Ultrasound (US) Measurement of Sarcopenia in the Elder Subject

Sarcopenia is a generalized, progressive and multifactorial muscle impairment, causing multiple pathologies and their consequences such as falls, fractures, dependence, worsening of cognitive disorders and death. Interventions to combat the progression of sarcopenia should be introduced as soon as clinically suspected, based on functional tests to measure muscle strength. Diagnostic confirmation of sarcopenia can be done using several validated methods of estimating muscle mass: magnetic resonance imaging (MRI), computed tomography (CT), biphotonic absorptiometry (DEXA) or bio-impedanceometry. Their availability in clinical routine remains limited due to their high costs and/or lack of accessibility depending on the place of practice. On the other hand, there are certain pitfalls for carrying out these various examinations, in connection with several common clinical problems in the study population: mobility disorders and neurodegenerative disorders disabling for transport and access to the examination table for imaging examinations, hydration disorders distorting measures for bio-impedancetry.

Previous studies suggest that ultrasound may be as effective a tool as previous methods for diagnostic confirmation of sarcopenia. Because of its non-invasive and non-irradiating nature, its affordability, its short duration of realization, its availability and its low constraints of realization, the ultrasound could help to remove some of the current limits to the diagnostic confirmation of sarcopenia.

The investigators hypothesis is that ultrasound can be used to implement a simple and reliable protocol for assessing sarcopenia in the elderly. It could also be used to detect sarcopenia at an early stage ("presarcopenia") while the decrease in muscle mass is not yet accompanied by a decrease in skeletal muscle strength.