Alzheimer’s disease and its evolution


The evolution of Alzheimer’s disease is slow, with stages associated with different types of common behaviors.

It affects most areas of your brain. The disease can affect memory, thinking, judgment, language, problem-solving, personality, and movement.

The course of Alzheimer’s disease distinguishes five phases: preclinical Alzheimer’s disease, mild cognitive deficit (decline) due to Alzheimer’s disease, mild dementia due to Alzheimer’s disease, moderate dementia due to Alzheimer’s disease and severe dementia related to Alzheimer’s disease.

As a reminder, dementia is a term used to describe a group of symptoms that affect the patient’s intellectual and social abilities enough to interfere with daily function.

Although Alzheimer’s disease theoretically has five stages, it is important to know that these stages are only rough generalizations. The disease is a continuous process. Each person has a different experience of Alzheimer’s disease and its symptoms.

Alzheimer’s disease in the preclinical stage

Alzheimer’s disease begins long before any symptoms appear. This stage is called preclinical Alzheimer’s disease and it is usually identified only in research settings. Neither the patient nor those around him notice any symptoms during this stage.

This phase of evolution of Alzheimer’s disease can last for years or even decades. Although no changes are seen, new imaging technologies can identify deposits of a protein called beta-amyloid, a hallmark of Alzheimer’s disease. The ability to identify these early deposits may be particularly important for clinical trials and in the future as new treatments are developed for Alzheimer’s disease.

Additional biomarkers – measures that may reflect an increased risk of disease – have been identified in Alzheimer’s disease. These biomarkers can be used to support the diagnosis of Alzheimer’s disease, usually after symptoms appear.

Genetic testing can also tell you if one has a higher risk of Alzheimer’s disease, especially early-stage Alzheimer’s disease. These tests are not recommended for everyone, but the doctor can determine if these genetic tests may be helpful.

As with new imaging techniques, biomarkers and genetic testing will become increasingly important as new treatments for Alzheimer’s disease are developed.

Mild cognitive impairment due to Alzheimer’s disease

People with mild cognitive impairment (MCI) experience slight changes in their memory and ability to think. These changes are not significant enough to affect work or relationships. People with MCI may have memory lapses for information that is usually easily remembered, such as conversations, recent events, or appointments.

These individuals may also have difficulty estimating the time required to complete a task or correctly assessing the number of steps required to complete a task. The ability to make good decisions may become more difficult.

Alzheimer’s disease is not associated with mild cognitive decline which is often diagnosed based on a doctor’s review of symptoms. However, the tests used to identify preclinical Alzheimer’s disease can be used to determine if the MCI is due to Alzheimer’s disease or something else.

Alzheimer’s disease is often diagnosed in the mild dementia stage, when it becomes apparent to family and doctors that a person has significant problems with memory and thinking that affect day-to-day functioning.

People may experience:

  • Loss of memory of recent events. Individuals may have particular difficulty remembering newly learned information and tend to ask the same question over and over.
  • Difficulty solving problems, complex tasks and good judgments. Planning a family event or balancing a checkbook can become overwhelming. Many people show poor judgment, for example when making financial decisions.
  • Personality changes. People may withdraw – especially in socially difficult situations – or show unusual irritability or anger. Reduced motivation to complete tasks is also common.
  • Difficulty organizing and expressing thoughts. Finding the right words to describe objects or express ideas clearly becomes more and more difficult.
  • Getting lost or misplacing property. Individuals are finding it increasingly difficult to find their way around, even in familiar places. It is also common to lose items, including valuables.

Moderate dementia due to Alzheimer’s disease

As the disease progresses to moderate dementia, people become more confused and begin to need more help with daily activities and self-care.

People with the moderate dementia stage of Alzheimer’s disease may:

Exhibit increasingly poor judgment and increasing confusion. Individuals lose track of where they are, the day of the week or the season. They may confuse family members or close friends or confuse strangers with their family.

