How do you solve a problem like apathy?
Most of us have probably experienced the feeling at some time in our lives. Lacking the motivation and drive to do things, feeling detached and listless and as though your get up and go has got up and gone… It’s perfectly normal to feel this way occasionally but when apathy becomes a way of life it can be a huge problem.
Apathy is much more common in people with Parkinson’s. Although the research evidence is limited, studies suggest it may affect up to 70% of people with the condition.
This comment made on the Parkinson’s UK forum shows just how profound the impact can be on relationships and families:
My lovely husband was diagnosed 18 months after our wedding... That was 3 yrs ago and we have all sorts to contend with now... What bugs ME though, to the point of craziness, is that he isn’t interested in planning anything long-term or talking about anything but the past — he is like a very old person in his mind (he’s 61, going on 91) — as if his life is over. Yet he plays tennis and could do much much more for himself, like voice exercises, maybe more fitness exercises. His life gets more and more diminished as if he is slowly vanishing, and I find it suffocating. I know it’s Parkinson’s apathy but I have to plan everything, do everything that makes our lives tick … He seems quite content with this. I can see him relying on me more and more to sort out everything — financial, social, physical etc — but if only he tried he could do so much more! I KNOW it’s not his fault — but I can’t stand it sometimes!!!
So what is apathy exactly? Why are people with Parkinson’s more susceptible and most importantly, what can we do about it?
The medical definition of apathy is:
…an absence or suppression of emotion, feeling, concern, or passion; an indifference to stimuli found generally to be exciting or moving.
So in many ways apathy is a lack of motivation.
We don’t fully understand the changes happening inside the brain to cause apathy but one brain chemical that we know plays an important role in motivation is dopamine.
Yes, dopamine, the very same chemical that plays a vital role in coordinating movement, that we know is severely depleted in people with Parkinson’s.
When we anticipate a reward or danger our brain cells release dopamine. This helps prime us for action and activity, encouraging us to act and getting us ready to move.
When we don’t have enough of it, as in Parkinson’s, activity becomes much more of an effort because we don’t have the ‘leg up’ we need from dopamine.
However, the timing, amount and location of dopamine release is key to making sure we have the right level of motivation. Too much dopamine can also have serious consequences.
For some people with Parkinson’s, the medication they take to help boost dopamine inside the brain can make them too motivated and this can result in disturbing changes in behaviour — known as impulsive and compulsive behaviours, such as gambling, hypersexuality or compulsive shopping.
A surprising way to study apathy
One of the barriers to understanding motivation and apathy has been finding a way to identify and study it accurately. Asking people how motivated they feel on a scale of 1 to 10 is not exactly scientific.
Dr Kinan Muhammed is a doctor and researcher at the University of Oxford and he’s using an innovative new technique to study apathy and motivation in people with Parkinson’s.
What we really need is a simple and objective way to measure motivation, something physiological that we don’t necessarily have control over would be ideal. If we look to the animal world to help guide us, interestingly we can find just that.
When a cat is preparing to pounce in order to get a reward, like its next meal for example, something interesting happens to its eyes….
Clearly, you can see that they dilate and it’s a really dramatic effect.
Remarkably the same thing happens to us when we’re anticipating a reward. It’s less obvious in humans than it is in cats, but it is possible to measure changes in pupil size in people using special infra-red eye tracking.
So, Kinan and his team decided to carry out a study using this phenomenon to objectively measure how people with Parkinson’s respond to rewards.
They recruited 40 people with Parkinson’s, 31 people of a similar age without the condition and 20 younger participants.
Participants would hear a voice over a loud speaker announce a ‘prize’ (a small sum of money between 0 and 50 pence). To win the money, participants had to move their eyes as quickly as possible to focus on a target on a computer screen. The faster they did this the more money they would win.
The team used infra-red eye tracking to measure how quickly people completed the task and also measured changes in their pupil size. Everyone also underwent clinical interviews that helped to identify apathy.
Back to Kinan:
We found that people with Parkinson’s who also suffered from apathy had less of a change in their pupil size when they were anticipating rewards compared to those who were more motivated.
Although more work still needs to be done, the study does suggest that pupil responses to reward may be a useful tool in helping us understand this complex brain problem.
The effect of a dopamine boost…
But perhaps even more crucially, the team also investigated the impact of Parkinson’s medication — which works by boosting dopamine levels in the brain. To look at the effect of dopamine, they asked each of the people who were already taking medication for their Parkinson’s to complete the assessments twice — once while on their medication and once while off.
When patients were off their medication, there was a reduction in pupil responses across all the groups, so dopamine seems to boost sensitivity to rewards while also improving the speed and accuracy of eye movements.
So does that mean Parkinson’s medications that are already available may be the answer to apathy?
Dopamine based medications may be at least part of the answer to apathy by helping to get dopamine levels back to where they should be, but it may not be the whole story.
In our study, although dopamine increased pupil responses to reward in patients who were apathetic, it didn’t bring it all the way up to the same level as those who were not apathetic.
So, whether that means different doses of the drug are needed to tackle motivation problems, or perhaps even a different brain chemical is involved still needs to be answered.
You can read the full scientific paper here or watch Kinan explain more below.
Dr Kinan Muhammed is a Wellcome Trust Neurology Clinical Research Fellow at the University of Oxford.
You can find him on Twitter @kinanmuha