Faces and stages

Symptoms of dementia

Dementia is a pattern of symptoms that can be the result of many causes. The pattern of symptoms is heterogeneous both regarding the type (e.g. cognition, behaviour) and severity (mild to severe) of symptoms.

The qualitative and quantitative spectrum of dementia symptoms

Key features of dementia include:

  1. Impairment of cognition: Memory disorder is not always the leading feature. Impairment of cognition may refer to attention and concentration, memory, language, executive functions, social cognition, and visuospatial abilities, and object use.
  1. Decline of activities of daily living: Decline of activities of daily living initially involves complex („instrumental“) tasks such as performing at work, organising the household, planning a holiday, or dealing with financial issues. Later, simpler („basic“) tasks become compromised, including travelling alone, preparing meals, taking medications, choosing proper clothing, maintaining personal hygiene. Finally, people with dementia need assistance with bathing, feeding, grooming, and finding their way even in familiar surroundings.
  1. Behavioural and psychological symptoms of dementia (BPSD): They represent a wide spectrum encompassing apathy and loss of initiative, dysphoria, agitation, delusional misperceptions, aimless wandering, and pacing (particularly in Alzheimer’s disease), emotional blunting, disregard for social rules, impulsivity, overeating, stereotyped and repetitive behaviours (particularly in Frontotemporal degenerations), night-time acting out and vivid hallucinations (particularly in Lewy-body diseases). Behavioural changes are partly due to a mismatch between capacities of people with dementia and environmental demands.
  1. Physical symptoms: dementia does not only cause problems in cognition, behaviour, and mood, it also affects the body. In Alzheimer´s disease, physical symptoms come in middle and late stages (e.g. incontinence), but in some other forms of dementia they can develop relatively early (e.g., Parkinsonian symptoms in Lewy-body dementia or overeating in frontotemporal dementia).

Cognitive symptoms of dementia

Attention, concentrationAttention
Slowness of responses, drowsiness, sleepiness;
Difficulty focusing on a task, distractibility
MemoryWorking memory

Episodic memory

Long-term memory
Forgetting the beginning of a sentence at its end;
forgetting a telephone number during dialing

Forgetting recent events or conversations; forgetting the names of people; losing items around the home; repeated questioning; inability to follow plots of movies

Forgetting events that happened years ago
Confusing own biography
OrientationOrientation in time
Orientation in space
Confusing time of day, day of week, year
Difficulty finding rooms, getting lost in unfamiliar surroundings

Loss of the meaning of single words; difficulty understanding spoken speech; unable to read

Word finding difficulty; distortion of words
Grammatical errors, effortful or halting speech
Executive functionsAbstraction, judgment
Set shifting
Planning, organising
Difficulty using concepts, generalisations, drawing conclusions
Difficulty applying and shifting between rules
Difficulty structuring tasks, following logical steps
Social cognitionEmotion recognition

Appropriate response to emotions of others
Lack of empathy

Abnormal social behaviour
Handling objectsSingle movements

Complex actions
Difficulty performing a movement with a body part despite intact sensory and motor function

Difficulty performing a motor sequence (e.g. opening a can)
Visuospatial abilitiesObject recognition
Inability to visually recognise familiar objects
Inability to draw or copy simple objects

Stages of dementia

There are several degrees of cognitive and behavioural impairment. By convention, they are grouped into the stages of subjective cognitive decline, mild cognitive or behavioural impairment, mild dementia, moderate dementia, and severe dementia. These stages are arbitrary and there are no sharp borders between them. Subjective cognitive decline and mild cognitive or behavioural impairment are summarised as the „prodromal“ stage. The stages of dementia are primarily defined by the involvement of activities of daily living.

Stages of Alzheimer’s disease

evolution of brain pathology

Subjective cognitive decline (SCD)

  • SCD means that the person perceives that their cognitive performance is not as it was previously, but results on neuropsychological assessment are within the normal range.
  • People who report SCD have an increased likelihood of developing dementia, therefore they need to be involved in continual long-term evaluation.
  • SCD may also occur in other conditions as e.g. depression.

