Deploying and Examining Beacon for At-Home Patient Self-Monitoring with Critical Flicker Frequency

Chronic liver disease can lead to neurological conditions that result in coma or death. Although early detection can allow for intervention, testing is infrequent and unstandardized. Beacon is a device for at-home patient self-measurement of cognitive function via critical flicker frequency, which is the frequency at which a flickering light appears steady to an observer. This paper presents our efforts in iterating on Beacon's hardware and software to enable at-home use, then reports on an at-home deployment with 21 patients taking measurements over 6 weeks. We found that measurements were stable despite being taken at different times and in different environments. Finally, through interviews with 15 patients and 5 hepatologists, we report on participant experiences with Beacon, preferences around how CFF data should be presented, and the role of caregivers in helping patients manage their condition. Informed by our experiences with Beacon, we further discuss design implications for home health devices.