A Mobile App Delivering a Gamified Battery of Cognitive Tests Designed for Repeated Play (OU Brainwave): App Design and Cohort Study.

Background: Mobile phone and tablet apps are an increasingly common platform for collecting data. A key challenge for researchers has been participant "buy-in" and attrition for designs requiring repeated testing.

Objective: The objective of this study was to develop and assess the utility of 1-2 minute versions of both classic and novel cognitive tasks using a user-focused and user-driven mobile phone and tablet app designed to encourage repeated play.

Methods: A large sample of app users (N=13,979 at first data collection) participated in multiple, self-paced sessions of classic working memory (N-back), spatial cognition (mental rotation), sustained attentional focus (persistent vigilance task), and split attention (multiple object tracking) tasks, along with the implementation of a comparatively novel action-learning task. The "OU Brainwave" app was designed to measure time-of-day variation in cognitive performance and did not offer any training program or promise any cognitive enhancement. To record participants' chronotype, a full Morningness-Eveningness questionnaire was also included, which measures whether a person's circadian rhythm produces peak alertness in the morning, in the evening, or in between. Data were collected during an 18-month period. While the app prompted re-engagement at set intervals, participants were free to complete each task as many times as they wished.

Results: We found a significant relationship between morningness and age (r=.298, n=12,755, P<.001), with no effect of gender (t=-1.036, P=.30). We report good task adherence, with ~4000 participants repeatedly playing each game >4 times each-our minimum engagement level for analysis. Repeated plays of these games allowed us to replicate commonly reported gender effects in gamified spatial cognition (F=154.861, P<.001, η=.035), split attention (F=11.047, P=.001, η=.003), and sustained attentional focus (F=15.993, P<.001, η=.004) tasks. We also report evidence of a small gender effect in an action-learning task (F=90.59, P<.001, η=.022). Finally, we found a strong negative effect of self-reported age on performance, when controlling for number of plays, in sustained attentional focus (n=1596, F=30.23, P<.001, η=.102), working memory (n=1627, F=19.78, P<.001, η=.068), spatial cognition (n=1640, F=23.74, P<.001, η=.080), and split attention tasks (n=1616, F=2.48, P=.02, η=.009).

Conclusions: Using extremely short testing periods and permitting participants to decide their level of engagement-both in terms of which gamified task they played and how many sessions they completed-we were able to collect a substantial and valid dataset. We suggest that the success of OU Brainwave should inform future research oriented apps-particularly in issues of balancing participant engagement with data fidelity.