• Energy Research

BackgroundResearch on alcohol consumption mostly relies on self‐reported data, which are subject to recall bias. Wearable transdermal alcohol concentration (TAC) monitors address this limitation by continuously measuring the ethanol excreted via the skin. This systematic review aims to provide an overview of TAC monitors’ reliability to detect alcohol consumption and methods to estimate breath alcohol concentration (BrAC) and number of standard drinks consumed in a given time frame.MethodsThe databases MEDLINE, PsycINFO, SCOPUS, Engineering Village, and CINAHL were systematically searched to identify 1,048 empirical research papers published from 2013 onwards, of which 13 were included after full‐text screening. The selected studies included 3 TAC monitors: SCRAM™, WristTAS™, and Skyn™.ResultsTAC measures of SCRAM, WrisTAS, and Skyn are found to be positively correlated with BrAC (r = 0.56 to 0.79) and/or self‐reports (r = 0.62). Using the AMS criteria for detection results in low sensitivity, adjusted criteria can increase the sensitivity of the SCRAM from 39.9 to 68.5%. The WrisTAS and an early prototype of the Skyn showed high failure rates (17 to 38%). Recent advances toward transforming the TAC data into more clinically relevant measures have led to the development of mathematical models and the BrAC Estimator Software. Using TAC data, both approaches produce estimates explaining 70 to 82% of actual BrAC and self‐reported drinking or to highly correlate with the actual BrAC measures (β = 0.90 to 0.91).ConclusionsTransdermal alcohol monitors offer an opportunity to measure alcohol consumption in a valid and continuous way with mathematical models and software estimating BrAC values improving interpretation of TAC data. However, the SCRAM seems unable to detect low‐to‐moderate drinking levels using the thresholds and criteria set by the manufacturer. Moreover, the WrisTAS and the Skyn prototype show a high failure rate, raising questions about reliability. Future studies will assess the validity of new‐generation wristbands, including the next Skyn generations.

New-generation transdermal monitors such as the ION Research Alpha Prototypes (ION RAP) hold promise for real-time alcohol measurement, with improvements in design features such as sampling frequency, size, and comfort. This paper aims to provide the first comparisons of the wrist-worn enzyme-based ION RAP and the fuel cell-based SCRAM-CAM against breath alcohol concentration (BrAC) readings.Participants (N = 23) completed a total of 69 laboratory alcohol administration sessions while wearing both a prototype of the ION RAP wristband and a SCRAM-CAM ankle monitor; they also gave breath samples each 10 min. Analyses focused on latencies of transdermal alcohol concentration (TAC) after alcohol ingestion, correlations, and cross-correlations between BrAC and TAC measurements.A high failure rate of the ION RAP was observed (61.5% of the sessions were excluded due to the sessions not containing enough valid data). On average, the SCRAM-CAM and ION RAP detected alcohol 43 (SD = 21) and 50 (SD = 27) minutes after the first drink, with peak values reached after 138 (SD = 47) and 154 (SD = 56) minutes, respectively. SCRAM-CAM TAC peak (r = 0.185, p = 0.375) and area under the curve (AUC; r = 0.320, p = 0.118) showed small- and medium-sized correlations to BrAC. ION RAP TAC peak (r = -0.082, p = 0.698) and AUC (r = 0.040, p = 0.852) correlations to BrAC were close to zero.In this study, the new-generation ION RAP and the traditionally used SCRAM-CAM show similar delays in detection and similar TAC curves over time, despite using either enzyme- or fuel cell-based technologies, respectively. Due to high failure rates of the ION RAP prototypes and close to zero correlations to BrAC, further developments and improvements of these TAC wristbands are required for reliable and valid use in real-time alcohol measurement.

AbstractIntroductionPrevious studies validating the transdermal alcohol concentration (TAC) as measured by the Secure Continuous Remote Alcohol Monitors Continuous Alcohol Monitoring (SCRAM‐CAM) have tested the monitor against self‐reports or breath alcohol concentration (BrAC). This study aims to provide further evidence of the reliability of the SCRAM‐CAM testing two monitors in parallel.MethodsParticipants (N = 21) received four standard drinks in a laboratory session while wearing SCRAM‐CAMs simultaneously on their left and right ankles. The SCRAM‐CAMs sampled TAC every 30 min and participants were monitored for at least 2–3 h after their BrAC levels reached zero. Weight and height measures were taken to calculate body mass index (BMI).ResultsThere was a positive correlation between the TAC measurements from the left and right SCRAM‐CAM (r = 0.718), a cross‐correlation model revealed that this correlation was not significantly different for sex or BMI. Area under the TAC curve (AUC) and peak TAC values as measured by the left and right SCRAM‐CAM also show positive correlations (r = 0.554 and r = 0.579, respectively). Cross‐correlation models show a significant effect of BMI on the relationship between left and right peak TAC values, which may be due to outlier effects. No further effects were significant for on both peak and AUC values.Discussion and ConclusionsResults show that TAC measured by SCRAM‐CAMs worn on the left and right showed a good correlation, with correlations between AUC and peak TAC values considered to be fair. TAC monitors show promise for use in research settings; however, work is needed testing the reliability of TAC as measured by two TAC monitors.