Memory Disorders

What is a Major Neurocognitive Disorder or Dementia?


Major Neurocognitive Disorders or Dementia, are a group of disorders that affects the brain. The disorder impairs a person's way of thinking, remembering and reasoning skills that interfere with a person's normal day to day activities. Memory loss is a common symptom of dementia. Many diseases can cause dementia such as strokes and Alzheimer's disease. Alzheimer's disease is the most common of these disorders. Other causes of dementia include but are not limited to Vascular Dementia, Lewy Body Dementia, Frontotemporal Dementia, and dementias associated with Parkinson's Disease and Huntington's Disease.

After Alzheimer's disease, Vascular Dementia is the second most common cause of dementia. Vascular dementia is caused by decrease or interrupted blood flow to parts of the brain. Risk factors that can be controlled are the same as those for heart and blood vessel disease in other parts of the body. These include high blood pressure, smoking, high blood fats or lipids including cholesterol, elevated homocysteine, little exercise, and being overweight.

The onset of vascular dementia is sudden differing from the gradual symptoms of Alzheimer's disease. Reduced ability to think, remember and process information is usually sudden and often follows restricted blood flow. Most common cause of poor blood flow is a stroke. Often the progression of Vascular Dementia occurs in steps as the brain experiences further blockage over time. This pattern is described as multi-infarct dementia (this term is sometimes substituted for Vascular Dementia).

Lewy Body dementia is caused by progressive destruction of brain cells by protein deposits. Visual hallucinations is a hallmark symptom of the dementia, the person usually also has problems with concentration and other symptoms of dementia. About one third of individuals with Parkinson's disease develop dementia. Lewy bodies are often found in regions of the brain associated with Parkinson's disease. Lewy bodies are also present in some people with Alzheimer's Disease

Frontotemporal Dementia (FTD), previously called Pick's Disease, involves primarily the frontal and temporal lobes of the brain. FTD is uncommon and may begins with substantial changes to personality, behavior, complex reasoning, or language abilities that precede problems with memory. There are currently no treatments in common use.

What is Mild Cognitive Impairment or Mild Neurocognitive Disorder?

Mild Cognitive Impairment (MCI) is described as having a problem with at least one area of brain function (cognition), but in decreased severity as compared to dementia or major neurocognitive disorder. Persons with Mild Cognitive Impairment are able to carry out their normal activities of daily living and instrumental activities of daily living. Persons with MCI, particularly those with amnestic (forgetful) MCI are more likely to develop AD.

What is Alzheimer's disease

Alzheimer's disease is a form of dementia; it is the most common among older people.

It is an irreversible and progressive brain disease that slowly destroys memory and thinking skills. Memory and language functions are the first to be targeted by the disease; plaques and tangles forming in the brain are considered the main signs of the disease.

These plaques and tangles attack healthy nerve cells affecting their communication with each other resulting in their death. As the nerve cells die, brain tissue begins to shrink.

Increasing age, family history, lifestyle (sedentary lifestyle, unhealthy diet, smoking, alcohol use, social isolation, among others), certain medical conditions (cardiovascular disease including hypertension and other forms of heart disease, diabetes, overweight or obesity, increased "bad" cholesterol, hearing loss, depression, and head injuries)  are all risk factors for this disease. It is worth noting that many of these risk factors are modifiable - please speak with your provider about steps you might take to optimize your health and potentially lower your risk for developing Alzheimer's Disease. 

This website from the National Institute on Aging provides additional information:

The Diagnosis & Treatment of Alzheimer's Disease

Alzheimer's is difficult to diagnose, not one doctor specializes in the diagnosis and treatment of the disease. It's best with a team of professionals including neurologists, neuropsychologists, psychologist, psychiatrists, geriatricians, and others. A total diagnostic workup includes medical history, imaging procedures, and neuropsychological testing, as well as other procedures depending on the individual's presentation When a neuropsychologist or other professional in the field of psychology, psychiatry, neurology, or geriatric medicine sees a person exhibiting symptoms of Alzheimer's, a set of criteria is often used to help make an accurate diagnosis. The DSM 5 TR outlines a detailed set of criteria for the diagnosis of Alzheimer's.

First at least one measurable deficit in cognitive function must be present in one or more of the following categories must be evident: complex attention, executive function, learning and memory, language, perceptual-motor, or social cognition. 

In order to meet the criteria for a neurocognitive disorder like Alzheimer's Disease, the measured deficits in cognition must affect one's ability to hold a job, fulfill domestic responsibilities, and/or maintain social relationships. The deficits must also represent a significant decline from the person's previous level of functioning.

(Neurocognitive Disorders. Diagnostic and Statistical Manual of Mental Disorders. June 2024. doi:10.1176/appi.books.9780890425787.x17_Neurocognitive_Disorders.)

What are the Stages of Alzheimer's Disease?

Stage 1: No impairment: Classified as normal brain activity. Unimpaired individuals have no memory problems.

Stage 2: Very Mild Cognitive Impairment: This is classified as normal aging or early signs of Alzheimer's disease. Many individuals may feel as if they have memory loss or lapses. They may lose their keys or forget familiar names.

Stage 3: Mild Cognitive Decline: Decreased ability in remembering people's names, reading a passage and retaining little detail; decline in ability to plan or organize.

Stage 4: Moderate Cognitive Decline: Reduced memory of personal history, the affected individual may seem subdued or withdrawn, especially in socially and mentally challenging situations.

Stage 5: Moderately Severe Cognitive Decline (Mid stage Alzheimer's disease): In this stage major gaps in memory and deficits in cognitive function emerge. The individual requires help with dressing appropriately for the season, they become confused about their whereabouts, time of the day, day of the week, or season.

Stage 6: Severe Cognitive Decline: Memory difficulties continue to worsen. Significant personality changes emerge, recall their own personal history imperfectly but generally can recall their own name. Occasionally individuals with AD forget the names of their spouses or caregivers but are able to distinguish between a familiar and unfamiliar face, and tendency to wander and get lost among other things.

Stage 7: Very Severe Cognitive Decline: This is the final stage when many of the individuals lose their ability to communicate, respond to their environment, and ultimately their ability to control movement. Frequently individuals lose their capacity for recognizable speech although words or phrases may occasionally be uttered.

Individuals lose their ability to walk, stand, or sit without assistance. Reflexes become abnormal and muscles get rigid. Swallowing is impaired.

6-Item Memory Disorder Screening

Do you or your family member have:

  1. Problems repeating or asking the same thing over and over?
  2. Problems remembering appointments, family occasions, holidays?
  3. Problems with writing checks, paying bills, balancing the checkbook?
  4. Difficulty shopping independently (e.g., for clothing or groceries)?
  5. Difficulties taking medications according to instructions?
  6. Problems getting lost while walking or driving in familiar places?

A positive response to 2 or more items suggests need for a more detailed evaluation.


Acknowledgment: National Chronic Care Consortium and the Alzheimer's Association.