Comparing GENEActiv against Actiwatch-2 over Seven Nights Using a Common Sleep Scoring Algorithm and Device-Specific...

Area of Science:

• Sleep science
• Biomedical engineering
• Wearable technology

Background:

• Inter-device reliability is crucial for comparing actigraphy data.
• Limited research exists on actigraph concordance beyond a single night.
• Actigraphy is widely used for objective sleep monitoring.

Purpose of the Study:

• To determine an optimal wake threshold for GENEActiv devices.
• To evaluate the concordance between Actiwatch-2 and GENEActiv actigraphs.
• To assess reliability over multiple nights using a common algorithm.

Main Methods:

• 33 participants (20 female, aged 20-35) wore both Actiwatch-2 and GENEActiv devices simultaneously for 7 days (213 nights).
• Sleep parameters analyzed included total sleep time, sleep efficiency, sleep onset latency, and wake after sleep onset.
• Paired t-tests, sensitivity, specificity, and accuracy analyses were performed with device-specific thresholds.

Main Results:

• An optimal wake threshold of 115 was identified for GENEActiv, compared to 40 for Actiwatch-2.
• GENEActiv demonstrated good sensitivity (86%) and overall accuracy (78%), with lower specificity (40%).
• No significant inter-device differences were found for sleep parameters, and mean biases were small.

Conclusions:

• GENEActiv and Actiwatch-2 exhibit reliable concordance for multiple-night sleep monitoring.
• Device-specific wake thresholds are recommended for accurate comparisons between GENEActiv and Actiwatch-2.
• This study provides empirical evidence supporting the interchangeable use of these actigraphs in sleep research.