Cognitive and behavioural symptoms in ALS: why are they there and how to assess them?

For more than a century, our understanding of ALS has been characterised by a tension between the concept of a purely motor degeneration and a growing realisation of the frequency and importance of cognitive symptoms that can culminate in dementia. The increasingly frequent reports of cognitive and behavioural symptoms in ALS patients seemed to contradict the very idea of a “motor neurone disease”. In my talk I will argue that cognitive and behavioural symptoms in ALS are a necessary and logical consequence of the motor character of the disease, as long as we extend our concept of the motor symptoms to encompass what I will call “motor cognition”: the aspects of cognition most closely related to planning, control and understanding of movement. Apart from offering an integrated concept of the disease such an approach underlines the importance of cognitive assessment as part of the routine examination in ALS. In practical terms, brief but focused assessment tools, such as the Edinburgh Cognitive ALS Screen (ECAS) allow a meaningful and accurate bedside assessment of cognitive functions in ALS patients