get started today
It effects more people than you may think
What we understand so far ...
Alzheimer’s disease (AD), also referred to simply as Alzheimer’s, is a chronic neurodegenerative disease that usually starts slowly and gradually worsens over time. It 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 (including easily getting lost), mood swings, loss of motivation, not managing self-care, and behavioural 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.
The cause of Alzheimer’s disease is poorly understood. About 70% of the risk is believed to be inherited from a person’s parents, with many genes usually involved. Other risk factors include a history of head injuries, depression, and hypertension. The disease process is associated with plaques and neurofibrillary tangles in the brain. A probable diagnosis is based on the history of the illness and cognitive testing with medical imaging and blood tests to rule out other possible causes. Initial symptoms are often mistaken for normal ageing. Examination of brain tissue is needed for a definite diagnosis. Mental and physical exercise, and avoiding obesity may decrease the risk of AD; however, evidence to support these recommendations is weak. There are no medications or supplements that have been shown to decrease risk.
No treatments stop or reverse its progression, though some may temporarily improve symptoms. Affected people increasingly rely on others for assistance, often placing a burden on the caregiver. The pressures can include social, psychological, physical, and economic elements. Exercise programs may be beneficial with respect to activities of daily living and can potentially improve outcomes. Behavioural problems or psychosis due to dementia are often treated with antipsychotics, but this is not usually recommended, as there is little benefit and an increased risk of early death.
In 2015, there were approximately 29.8 million people worldwide with AD. It most often begins in people over 65 years of age, although 4–5% of cases are early-onset Alzheimer’s. It affects about 6% of people 65 years and older. In 2015, dementia resulted in about 1.9 million deaths. The disease is named after German psychiatrist and pathologist Alois Alzheimer, who first described it in 1906. In developed countries, AD is one of the most financially costly diseases.
The disease course is divided into four stages, with a progressive pattern of cognitive and functional impairment.
The first symptoms are often mistakenly attributed to ageing or stress. Detailed neuro-psychological testing can reveal mild cognitive difficulties up to eight years before a person fulfils the clinical criteria for diagnosis of AD. These early symptoms can affect the most complex activities of daily living. The most noticeable deficit is short term memory loss, which shows up as difficulty in remembering recently learned facts and inability to acquire new information.
Subtle problems with the executive functions of attentiveness, planning, flexibility, and abstract thinking, or impairments in semantic memory (memory of meanings, and concept relationships) can also be symptomatic of the early stages of AD. Apathy and depression can be seen at this stage, with apathy remaining as the most persistent symptom throughout the course of the disease. The preclinical stage of the disease has also been termed mild cognitive impairment (MCI). This is often found to be a transitional stage between normal ageing and dementia. MCI can present with a variety of symptoms, and when memory loss is the predominant symptom, it is termed “amnestic MCI” and is frequently seen as a prodromal stage of Alzheimer’s disease.
In people with AD, the increasing impairment of learning and memory eventually leads to a definitive diagnosis. In a small percentage, difficulties with language, executive functions, perception (agnosia), or execution of movements (apraxia) are more prominent than memory problems. AD does not affect all memory capacities equally. Older memories of the person’s life (episodic memory), facts learned (semantic memory), and implicit memory (the memory of the body on how to do things, such as using a fork to eat or how to drink from a glass) are affected to a lesser degree than new facts or memories.
Language problems are mainly characterised by a shrinking vocabulary and decreased word fluency, leading to a general impoverishment of oral and written language. In this stage, the person with Alzheimer’s is usually capable of communicating basic ideas adequately. While performing fine motor tasks such as writing, drawing, or dressing, certain movement coordination and planning difficulties (apraxia) may be present, but they are commonly unnoticed. As the disease progresses, people with AD can often continue to perform many tasks independently, but may need assistance or supervision with the most cognitively demanding activities.
Progressive deterioration eventually hinders independence, with subjects being unable to perform most common activities of daily living. Speech difficulties become evident due to an inability to recall vocabulary, which leads to frequent incorrect word substitutions (paraphasias). Reading and writing skills are also progressively lost. Complex motor sequences become less coordinated as time passes and AD progresses, so the risk of falling increases. During this phase, memory problems worsen, and the person may fail to recognise close relatives. Long-term memory, which was previously intact, becomes impaired.
Behavioural and neuropsychiatric changes become more prevalent. Common manifestations are wandering, irritability and labile affect, leading to crying, outbursts of unpremeditated aggression, or resistance to caregiving. Sundowning can also appear. Approximately 30% of people with AD develop illusionary misidentifications and other delusional symptoms. Subjects also lose insight of their disease process and limitations (anosognosia). Urinary incontinence can develop. These symptoms create stress for relatives and carers, which can be reduced by moving the person from home care to other long-term care facilities.
During the final stages, the patient is completely dependent upon caregivers. Language is reduced to simple phrases or even single words, eventually leading to complete loss of speech. Despite the loss of verbal language abilities, people can often understand and return emotional signals. Although aggressiveness can still be present, extreme apathy and exhaustion are much more common symptoms. People with Alzheimer’s disease will ultimately not be able to perform even the simplest tasks independently; muscle mass and mobility deteriorates to the point where they are bedridden and unable to feed themselves. The cause of death is usually an external factor, such as infection of pressure ulcers or pneumonia, not the disease itself.
- New Alzheimer's research could inspire better treatments and earlier diagnosis
Neuroscientists at the University of Portsmouth, with collaborators in the UK and the U.S., have made a breakthrough in the study of Alzheimer's which could inspire better treatments and earlier diagnosis.
- Following the hops of disordered proteins could lead to future treatments of Alzheimer's disease
Researchers from the University of Cambridge, the University of Milan and Google Research have used machine learning techniques to predict how proteins, particularly those implicated in neurological diseases, completely change their shapes in a matter of microseconds.
- Memory may be preserved in condition with brain changes similar to Alzheimer's disease
Primary progressive aphasia is a rare neurodegenerative condition characterized by prominent language problems that worsen over time. About 40% of people with the condition have underlying Alzheimer's disease. But a new study has found that people with the condition may not develop the memory problems associated with Alzheimer's disease. The study is published in the January 13, 2021, online issue of Neurology.
- Approximately half of AD dementia cases are mild, one-fifth are severe
What percent of patients with Alzheimer's Disease (AD) currently have severe dementia? Do more people have mild disease? Or are the majority suffering with moderate dementia? A new study using data from the Framingham Heart Study (FHS) sheds light on these trends. Boston University School of Medicine researchers have found that slightly more than half (50.4 percent) of cases are mild, just under one-third (30.3 percent) of cases are moderate and 19.3 percent are severe cases. Among all participants with mild cognitive impairment (MCI) and AD, the pooled percentage was 45.2 percent for the combined group of mild AD dementia and MCI that later progressed to AD.
- New report estimates 10,000 people 65 and older living with dementia in nation's capital
A report released today estimates that about 10,000 Washington, D.C. residents 65 and older are living with dementia, a general term for a range of memory loss disorders, including Alzheimer's disease. The report also discusses risk factors for dementia and unmet needs of Washington, D.C. residents living with dementia and their care partners.