Validity of proximity sensor-based wear-time detection using the ActiGraph GT9X

Abstract

Our study investigated the performance of proximity sensor-based wear-time detection using the GT9X under laboratory and free-living settings. Fifty-two volunteers (23.2 ± 3.8 y; 23.2 ± 3.7 kg/m) participated in either a laboratory or free-living protocol. Lab participants wore and removed a wrist-worn GT9X on 3-5 occasions during a 3-hour directly observed activity protocol. The 2-day free-living protocol used an independent temperature sensor and self-report as the reference to determine if wrist and hip-worn GT9X accurately determined wear (i.e., sensitivity) and non-wear (i.e., specificity). Free-living estimates of wear/non-wear were also compared to Troiano 2007 and Choi 2012 wear/non-wear algorithms. In lab, sensitivity and specificity of the wrist-worn GT9X in detecting total minutes of wear-on and off was 93% and 49%, respectively. The GT9X detected wear-off more often than wear-on, but with a greater margin of error (4.8 ± 11.6 vs. 1.4 ± 1.4 min). In the free-living protocol, wrist and hip-worn GT9X's yielded sensitivity and specificity of 72 and 90% and 84 and 92%, respectively. GT9X estimations had inferior sensitivity but superior specificity to Troiano 2007 and Choi 2012 algorithms. Due to inaccuracies, it may not be advisable to singularly use the proximity-sensor-based wear-time detection method to detect wear-time.

Comparison of Subjective and Objective Methods to Measure the Physical Activity of Non-Depressed Middle-Aged Healthy Subjects with Normal Cognitive Function and Mild Cognitive Impairment—A Cross-Sectional Study

“…Furthermore, most participants achieved a higher step number than declared before recruitment, which could be caused by awareness of PA measuring. Moreover, the GT9X sensing technology relies on the proximity of the sensor electrode to the skin; therefore, vibrations or movements with simultaneous loose wear of the band may impair accuracy [71]. Finally, PA in our study was measured with wrist-worn accelerometers; whereas, the previous study shows that the specificity and the sensitivity values of the wrist-worn and hip-worn accelerometers were lower than those of the thigh accelerometer [72].…”

Reliability and validity of a new accelerometer-based device for detecting physical activities and energy expenditure

“…However, the larger variance of ICCs (−0.165 to 0.609) indicated larger individual errors of the measurements for both FT and ActiGraph. The larger individual errors are likely due to the relatively shorter (i.e., 3 × 15 min) duration of our measurements compared to previous studies, which typically utilized durations of multiple hours up to several weeks ( Aadland & Ylvisåker, 2015 ; Loprinzi & Smith, 2017 ; Hibbing et al, 2018 ; Arguello et al, 2018 ). Consequently, reliability design with longer duration may be further needed for Fibion.…”

Validation of a consumer-grade activity monitor for continuous daily activity monitoring in individuals with multiple sclerosis

“…31 The Troiano (2007) wear-time validation parameters were used. 32,33 At least 10 hours of valid wear time per day and 3 days of valid data were required for comparative assessment. 34 Interclass correlation coefficients (ICCs) with 95% confidence intervals (CIs) were calculated.…”