Behaviour in Fronto-temporal dementia and Semantic dementia

Dr Julie Snowden , Consultant Neuropsychologist

Behavioural and emotional changes in FTD and SD are often the most distressing aspect of the condition for carers and have a major impact on day-to-day life. As with mental symptoms, behavioural changes are an inherent part of the disease and are not voluntarily caused by the sufferer. This talk describes how degenerative brain disorders can cause behavioural symptoms, what the main behavioural problems are in FTD and SD as well as how such behaviours can be managed more effectively.

How does the brain affect behaviour?

To get a good understanding of the behavioural changes in fronto-temporal dementia and semantic dementia, it is useful to look at the brain and the way it functions (see diagram). The areas at the back of the brain (the ‘parietal’ and ‘occipital’ lobes) are very important in terms of processing what comes in through our senses.  In contrast, the areas at the front (the ‘frontal’ and ‘temporal’ lobes) act as a control centre, and help us to integrate and make sense of this information.  This is very important in our understanding of the meaning of things.  It is the front of the brain that is affected in fronto-temporal dementia (FTD) and semantic dementia (SD).   

For a more detailed overview of brain functions and dementia, please see Prof Neary’s talk ‘Frontotemporal dementia: An overview’.

FTD - The frontal lobes

The frontal lobes develop later in maturity.  They help to control incoming information from the environment, and to guide our actions and behaviour (see diagram). When the frontal lobes don’t work as they should, the system of control begins to break down.  This can affect behaviour in a number of ways. 

Planning and foresight
People with FTD may lose the ability to plan future actions and anticipate the consequences of their actions.  This lack of planning may lead to the following behaviours:

  • Inertia, apathy, lack of motivation – people with damage to the frontal lobes can become less proactive
  • Purposeless activity, impulsivity – sometimes people act quickly without thinking things through
  • Neglect of self care and personal responsibilities – lack of motivation to carry out simple tasks
  • Behaviour governed by immediate wants – lack of foresight may result in inappropriate judgements about things such as money or eating

So, inability to anticipate the consequences of actions may lead to poor judgement and decision-making.  

Frontal lobe dysfunction may also result in disorganised behaviour. FTD sufferers may fail to complete tasks, or may attempt to carry out activities in a rather unusual manner.  Even a simple task such as making a cup of tea might present problems, as there are several components involved, and the order in which they are carried out affects the outcome.  Difficulties occur because the frontal lobes play an important role in our ability to sequence and organise our thoughts and actions. 

People with FTD may also have impaired attention.  It may be difficult to engage them in tasks and they may fail to complete activities because they are easily distracted by something else. 

As mentioned earlier, there can be a loss of motivation and subsequent failure to anticipate the consequences of actions.  People with FTD may have little insight into the effects of their behaviour and fail to ‘check’ their conduct.  Thus, they may make numerous mistakes, and may be oblivious to their errors.

People with FTD may demonstrate ‘concrete’ or literal thinking.  For example, a figure of speech such as ‘too many cooks spoil the broth’ might be interpreted literally as having something to do with cooking.  The frontal lobes play an important part in our ability to understand abstract concepts, meaning that people with FTD may interpret things differently, often with reference to their own personal experience.  Thus, they may appear self-centred, with little interest in others’ viewpoints. 

A common symptom is a loss of flexibility in behaviour.  The frontal lobes are very important in allowing us to adapt our behaviour according to the situation.  People with FTD often lose this ability, and become quite rigid in their thinking.  They may be unable to adjust their actions in unfamiliar situations, and thus behave inappropriately.  Also, they may ‘perseverate’ (do/say the same thing over and over again).  This is because their brain fails to tell them that the action/information is no longer relevant to the current situation. 

Emotions and social behaviour
The frontal lobes are not only important in cognition.  They also play a key role in our emotions.  Often, one of the most difficult factors that carers encounter is their relatives’ loss of feeling towards them and their family.  People who may have once been very affectionate towards their loved ones may become ‘cold’ in manner.  There may be a loss of sympathy and empathy, and people may no longer respond appropriately to situations.  In contrast to this picture of a ‘loss’ of emotion, it is also common for people with FTD to show inappropriate demonstration of emotion.  People may become ‘disinhibited’ and tactless, for example they may laugh loudly or tell jokes at a funeral.  They are typically unembarrassed by their behaviour, and lack insight into the effect it has on others. 

