BellsTrace: spatial neglect assessment on Vision Pro
I built a Vision Pro test for spatial neglect after stroke with Apple and NUS's Interactive 3D Design Lab. A clinician runs it from an iPad, and we tried it with 30+ stroke patients at NUH and Alexandra Hospital.
01The problem
After a stroke, some patients stop noticing one side of the space around them. Doctors test for this with the Bells Test, a sheet of paper covered in small pictures. It is hard to run the same way every time, hard to time precisely, and it tells you nothing about how the patient searched.
02What I did
I built the Vision Pro app and the iPad app the clinician uses to control it. I also joined the testing sessions, helped with the analysis and co-wrote the paper.
03What made it hard
These were real stroke patients in real clinic sessions. The clinician had to run everything without touching the headset, the timing had to be exact, and a session could not be repeated because the software glitched.
04How it works
The headset shows 135 targets in 3D space, and the patient selects them by looking and pinching while the app times everything. The iPad finds the headset over local Wi-Fi and controls the session. At the end, the clinician gets a report showing which areas the patient missed and the path their eyes took.
05Other options I ruled out
Putting the paper test on a tablet would have been simpler, but you lose the 3D view, which is the whole point. We started with this test because doctors already trust the paper version.
06How I tested it
About seven months of feedback from clinicians and stroke survivors, then trial sessions in hospitals.
07Results
Tried with 30+ stroke patients at NUH and Alexandra Hospital. I co-authored a paper submitted to ISMAR 2026, which is under review.
08What's next
The paper decision, the final author list and a larger study are still to come. No patient data will ever appear on this site, and any demo uses made-up data.