Mild cognitive impairment (MCI)

  • MCI has been conceptualised as a transitional state between normal cognitive ageing and mild dementia. There should be evidence of concern about a change in cognition, in comparison to the person’s previous level and the person’s performance is lower than would be expected for the individual’s age and educational background. These complaints, however, do not fulfil the criteria for dementia, and the person is functionally independent in everyday activities.
  • The change can be in one or more cognitive domains (e. g. memory, executive function, attention, language or visuospatial skills). Usually, MCI is divided based on the presence of impairment of memory into amnestic and nonamnestic types of MCI. Based on the affected domains, the aetiology of MCI can be estimated.
  • MCI can negatively affect marital relationships in terms of deficits in communication, loss of mutuality, impaired expression of positive affect and marital cohesion.
  • In MCI, becoming aware of symptoms can induce anxiety and irritability.
  • MCI in 10-12% progresses to dementia per year. The condition may also revert over time or remain unchanged.

Mild behavioural impairment (MBI)

  • The key features of MBI are persistent or increasing changes in behaviour or personality.
  • The changes may refer to motivation (e.g., apathy, aspontaneity, indifference), regulation of mood (e. g. anxiety, irritability), impulse control (e.g., disinhibition, stimulus-dependent behaviour), social inappropriateness (e. g. loss of empathy, loss of tact) or abnormal perception or thought control (e. g. delusions, hallucinations).
  • The changes in behaviours must be severe enough to produce impairment in interpersonal relationships or in the ability to perform at the workplace, but individuals are generally able to maintain independence of function in daily life.
  • The changes are not due to a medical or psychiatric disorder.
  • MBI and MCI may coexist.
  • MBI is usually a forerunner of the behavioural variant of frontotemporal dementia.

Mild dementia

  • The dividing line between MCI or MBI and mild dementia is the impact of the changes on the individual’s daily life and activities.
  • Functional decline shows a distinct hierarchy, with instrumental (more complex) activities such as cooking, shopping, and managing medication becoming slightly limited, while basic activities including personal hygiene, dressing, and eating are usually affected at the stage of moderate dementia.
  • The specific features of mild dementia depend on the underlying disease.

Moderate dementia

  • At the stage of moderate dementia the differences associated with the underlying diseases begin to fade.
  • People have severe memory problems and poor judgement. They may be disoriented regarding time or place. They may also have difficulty recalling personal information such as their address or telephone number.
  • At this stage, people are likely to need help with basic daily tasks such as dressing, bathing, grooming, and personal hygiene, and particularly with more complex tasks such as preparing meals, taking medications, and performing leisure activities.
  • From the perspective of diagnosis, the focus is on impaired activities of daily living. For the purpose of preserving quality of life and self esteem it is crucial that people with mild and moderate dementia are still able to initiate and perform many tasks. Often performance of activities may be better preserved that initiation.
  • Changes of behaviour become more frequent including apathy, agitation, delusions, and hallucinations.
  • At the stage of moderate dementia, the previous lifestyle can no longer be maintained. Work needs to be given up, there is role change within and outside the family, the social network shrinks, activities outside the home (clubs, volunteer work etc.) are reduced, people are in need of support with daily activities such as shopping, maintaining household routines, family gatherings, travel etc. 

Severe dementia

  • In addition to decline in cognition and behaviour, physical functioning deteriorates. The sleep-wake-cycle may be disturbed. People may develop difficulty eating and swallowing, inability to control bladder and bowel movements may occur. People often develop problems with walking and experience falls. Seizures may occur. People develop increased susceptibility for infections such as pneumonia which the most common cause of death in individuals with dementia.
  • In the late stage of dementia most individuals require fulltime assistance and often need to be admitted to nursing homes.
  • Caregivers as well as professionals should be aware that people with severe dementia can still experience positive emotions (comfort, touch, voice).