Sensory information
People with FTD are able to feel normally, but it is our experience that sometimes their responses to stimuli are abnormal.  For example, there may be no response to painful stimuli such as scalding hot water.  The reason for this behaviour is yet to be clarified, but it is possible that there may be a relationship with impaired attention.  There is evidence to suggest that how we behave is governed by attention, for example, a runner focussed on winning a race may complete the circuit without feeling the pain of a sprained ankle, simply because they are not attending to it.  Impaired attention may therefore influence FTD sufferers’ reactions to stimuli. 

Eating behaviours
It is common for people with FTD to demonstrate odd eating habits.  There is often a preference for sweet foods, such as biscuits and chocolate.  People may become gluttonous, eating everything that is put in front of them (sometimes including food on others’ plates).  This relates to a lack of ability to inhibit behaviour, and also a tendency to respond indiscriminately to environmental stimuli (this is called ‘utilisation behaviour’).  In addition, people with FTD may even seek out food, and also may ‘cram’ food into their mouths instead of chewing and swallowing one item at a time.  This may relate to problems in sequencing, or may reflect a ‘repetitive’ behaviour as discussed below. 

Repetitive behaviours
It is very common for people with FTD to show repetitive behaviours and mannerisms such as humming the same tune, or repeating the same phrases or words.  People often develop repetitive routines and rituals, and it is common for carers to report behaviours such as pacing, wandering, and hoarding. 

SD - The temporal lobes

There is some overlap between the behavioural changes of FTD and SD patients, and some of you caring for people with SD may have already recognised several of the symptoms described in the previous section.  However, there are some subtle differences. 

The temporal lobes play a vital role in our understanding of the world.  One of the first symptoms of SD that relatives tend to notice is that of impaired comprehension of words and inability to name things.  The ‘tools’ of language (i.e. the sounds and grammar) are well preserved, so speech is fluent and effortless, however the meaning of individual words and concepts is reduced, resulting in non-sensical speech and odd behaviour.

Although problems in language are prominent, there are effects on other aspects of functioning, for example, recognition of the following may be impaired:

  • Visual stimuli - faces and objects
  • Auditory stimuli - non-verbal sounds
  • Olfactory stimuli – smells
  • Tastes
  • Tactile stimuli

The actual perception of the information is normal – it is the person’s ability to understand the meaning of the information that is impaired.  For example, they might see the person below perfectly well, and be able to pick out individual features, but they may be unable to recognise the meaning and consequently name the person. 

Similarly, the properties of items may be lost – for example, when shown a picture of fruits they may be unable to state which one is soft or hard, or sweet or sour. 

Preservation of ability
The loss of meaning is not uniform.  There can be variance in understanding of visual information versus verbal information, relating to right/left emphasis of problems in the brain.  Also, there are some areas in which there is preservation of function, such as understanding of number – it is common for patients to enjoy number games and quizzes.  Also, personal experience has a strong effect upon what is recognised – things that are frequently experienced and are highly relevant to their daily life are more likely to be understood than things that are not.  For example, a person who owns a budgerigar may be more likely to recognise, use, and understand the word ‘budgerigar’ than the word ‘hamster’.  Similarly, people with SD can often recognise and name their own items (e.g. kettle), despite being unable to recognise another example of the same item.  

Behavioural consequences
The loss of meaning that occurs in SD influences behaviour in a number of ways: 

  • Using the wrong words: People with SD often use inappropriate terms, and sometimes use words in a peculiar fashion
  • Inappropriate object use: Lack of understanding may lead to poor recognition of objects and poor discrimination between objects
  • Loss of sense of danger: People with SD may lose sense of the properties of things, for example, hot oil
  • Obsessional behaviour and routines: As the world around them is beginning to lose all sense of meaning, people with SD often stick to things that they know, and become suspicious of non-routine things
  • Narrowed behavioural repertoire/preoccupations: Again, this is likely to be due to their preference of ‘known’ things
  • Rigid routine, clockwatching: This may be due to preserved number concepts – people with SD may recognise time as meaningful, thus providing a tangible sense of meaning for their life
  • Self-centredness: Like people with FTD, it is common for people to fail to recognise others’ needs and emotions
  • Hyper-reactivity: Unlike people with FTD, who show reduced reaction to sensory stimuli, people with SD may show hyper-reactivity, with excessive response to even the slightest touch.  As SD sufferers are able to attend to stimuli, but have impaired understanding of its meaning, they may find it difficult to react appropriately to things.  Also, they may have difficulty adapting to and accepting novel stimuli – they are unable to ‘filter out’ things that have little relevance e.g. background noise.


