Momentary assessment of drinking: Past methods, current approaches incorporating biosensors, and future directions

Ecological momentary assessment methodologies are valuable tools for alcohol researchers, allowing for comprehensive real-time assessment of subjective and objective alcohol use in naturalistic, ecologically valid drinking environments. This methodology has long been used in alcohol research, but the wide-spread availability and multiple features of smartphones now provide an accessible and low-cost means to schedule and administer surveys assessing alcohol use, behavioral measures, and other variables of interest as well as to capture movement, location, drinking context, and other relevant aspects of the drinking environment. Coupled with objective measures of alcohol levels in the body, including transdermal alcohol concentration, these methods become powerful research tools. In addition to describing the history of the field, the current status of methods and measurement tools, and the potential integration of various technologies, we also provide a detailed review of our research team’s efforts to convert transdermal data into estimates of breath alcohol concentration so that researchers will have a non-invasive, continuous, passive, and easily interpretable measure of alcohol levels in the body. This work includes the development of physics-based deterministic and population-based models coupled with machine learning techniques, creation of software to produced estimated BrAC curves and summary scores, development of internet-based cell phone-optimized assessment techniques and web-based applications, and collection of biosensor and behavioral data during laboratory drinking episodes where participants consume alcohol in various patterns over multiple sessions for testing within and between person- and episode-level variation. We conclude with a brief discussion of future directions for the field.