Table 3.

Usability issues and prototype revisions based on usability testing.

Version number	Changes from previous version	New usability issues identified
0	N/Aa	Animation demonstrating the task was confusing, and participants expected to interact with the animation Transition from 4-picture practice item to 14-picture live items on PSMb felt drastic Navigating to the next activity from the menu was confusing and added unnecessary clicks to the workflow Landscape view made it easy to accidentally swipe out of PSM Text was too small Navigation arrows to move forward were ambiguous Delay between the end of audio instructions and perceived start of the activity causes false starts in PSM
1	Demo animation removed and instruction and practice rounds merged to provide an interactive learning experience in both tasks 8-picture practice item included to gradually prepare participants for the live item in PSM Removed navigation menu so that the first activity flows seamlessly into the next PSM redesigned for portrait view Text size increased End of audio instructions aligned with start of PSM live items Welcome screen added to explain the purpose of screening, provide instructions, and set expectations for results (Figure 5) Exit screen added with instructions to delete the app and reminder that the results will be discussed during the visit (Figure 6)	Participants noted difficulty with dragging pictures in PSM Potential frustration with being forced to “Try Again” on the PSM 8-picture practice item
2	Option to drag or tap to arrange pictures in PSM “Try Again” or “Move On” options added after errors on practice items	“Try Again” button obscured error feedback in PSM practice item Tapping preferred to dragging in PSM Participant unaware that tapping was an option
3	PSM instructions updated to make tapping gestures explicit (Figure 7) “Try Again” button floats in from the top of the screen, so error feedback is visible (Figure 8) Dragging functionality removed	No significant usability issues identified by participants
4	Education question added to improve predictive validity Navigation buttons labeled with words instead of symbols (“Next,” “Back,” and “Help”)	No significant usability issues identified by participants

^aN/A: not applicable.

^bPSM: Picture Sequence Memory.