They may wander, possibly in search of more familiar surroundings. These difficulties make it dangerous to leave people with moderate dementia alone.

Memory loss is even greater. People may forget details of their personal history, such as their address or phone number, or the location of the school they attended. They repeat their favorite stories or make up stories to make up for their memory loss.

Need help with some daily activities. Assistance may be required in selecting appropriate clothing for weather conditions, as well as with bathing, grooming, using the restroom and other personal care.

Significant changes in personality and behavior. It is not uncommon for people in the moderate stage of dementia to have unfounded suspicions – for example, they convince themselves that friends, family members or professional caregivers are robbing them or that their spouse is having an affair. Others may see or hear things that aren’t really there.

Individuals often become restless or restless, especially late in the day. Some people may have outbursts of aggressive physical behavior.

Severe dementia due to Alzheimer’s disease

When the progression of Alzheimer’s disease leads to the stage of severe dementia, mental function continues to deteriorate and the disease has an increasing impact on physical abilities and movements.

In advanced stages of severe dementia due to Alzheimer’s disease, people:

Lose the ability to communicate coherently. She no longer speaks sensibly, although she can sometimes speak words or phrases.

Need daily personal care assistance with eating, dressing, using the bathroom and all other daily personal care tasks.

Show a decline in their physical abilities. They are unable to walk without assistance, sit up or raise their head without support. Muscles may become stiff and reflexes abnormal. Eventually, a person loses the ability to swallow and control bladder and bowel functions.

Practical case

In September 2006, a 76-year-old man, a worker by profession, came to consult a geriatrician for memory problems accompanied by depressive symptoms (he suffered from bereavement for his sister).

This visit follows a surgical operation (January 2006) and a visit to a psychiatrist (May 2006).

During the episodic memory evaluation test  (Grober and Buschke test) consisting in learning and retaining a list of 8 words (the Grober and Buschke test in its long version), the patient commits two intrusions (the patient names words that are not on the list). Moreover, passing the clock test), seems to evoke a semantic problem, despite correct visual and spatial ability.

The doctor hypothesizes a deficit of the brain structures involved in episodic memory (hippocampus) because the patient has a problem during encoding (encoding is the first stage of memory. The information obtained by a stimulus is memorized before being stored).

Despite fluent speech, semantic fluency is low with a score of 12 words, suggesting abnormal frontal and temporal structures of the dominant left hemisphere for language. In addition, the patient scored poorly on the working memory assessment test.

On the other hand, the patient does not suffer from apraxia, attention disorder, manages to conceptualize and orients himself well in time and space.

A year later, the patient consults the geriatrician again following the concerns of his wife who finds him apathetic and detached from the joys of everyday life. Neuropsychological tests are carried out. The patient has difficulty naming the day of the week and the month (temporal disorientation).

Episodic memory (Grober and Buschke test): the patient has a problem during encoding. He has difficulty remembering words that have just been presented to him (immediate recall). In addition, the patient this time commits eight intrusions. The neuropsychologist decides not to carry out the two other parts (ie interfering test and deferred recall) of the test in order not to aggravate the state of anxiety in which the patient finds himself. The neuropsychologist hypothesizes that the patient suffers from short-term memory problems affecting the temporal lobe.

Executive functions: the patient has difficulties with conceptualization and planning according to the Rey Figure test 3. His literal fluency is weak.

The neuropsychologist hypothesizes that the patient suffers from executive function disorders affecting the frontal lobe.

3  The Rey figure test is a quick test consisting in reproducing from memory a complex geometric figure with no obvious meaning. It assesses the perceptual activity of the person (whether a teenager or an elderly person), as well as his memory and attention.

Moreover, despite a good understanding of sentences and fluent speech, the patient has difficulty naming the objects presented to him on cards, confirming impairment of the frontal and temporal areas of language in the left hemisphere.

Finally, his wife thinks that her husband has difficulty living in everyday life (running errands, paying bills).

Following these observations, a diagnosis of possible Alzheimer’s disease is made.