What aspect of sleep does the actigraph commonly measure?

The actigraph is primarily designed to measure movement and activity levels. This device is worn on the wrist, similar to a watch, and it records movement over time, allowing healthcare providers to assess sleep patterns and activity levels during both sleep and wakefulness. By analyzing this data, clinicians can infer sleep quality and quantity, as increased movement may indicate restlessness or wakefulness, while reduced movement can suggest better sleep continuity.

This focus on movement distinguishes the actigraph from other tools used in sleep studies, such as EEG, which measures electrical activity in the brain (as seen in electroencephalogram readings), or other methods that assess specific sleep stages or cycles. While the actigraph provides important insights related to sleep and daily activity, it does not measure sleep cycle duration or the features of dreams directly. Thus, it serves a unique purpose in monitoring sleep patterns within the context of overall activity levels.