Neck muscle cross-sectional area, brain volume and cognition in healthy older men; a cohort study

Alixe Hm Kilgour,Calum D Gray,Joanna M Wardlaw,John M Starr,Alasdair Mj Maclullich,Karen J Ferguson,Ian J Deary

doi:10.1186/1471-2318-13-20

Abstract

BackgroundTwo important consequences of the normal ageing process are sarcopenia (the age-related loss of muscle mass and function) and age-related cognitive decline. Existing data support positive relationships between muscle function, cognition and brain structure. However, studies investigating these relationships at older ages are lacking and rarely include a measure of muscle size. Here we test whether neck muscle size is positively associated with cognition and brain structure in older men.MethodsWe studied 51 healthy older men with mean age 73.8 (sd 1.5) years. Neck muscle cross-sectional area (CSA) was measured from T1-weighted MR-brain scans using a validated technique. We measured multiple cognitive domains including verbal and visuospatial memory, executive functioning and estimated prior cognitive ability. Whole brain, ventricular, hippocampal and cerebellar volumes were measured with MRI. General linear models (ANCOVA) were performed.ResultsLarger neck muscle CSA was associated with less whole brain atrophy (t = 2.86, p = 0.01, partial eta squared 17%). Neck muscle CSA was not associated with other neuroimaging variables or current cognitive ability. Smaller neck muscle CSA was unexpectedly associated with higher prior cognition (t = −2.12, p < 0.05, partial eta squared 10%).ConclusionsIn healthy older men, preservation of whole brain volume (i.e. less atrophy) is associated with larger muscle size. Longitudinal ageing studies are now required to investigate these relationships further.

Highlights

Two important consequences of the normal ageing process are sarcopenia and age-related cognitive decline
Muscle and brain ageing had rarely been studied in tandem; studies demonstrating improved cognition in later life with increased physical activity have highlighted this important area of research
Using the negatively associated with estimated prior cognitive ability (NART) score as an outcome variable, we found that total neck muscle cross-sectional area (CSA) predicts 10% of the variance in the NART score (t = −2.12, p < 0.05) after adjusting for intracranial area (ICA) and age

Summary

Introduction

Two important consequences of the normal ageing process are sarcopenia (the age-related loss of muscle mass and function) and age-related cognitive decline. Existing data support positive relationships between muscle function, cognition and brain structure. Studies investigating these relationships at older ages are lacking and rarely include a measure of muscle size. Muscle and brain ageing had rarely been studied in tandem; studies demonstrating improved cognition in later life with increased physical activity have highlighted this important area of research. For example a Cochrane review of randomised controlled trials found evidence that aerobic physical activities improved cognitive function in healthy older adults, with effects observed for motor function, cognitive speed, and auditory and visual attention [15]. It was hypothesized that these relationships were due solely to cardiovascular fitness, and this may play a role, animal studies have found other underlying mechanisms including: increased levels of brainderived neurotrophic factor which may contribute to neurogenesis, effects on neurotransmitter systems and increased insulin-like growth factor 1 [19]

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