What are the often invisible cognitive consequences of multiple sclerosis? Maureen van Dam mapped these out during her doctoral research. 'People usually notice the physical symptoms, but the cognitive symptoms deserve at least as much attention.'
For Van Dam, the interest in the cognitive problems associated with multiple sclerosis (MS) started during her master's internship. 'It really affected me to see how young people, in the midst of their working lives and with young families, were suddenly faced with the unpredictability and uncertainty of MS,' she says. 'You never know exactly how the condition will develop further, and it is this unpredictability that has such a big impact on daily life.'
The cognitive side of multiple sclerosis
MS is a chronic auto-immune condition where the immune system damages the protective sheath around nerve cells in the brain and the spinal cord. Signals between brain areas are then transmitted less effectively, which can cause a range of diverse impairments: from problems with movement and tingling in the fingers to changes in memory and concentration.
As the cognitive symptoms are often subtle and differ per person, they are often not discovered until a later stage. Problems with concentration, memory or thinking more slowly are easily put down to stress and fatigue. 'Incidental problems are not necessarily cause for concern,' Van Dam says. 'But when symptoms keep recurring or increase over time, it is important to take a closer look.'
What biomarkers and brain networks tell us
In her research, Van Dam focused on factors such as biomarkers in the blood and cerebrospinal fluid. These give information on damage processes in the central nervous system. 'With MS there is damage to the neural pathways. This damage causes substances like NfL and GFAP to be released, which we can measure.' From her study it appeared that people with MS who experience cognitive symptoms generally have higher levels of these biomarkers. 'If these levels are raised in someone with MS, this can be a signal to look for cognitive problems.' Van Dam does, however, warn against drawing too firm conclusions. 'Biomarkers can help to focus the attention on possible cognitive problems, but they are not a replacement for existing diagnostics.'
Van Dam also looked at brain networks using structural and functional MRI. Her studies showed that it is not only the amount of damage that is important, but mainly the way brain areas communicate with each other. The brain areas are like stations and the connections between them are like railway tracks,' Van Dam explains. 'Just as with the rail network, a lot of brain traffic runs via one central point: in the case of the brain, this is the thalamus. You can think of it as the brain's version of Utrecht Central Station.'
Because the thalamus is such an important junction, damage to this area has major consequences for the whole network. In people with cognitive complaints the researchers saw indications of disruptions in the organisation and flexibility of brain networks, particularly in and around the thalamus. It is not just about where the damage is, but also about how the brain tries to maintain or compensate for its connections.
Six cognitive profiles
There is considerable variation in the problems experienced by people with MS: one person may mainly have difficulty with planning things and keeping an overview, while another is conscious that information is processed more slowly. Based on neuropsychological tests, Van Dam identified six cognitive profiles, each with its own combination of strong and weak functions. 'There isn't just one pattern of cognitive decline,' she says. 'These profiles show that people can have different problems.'
Van Dam believes that these profiles offer a starting point for future research on more person-centred support, although she emphasises that further research is needed to determine how stable and useful these profiles are in practice.
A new questionnaire: the MS-IADL-Q
Together with people with MS, their relatives and care professionals, Van Dam developed the Multiple Sclerosis Instrumental Activities of Daily Living Questionnaire (MS-IADL-Q). This questionnaire shows how cognitive problems carry over into daily life, in such activities as planning, driving or remembering appointments. The MS-IADL-Q makes a unique distinction between the physical and cognitive causes of limitations. 'This distinction is important,' says Van Dam. 'If someone has problems taking medication, this could be the result of forgetfulness, but it can also be due to physical restrictions. These are totally different challenges.'
Towards a more person-centred treatment
Working with people with MS made a deep impression on Van Dam. 'Many of the participants had only recently been diagnosed. Their willingness to take part in research aimed at improving care in the future really sticks in my mind.'
She hopes that her research will contribute to more attention being paid to cognition within MS care. 'Cognitive functioning says something about the person you are dealing with, and possibly about how disorders develop,' she says. 'By considering not only objective test results, but also experiences, psychological factors and daily functioning, we will ultimately be better able to understand what a person needs.'
