Keywords

Muscle quality, functional domain, non invasive techniques, older adults, assessment methods

The aging process induces neural and morphological changes in the human musculoskeletal system, leading to a decline in muscle function and structure. These changes result in a progressive reduction in muscular strength, mass, and quality, primarily due to the natural degeneration of muscle, bone, and joint tissues that accompanies aging [1]. These decreases in muscular parameters reflect both qualitative and quantitative alterations in skeletal muscle structure and function, which can lead to sarcopenia [2]. According to European Working Group on Sarcopenia in Older People (EWGSOP), sarcopenia is a gradual, widespread skeletal muscle condition that is linked to a higher risk of experiencing negative health consequences such as falls, fractures, physical impairment, frailty, and death [2].
The latest EWGSOP update, as well as other recognised working groups, take to the forefront the importance of assessing muscle quality (MQ) as a crucial indicator of the physiological properties of skeletal muscle tissue, which influence both muscle strength and functional capacity [2]. The term “muscle quality” describes the physiological potential and functional performance of muscular tissue. MQ involves various aspects of muscle composition, including both microscopic and macroscopic features of muscle structure, along with functional performance relative to muscle mass [2, 3]. For these reasons, it is typically defined by two primary domains: morphological and functional. The morphological domain involves direct evaluations of muscle architecture, considering both microscopic and macroscopic characteristics of muscle structure, as well as its composition [2-4]. In contrast, the functional domain involves indirect evaluations of muscle performance relative to its mass. This domain aims to measure how effectively a muscle generates force in relation to its size, often represented by a MQ index [3, 5, 6]. Assessing MQ from this functional standpoint involves examining key performance metrics, such as muscle performance, taking into account the type and direction of the movement, such as strength and power (including peak torque (PT), 1 repetition maximum (RM), 5RM, isometric strength, and others) alongside quantitative parameters of muscle size, including muscle mass, lean mass, muscle thickness, muscle volume and/or cross-sectional area [3, 5, 6].
Age-related alterations in MQ tend to occur before any noticeable decline in muscle mass, indicating that MQ might serve as a more sensitive indicator of muscle function than muscle mass alone [3]. This finding is significant, as shifts in MQ could offer a clearer explanation for the declines in muscle strength and function commonly seen with aging [7]. In this regard, maintaining and assessing MQ becomes essential for older adults in order to slow down changes in muscle metabolism and assist avoid the loss of muscle mass and strength [8]. Additionally, it is important to take into account that MQ is a relatively recent term, and the diagnostic methods for evaluating it are not yet fully standardized [2], underscoring the need for further research in this field.
MQ assessment methods can be divided into three primary categories: first, invasive techniques that involve direct intervention; second, direct non-invasive techniques; and third, indirect non-invasive methods, which evaluate MQ through external measures or estimates [2-4]. Specifically, this scoping review will focus on indirect techniques that measure the functional domain of MQ. These techniques are relatively easy to perform, do not require the insertion of invasive devices and are an important tool for assessing functional MQ in older adults [5, 6, 9].
To assess functional MQ, commonly used tools are designed to measure both strength or power and muscle mass. These measurements are crucial as they form the basis for calculating the MQ index, estimated by indirect assessments of muscle performance in relation to muscle mass [3, 5, 6]. In terms of measurement tools for assessing MQ, each has specific applications in clinical practice. For measuring muscle strength, simpler tools such as isometric dynamometers and RM strength tests can be used, while more advanced devices such as power gauges and isokinetic strength testers offer more detailed assessments [2, 10, 11]. For muscle mass, there are several techniques: Bioelectrical Impedance Analysis (BIA), Dual energy Xray absorptiometry (DXA), B-Mode Ultrasound, Computed Tomography (CT) and Magnetic Resonance Imaging (MRI). Each tool provides different information on muscle mass, capturing measures such as muscle mass, lean mass, muscle thickness, muscle volume or cross-sectional area [9, 12, 13].
Institutions such as ICFSR and EWGSOP highlight the need for standardized definitions and reliable methods to assess MQ. However, effective evaluation techniques remain unclear, emphasizing the importance of reviews that compile and analyze current evidence on functional MQ assessment methods [2, 9]. This scoping review aims to map and synthesize current evidence on non-invasive tools for assessing functional MQ in older adults, identifying methods currently used in the literature, trends, and advances. It also examines tool limitations and factors influencing their selection, including accessibility, cost, and training, to promote simple, community-based applications.

