Dementia(Greater Neurocognitive Disorder): Definition, Etiology, Classification, Evaluation and Diagnosis

The dementia also known as greater neurocognitive disorder according to DSM-5, it is not necessarily linked to senescence as misbelieved, since there are various causes which can lead an individual to develop this condition. Mental health professionals have a series of instruments that allow the evaluation and subsequent diagnosis of dementia.

Dementia is defined as a neurocognitive impairment that produces cognitive, motor and social deficits, which involve changes in the personality that limit the ability and normal functioning of a subject. The memory is present mainly affected the mental detriment, significant changes are also observed disturbance in executive functions and the inability or difficulty communicating through speech, writing or mimicry. Likewise, the inability to execute coordinated movements can be observed, which are not due to physical problems. The senses are also affected when there is a loss of cognitive ability.

Etiology of dementia

There is research that indicates that approximately 60 percent of dementia is caused by Alzheimer’s disease. However, there are other specific and identifiable diseases that can lead to dementia, such as:

Degenerative diseases:

  1. Pick’s disease.
  2. Parkinson’s disease.
  3. Guam Dementia (Required Item)
  4. Huntington’s disease

Vascular dementias:

  1. Multiinfarction
  2. Binswanger’s disease(Required item) 

Infectious dementias:

  1. Neurolues (Progressive general paralysis) (Required item) 
  2. Creutzfeldt-Jakob disease (Item required) 
  3. Subacute Sclerosing Panencephalitis (Required Item)
  4. Progressive multifocal leukoencephalopathy (Item required) 

Deficiency dementias:

  1. Folic acid

Toxic dementias:

  1. Alcohol
  2. Drugs
  3. Metals


  • Brain Neuroplasias  (Required Item) 
  • Metabolic dementias  (Item required) 
  • Traumatic dementias  (Required item) 
  • Demyelinating diseases  (Required article) 
  • Psychiatric illnesses  (Required article) 

Neuroanatomic and clinical classification of dementia


Regarding the neuroanatomical classification of dementia , two basic patterns of neuropsychological deterioration can be differentiated, which are cortical and subcortical. Within the cortical pattern is the presence of the so-called “aphasic-apracto-agnosic ” syndrome . (Required item)

The aphasic-apracto-agnosic syndrome is the expression of the joint and homogeneous disintegration of the superior cortical functions. Functions are compromised by Alzheimer’s disease and Pick’s disease . These diseases damage the anatomical structures of the brain and these physical changes can be observed through imaging studies.

In relation to clinical categorization, the progression of dementia can be evaluated in an individual considering the guidelines based on the degree of intensity of the disorder. They are classified into four levels of increasing order, which are dementia: minimal, mild, moderate and severe.

Minimal dementia

The person manifests a limited and variable deficit in the acquisition of new information, as well as short-term memory deficits and slight orientation deficits.

Mild dementia

There is a loss in the ability to acquire new information, a decrease in the ability to be temporally and spatially oriented, evident difficulties in solving problems, subtle linguistic alterations and an inability to perform tasks of daily living and caring for oneself.

Moderate dementia

At this level, there is a significant inability to retain, remember, and evoke new information, along with amnesia of recent events associated with the collusion, decreased orientation indexes, inability to solve problems, incoherent oral expressive language , and inability to handle speech. daily life, as well as in the tasks of personal care and hygiene, feeding and a deteriorated general appearance.

Severe dementia

In this category, significant loss of memory processes can be observed, completing the gaps with confabulatory pictures; the orientation repertoires are intensely affected, the inability to resolve conflicts or problems is total, the language is clearly incoherent, and the individual is incapable of subsisting independently. Sometimes fleeting delusional thoughts are detected. The affected person reaches the point of not recognizing close relatives, does not control sphincters, emotional poverty, apathy and inertia.

Evaluation and diagnosis of dementia

Changes in mental ability can range from the most subtle, being confused with casual forgetfulness due to the amount of activity, stress among others, even the most obvious ones such as the presence of mental gaps, incoherence in speech and temporal-spatial disorientation.

The evaluation of an individual who impresses with possible dementia requires a thorough examination and testing, always considering the following aspects:

  • The exact origin of the disease,
  • If the symptoms are irreversible or can be treated,
  • What is the cause and the extent of your disability,
  • The areas that are not yet affected and that allow the person to function satisfactorily,
  • If the affected person suffers from other diseases and is under drug treatment that aggravates the mental problem,
  • The psychological and social resources available to the patient and his family to be able to assume responsibility for the treatment and the changes that will manifest in the future in the person’s life.

The aspects that the complete evaluation of dementia must understand are:

  • Physical exam
  • Neurological examination
  • Mental state examination
  • Analytical tests – biochemical analyzes
  • Syphilis and HIV test
  • CSF (cerebrospinal fluid)
  • EEG (electroencefalograma)
  • CT (computerized axial tomography)
  • Psychopathological and psychiatric evaluation
  • Neuropsychological evaluation
  • Assessment of activities of daily living
  • Others, such as PE (evoked potentials) PET (positron emission tomography) thyroid function, toxicological tests.

Diagnosis in the early stages of dementia syndrome could be difficult to carry out because it tends to be confused with othermental disorders, so all variables must be considered and controlled, in order to avoid an erroneous assessment that leads to a bad diagnosis.

As for the variables, they can be internal and external. The inmates are referred to the patient himself, such as the cultural level, age, among others. As external variables are the family organization, environmental requirements and professional level.

When dementia is already established of a moderate or severe degree, its diagnosis is made with a high percentage of zero errors. Among the aspects to consider to determine the mental commitment of the patient we find the assessment of the visuospatial areas ( visual perception and spatial orientation), attention (attentional control), language (receptive speech and expressive speech), memory (immediate and logic) and the intellectual area (thematic drawings and texts, conceptual and discursive activity).

Among the organic mental disorders, dementia constitutes one of the most important due to the pathological deterioration of an individual’s intelligence, leading him to present difficulty in adapting to the demands of daily life and limiting his possibilities for personal autonomy. To achieve good care and management of the syndrome, it is necessary to be assertive in the classification, evaluation, thus avoiding erroneous diagnoses that generate uncertainty and poor care for the patient and family.

Frequent questions:

Can dementia cause death?

Yes, in the case of Alzheimer’s disease due to damage to the brain structure that affects vital information for the organs. Senescence dementia does not lead to death.

What is mixed dementia?

It is a neurocognitive disorder where two types of dementia coexist. A person can have vascular dementia and Alzheimer’s at the same time.

At what age can you suffer from dementia?

At any stage of life there is a risk of suffering from dementia, because it has different causes (infections, physical trauma, toxic, among others).

Does a person with dementia classify as a person with a disability?

Yes, due to his progressive cognitive deterioration that makes him depend on a caregiver or tutor.

Should I fear if my memory is failing?

No, if I realize that after a period of time I remember what I forgot, but if I make an effort to remember or it is simply others who notice that I do not remember, for example names or addresses, I must go to a specialist.

Georgia Tarrant
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Hello, how are you? My name is Georgia Tarrant, and I am a clinical psychologist. In everyday life, professional obligations seem to predominate over our personal life. It's as if work takes up more and more of the time we'd love to devote to our love life, our family, or even a moment of leisure.