# MScope: A Reliable Battery for Functional Status Assessment in Multiple Sclerosis
## 4 Discussion  
This study aimed to evaluate the reliability and validity of a battery of tests (MScope battery) designed to assess functional capacity in PwMS. The reliability of the test battery was confirmed by high ICC values, indicating a high degree of consistency in the measurements. All the analyzed structural, functional, and neuromuscular variables demonstrated excellent intra-day reliability, with ICC values exceeding 0.92. These high values showed that the tests yielded consistent results on the same day. Moreover, most tests exhibited  
Figure 4: Bland–Altman plots for neuromuscular assessments. Abbreviations: GRF, peak isometric ground reaction force; MVIC\({}_{\text{LEXT}}\), maximal voluntary isometric contraction during the leg extension exercise; MVIC\({}_{\text{SQ}}\), maximal voluntary isometric contraction during the squat exercise; UMVIC\({}_{\text{LEXT}}\),\({}_{\text{L}}\), unilateral left leg extension maximal voluntary isometric contraction; UMVIC\({}_{\text{LEXT}}\),\({}_{\text{R}}\), unilateral right leg extension maximal voluntary isometric contraction. good-to-excellent test-retest reliability, with ICC values ranging from 0.775 to 0.973, indicating consistent results across different assessment sessions. However, significant differences between sessions were observed in functional tests, likely due to factors such as task familiarization or sensitivity to minor changes in functional capacity, while structural and neuromuscular assessments showed greater stability. This reproducibility, coupled with the exploratory factor analysis supporting the construct validity, underscores the robustness of the battery. Thus, this is the first study to propose a reliable and valid set of functional, structural, and neuromuscular tests to comprehensively assess functional status in PwMS. Functional assessments included the TUG test, 5 RSTST, 60 STST, 10 MWT, and 6 MWT. These tests are frequently used to assess various aspects of functional capacity, including balance, lower limb strength, and walking endurance. The intra-day reliability, defined as the consistency of measurements taken on the same day, was excellent (ICC > 0.9) for all functional assessments, except for the 6 MWT, for which intra-day reliability was not assessed as it was performed only once per laboratory visit due to its potentially exhaustive nature. These findings indicate that the tests are relatively free from measurement errors when administered multiple times within a short period, even though participants were unfamiliarized with testing protocols. However, despite good-to-excellent test-retest reproducibility for functional outcomes, the agreement between measurements obtained on different days demonstrated greater variability, showing significant differences between measurements on Day 1 and 2 for all the functional tests (Table 2, Figure 3). This variability may be attributed to learning effects or daily fluctuations in participant motivation [28]. However, despite the observed differences in variability between the two measurements, only the TUG test demonstrated significant heteroscedasticity (Supplementary File S2). This finding suggests that discrepancies tend to increase or decrease based on the magnitude of the variable, which should be considered when interpreting the results. Previous studies have also reported a high level of reliability of the TUG test in PwMS. For example, [PERSON] et al. [18] found an ICC of 0.93 in their investigation of the validity of the TUG test in relation to the MSWS-12. Furthermore, the favorable test-retest reproducibility shown in our study, with an ICC of 0.866, is consistent with previous findings reporting ICCs of 0.97 and 0.91 [34; 35]. This highlights the utility of the TUG test as an effective measure for assessing functional capacity across various conditions in PwMS [34; 35], and as a valid tool for assessing fall risk [36]. Similarly, the sit-to-stand test has been widely employed in its various forms in patients with MS across scientific literature [16].