How much do you know about Alzheimer's disease?

Alzheimer's disease is a progressive neurodegenerative disease that affects memory and cognitive functions, leading to a decline in bodily functions and ultimately death.

The cause of Alzheimer's disease is not fully understood, but it is associated with amyloid plaques, neurofibrillary tangles, and loss of neuronal connections in the brain.

There are no medications or supplements that have been shown to decrease the risk of Alzheimer's disease or to stop or reverse its progression.

The disease is named after German psychiatrist and pathologist Alois Alzheimer, who first described it in 1906.

The course of Alzheimer's is generally described in three stages, with a progressive pattern of cognitive and functional impairment.

Familial Alzheimer's disease is an inherited and uncommon form of Alzheimer's disease, while sporadic Alzheimer's disease is more common and is not inherited.

The strongest genetic risk factor for sporadic Alzheimer's disease is APOEε4.

Environmental factors such as head injury, clinical depression, and high blood pressure are also risk factors associated with Alzheimer's disease.

Sleep disturbances and oxidative stress have been linked to Alzheimer's disease.

There are no treatments that can stop or reverse Alzheimer's disease, and affected people increasingly rely on others for assistance, often placing a burden on the caregiver.Overview of Alzheimer's Disease

• Alzheimer's disease is a neurodegenerative disorder that is characterized by the progressive loss of neurons and synapses in various regions of the brain, leading to atrophy and degeneration.

• The disease is associated with the accumulation of abnormally folded amyloid beta protein into amyloid plaques and tau protein into neurofibrillary tangles in the brain.

• Alzheimer's disease is usually clinically diagnosed based on the person's medical history, history from relatives, and behavioral observations, and can only be definitively diagnosed with autopsy findings.

• There are three sets of criteria for the clinical diagnoses of the spectrum of Alzheimer's disease: the 2013 fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5); the National Institute on Aging-Alzheimer's Association (NIA-AA) definition as revised in 2011; and the International Working Group criteria as revised in 2010.

• There are no disease-modifying treatments available to cure Alzheimer's disease and because of this, AD research has focused on interventions to prevent the onset and progression.

• Cardiovascular risk factors, such as hypercholesterolaemia, hypertension, diabetes, and smoking, are associated with a higher risk of onset and worsened course of AD.

• Physical exercise is associated with a decreased rate of dementia, and is effective in reducing symptom severity in those with AD.

• Certain lifestyle activities, such as physical and cognitive exercises, higher education and occupational attainment, cigarette smoking, stress, sleep, and the management of other comorbidities, including diabetes and hypertension, may affect the risk of developing Alzheimer's.

• Alzheimer's disease is characterised by loss of neurons and synapses in the cerebral cortex and certain subcortical regions, resulting in gross atrophy of the affected regions.

• Both Aβ plaques and neurofibrillary tangles are clearly visible by microscopy in brains of those with Alzheimer's disease, especially in the hippocampus.

• Inflammation is a general marker of tissue damage in any disease, and may be either secondary to tissue damage in Alzheimer's disease or a marker of an immunological response.

• Alzheimer's disease may occur without neurofibrillary tangles in the neocortex.

• Exposure to air pollution may be a contributing factor to the development of Alzheimer's disease.Summary of Alzheimer's Disease

• Lifestyle interventions such as physical activity, mental exercises, and cessation of smoking can reduce the risk of developing Alzheimer's disease.

• Higher education, occupational attainment, and participation in leisure activities can delay the onset of Alzheimer's symptoms.

• Medications used to treat cognitive problems include acetylcholinesterase inhibitors and memantine, with small benefits.

• Psychosocial interventions such as reminiscence therapy and cognitive retraining can improve cognitive deficits.

• Caregiving is essentially the treatment for Alzheimer's disease, with modifications to the living environment and lifestyle to increase safety and reduce caretaker burden.

• Diet, such as the Mediterranean and DASH diets, may be a modifiable risk factor for Alzheimer's disease.

• Life expectancy is reduced following Alzheimer's diagnosis, with a range of 7-10 years for those in their 60s and early 70s, and 3 years or less for those in their 90s.

• Alzheimer's disease incidence rates increase with age and are higher in females than males, but incidence rates are not equal for all ages.

• Alzheimer's dementia prevalence increases with age, with rates estimated to be 5.3% for those in the 60-74 age group, 13.8% in the 74-84 group, and 34.6% for those greater than 85 in the United States in 2020.

• Alois Alzheimer identified the first case of Alzheimer's disease in 1901, and the terminology changed after a 1977 conference on Alzheimer's disease.

• Diagnosis of Alzheimer's disease was previously reserved for individuals between the ages of 45 and 65 who developed symptoms of dementia.

• Pneumonia and dehydration are the most frequent immediate causes of death brought by Alzheimer's disease.

• Research is needed in minority groups, such as the African American and Hispanic/Latino populations, who are underrepresented in clinical trials and do not have the same risk of developing Alzheimer's when carrying certain genetic risk factors compared to their Caucasian counterparts.Alzheimer's Disease: Social Costs, Caregiving Burden, and Research Directions

• Alzheimer's disease was first described by Alois Alzheimer in 1906, and it was initially considered a rare condition.

• Alzheimer's disease is a neurodegenerative disorder that affects memory, thinking, and behavior and is characterized by the presence of amyloid plaques and neurofibrillary tangles in the brain.

• The National Institute of Neurological and Communicative Disorders and Stroke (NINCDS) and the Alzheimer's Disease and Related Disorders Association (ADRDA) established the most commonly used NINCDS-ADRDA Alzheimer's Criteria for diagnosis in 1984, extensively updated in 2007.

• Dementia, and specifically Alzheimer's disease, may be among the most costly diseases for societies worldwide.

• The role of the main caregiver is often taken by the spouse or a close relative, and Alzheimer's disease is known for placing a great burden on caregivers which includes social, psychological, physical, or economic aspects.

• Home care is usually preferred by people with Alzheimer's disease and their families, but two-thirds of nursing home residents have dementias.

• Dementia caregivers are subject to high rates of physical and mental disorders, and family caregivers often give up time from work to spend 47 hours per week on average with the person with Alzheimer's disease.

• Alzheimer's disease has been portrayed in films, documentaries, music, and paintings.

• Additional research on the lifestyle effect may provide insight into neuroimaging biomarkers and better understanding of the mechanisms causing both Alzheimer's disease and early-onset AD.

• Alzheimer's disease is associated with neuroinflammation and loss of function of microglia, the resident immune cells of the central nervous system.

• Specific medications that may reduce the prevalence or progression of AD have been studied, but none identified a prevention strategy.

• Antibodies are being developed that may have the ability to alter the disease course by targeting amyloid beta, such as donanemab and aducanumab.