# User Experience of Older People While Using Digital Health Technologies: A Systematic Review
## 4 Discussion  
According to the findings of this review, the SUS emerged as the most used standardized questionnaire to assess the UX of digital health technologies among older people, and it was used without modifications in its standard form. Despite being a self-described \"quick and dirty\" usability scale, the SUS has garnered widespread popularity in usability assessments [51; 68; 69]. It comprises 10 items, each offering five scale steps, and includes relevant questions that produce findings useful in understanding UX, with odd-numbered items conveying a positive tone and even-numbered items expressing a negative tone. Participants are instructed to complete the SUS immediately after interacting with the digital health technologies, recording their prompt responses to each item. The SUS generates an overall score range from 0 to 100 in 2.5-point increments, and online tools for calculating SUS scores are freely available. No license fee is required for using the SUS; the only prerequisite is acknowledgment of the source. Various translations of the SUS exist, but only a few have undergone psychometric evaluation [70]. Recent studies have consistently demonstrated high reliability for the SUS (approximately 0.90) and established its validity and sensitivity in discerning usability disparities, interface types, task accomplishment, UX, and business success indicators [53]. Furthermore, its concise 10-item format makes it user-friendly, especially for older people. Additionally, the global average score for overall SUS is 68.0 \(\pm\) 12.5 [53]. The grading scale is as follows: F, SUS score \(<\) 60; D, 60 \(\leq\) score \(<\) 70; C, 70 \(\leq\) score \(<\) 80; B, 80 \(\leq\) score \(<\) 90; A, score \(\geq\) 90 [52]. This grading scale is structured in a way that considers a SUS score of 68 as the center of the range for the 'C', such as grading on a curve. Furthermore, the high correlation between the SUS and the UEQ (r between 0.60 and 0.82, \(p<\) 0.0001) [57] could further emphasize its potential as a standard tool for evaluating usability and UX in digital healthcare technologies for older people. The UEQ was the second most frequently employed standardized questionnaire. Furthermore, the UEQ was utilized in conjunction with the SUS in four of the five studies it was employed in [35; 42; 44; 45]. The UEQ and SUS serve similar purposes in assessing the UX and usability of digital products, but have some differences and unique advantages. The UEQ includes six aspects--attractiveness, perspicuity, efficiency, dependability, stimulation, and novelty [54]--and offers a more comprehensive and detailed assessment of UX, including emotional and experiential aspects. On the other hand, the SUS is a simple and effective tool for assessing overall usability [51; 68; 69]. It focuses on the usability aspect of UX, providing a single score that indicates overall usability [51]. [PERSON] et al. [35] assessed the usability of three smartphone app-based self-tests of physical function in home-based settings using the SUS and UEQ, and reported that the participants experienced high levels of perceived ease of use when using the apps. [PERSON] et al. [45] employed the SUS and UEQ to assess the usability and UX of a novel mobile system to prevent disability; in particular, the UEQ was included as an evaluation tool to complement the domains addressed by the SUS. Thus, combining both the UEQ and SUS might provide a more holistic understanding of UX. The following additional questionnaires were also used: PSSUQ, QUEST, FABS/M, PIADS, TSQ-WT, and USEQ. Only TSQ-WT was used individually. The PSSUQ focuses on assessing system usability and measures factors such as system performance, reliability, and overall satisfaction [58; 59]. The QUEST evaluates user satisfaction with assistive technology specifically and considers factors such as the device's effectiveness, ease of use, and impact on daily life [60].