Registration

The scoping review was registered on the Open Science Framework (OSF) platform in which the search strategy and supplementary materials are available. ( https://osf.io/ anjr4/?view_only=05969c336a0847028766e96f574eb6 3e), on November 4, 2024 (registration DOI:https://doi. org/10.17605/OSF.IO/QV28T).

Procedures

The review was carried out in accordance with the 2020 preferred reporting items for systematic reviews and metaanalyses (PRISMA) standards.

Research questions

This scoping review aims to address the following research questions: 1. Which are the non-invasive tools and their principles used to measure functional domain of MQ in older adults? 2. Which non-invasive tools are commonly used and reported in the literaturefor assessing the functional domain of MQ in geriatric populations? 3. What are the main limitations of current non-invasive tools for measuring functional domain MQ in older adults? 4. What factors, such as cost, accessibility, and required training, influence the choice of non-invasive tools for assessing functional MQ, particularly in community settings, and how can accessible and simple methods be implemented to facilitate their use in the community? What recent trends or advances have been observed?.

Eligibility criteria

PICOS (participants, interventions, comparators, outcomes, and study design) was used to include and exclude original, peer-reviewed, full-text studies. Table 1 provides a summary of the selection criteria.

Literature search and screening process

The initial search strategy was developed by one reviewer (NV) specifically for PubMed (outlined below), targeting title, abstract, and keyword fields. This strategy was subsequently adapted to conform with the syntax and subjectspecific headings of additional databases. A comprehensive literature search was then executed in PubMed, Web of Science, and Scopus databases, employing Boolean operators to combine relevant keywords systematically (aged OR old OR elder* OR aging OR frail* OR older OR senior OR geriatric) AND (measure* OR determine OR analyze OR evaluate OR “sensitivity and specificity” OR screening OR tool* OR assess* OR “diagnostic accuracy”) AND (“muscle function” OR “muscle performance” OR “muscle functional performance” OR “muscle functional capacity” OR “muscle quality” OR “functional domain” OR “muscle quality index”). The search was performed without date restriction and was updated until October 2024.
An initial search was conducted by one author (NV), and records were uploaded to Rayyan QCRI to remove duplicates. Two reviewers (NV and XR) independently screened titles and abstracts, resolving discrepancies collaboratively. Full texts were assessed using predefined criteria, with exclusions recorded. Non-invasive imaging modalities were not used as search terms in the search strategy to avoid biasing the retrieval of studies toward specific measurement techniques. The search instead focused on the concept of MQ and its functional assessment.
Nevertheless, studies using these methods were included during the screening process when they reported functional MQ indices.

Data collection

Data from the included studies were collected and coded in Microsoft Excel (Microsoft Corp). The following information was extracted from each included study: (1) reference, author, year of publication and country, (2) participants characteristics (sample size; sex; age (mean and standard deviation) and health status), (3) muscle quality definition, (4) muscle quality assessment methods (test and instruments; principles of measurement), (5) group of muscles on which the measurement has been performed, and (6) reported advantages and limitations of the measurements tools. In addition to extracting the operational definition of MQ reported in each study, all metrics were categorised according to the physiological construct they primarily represented. Based on previous conceptual descriptions of MQ, the identified indicators were grouped into three categories: (1) strength-to-mass ratios, defined as muscle strength normalised to a measure of muscle or body mass; (2) strength-to-morphology ratios, in which muscle strength was normalised to a muscle-specific morphological parameter obtained through imaging techniques such as cross-sectional area, muscle thickness or echo intensity; and (3) field-test surrogate measures, which estimate MQ indirectly through functional performance tests.

Study selection

Potential studies were directly exported from scientific databases into Rayyan (https://www.rayyan.ai/) for the removal of duplicates and subsequent screening based on the predefined inclusion and exclusion criteria. After completing these steps, a total of 10,559 records were identified. The study selection process is outlined in Figure 1. Duplicates were removed (n = 6,591), and following the screening of titles and abstracts, 6,382 records were excluded. This left 209 full-text articles for further evaluation. Of these, an additional 130 studies were excluded after full-text review for eligibility. Ultimately, 79 studies were deemed eligible for inclusion in the scoping review.

