MS can affect all aspects of thinking, including memory, concentration and planning.
This study looked at how MS might affect planning, problem solving and performance using a test called the Tower of London test. This test has many varieties but they are all similar to the following.
There is usually a board with a few posts stacked with a small number of beads of different colours. These have been arranged by the researcher to show what the target result is.
The person being tested is given an identical board with beads but arranged in a different order on the posts. They have to rearrange the beads, moving only one at a time from one post to another, to get the target result. This requires thinking ahead to move some of the beads to the "wrong" post so that others can then be moved. Finally, beads can be moved from the "wrong" post to the correct post to complete the task.
Successfully completing the test requires someone to plan all the moves before carrying out what they have planned. You can see one version of the Tower of London test on YouTube.
In this study, three groups (people with relapsing remitting MS or secondary progressive MS and healthy controls) were tested on a difficult version of the Tower of London test. The researchers measured how long the person took in planning all their moves as well as whether they were successful in completing the test.
They found that people with both types of MS took much longer to plan their moves than the healthy controls. They also showed a greater variation in how long they took to plan as the task was made harder.
However, there was no difference between the three groups in how well they completed the task (whether they had all the coloured beads on the correct posts), it just took people with MS longer to think ahead and make their plan.
The researchers suggest that imposing a time limit, as has been done in many other studies, would affect how well someone seemed to complete the task when, in fact, it was just more time for planning that was needed to be successful.
Denney DR, Hughes AJ, Owens EM, et al.
Deficits in planning time but not performance in patients with multiple sclerosis.
Arch Clin Neuropsychol. 2011 Dec 15. [Epub ahead of print]
Abstract - PubMed website
