Increased heart rate and energy expenditure in frontotemporal dementia.

Abstract

This scientific commentary refers to ‘Energy expenditure in frontotemporal dementia: a behavioural and imaging study’ by Ahmed et al . (doi:10.1093/aww263) . The obesity paradox, whereby being overweight or obese during mid-life is associated with higher rates of dementia in later life, while low body mass index (BMI) in older populations is associated with a higher risk of dementia, has been demonstrated in multiple studies of patients with Alzheimer’s disease (Fitzpatrick et al. , 2009). In another neurodegenerative disorder, frontotemporal dementia (FTD), classic descriptions suggest a different pattern, specifically weight gain with disease onset due to hyperphagia and increased sweet intake. However, BMI has not been found to correlate with food intake in FTD, raising the possibility of altered metabolism in patients with FTD (Ahmed et al. , 2016). In this issue of Brain , Ahmed et al. test this hypothesis by measuring activity levels and heart rate to characterize energy expenditure in patients with FTD (Ahmed et al. , 2016). They conclude that resting and total energy expenditure are increased in FTD, suggesting that the basal metabolic rate in patients with FTD may be altered as a part of the disease. A relationship between BMI, metabolism and several neurodegenerative disorders including Alzheimer’s disease, Parkinson’s disease and amyotrophic lateral sclerosis is now generally established, though the complex pathways mediating these associations …