JMIR Publications

ABSTRACT

Background:

The most common symptom of atopic dermatitis (AD) is pruritus, which is often exacerbated at night and leads to nocturnal scratching and sleep disturbance. The quantification of nocturnal scratching provides an objective measure, which could be used as a clinical trial endpoint tracking this AD-related behavior. However, it is not clear how digital health technologies (DHTs) intended to measure scratching perform in the real-world environment of patient homes.

Objective:

In this study, we present the analytical validation of two DHTs: the GENEActiv wrist band with Philips sleep and scratch algorithms (“Philips”) and the Emerald radio frequency touchless sensor (“Emerald”) to measure nocturnal scratching in adults with AD.

Methods:

Nocturnal scratching was assessed by each DHT in the study participant’s home environment together with infrared videos. Videos were manually annotated to label the sleep window and scratching events which was used as the reference for comparison with DHTs (“Reference”).

Results:

We found that the intended sleep window was quantified accurately with both tools having a mean bias of <30 minutes. The within-night agreement with Reference of scratch detection performance for each 10s window resulted in F1 scores at the disease group level ranging from 0.51-0.68 for the Emerald and 0.47-0.56 for the Philips DHTs. The night-level agreement of nocturnal scratch duration and frequency with human raters fell mostly in the moderate – good range of intra-class correlation coefficients (0.5 – 0.9) in participants with AD and was not significantly lower than the level of agreement between any two human raters.

Conclusions:

While improvements to the tools can still be made, especially in the precision of wrist-worn scratch detection, these results support the use of both tools as analytically valid for continuous measurement of nocturnal scratching in the home environment.