Study characteristics

The characteristics of the included studies are detailed in Table 2 and a subset of representative studies illustrating the different operational definitions of MQ characteristics is detailed in Table S1. A total of 32,892 participants, with an age older than 60 years, were analyzed in this review. Regarding participants sex, 42 studies reported a sample consisting of both males and females (n = 26,572, 80.8% of total participants). 30 studies were composed of only females (n = 3,719, 11.3% of total participants) and 7 groups involved only males(n = 2,601, 7.9% of total participants). The selected studies were published between 1999 and 2024, with approximately a third being published since 2021 (n = 24, 30%).

The literature shows considerable heterogeneity in the operational definition of MQ (Table 2). However, most definitions within the functional domain align with indirect measures of muscle function relative to muscle mass, typically expressed as strength per unit of muscle mass, a definition employed by 70 studies. Various methods are employed to assess muscle strength, including PT, 1RM, 5RM, isometric strength, and others. Muscle mass is generally quantified through metrics such as body mass, muscle thickness, muscle volume, cross-sectional area, and lean mass. Among the alternative definitions, four studies utilize established formulas to measure MQ functionally. One of these applies the muscle quality index (MQI) formula: MQI = [(L - 0.5) × body mass × g × 5] / _{Tsit-tostand.} The remaining three studies use the formula MQI = [(leg length × 0.4) × body mass × gravity × 10] / time sitto-stand. Additionally, two studies employ the power-tomass ratio, while another uses the specific tension-to-mass ratio as a measure of MQ.
The review identified various non-invasive tools for assessing functional MQ in older adults, focusing on strength and mass (Table 2). For strength, 16 studies used handheld dynamometers for handgrip strength (HGS), knee extension involved 23 isokinetic, 6 handheld isometric, and 1 combined method. Leg power was assessed in 4 studies, RM in 10, and 11 combined upper and lower strength. For muscle mass, 44 studies used DXA, 11 ultrasound, 12 BIA, 4 MRI, and 8 CT, with CT and ultrasound assessing CSA, volume, or composition.
The most effective non-invasive tools for assessing functional MQ in older adults balance accuracy and accessibility (Table 3). The MQI is emerging to assess strength– mass relationships. BIA use has increased, with 92% of studies published since 2020, and ultrasound use has grown since 2012, especially with portable devices enhancing accessibility. However, heterogeneity and lack of consensus in definitions limit comparability between studies, with specific tool limitations detailed in Table 3.

