Accuracy of the GENEActiv Device for Measuring Light Exposure in Sleep and Circadian Research

Abstract

Light is a variable of key interest in circadian rhythms research, commonly measured using wrist-worn sensors. The GENEActiv Original is a cost-effective and practical option for assessing light in ambulatory settings. With increasing research on health and well-being incorporating sleep and circadian factors, the validity of wearable devices for assessing light environments needs to be evaluated. In this study, we tested the accuracy of the GENEActiv Original devices (n = 10) for recording light under a range of ecologically relevant lighting conditions, including LED, fluorescent, infrared, and outdoor lighting. The GENEActiv output had a strong linear relationship with photopic illuminance. However, the devices consistently under-reported photopic illuminance, especially below 100 lux. Accuracy below 100 lux depended on the light source, with lower accuracy and higher variability under fluorescent lighting. The device’s accuracy was also tested using light sources of varying spectral composition, which indicated that the device tends to under-report photopic illuminance for green light sources and over-report for red light sources. Furthermore, measures of photopic illuminance were impacted by infrared light exposure. We conclude that the GENEActiv Original is suitable for mapping light patterns within an individual context, and can reasonably differentiate indoor vs. outdoor lighting, though the accuracy is variable at low light conditions. Given the human circadian system’s high sensitivity to light levels below 100 lux, if using the GENEActiv Original, we recommend also collecting light source data to better understand the impact on the circadian system, especially where participants spend prolonged periods in dim lighting.

Bidirectional association between light exposure and sleep in adolescents

“…First, the reduced number of participants and the voluntary basis of their participation force us to be cautious about the generality of our results. Second, it has been reported that GENEactive accelerometers had a bad light recording performance under 100 lux although having a strong linear relationship with illuminance (Stone, McGlashan, Facer‐Childs, Cain, & Phillips, 2020). As we used average values, and given the exponential differences between indoor/artificial and daytime light intensities, the underestimation of low light exposure may not be relevant.…”

Effects of adjunctive brexpiprazole on sleep-wake and circadian parameters in youth with depressive disorders: study protocol for a clinical trial

“…GENEActiv devices have been validated against several types of accelerometry-based activity monitors89–92 as well as for sleep-wake scoring 93 94. For decades, actigraphy monitors like the GENEActiv devices have been used extensively in research to measure sleep and activity patterns in diverse clinical settings including sleep disorders, medical illnesses (eg, neurodegenerative diseases) and various major mental disorders 19 95 96…”

Feasibility, acceptability and validation of wearable devices for climate change and health research in the low-resource contexts of Burkina Faso and Kenya: Study protocol

“…We will continuously monitor activity with a validated wrist-worn tri-axial accelerometer (resolution up to 100Hz) device (GENEActiv Original, ActiveInsights, UK). The accelerometers are small, rugged, waterproof, actigraphy-based data loggers that record a digitally integrated measure of gross motor activity, as well as sleep schedule variability, sleep quantity, and sleep quality statistics and daytime [ 54 – 58 ]. In addition, the systems are equipped with luminous flux recording, to distinguish between time spent outdoors and indoors, and near body temperature sensor, to define precisely wearing time.…”