A Wearable User Interface for Measuring Reaction Time

Reaction time (RT) tests are known as simple and sensitive tests for detecting variation in cognitive efficiency. RT tests measure the elapsed time between a stimulus and the individual's response to it. A drawback of existing RT tests is that they require the full attention of a test person which prohibits the measurement of cognitive efficiency during daily routine tasks. In this contribution we present the design and the evaluation of a wearable RT test user interface which can be operated throughout everyday life. We designed a wearable watch-like device which combines the generation of a haptic stimulus and the recognition of subject’s hand movement response. In order to show to what extent the wearable RT test is convenient to measure reaction times, we designed an experiment in which we measured the reaction times of ten subjects from two different setups. In the first half of the experiment, the participants performed a desktop-based RT test whereas in the second half of the experiment they performed the wearable RT test. In order to measure changes in the duration and variability of reaction times we induced additional cognitive load in both setups. We show that individual changes of reaction times occurred due to the cognitive load manipulation are similar for both desktop-based and wearable RT test. Additionally we investigate the subjective ratings of perceived workload. We conclude that the presented wearable RT test allows to measure changes in reaction times occurred due to additional cognitive load and hence would allow the assessment of changes in cognitive efficiency throughout everyday life.