairment. [27] So, more large and higher quality evidence is needed to evaluate memory improvement and find nutritional issues due to carbohydrates.
MCI does not usually interfere with daily life, but around 50 percent of people diagnosed with it go on to develop Alzheimer's disease within five years (mainly for people diagnosed with memory impairments). This diagnosis can also serve as an early indicator for other types of dementia, although MCI may remain stable or even remit. [4]
The prevalence of MCI varies by age. [4] The prevalence of MCI among different age groups is as follows: 6.7% for ages 60–64; 8.4% for ages 65–69, 10.1% for ages 70–74, 14.8% for ages 75–79, and 25.2% for ages 80–84. [4] After a two-year follow-up, the cumulative incidence of dementia among individuals who are over 65 years old and were diagnosed with MCI was found to be 14.9%. [4]
Due to the emphasis shifting to the earlier diagnosis of dementia, more people are assessed who report memory problems. In turn this also leads diagnosing more people who might have MCI which is a risk factor for dementia. [21] [22] Globally, approximately 16% of the population over the age of 70 experiences some type of mild cognitive impairment.[ medical citation needed ]
Dementia is the general name for a decline in cognitive abilities that impacts a person's ability to perform everyday activities. This typically involves problems with memory, thinking, and behavior. Aside from memory impairment and a disruption in thought patterns, the most common symptoms include emotional problems, difficulties with language, and decreased motivation. The symptoms may be described as occurring in a continuum over several stages. Dementia ultimately has a significant effect on the individual, caregivers, and on social relationships in general. A diagnosis of dementia requires the observation of a change from a person's usual mental functioning and a greater cognitive decline than what is caused by normal aging.
Dementia with Lewy bodies (DLB) is a type of dementia characterized by changes in sleep, behavior, cognition, movement, and regulation of automatic bodily functions. Memory loss is not always an early symptom. The disease worsens over time and is usually diagnosed when cognitive impairment interferes with normal daily functioning. Together with Parkinson's disease dementia, DLB is one of the two Lewy body dementias. It is a common form of dementia, but the prevalence is not known accurately and many diagnoses are missed. The disease was first described by Kenji Kosaka in 1976.
Vascular dementia (VaD) is dementia caused by problems in the blood supply to the brain, resulting from a cerebrovascular disease. Restricted blood supply (ischemia) leads to cell and tissue death in the affected region, known as an infarct. The three types of vascular dementia are subcortical vascular dementia, multi-infarct dementia, and stroke related dementia. Subcortical vascular dementia is brought about by damage to the small blood vessels in the brain. Multi-infarct dementia is brought about by a series of mini-strokes where many regions have been affected. The third type is stroke related where more serious damage may result. Such damage leads to varying levels of cognitive decline. When caused by mini-strokes, the decline in cognition is gradual. When due to a stroke, the cognitive decline can be traced back to the event.
Binswanger's disease, also known as subcortical leukoencephalopathy and subcortical arteriosclerotic encephalopathy, is a form of small-vessel vascular dementia caused by damage to the white brain matter. White matter atrophy can be caused by many circumstances including chronic hypertension as well as old age. This disease is characterized by loss of memory and intellectual function and by changes in mood. These changes encompass what are known as executive functions of the brain. It usually presents between 54 and 66 years of age, and the first symptoms are usually mental deterioration or stroke.
Donepezil, sold under the brand name Aricept among others, is a medication used to treat dementia of the Alzheimer's type. It appears to result in a small benefit in mental function and ability to function. Use, however, has not been shown to change the progression of the disease. Treatment should be stopped if no benefit is seen. It is taken by mouth or via a transdermal patch.
Cognitive disorders (CDs), also known as neurocognitive disorders (NCDs), are a category of mental health disorders that primarily affect cognitive abilities including learning, memory, perception, and problem-solving. Neurocognitive disorders include delirium, mild neurocognitive disorders, and major neurocognitive disorder. They are defined by deficits in cognitive ability that are acquired, typically represent decline, and may have an underlying brain pathology. The DSM-5 defines six key domains of cognitive function: executive function, learning and memory, perceptual-motor function, language, complex attention, and social cognition.
The mini–mental state examination (MMSE) or Folstein test is a 30-point questionnaire that is used extensively in clinical and research settings to measure cognitive impairment. It is commonly used in medicine and allied health to screen for dementia. It is also used to estimate the severity and progression of cognitive impairment and to follow the course of cognitive changes in an individual over time; thus making it an effective way to document an individual's response to treatment. The MMSE's purpose has been not, on its own, to provide a diagnosis for any particular nosological entity.
Primary progressive aphasia (PPA) is a type of neurological syndrome in which language capabilities slowly and progressively become impaired. As with other types of aphasia, the symptoms that accompany PPA depend on what parts of the left hemisphere are significantly damaged. However, unlike most other aphasias, PPA results from continuous deterioration in brain tissue, which leads to early symptoms being far less detrimental than later symptoms.
Cognitive impairment is an inclusive term to describe any characteristic that acts as a barrier to the cognition process or different areas of cognition. Cognition, also known as cognitive function, refers to the mental processes of how a person gains knowledge, uses existing knowledge, and understands things that are happening around them using their thoughts and senses. A cognitive impairment can be in different domains or aspects of a person's cognitive function including memory, attention span, planning, reasoning, decision-making, language, executive functioning, and visuospatial functioning. The term cognitive impairment covers many different diseases and conditions and may also be symptom or manifestation of a different underlying condition. Examples include impairments in overall intelligence ,specific and restricted impairments in cognitive abilities, neuropsychological impairments, or it may describe drug-induced impairment in cognition and memory. Cognitive impairments may be short-term, progressive or permanent.