This scoping review aimed to assess studies on non-invasive tools for evaluating functional MQ in older adults, focusing on both effectiveness and practical aspects. Objectives included identifying commonly used methods, examining recent advances, and exploring limitations and practical factors, such as cost, accessibility, and training, that influence tool selection and the feasibility of community-based applications.
MQ is a central concept in the study of sarcopenia and other age-related musculoskeletal disorders, as it appears to be more sensitive to age-associated changes than either strength or muscle mass, thus serving as a valuable indicator of muscle health and function [3, 7]. However, although the findings of this review demonstrate substantial heterogeneity in the definitions of MQ, definitions of functional MQ primarily involve indirect assessments of muscle performance relative to muscle mass, typically expressed as strength per unit of muscle mass, consistent with findings from the literature [3, 7]. This definition, adopted by 70 studies, is grounded in the same fundamental concept of the strength-to-mass ratio; nonetheless, heterogeneity arises due to the variability in the methods used to assess both strength and muscle mass. Consequently, despite the use of a common conceptual framework for MQ, variations in measurement techniques result in inconsistencies in the outcomes obtained, underscoring the need for methodological standardisation to enhance the comparability across studies.
The diversity of tools used to measure muscle strength and mass contributes to heterogeneity in functional MQ assessments. Among non-invasive methods, 16 studies measured HGS with handheld dynamometers; for knee extension, 23 used isokinetic devices, 6 handheld isometric, and 1 both. Additionally, 4 assessed leg power, 10 used RM, and 11 combined measures.
An additional source of heterogeneity may stem from differences in the anatomical sites used to evaluate muscle strength and mass. Twelve studies have assessed strength in a specific muscle group, such as the knee extensors or handgrip, while estimating muscle mass from whole-body or appendicular lean mass derived from DXA or BIA. This discrepancy between the anatomical sites used for strength and muscle mass assessment, may not accurately represent the functional relationship between muscle size and performance, which may contribute to the observed variability in MQ indices across studies [5, 9].
Evaluating muscle force output is a critical clinical consideration, and one of the most reliable methods for objectively measuring strength is through the use of dynamometry. Dynamometry quantifies and provides objective measurements of force, torque, or power generated during muscle contraction and is classified as the primary laboratory-based methodology. There are several types of dynamometry, each addressing different assessment needs. Among the types identified in the literature are isokinetic dynamometry and handheld dynamometry (isometric). As for the gold standard, isokinetic dynamometry is considered the most valid and reliable method for measuring muscle force. These computerised machines are capable of providing multiple metrics related to muscle force, allowing accurate force measurements at various angles and speeds, while minimising problems associated with the measurements [11, 92, 93]. However, isokinetic dynamometers are expensive and not portable, thereby making them unsuitable for routine clinical examinations in many settings [11, 93]. On the other hand, isometric dynamometers, such as hand-held dynamometers (HHD), are more accessible in clinical practice due to their portability, simplicity, and lower cost compared to isokinetic devices. However, the information they provide is more limited, as they primarily offer a portable, quantitative method for assessing isometric muscle strength and power [15, 92]. The affordability of these dynamometers may justify their widespread use in clinical settings, but although correlations between HHD and isokinetic measurements exist and they are considered reliable and valid, they do not offer the same level of detailed information as isokinetic testing [2, 41, 94].
On the other hand, among the most commonly used field tests for measuring strength is the one repetition maximum (1RM) strength test, defined as the maximum weight that can be lifted once with correct lifting technique. This test is widely used to determine the maximum force for a specific movement, is simple, safe, inexpensive and is considered the gold standard in non-laboratory situations. Furthermore, it follows the same patterns as those performed by individuals during their regular training sessions or in daily life allowing the assessment of strength in multi-joint exercises [10, 95].
Power assessment is crucial for evaluating an individual’s ability to generate force rapidly, which is the product of force and velocity [10]. This can be measured using isokinetic dynamometers or more specific methods, such as the Nottingham Power Rig and the PLEE power lift, which are the ones used in the studies analizes in this review. Both tools exhibit high precision in measuring explosive power, integrating force and velocity. In terms of more specific differences, the Nottingham Power Rig is particularly suited for clinical populations or isolated leg tests, whereas the PLEE power lift is primarily used for assessing athletic performance in functional movements being more challenging to perform safely in older populations [53, 96].
Muscle mass evaluation can be assessed using a range of non-invasive methods, among the methods used in the studies analysed by the review, DXA was employed in 44 studies, ultrasound was used in 11 studies, BIA was utilized in 12 studies, MRI in 4 studies, and CT in 8 studies. CT and MRI are considered the gold standard for assessing muscle composition being endorsed methodologies by EWGSOP2, especially MRI. These methods allow both qualitative and quantitative assessments of body composition, and are notable for their high ability to differentiate tissue types, such as intramuscular fat infiltration, muscle volume, cross-sectional area and other structural characteristics [12, 13]. While CT provides a faster and more cost-efficient option, it is associated with radiation exposure, whereas MRI offers a radiation-free alternative, albeit at a higher cost and requiring greater technical expertise. Despite their strong correlation in clinical evaluations of muscle quantity and quality, their high cost, specialized equipment requirements, and the need for trained personnel limit their use in routine community-based practice [12, 13].
Another commonly utilized method for evaluating muscle composition is DXA, which is the most frequently employed tool in clinical practice for assessing body composition and diagnosing sarcopenia [2, 97]. This is evidenced by the findings of the conducted review, where 56% of all analyzed studies utilized DXA to measure muscle mass. However, there is considerable controversy in the literature regarding the appropriateness of referring to DXA as the “gold standard”. On the one hand, DXA is considered a precise, valid, reproducible, and widely available imaging modality that quantifies lean mass, appendicular skeletal muscle mass, fat, and bone mineral density, and it is also a good indicator of the relationship between muscle strength and muscle mass. However, it does not measure muscle composition at a more structural level, can be influenced by hydration status, is relatively expensive, and is not portable [2, 97].
Ultrasonography is increasingly recognized as a fast, noninvasive, and accessible method for musculoskeletal assessment, enabling the evaluation of both quantitative and qualitative muscle parameters [9, 98, 99]. Recent systematic reviews assessing the validity and reliability of ultrasonography for skeletal muscle evaluation have reported high interclass correlation coefficients and confirmed its comparability with other imaging modalities [2, 9, 98, 99]. Despite ongoing efforts to standardize these measurements, their high operator dependency underscores the need for further research to enhance their clinical applicability and to increase lack of reference [9, 98, 99]. Notably, recent studies have begun to demonstrate strong correlations between ultrasound-derived parameters and other reference measures of muscle mass [9, 98, 99].
BIA is an effective non-imaging method for estimating total or appendicular skeletal muscle mass by measuring the body’s electrical conductivity and applying predictive equations. While it is non-invasive, quick, and accessible, its accuracy depends significantly on the predictive equation used and can be influenced by factors such as hydration status [9, 100]. Compared to reference methods like DXA and CT, BIA may slightly overestimate or underestimate skeletal muscle mass, but it generally demonstrates strong correlations with these techniques [2, 70].
A major challenge of these tools is the lack of standardised assessment criteria, makes it difficult to identify the most appropriate and consistently applied methods across studies. The most efficient tools for assessing the functional domain of MQ aim to capture muscle function (strength, power) while considering structural properties (mass). They must be reliable, reproducible, and capable of providing objective, clinically meaningful data. CT, MRI, and DXA are the most commonly used for structural and compositional assessment, with MRI and DXA being preferable due to the absence of radiation and greater accessibility. However, ultrasound and BIA offer practical, low-cost, and rapid alternatives for non-invasive assessment, despite slightly lower accuracy [2, 9, 12, 98]. In the context of strength, isokinetic dynamometry, 1RM test and hand-held isometric dynamometers assess muscle strength, but vary in accuracy, cost and applicability. Isokinetic dynamometry offers the greatest accuracy, but is limited by cost and portability. The 1RM test is inexpensive and practical, but lacks the detailed measurements of isokinetic devices. Portable dynamometers are more accessible and affordable, but provide less detailed data [10, 11, 94]. Each technique relies on different technologies and focuses on specific dimensions of functional MQ, underscoring the importance of careful selection based on the goals of the assessment and available resources. This can be seen in detail in Table 3, which summarises the advantages and limitations of each tool.
Current non-invasive tools for assessing the functional domain of MQ in older adults are limited primarily by the absence of standardized criteria and significant methodological heterogeneity. This variability hinders direct comparisons across studies and complicates the identification of the most effective tool for this purpose. Notably, other papers and reviews on MQ have similarly reported challenges stemming from the heterogeneity of assessment methods [3, 4, 9]. A detailed evaluation of the strengths and weaknesses of each method, as outlined in Table 3, highlights the specific limitations inherent to each approach.
When interpreting Table 3, the selection of a MQ assessment tool should consider the specific context in which it will be applied. For community screening or large epidemiological studies, portable and low-cost tools such as hand-held dynamometry or BIA may be more feasible, despite their lower precision. In routine clinical settings, methods that balance feasibility and accuracy, such as one-repetition maximum testing or regional assessments with DXA or ultrasound, may provide more informative estimates of functional MQ. Conversely, research settings requiring high precision may benefit from techniques such as isokinetic dynamometry combined with imaging methods like MRI or CT [2, 9].
The EWGSOP stresses the importance of assessing both muscle quality and quantity [2]. However, our review highlights that a clear criterion for selecting a specific assessment tool based on an individual’s characteristics has not yet been established [2, 9]. When assessing the functional domain of MQ, several factors influence the choice of non-invasive tools. These include cost, accessibility and the level of training required to use the tool effectively. In clinical settings, accurate and validated tools such as DXA and MRI are frequently used despite their high cost, limited accessibility and the need for specialised staff. While these direct methods provide reliable data, their limited accessibility creates barriers for widespread use, especially in non-clinical settings [2, 9]. As a result, indirect measures that rely on simpler, portable and more affordable tools, such as BIA or ultrasound are gaining traction in everyday use. However, they are limited by their moderate to low level of precision, compared with those referred above [99]. The increasing adoption of portable ultrasound and BIA devices in community settings highlights the potential for integration of affordable and simple methods in these settings [2]. These approaches offer a practical solution to bridge the gap between clinical and community settings, making MQ assessment more accessible and scalable, especially when resources are limited. While more expensive methods are often reserved for clinical use, simpler and more cost-effective tools are more viable for community settings, where ease of use and affordability are critical for widespread implementation [2, 97, 98]. The need for accessible tools is important because changes in MQ often occur earlier than changes in other functional variables, and detecting these changes might serve as a more sensitive indicator of muscle function preventing further deterioration in health [3, 7]. Key parameters for the selection of MQ assessment methods are summarized in Figure 2.

