A small actigraph unit, also called an actimetry sensor,[2] is worn for a week or more to measure gross motor activity.
Sleep actigraphs are generally watch-shaped and worn on the wrist of the non-dominant arm for adults and usually on the ankle for children.
The data, recorded over time, is in some cases more relevant than the result of polysomnography, particularly in assessing circadian rhythms and disorders thereof as well as insomnia.
When compared, data collected through polysomnographs and actigraphs defines sensitivity; which is the proportion of sleep correctly detected by both methods.
[13] It has not traditionally been used in routine diagnosis of sleep disorders, but technological advances in actigraph hardware and software, as well as studies verifying data validity, have made its use increasingly common.
They are useful for determining the amount of wake-time activity, and possibly estimating the number of calories burned, by the wearer.
[citation needed] Movement actigraphs are generally larger and worn on the shoulder of the dominant arm.
PIM (proportional integral mode) measures the area under the curve, and adds that size for each time period.
Literature shows that PIM provides most accurate measurements for both sleep and activity, though the difference with ZCM is marginal.
Recording is longer than laboratory settings, duration of collection of data may be adapted to each patient and highlight information that cannot be found through one-night measurements such as sleep habits.
[20] Some consumer electronics devices, such as the Oura Ring and the Huawei Honor Band, employ actigraphy to estimate sleep patterns.