Behaviour in Fronto-temporal dementia and Semantic dementia
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.
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.
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.
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.