Richer R, Abel L, Küderle A, Eskofier B, Rohleder N (2023)
Publication Language: English
Publication Type: Journal article, Original article
Publication year: 2023
Book Volume: 151
Pages Range: 106073
Article Number: 106073
URI: https://www.sciencedirect.com/science/article/abs/pii/S0306453023000513
DOI: 10.1016/j.psyneuen.2023.106073
Background
Many studies investigating the cortisol awakening response (CAR) suffer from low adherence to the study protocol as well as from the lack of precise and objective methods for assessing the awakening and saliva sampling times which leads to measurement bias on CAR quantification.
Methods
To address this issue, we have developed “CARWatch”, a smartphone application that aims to enable low-cost and objective assessment of saliva sampling times as well as to concurrently increase protocol adherence. As proof-of-concept study, we assessed the CAR of N=117 healthy participants (24.2 ± 8.7 years, 79.5% female) on two consecutive days. During the study, we recorded awakening times (AW) using self-reports, the CARWatch application, and a wrist-worn sensor, and saliva sampling times (ST) using self-reports and the CARWatch application. Using combinations of different AW and ST modalities, we derived different reporting strategies and compared the reported time information to a Naive sampling strategy assuming an ideal sampling schedule. Additionally, we compared the AUCI, computed using information from different reporting strategies, against each other to demonstrate the effect of inaccurate sampling on the CAR.
Results
The use of CARWatch led to a more consistent sampling behavior and reduced sampling delay compared to self-reported saliva sampling times. Additionally, we observed that inaccurate saliva sampling times, as resulting from self-reports, were associated with an underestimation of CAR measures. Our findings also revealed potential error sources for inaccuracies in self-reported sampling times and showed that CARWatch can help in better identifying, and possibly excluding, sampling outliers that would remain undiscovered by self-reported sampling.
Conclusion
The results from our proof-of-concept study demonstrated that CARWatch can be used to objectively record saliva sampling times. Further, it suggests its potential of increasing protocol adherence and sampling accuracy in CAR studies and might help to reduce inconsistencies in CAR literature resulting from inaccurate saliva sampling. For that reason, we published CARWatch and all necessary tools under an open-source license, making it freely accessible to every researcher.
APA:
Richer, R., Abel, L., Küderle, A., Eskofier, B., & Rohleder, N. (2023). CARWatch – A smartphone application for improving the accuracy of cortisol awakening response sampling. Psychoneuroendocrinology, 151, 106073. https://dx.doi.org/10.1016/j.psyneuen.2023.106073
MLA:
Richer, Robert, et al. "CARWatch – A smartphone application for improving the accuracy of cortisol awakening response sampling." Psychoneuroendocrinology 151 (2023): 106073.
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