Symptoms at different stages of dementia

CategoryMild cognitive impairmentMild dementiaModerate dementiaSevere dementia
MMSE Score30-2726-2019-1110-0
Mean duration [yrs]5-72-32-42-5
Cognitive symptomsMinor memory problemsForgetfulness Word finding difficulty Poor problem solvingSevere memory loss Poor judgment Disorientation Communication difficultySevere memory loss Disorientation Loss of recognisable speech
Activities of daily livingSubtle problems with complex tasksComplex activities impaired (e.g. managing finances)Basic activities impaired (e.g. taking care of hygiene); assistance neededFull-time assistance needed
Behavioural and psychological symptomsNoneApathy Depression Social withdrawalIrritability, Agitation Restlessness, Wandering, Delusions, anger Hallucinations Disinhibition  Aggressiveness Delusions Hallucinations Restlessness Crying, Shouting
Physical symptomsNoneNoneIncontinence Change in sleep-wake patternDifficulty walking, eating, swallowing Falls, Seizures
Incontinence Weight loss

This table provides an overview of symptoms at different stages of dementia that refers to dementia in Alzheimer’s disease. It may not apply to dementia in frontotemporal degeneration where behavioural or physical symptoms occur earlier.

Particular features of different forms of dementia

Difficulties in cognition, changing of behaviour, problems with handling activities of daily living – these are common for all types of dementia. However, diseases that cause dementia involve different parts of the brain differently. Therefore, some problems prevail in one form of dementia, while others are less significant. These differences apply mostly in the mild to moderate stages of dementia.

  • In dementia due to Alzheimer´s disease, people usually experience forgetfulness, are unable to recall a recent conversation, lose or misplace objects. They may have difficulty finding correct words when speaking or problems with planning and decision making. Commonly they avoid challenging tasks and withdraw from social contacts.
  • The behavioural variant of frontotemporal dementia is characterised by behavioural alterations as for example impulsivity, overeating, weight gain, apathy, emotional blunting, inappropriate social conduct, repetitive, stereotyped, or obsessive-compulsive behaviours. In the language variants of frontotemporal dementia, verbal expression or comprehension are compromised.
  • In vascular dementia, speed of thought is slowed, and mood swings occur. Cognitive impairment depends on the localization of vascular changes.
  • In Lewy-body dementia, people experience visual hallucinations. Cognitive ability typically fluctuates throughout the day. Acting-out behaviour dreams by yelling, flailing, punching bed partners, and falling out of bed occurs during the REM phases of sleep.

Psychological and environmental causes of behaviour change

Often, behaviour change is caused or aggravated by specific triggers in the environment. In such cases, identifying and addressing these factors may be more appropriate than pharmacological treatment.

  • Too much or too little activity: a person with dementia may be overwhelmed by too many stimuli such as background noise, too many options to choose from, too much activity, confusing environment, several people speaking to them at the same time, a TV or radio constantly playing. On the other hand, lack of activity, understimulation, or social isolation is the other extreme that can cause behaviour change.
  • Caregiver behaviour: acting from a position of authority, patronizing the person, rushing them, and giving orders can make the individual feel unappreciated, unable to make own decision, or even rejected. This may result in resistance or aggressive behaviour. Also, the introduction of an unfamiliar caregiver may initially cause uncertainty, anxiety or even hostility.
  • Changes of routine and environment: These may give rise to agitation, confusion, disorientation and inability to understand why and what is happening.
  • Physical characteristics of the environment: Behaviour change can be triggered by the room temperature being too high or too low as well as by inappropriate lighting, insufficient cues for orientation, and cluttering.


Thomas’ condition worsened, and his family was unable to continue caring for him at home. Therefore, he was admitted to a 24-hour care facility. However, the transition was not well handled. Not only was the environment new for Thomas, but also routines changed and staff whom he did not know told him when to take a bath, when to eat and when to take medications. Thomas, having problems with expressing his needs verbally, started screaming, threw objects and pushed people away. A psychiatrist was called who prescribed sedative drugs. By looking at things from the perspective of Thomas, adopting a respectful way of communication, providing enough time to adapt to the new situation and applying a non-pharmacological approach the additional medication might have been avoided.