The concept “senile dementia” is used to refer to degenerative diseases that affect cognitive functioning, particularly memory, and that occur at advanced ages. In contrast, we speak of early or pre-senile dementia when the symptoms occur earlier than would be expected, usually in maturity.

In this article we will describe the 7 phases of senile dementia and early dementia indistinctly, since the development of cognitive impairment follows the same approximate lines regardless of the age at which the symptoms begin to manifest.

The 7 phases of dementia

There are a large number of diseases that can cause dementia; some of the most common and well-known are Alzheimer’s, Lewy’s and recurrent strokes. Each such disorder initially affects different regions of the brain, although symptom differences are reduced in advanced stages.

Although the symptoms of dementia depend on the specific alteration of each patient, the overall progress of these diseases has been divided into seven phases according to the degree of cognitive impairment that the person presents at any given time.

1. Absence of cognitive impairment

The first stage of cognitive impairment corresponds to the absence of it; therefore, most people are in this phase, which can be included together with the following two in the “pre-dementia” category, characterized by normal or practically normal cognitive functioning.

A person is considered to be in phase 1 when does not present significant cognitive symptoms that could be attributable to a deterioration of the brain, such as more relevant memory losses than those produced by lack of energy or attention, among other common factors.

2. Age-related memory deficits

Ageing, and in particular the onset of senescence, is naturally associated with small losses of memory which are mainly manifested in the forgetting of names or locations of objects. The second phase of cognitive impairment is characterized by the presence of these deficits in a more or less habitual manner.

Although in many cases the appearance of occasional forgetfulness is only a consequence of age, on some occasions memory loss may indicate a future severe deterioration of cognition , especially if the frequency of these is high and if the person is relatively young to have forgetfulness typical of old age.

3. Mild cognitive impairment

The concept of “mild cognitive impairment” is used to describe cases in which there are noticeable signs of impairment in memory and in the performance of everyday tasks. In this phase the cognitive deficits are more marked than would be expected for the person’s age, even taking into account aging.

People with mild cognitive impairment have a higher risk of developing dementia than those without, although the progression of deficits often stops at this stage. It is common for people with this type of impairment to have problems retaining information, remembering words, concentrating or finding their way around.

4. Mild or early dementia

The fourth phase corresponds to the onset of dementia as such. In this stage, which usually lasts about two years, changes in personality and mood begin to appear . Since social skills also deteriorate, it is very frequent that the frequency of social interaction decreases.

Cognitive problems become much more evident from the onset of dementia. Patients usually have some awareness of their disease when they reach this stage, although dementia also affects this recognition. They also tend to deny their symptoms as a defense mechanism.

5. Moderate dementia

During the intermediate stage of dementia, affected people begin to need the help of others to carry out everyday tasks . As the disease progresses, abilities such as using money, telephones or cooking instruments, reading and writing, remembering information about oneself and even dressing, deteriorate.

6. Moderately severe dementia

At this stage, memory and cognitive problems have become so severe that they interfere with the performance of many activities; this will continue to increase as dementia progresses. Most often, when reaching this stage, the person needs constant supervision by one or more caregivers .

As for the most common symptoms and signs, in addition to worsening memory problems (which already include recognition of people close to you) we find the appearance of feelings of anxiety and agitation, sleep problems, wandering, obsessive and repetitive behaviour, delusions or aggression.

7. Severe or advanced dementia

The average duration of the final stage of dementia is approximately two and a half years. Advanced dementia is characterized by a generalized loss of psychomotor skills , including those needed for talking, walking, eating, or using the bathroom.

Although the progress of each case of dementia depends on the disease that causes it, they are all very similar during the final period because the structural deterioration has spread to all regions of the brain.