What is Alzheimer’s?

Alzheimer’s disease is a type of dementia.  People often confuse the terms dementia, Alzheimer’s disease, and mild cognitive impairment (MCI).

A lesson in terms

  • Dementia – Decline in intellectual ability impacting memory plus one or more other cognitive abilities severe enough to interfere with everyday functioning.
  • Alzheimer’s disease (AD) – The most common type of dementia.
  • Mild Cognitive Impairment (MCI) – The “borderland” or transitional stage between normal aging and dementia

Overview of Alzheimer’s disease

Alzheimer’s disease is the most common type of dementia, accounting for an estimated 70% of cases.  AD is an irreversible and progressive brain disease, with the most common early symptoms being memory difficulties and trouble learning new information.

Alzheimer’s disease was first identified more than 100 years ago by Dr. Alois Alzheimer, a German neuropsychiatrist, in his patient, Auguste Deter, a woman in her 50s who developed memory, language, visual-spatial, and orientation problems as well as delusional thinking.  Upon Auguste’s death, Dr. Alzheimer autopsied her brain, finding atrophy and the two hallmark neuropathological signs of AD, amyloid plaques and neurofibrillary tangles.

AD was originally thought to be a rare presenile dementia. Until the 1970s, most cases of senile dementia were attributed to arterioscelerosis.  Today Alzheimer’s disease is recognized as the primary cause of cognitive impairment in the elderly.

An estimated 5.3 million Americans of all ages are living with Alzheimer’s disease.  According to the Alzheimer’s Association report, 2015 Alzheimer’s Disease Facts and Figures:

  • One in nine people age 65 and older and one in three people age 85 and older are living with Alzheimer’s disease.
  • One in three seniors dies with Alzheimer’s or another dementia.
  • Alzheimer’s is the 6th leading cause of death in the United States.
  • Almost two thirds of Americans with Alzheimer’s are women.
  • In 2015, Alzheimer’s and other dementias will cost the nation $226 billion; these costs could rise as high as $1.1 trillion by 2050.

While memory difficulties are the most common early symptoms of Alzheimer’s, the disease can start with other symptoms.  Warning signs that indicate the need for an evaluation include:

  • Memory loss significant enough to disrupt daily life and activities
  • Difficulty planning or solving problems
  • Challenges carrying out familiar tasks
  • Confusion or disorientation to time or place
  • Difficulty understanding visual images and spatial relationships
  • New problems with speaking or writing
  • Forgetting and misplacing things, while losing the ability to retrace steps
  • Decreased or poor judgment
  • Withdrawal from activities (social, work, etc.)
  • Changes in mood and personality

For more information about the warning signs of Alzheimer’s disease, visit the Alzheimer’s Association.

Brain changes in Alzheimer’s disease

Beta amyloid fragments clump into plaques that suffocate neurons

Beta amyloid fragments clump into plaques that suffocate neurons

Although identified more than 100 years ago, researchers have only actively been studying the symptoms, causes, risk factors, and treatment of Alzheimer’s disease since the mid-1970s.  While we do not know what initiates Alzheimer’s, we do know  the disease is damaging and progressive, and like other common chronic conditions, probably a result of multiple factors. Researchers believe that the accumulation of senile plaques – comprised of the toxic beta-amyloid protein – and neurofibrillary tangles – aggregates of the tau protein – in the brain contribute to the development of Alzheimer’s disease. These neuropathological markers of AD start developing as early as 20 to 30 years before the onset of clinically noticeable symptoms. As more and more plaques and tangles form in particular areas of the brain, neurons begin to lose their ability to function and communicate with one another and die. Neurons are a vital part of the communication within the brain, allowing information and signals to be detected and transferred. In Alzheimer’s disease, abnormal accumulation of plaques and tangles cause neuron cells to die, leading to dramatic shrinkage and cell loss affecting areas of the brain that are responsible for memories, thoughts, sensations, emotions, movements, and skills.

Mild Cognitive Impairment (MCI)

Mild Cognitive Impairment (MCI) is widely considered a transitional state between normal aging and Alzheimer’s or another dementia. In MCI, memory and/or other cognitive difficulties (e.g., language, visual-spatial skills) disrupt everyday life (e.g., missing appointments) and are noticeable to the person affected and/or others (e.g., family, friends, work colleagues), but are not severe enough to interfere with basic living skills.  Click here to learn more about the transition from normal aging to Alzheimer’s disease or another dementia.

Progression of Alzheimer’s disease

Memory problems are the most frequently reported early symptom of AD and often precipitate the individual and/or family seeking a diagnosis. Initially, short-term memory and the ability to learn new information are affected.  Memory difficulties may appear subtle at first, often leading many individuals and families to question whether the symptoms are just signs of “normal aging.”  As Alzheimer’s disease progresses, a person may ask the same question repeatedly.  Objects may be misplaced or lost, and details about recent events may be forgotten.  These problems worsen consistently, often slowly.

Mild Alzheimer’s disease

As Alzheimer’s disease progresses, memory loss continues and other cognitive abilities are affected.  Problems may include difficulty with finding words and expressing ideas, getting lost, difficulty handling money and paying bills, taking longer to complete normal daily tasks, and poor judgment.  Mood (e.g., apathy and depression) and personality changes are also common. Long-term memory, however, remains relatively intact at this stage. Driving becomes hazardous and should be stopped. People are often first diagnosed in this stage.

Moderate Alzheimer’s disease

As the disease progresses, reasoning, visual-spatial skills, planning and organization, sensory processing, and conscious thought become increasingly affected.  Memory loss and confusion increase, and people may begin to have problems recognizing family and friends.  They may increasingly have challenges completing other basic daily activities, such as getting dressed.  As a result, affected individuals become increasingly reliant on their caregivers. Patients may exhibit a variety of behavioral and psychological symptoms (e.g., agitation, wandering, delusions, and hallucinations) common to this stage.

Severe Alzheimer’s Disease

In late disease, long-term as well as short-term memory is lost. Speech is often limited to a few words. People become increasingly less responsive to others and the environment, and completely dependent on others for their care. Affected individuals may become bedridden.  Pneumonia or another infection may result in death, however, the actual cause of death is Alzheimer’s disease.