It is essential to expand the evaluation of this parameter to the community level since variations in MQ frequently appear before changes in other functional variables [3, 7]. This encompasses a broad range of uses, from community events and health promotion initiatives to incorporation into exercise and training facilities tailored to the needs of senior citizens. As previously said, accessibility and measurement speed are crucial, particularly in situations with a large number of people and few resources. In this regard, creating and utilizing instruments that are quick, precise, and profitable might be a crucial remedy [3]. A viable substitute are functional quality measurement formulas derived from indirect evaluations of muscle performance in relation to muscle mass [9]. These formulations could be successfully integrated into community settings when muscle examinations are carried out with easily available equipment, allowing for widespread tracking and enhancement of muscle health. Handheld dynamometers, which may be used for both upper and lower limbs and include 1RM evaluations, are among the most widely used and reasonably priced instruments for measuring muscle strength. US and BIA are the most widely available methods for measuring muscle mass in community settings, with BIA being the most straightforward and useful alternative for broad use.
In recent years, several emerging trends have highlighted the growing use of accessible and portable technologies for assessing MQ in community and clinical settings, including handheld dynamometers, portable force measurement devices, and BIA. At the same time, increasing attention has been given to improving the standardization of portable ultrasound based measurements, particularly regarding acquisition protocols and operator training, to enhance reproducibility across studies. In addition, functional indicators such as the MQI have gained interest for evaluating the relationship between muscle strength and muscle mass using simple field-based approaches.

