Cognitive impairment and sodium concentration in gray matter

More than 50% of people with MS experience cognitive problems at some point during the course of their disease. Cognitive problems can include a wide range of difficulties related to memory, complicated tasks (such as planning) or predicting other people’s behaviour.

Numerous magnetic resonance imaging (MRI) studies have highlighted the key role of gray matter injury on cognitive impairment. These studies suggest that cognitive problems are, to a large extent, irreversible because they are mainly underpinned by the death of neurons (neuronal death). However, we cannot rule out that neuronal dysfunction, occurring before neuronal death, may also affect cognitive functioning.

More advanced MRI technologies can detect neuronal dysfunction before their death. When brain cells dysfunction, sodium accumulates between these cells and this can be detected by advanced sodium MRI.

In this study from Aix-Marseille Université in France, investigators recruited 89 participants including 58 people who had had relapsing-remitting MS for less than ten years, and 31 healthy volunteers. 21 people with MS were classed as cognitively impaired as they failed at least two tasks on a neurological test known as the ‘Brief Repeatable Battery’.

Using sodium MRI, the investigators found that the total sodium concentration was higher in the gray matter in people with MS who were cognitively impaired. This is a stronger correlation than has previously been shown with cognitive impairment and atrophy as shown by conventional MRI measures.

Read the full article (external website opens in a new window)