We have extensively mentioned that all types of dementia are
progressive, meaning that very rarely will a patient exhibit an abrupt
cognitive decline from one day to another. Instead, the disease
usually progresses in stages, which differentiate from one another
based on symptoms. It’s widely accepted that dementia can be
divided into seven different stages, following the seven-stage model
(Reinsberg et al., 1982). severe Alzheimer’s disease.

Stage 1 – No Impairment

The very first stage is when no symptoms are visible, but the disease
has already started its course in the brain. Cerebral degradation
occurs long before the slightest memory slip is detectable. An
example is tau tangles which, if detected by a brain scan, can help
predict the location and future spatial distribution of brain atrophy a
year before the first symptoms become visible. Amyloid PET scans,
which can show signs of amyloid clumps up to two decades before
symptoms (Bhandari, 2021), can be useful for diagnosing dementia
before symptoms appear.

Stage 2 – Very Mild Cognitive Decline

Stage two could be referred to as “Slight Cognitive Decline” when
the first signs of memory or cognitive confusion start to occur in a
patient but might still go undetected. Because the patient’s social
and organizational skills are still intact, they pass unnoticed the
majority of the time. Common symptoms of this stage are misplacing
keys, forgetting familiar names, or the position of frequently used
objects. These innocent memory slips can happen to anyone.

Stage 3 – Mild Cognitive Decline

During the third stage, mild cognitive declines start to catch people’s
attention. This is because the memory slips are related to recently
occurring things or names learned. A patient in this stage might also
start experiencing trouble finding the correct words or misusing
words in ways never before. Working memory is usually the first skill
to be impaired. Symptoms of this are the inability to consolidate new
short-term memories: an individual might start having trouble
remembering a name just heard, a passage read in a book, or a
recent conversation. Concentration and attention are more difficult
too, which might start affecting an individual’s working life. Planning
and organizational skills, similarly, require a more significant mental
effort, and routine tasks (such as taking meds and going to an
appointment) are usually forgotten more frequently. However,
because the symptoms of this stage can exist for three or four years
before progressing to the following stage, dementia is usually not yet
diagnosed.

Stage 4 – Moderate Cognitive Decline (early-stage dementia)

Diagnosis most often occurs at stage four, where the cognitive
impairments become entirely noticeable. All the symptoms
mentioned above tend to worsen, while others add up visibly. For
example, long-term memory slips start to occur, where the patient
forgets – or at least needs more effort to remember – events from the
far past, while social and behavioral aspects decline too. Symptoms
of withdrawal, apathy, and irritability begin to impact the social life of
a patient, who at the same time will exhibit denial and refusal to
acknowledge their condition. Because the cognitive and behavioral
skills are significantly worsening, the individual will start needing
part-time care and support from their family.

Stage 5 – Moderately Severe Cognitive Decline (mid-stage
dementia)

A patient enters stage five when they start needing a full-time
caregiver because the cognitive decline is severe enough to impact
their daily life. In practical terms, this means that episodes of
confusion (both spatial and mental), feelings of being lost, and
forgetting relatives’ names are more frequent. Because long-term
memory is not entirely compromised, a patient might still be able to
remember information about their identity: who they are, their
adolescence, relatives’ faces, and generally their history.
Nevertheless, cognitive difficulties might impair critical aspects of
their daily life. A patient in this stage might need special assistance
to prepare their meals, get dressed, or any cognitively demanding
task will need to be looked after. On the other hand, tasks
concerning the person’s primal needs, such as using the toilet, might
still be carried out by the patient alone.

Stage 6 – Severe Cognitive Decline (late mid-stage dementia)

Stage six is usually referred to as “middle dementia,” where, along
with the severe cognitive decline, the patient will experience even
worse physical difficulties. At this stage, a caregiver will need to take
complete care of the patient, who will need help with toileting and
showering. Because the patient might still recall episodes of past life,
this is a highly debilitating phase in which the person sadly
acknowledges their condition and realizes the amount of care that
they need. Due to this and to sleep pattern irregularities, the patient
will also experience drastic mood changes, characterized mainly by
agitation, anger, and depression. This phase can last up to three
years, and their ability to speak undergoes worsening symptoms
during this time.

Stage 7 – Very Severe Cognitive Decline (late-stage dementia)

The seventh and last stage of dementia is the hardest one to handle
because the physiological capabilities of the patient start to
surrender. Here, most individuals will have difficulty controlling their
bowel movements and carrying out other tasks, such as swallowing
and speaking. Speaking abilities might be almost completely lost,
and the patient might not be able to articulate phrases. They may be
able to say a few words, but they might be out of context and
disconnected. Physical slowing might also impact walking and
movements in general, given the dopamine deficiencies they will be
experiencing. The difficulties in swallowing can cause recurrent
pneumonia due to aspiration, which can put the patient’s life at
severe risk, given that their immune system is significantly
compromised at this stage. However, if dementia is detected early
enough, current treatments can slow down the progression of the
disease and its symptoms.