Management of behaviour

The following section provides some advice on how to manage challenging behaviours. This is really something that we’ve gleaned by talking to carers over the years. Firstly, it’s important to recognise that changes in behaviour are an integral part of FTD and SD and that sufferers are not being deliberately difficult. Carers shouldn’t feel that they are to blame for their relative’s emotional or behavioural changes, it is simply part of the disease process.  

Reasoning with the person about their behaviour will only have a limited effect as one of the main difficulties for people with FTD and SD is thinking about the consequences and repercussions of their behaviour. For example, if a sufferer repeatedly starts drinking a cup of tea when it is still scalding hot, explaining to them why they should wait till the tea has cooled down will probably not stop them from doing the same thing again next time. Many carers have found that using rational arguments only serves to increase sufferers’ irritability because they are unable to use reason to guide their actions. The best way to cope with challenging behaviours is to adapt your lifestyle to accommodate them. For example, one way of stopping someone from scalding themselves would be to remove the cup of tea and only hand it to the person when it is cool enough to drink. 

Rigid behavioural routines
People with FTD and SD often have strict routines and like to do the same things at set times. Although these routines are very difficult to change, it may be possible to use them to benefit other behavioural problems. For example, one FTD sufferer in our unit used to repeatedly steal food from other people’s plates. The staff at his home had observed that he tended to pace along the same route every day and never ventured beyond the boundaries he had imposed himself. Using this, they placed some sticky tape around his table and told him he was not allowed to venture beyond the tape during lunch times. The patient adopted these rules as part of his daily routine and from then on remained sitting at his table during lunch. 

Certain routines are so engrained that sufferers get very frustrated when these need to be changed. A common problem is having to stop driving: people with FTD and SD can become very irritable and may even continue to drive despite being told they shouldn’t. The best way to change routines if they do need to be altered is to do so gradually. Suggesting that the person perhaps only drive locally at first or that taking the bus or train to a certain place might be more enjoyable will be more likely to result in positive action rather than suddenly explaining to the person that they are no longer allowed to drive. 

Taking care of yourself
In the midst of all these changes, carers often forget to look after themselves. However, you’re the one who’s constantly under pressure and being asked to adapt, so it’s important to make sure that you make time for yourself. Some carers often feel that they should shoulder the burden by themselves and be entirely responsible for their relative. As a consequence, they often end up isolated from others and physically worn out. It’s important to be open to others and to seek support from your family, friends and neighbours, telling them about the disease and the problems you have to deal with on a day-to-day basis. 


Coping with behaviours in Semantic dementia

The following section focuses on changes in behaviour that are more specific to people with SD and are a direct result of their inability to understand the meaning of things.

People with SD have difficulty in understanding the meaning of individual words.  It can often help understanding if words are put into context: speaking in complete sentences is better than communicating in short phrases or by single words. For example, sufferers might have difficulty understanding the meaning of the word “chicken”, but their understanding will improve if it is linked with a specific experience they can remember (e.g. “chicken that you had for your tea on Monday”). Similarly, a sufferer may not recognise the name “Lizzie” but might recognise “ Lizzie who lives next door”. 

It may also help to use the same vocabulary that the sufferer uses on a day-to-day basis as they may not understand words that are no longer familiar to them. Using names and words in a consistent manner may also boost communication. For example, if a relative is always referred to as “Aunt Claire”, sufferers may not understand that other names (e.g. “Claire Townsend”, “Our Claire”) also refer to the same person. Similarly, if a person always talks about their pet as a “budgie”, they may not understand that “budgerigar” also means the same thing. 

Object recognition
Loss of understanding is not just restricted to words, people with SD can also lose their understanding of the meaning of objects. This can result in them using the wrong object, for example, washing their hair with bath cleaner instead of shampoo. A good way to get round this is to always keep objects in the same place. People with SD are generally better at remembering where things are as opposed to what things are. If they remember that the last time they washed their hair they used the bottle on the shelf next to the bath, then they will be more likely to go back to that place the next time round. Similarly, it’s important to keep objects with different functions in separate places. Putting the bath cleaner in a separate place would reduce the risk of it being confused with the shampoo bottle. Putting distinctive labels, such as a red sticker, on objects that are regularly used may also help to get round this problem. 

If a person goes into respite care or leaves their home, it is important to remember that they may not recognise novel objects, even if they have similar ones at home. For example, one patient in our unit would stop shaving every time he went into respite care. The staff eventually realised that this was because he didn’t recognise the razor he had been given because it wasn’t the one he was used to. Sure enough, once he was handed his own razor, he was able to shave as normal.