Sarcopenia is a progressive and generalised skeletal muscle disorder involving the accelerated loss of muscle mass and function that is associated with increased adverse outcomes including falls, functional decline, frailty, and mortality.

In this pilot project, the investigators want to explore the potential of the high-definition surface electromyography technology (HD-sEMG) for the diagnosis of sarcopenia.

This is a monocentric, descriptive, cross-sectional, parallel group study to develop a new diagnostic method.

It is planned to include 50 people aged 75 years and over hospitalized in the acute geriatric ward and suspected of sarcopenia (Score ≥4 on the SARC-F screening questionnaire).

The inclusion duration will be 36 months and adding a 1-month patient follow-up as part of routine care, the total study duration will be 37 months.

Patients will have their body composition (muscle mass, fat mass, and bone mass) using dual X-ray absorptiometry (DEXA). Muscular strength will be assessed by handgrip strength. Physical performance will be assessed. Additional data will be collected from their medical records.

The aging of the population is a major public health problem with its multifactorial impact on quality of life and maintenance of autonomy. Unfortunately, one consequence of aging is sarcopenia, which affects the intrinsic and functional properties of muscle. It is a risk factor for loss of autonomy, falls, frailty and is associated with increased mortality.

Sarcopenia is defined as a progressive loss of muscle mass, strength and physical performance. Classically, sarcopenia is assessed by imaging techniques (MRI, DEXA) or bioelectrical impedancemetry for aspects related to the assessment of muscle mass loss. MRI or DEXA are not widely available and/or access is limited.

For functional aspects, grip strength measurements are often used. Currently sarcopenia cannot be diagnosed and evaluated by a single examination, including both the morphological (muscle mass) and functional aspects. Furthermore, several biological markers are associated with muscle mass, strength, and function, but these biomarkers are not specific to skeletal muscle and are weakly associated with clinical goals.

Finally, despite the important interest in assessing the qualitative/functional and quantitative aspect of skeletal muscle in neuromuscular impairment, there is currently no tool that routinely assesses these aspects.

In this context, developing new approaches for non-invasive assessment of sarcopenia, is a major issue. In this pilot project, the investigators aim to develop a medical device derived from high-definition surface electromyography (HD-sEMG) technology, non-invasive and portable, for the diagnosis of sarcopenia.

Inclusion Criteria:

• Patient aged 75 years and over
• Score ≥4 on the SARC-F screening questionnaire
• Enrolled in a social security plan (no AME)
• Informed and consenting patient

Exclusion Criteria:

• BMI ≥30 kg/m2
• Untreated/unbalanced endocrinological pathology
• Myopathy
• Inflammatory or autoimmune pathology
• Severe psychiatric pathology or severe cognitive disorders that do not allow the performance of examinations
• Patients who are dependent for all acts of daily life
• Patients with a very short life expectancy
• Recent fracture or trauma of the lower limbs preventing dynamic measurement of HD-sEMG recording
• Bilateral hip prosthesis
• Skin problem that may interfere with the recording of surface EMG activity
• Patient under guardianship / curatorship

Data are available upon reasonable request The procedures carried out with the French data privacy authority (CNIL, Commission nationale de l'informatique et des libertés) do not provide for the transmission of the database, nor do the information and consent documents signed by the patients.

Consultation by the editorial board or interested researchers of individual participant data that underlie the results reported in the article after deidentification may nevertheless be considered, subject to prior determination of the terms and conditions of such consultation and in respect for compliance with the applicable regulations.

Beginning 3 months and ending 3 years following article publication. Requests out of these time frame can also be submitted to the sponsor

Researchers who provide a methodologically sound proposal