This review highlights the considerable heterogeneity of definitions of MQ in the functional domain, where indirect measures of muscle function in relation to muscle mass predominate. Although the concept itself is based on a shared fundamental framework, relating strength to muscle mass, variability arises primarily from the various methods used to assess both strength and muscle mass. These differences in measurement techniques lead to poorly comparable results between studies, underlining the need for methodological standardisation.
A wide array of non-invasive tools is available for assessing the functional domain of MQ in older adults, with a growing preference for accessible technologies suitable for both clinical and community settings. Among strength measurement tools, handheld dynamometers and 1RM tests stand out as the most straightforward and practical options, particularly for community applications. In contrast, isokinetic dynamometers and power assessments, while offering greater precision, are more specialized and less feasible for widespread use outside clinical or research environments. For muscle mass evaluation, gold-standard tools such as MRI, DXA, and CT provide exceptional accuracy and validity but are often limited by their high cost and complexity, making them less practical for community implementation. More accessible alternatives like BIA and US offer scalable and cost-effective solutions, making them well-suited for use in communitybased settings.
One of the main outcomes of this review is to provide practical recommendations for the selection and use of functional MQ assessment tools, adapted to budgetary constraints and community practice settings. One recommendation involves using formulas to assess functional MQ based on indirect evaluations of muscle performance relative to muscle mass, offering a practical and scalable approach. When combined with accessible tools such as handheld dynamometers, BIA, or ultrasound, these methods can facilitate large-scale monitoring of muscle health in community settings. Another suggestion is to align the anatomical sites for assessing muscle strength and muscle mass; if strength is evaluated at a specific site, muscle mass should also be measured at the same location to ensure consistency and accuracy.
This review has several limitations. Firstly, studies that did not explicitly mention MQ in their title or abstract, or those that defined functional MQ differently from preestablished definitions, may have been excluded. In addition, the scope of the review was limited to individuals aged 60 years and older, potentially overlooking interventions targeting other populations that might offer broader perspectives. However, this approach aligns with the goal of understanding MQ in the ageing population. Finally, the lack of standardisation and the high heterogeneity of tools used to assess MQ justify the decision to conduct a scoping review rather than a systematic review, as it allows for a more flexible exploration of emerging techniques and tools in this area.
A valuable avenue for future research lies in creating personalized protocols for selecting measurement tools, customized to the unique circumstances of each patient.

Author contributions

NV conceived the idea and design for the article. NV and XR performed the literature search. NV performed data acquisition, analysis, and/or interpretation. NV prepared the first draft. NV, XR, AM-Z and BG-Z drafted and/or critically revised the work. All authors have read, and approved the final version of the manuscript.

Availability of data and materials

The systematic search queries and data charting methods employed in this study are available upon request. Additionally, our systematic review was registered on the Open Science Framework (OSF) platform on November 4, 2024 with the registration doi (DOI: https://doi.org/10.17605/OSF. IO/QV28T). The authors are committed to fostering transparency in research, and for any inquiries or requests for specific methodological details, we welcome communication with the corresponding author.

Financial support and sponsorship

N.V received a University of Deusto grant from the researcher education program (Award number: FPI UD_2022_10).

Conflicts of interest

Not applicable.

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