Relationship Between Aging-related Declines In Leg Muscle Volume And Quality And Cognitive Functions

Abstract

PURPOSE: Aging is associated with declining in not only skeletal muscular function but also cognitive function including speed of processing, working memory, and long-term memory. However, it remains unclear whether aging-related decline in muscular function is related to impaired cognitive function. In addition to decreased muscle volume, aging-related decline in muscular function can be attributed to impaired muscle quality such as increased intramuscular fat and connective tissue (Akima et al, 2018; Goodpaster et al, 2006). The aim of the present study was to examine whether the aging-related declines in lower body muscle volume and quality are associated with cognitive function in Japanese adults. METHODS: The participants in this study were 86 adults (43 males, 43 females; age range 30 to 77 years old). The participants’ thigh muscle volume was assessed by bioelectrical impedance analysis. Muscle quality (i.e., levels of intra- and extra-myocellularlipid and connective tissue)of the vastus lateralis was determined using 1H-magnetic resonance spectroscopy at 3T MR system andecho intensity measured with ultrasound. Cognitive functions (inhibitory control, short memory, working memory) were determined with the color-word Stroop task, Face-name matching task and Reading Span Test, respectively. RESULTS: Aging was associated with a decline in muscle volume and an increase in echo intensity (p<0.05). The aging-related decline in muscle volume was correlated to impaired inhibitory control scorein both male and female (p<0.05). In addition, aging-related increase in echo intensity was correlated to impaired inhibitory control score(p<0.05). There were no relationships between those muscle properties and short memory score or working memory score. CONCLUSIONS: These findings suggest a link between aging-related impairment in inhibitory control and reduction in muscle volume and quality. Further studies are needed to determine whether ameliorating muscular function can be a therapeutic target against the aging-related decline in cognitive function.