Dawn Langdon is a neuropsychologist, specialising in the cognitive
problems caused by MS. She spoke with Hilary Freeman.

What exactly is neuropsychology?

It's basically about understanding how the brain relates to behaviour and how diseases which affect the brain impact on functions such as memory, concentration and the emotions. Neuropsychologists work as part of a multi-disciplinary team, together with nurses, physiotherapists, occupational therapists, speech and language therapists and neurologists.

What sort of cognitive problems do people with MS experience?

It's important to stress that not everybody with MS experiences cognitive problems, it's not a forgone conclusion. But many people with MS do at some point become aware that there are aspects of their psychological function which they feel aren't as good as they once were. No two people share exactly the same pattern of problems, or to the same extent, but in general there is a fairly common picture: difficulties with memory, concentration, problem-solving and reasoning.

How do these problems present themselves?

Typically people will realise they're having cognitive problems when they find it hard to read books or follow conversations, which can have a huge impact on their ability to work, socialise and enjoy leisure time. Memory loss is the most commonly reported difficulty and also most often demonstrated in studies. People are likely to find that their recall memory is affected, that is remembering things without prompts. They may suddenly find they're having to write a shopping list, for example, when they never had to before.

But how do you know that these cognitive problems are due to MS? My husband doesn't have MS, but he can't remember phone numbers.

We know these cognitive problems are not just a result of normal variation and ageing because when we compare a group of people with MS with those who are 'healthy', the people with MS will do less well in tests of memory, concentration and reasoning.
Many people need to use mental tricks to help trigger their memory, such as the well known rhyme, Thirty days hath September. Scientific tests prove, however, that there is a greater proportion of people with MS who have cognitive problems than the norm. In most experiments researchers allow for one in 20 of the control group ('healthy' volunteers) to perform worse than expected. The MS group will still always include a higher proportion of people who perform at a lower level.

How do you know people with MS aren't performing badly in the tests because of physical problems? They might find it hard to write or speak.

With the MS Society's support, my colleagues and I have developed tests which are specially designed to measure the psychological functioning of people with MS without being affected by sensorimotor difficulties. This has been one of the most important parts of my research.

Once you experience cognitive problems, will you be permanently affected?

People believe that once you've experienced cognitive dysfunction, it's an inevitable long, slow decline. That's not the case. Cognitive deficits can come and go just like other symptoms. I've worked with a young woman, a bank clerk, who had difficulties with mental arithmetic following a relapse. An MRI scan showed a large lesion in the part of the brain thought to be important for calculation. But when she remitted and was rescanned, the lesion had disappeared and tests showed an improvement in her numerical skills. This is a clear demonstration that cognitive dysfunction can arise and go away again.

Does this mean that all cognitive problems are visible on an MRI scan? Can you predict the severity of cognitive dysfunction by locating brain lesions?

It's not quite as simple as that. MS is a very disseminated disease, with lots of small areas of lesions over a fairly large area, rather than just one area of damage. Also, there is not a perfect relationship between the number of lesions a patient has and the amount of dysfunction they experience. When we looked at MRI scans of patients with primary progressive MS we found some correlation but that isn't the whole story. There's a lot that's not explained by the number of lesions detected on an MRI scan.
One reason we think there's such an imperfect correlation between MRI scan lesions and psychological function is that the visible lesions only partially represent existing pathology. There may actually be small areas of damage and inefficiencies in parts of the brain that appear normal on the MRI scan. MRIs only tell you about areas of abnormality above a certain size, they reveal structural abnormality, not functional abnormality, the architecture of the brain, not what's happening in it.
A good analogy is to take the motorway system across Britain. Even if you knew which bridges had road works and which roundabouts were very busy, you wouldn't know whether you could still get from London to Birmingham. Structure and function are not the same thing.

What's the benefit to people with MS of diagnosing cognitive difficulties?

Once we have identified the problem, we can then offer the right advice and information to MS patients and their families. People may sometimes feel they're going mad because, for example, they can't watch a film like they used to. When they're given some information or a model for what's happening, they may feel more at case with themselves.
It can help a person's family to understand what's happening, thereby improving family relationships, and it can also allow a committed employer or educator to make changes to enable the person with MS to partake fully in their job or course.

What sort of help can be given?

Let me give you an example. A young woman with MS was studying for a social work course at university. She found it very hard to take notes in lectures and at the end of her first year, found she'd failed her exams. Following a cognitive assessment, we were able to identify her problem areas and, with the support of her lecturers, to develop a technique whereby she was able to take comprehensible notes in lectures using clearly defined headings. We discovered that in exams she always passed the first essay very well but failed the others, which we thought to be due to a fatigue effect. It was agreed that she would be allowed to stagger her exams, writing just one essay per day. The result, She passed! Simple changes like these can make a huge difference to a person's independence and quality of life.

Shouldn't everyone with MS undergo cognitive tests at diagnosis together with other neurological examinations?

It wouldn't be practical or particularly beneficial to have blanket testing. For a start, there aren't many neuropsychologists, and cognitive assessment can be very time intensive. It's probably better that access to a neuropsychologist is focused on those people who have a reason for wanting to see one, who are experiencing problems or have concerns.

People with physical disabilities often have to dispel the myth that they are 'stupid', won't increasing awareness that MS can have an impact on mental processes simply confirm this stereotype?

For a long time many of the MS charities across the world were against any mention of cognitive difficulties associated with MS for this very reason. I don't agree. My belief is that good, accurate information is the best defence against ignorance and maltreatment. The truth is that most people with MS do not have severe cognitive problems, dementia in MS is very rare. What's important is to understand the difficulties that people with MS do have, and to use that information to increase their independence and well-being. Sweeping things under the carpet is often counterproductive, causing problems within families and with employers.

Has your work told you anything about the link between the brain and the mind?

Our research has shown that the way people with MS perceive their cognitive difficulties is sometimes very different from the way our objective tests characterise them. It may be that the tests in which a person performs badly may be evaluating skills they perceive they don't actually need or use. What is particularly interesting is that there is a link between what their relatives say about their problems and their performance on tests.
In the end it's the person, not the MS that matters. Cognitive assessment is merely one method of finding a way around the restrictions and difficulties that MS imposes on people's lives.

Reference

Reproduced with the kind permission of
The Multiple Sclerosis Society of Great Britain and Northern Ireland
from MS Matters Issue No28 November/December 1999