**1. Introduction**

Sarcopenia was defined by the International Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10-CM) and recognized as a disease in 2016 [1–3]. In 2019, the European Working Group on Sarcopenia in Older People (EWGSOP) published important recommendations for the diagnosis of Sarcopenia for Caucasian People [4]. These recommendations are currently used as guidelines for the assessment of sarcopenia.

The first guidelines for the diagnosis of sarcopenia were written on the occasion of the first EWGSOP Congress in 2010 [5]. They also included some criteria for the diagnosis of *pre-sarcopenia* (loss of muscle mass and its variability).

The functional and anatomical areas to investigate for diagnosis, defined in both the first and second EWGSOP Congress [4], are muscle strength (hereinafter referred to as MS); muscle quality (hereinafter referred to as MQ ), and physical performance

(hereinafter referred to as PP). Nowadays, in accordance with the second EWGSOP guidelines, MS is evaluated through the assessment of grip strength (subsequently referred to as handgrip strength or HGS). The dynamometer is an inexpensive and efficient tool, but it investigates only the strength exerted by the upper limbs and has several limitations [6]. The recommended tests for MQ are magnetic resonance imaging (MRI) or magnetic resonance spectroscopy (MRS); computed tomography (CT); dual-energy X-ray absorptiometry (DXA) [4], including the alternative use of the biological impedance analysis (BIA) [7]. Regarding PP, the suggested gold standards are the short physical performance battery (SPPB) combined with the time-up and go test (TUG), or, as an alternative, the gait speed test (GS) [4].

However, the problem is that DXA, MRI, and BIA are not always available in hospitals and at the surgeries of general practitioners, and are fairly expensive.

Therefore, the aim of this review is to suggest some new and less expensive tools and technologies that may substitute the three tests mentioned above and that are able to maintain a reliable level of diagnostic accuracy. Moreover, we would like to extend the MS parameters not only to the upper limbs but also to the lower limbs and to the assessment of balance and spatial coordination. The use of these accurate and cheaper tools would favor the diagnosis of sarcopenia and, consequently, the prevention of loss of muscle mass, in a higher number of patients. Alternative tools for the evaluation of MS and PP as well as some rehabilitation tools for the prevention of bad outcomes in pre-sarcopenic and sarcopenic patients will also be proposed.

## **2. Methodology**

This is a review of five randomized control trials (RCT), three cohort studies (CS), 13 cross-sectional studies (CSS), two systematic reviews (SR), two systematic reviews & meta-analyses (SR&M), one quasi-experimental study (Q-ES), one design and validation study (DVS), one exploratory study (ES), four randomized control studies (RCS), and four articles on new integrated technologies, some of which not yet tested on humans. The research was carried out between April 2021 and July 2021. The following libraries were searched: PubMed, Cochrane Library, Google Scholar, and Scopus.

A total of 6069 records were obtained. Of these, 5931 were discarded: 1833 were duplicates and 4098 were eliminated because of the type of population or because they focused on populations affected by cancer, or having post-operative outcomes or head and neck cancer with post-surgical outcomes affecting the tongue, or because they were studies based the use of ultrasound, MRI, CT, and DXA. Also, we excluded papers dealing with the rehabilitation of sarcopenia after a hip fracture or other similar events.

The eligibility criteria were: (1) community-dwelling older adults; (2) older adult volunteers: out-patient or hospitalized patients; (3) frail subjects according to the frailty criteria defined by Fried et al. [8]. About age, some of the studies focused on patients aged ≥50 years (middle-aged), others on patients aged ≥65 years (older), and others on patients aged 19 to an older age. Studies that did not include older adults were excluded.

Works referring to the Asian Working Group for Sarcopenia guidelines were also excluded.

Moreover, of the remaining 138 articles, 102 were discarded because they were duplicates or because they were not pertinent to the aim of the research.

The studies analyzed for this review were 36: 32 dealing with tested technologies whose results were compared with the parameters established in the EWGSOP guidelines, and four studies presenting new and not tested technologies.

The article search was carried out by using the following word strings and the PubMed's Boolean operators: "*phase angle and sarcopenia*"; "*rehabilitation and*  *Sarcopenia: Technological Advances in Measurement and Rehabilitation DOI: http://dx.doi.org/10.5772/intechopen.101278*

*sarcopenia*"; "*sarcopenia and measurement*"; "*actigraphy and sarcopenia*"; "*jumping mechanography*"; "*sarcopenia and wearable devices*"; "*sarcopenia robotic measurements*". The search was restricted to the 2015–2021 period, including extremes.

To assess the quality of the paper, the Newcastle-Ottawa quality assessment scale was used [9].
