Table 2.
GGIR actigraphy feature calculations.
| Feature | GGIR part5_daysummary Feature Calculation | Description |
|---|---|---|
| Duration of MVPA Fragments (mins) | FRAG_mean_dur_MVPA_day | The average duration (in minutes) of detected moderate-to-vigorous physical activity fragments. |
| Duration of Physical Activity During Sleep Period (mins) | dur_spt_wake_LIG_min + dur_spt_wake_MOD_min + dur_spt_wake_VIG_min | The measured duration of physical activity (light, moderate, vigorous) (in minutes) during the sleep period. |
| Duration of Sleep During Sleep Period (mins) | dur_spt_sleep_min | The measured duration of sleep (‘sustained inactivity bouts’) (in minutes) during the sleep period. |
| Duration of Wakeful Inactivity During Sleep Period (mins) | dur_spt_wake_IN_min | The measured duration of physical activity not considered to be sleep or light/moderate/vigorous physical activity during the sleep period. |
| Number of Blocks of Physical Activity During Sleep Period (#) | Nblocks_spt_wake_LIG + Nblocks_spt_wake_MOD + Nblocks_spt_wake_VIG | The number of total blocks of physical activity (light, moderate, vigorous) that occurred during the sleep period. |
| Number of Blocks of Sleep During Sleep Period (#) | Nblocks_spt_sleep | The number of total blocks of sleep that occurred during the sleep period. |
| Number of Blocks of Wakeful Inactivity During Sleep Period (#) | Nblocks_spt_wake_IN | The number of total blocks not considered to be sleep or light/moderate/vigorous physical activity that occurred during the sleep period. |
| Number of MVPA Fragments (#) | FRAG_Nfrag_MVPA_day | The number of fragments of moderate/vigorous activity that occurred per day (part of the behavioral fragmentation analysis methodology) (39). |
| Number of Sustained Inactivity Bouts During Wake Period (#) | See “Description” | Derived using GGIR ms3.out list “sib.cla.sum” – the total number of SIBs occurring within the defined waking period and not falling within a period of suspected non-wear. |
| Duration of Sustained Inactivity Bouts During Wake Period (min) | See “Description” | Derived using GGIR ms3.out list “sib.cla.sum” – the average duration of SIBs in minutes occurring within the defined waking period and not falling within a period of suspected non-wear. |
| Sleep Efficiency (%) | sleep_efficiency | The percentage of time spent asleep during the entire sleep period. |