Alcohol-related dementia (ARD) is a form of dementia caused by long-term, excessive consumption of alcoholic beverages, resulting in neurological damage and impaired cognitive function.
The NINCDS-ADRDA Alzheimer's Criteria were proposed in 1984 by the National Institute of Neurological and Communicative Disorders and Stroke and the Alzheimer's Disease and Related Disorders Association and are among the most used in the diagnosis of Alzheimer's disease (AD). These criteria require that the presence of cognitive impairment and a suspected dementia syndrome be confirmed by neuropsychological testing for a clinical diagnosis of possible or probable AD; while they need histopathologic confirmation for the definitive diagnosis. They specify as well eight cognitive domains that may be impaired in AD. These criteria have shown good reliability and validity.
Psychological therapies for dementia are starting to gain some momentum. Improved clinical assessment in early stages of Alzheimer's disease and other forms of dementia, increased cognitive stimulation of the elderly, and the prescription of drugs to slow cognitive decline have resulted in increased detection in the early stages. Although the opinions of the medical community are still apprehensive to support cognitive therapies in dementia patients, recent international studies have started to create optimism.
Alzheimer's disease (AD) is a neurodegenerative disease that usually starts slowly and progressively worsens, and is the cause of 60–70% of cases of dementia. The most common early symptom is difficulty in remembering recent events. As the disease advances, symptoms can include problems with language, disorientation, mood swings, loss of motivation, self-neglect, and behavioral issues. As a person's condition declines, they often withdraw from family and society. Gradually, bodily functions are lost, ultimately leading to death. Although the speed of progression can vary, the typical life expectancy following diagnosis is three to nine years.
Depression is one of the most common psychiatric symptoms in Alzheimer's disease, occurring at all stages of the disease, but it often appears in a different form than other depressive disorders. In 2000, a workgroup of the U.S. National Institute of Mental Health created a set of provisional diagnostic criteria for depression of Alzheimer disease (dAD) as a separate diagnostic entity in its own right.
The Montreal Cognitive Assessment (MoCA) is a widely used screening assessment for detecting cognitive impairment. It was created in 1996 by Ziad Nasreddine in Montreal, Quebec. It was validated in the setting of mild cognitive impairment (MCI), and has subsequently been adopted in numerous other clinical settings. This test consists of 30 points and takes 10 minutes for the individual to complete. The original English version is performed in seven steps, which may change in some countries dependent on education and culture. The basics of this test include short-term memory, executive function, attention, focus, and more.
Alzheimer's Disease Neuroimaging Initiative (ADNI) is a multisite study that aims to improve clinical trials for the prevention and treatment of Alzheimer's disease (AD). This cooperative study combines expertise and funding from the private and public sector to study subjects with AD, as well as those who may develop AD and controls with no signs of cognitive impairment. Researchers at 63 sites in the US and Canada track the progression of AD in the human brain with neuroimaging, biochemical, and genetic biological markers. This knowledge helps to find better clinical trials for the prevention and treatment of AD. ADNI has made a global impact, firstly by developing a set of standardized protocols to allow the comparison of results from multiple centers, and secondly by its data-sharing policy which makes available all at the data without embargo to qualified researchers worldwide. To date, over 1000 scientific publications have used ADNI data. A number of other initiatives related to AD and other diseases have been designed and implemented using ADNI as a model. ADNI has been running since 2004 and is currently funded until 2021.
For patients with Alzheimer's disease, music therapy provides a beneficial interaction between a patient and an individualized musical regimen and has been shown to increase cognition and slow the deterioration of memory loss. Music therapy is a clinical and evidence-based intervention that involves music in some capacity and includes both a participant and a music therapist who have completed an accredited music therapy program.
Florbetaben, a fluorine-18 (18F)-labeled stilbene derivative, trade name NeuraCeq, is a diagnostic radiotracer developed for routine clinical application to visualize β-amyloid plaques in the brain. It is indicated for Positron Emission Tomography (PET) imaging of β-amyloid neuritic plaque density in the brains of adult patients with cognitive impairment who are being evaluated for Alzheimer's disease (AD) and other causes of cognitive impairment. β-amyloid is a key neuropathological hallmark of AD, so markers of β-amyloid plaque accumulation in the brain are useful in distinguishing AD from other causes of dementia. The tracer successfully completed a global multicenter phase 0–III development program and obtained approval in Europe, US and South Korea in 2014.
The Cogstate Brief Battery (CBB) is a computer-based cognitive assessment used in clinical trials, healthcare, and academic research to measure neurological cognition. It was developed by Cogstate Ltd.
Alzheimer's disease (AD) in African Americans is becoming a rising topic of interest in AD care, support, and scientific research, as African Americans are disproportionately affected by AD. Recent research on AD has shown that there are clear disparities in the disease among racial groups, with higher prevalence and incidence in African Americans than the overall average. Pathologies for Alzheimer’s also seem to manifest differently in African Americans, including with neuroinflammation markers, cognitive decline, and biomarkers. Although there are genetic risk factors for Alzheimer’s, these account for few cases in all racial groups.
In patients with MCI, exercise training (6 months) is likely to improve cognitive measures and cognitive training may improve cognitive measures. ... Clinicians should recommend regular exercise (Level B). ... Recommendation: For patients diagnosed with MCI, clinicians should recommend regular exercise (twice/week) as part of an overall approach to management (Level B).