Actical (Philips Respironics, Bend, OR) is a compact, battery-operated activity monitor similar in size to a wristwatch and worn on the non-dominant wrist. The portable actigraph is designed to be worn 24 hours a day as it is completely waterproof (i.e., subjects can bathe or shower with the device). The Actical uses a piezoelectric triaxial accelerometer to monitor the occurrence and degree of motion. This type of sensor and the associated digital integration signal processing considers both the degree and intensity of motion to produce an electrical current that varies in magnitude. An increased degree of speed and motion produces an increase in voltage, which is stored by the device as 1-second sample activity counts. Upon retrieval of the actigraph, raw data are downloaded and viewed using software provided by Respironics, Inc. to confirm if recording failures occurred. Activity counts are then summed over 15-second intervals (epochs).

Raw data file available - subject to committee review.

See the Sleep and Circadian Rhythm category for measures of sleep.


Actigraphy data

Actigraphy measures

Average total daily activity Actical activity measure - Average total daily activity (MAP only)
Average daily activity per active hour Actical activity measure - Average activity per hour of activity (MAP only)
Average daily inactivity Actical activity measure - Average percentage of day without activity (MAP only)

Variables listed in another category

Transition probability - Activity to rest From Sleep and Circadian Rhythms
Transition probability - Rest to activity From Sleep and Circadian Rhythms
Interdaily stability From Sleep and Circadian Rhythms
Interdaily variability From Sleep and Circadian Rhythms