What does actigraphy measure?

What does actigraphy measure?

• A. Heart rate
• B. Blood oxygen
• C. Sleep-wake patterns from wrist movement
• D. Brain waves

Answer: (C)

Actigraphy uses a wrist-worn accelerometer to monitor movement and infer sleep or wakefulness over time. By analyzing activity levels, it estimates sleep-wake patterns in each time interval, allowing calculation of total sleep time, sleep efficiency, sleep onset latency, and awakenings. The underlying idea is that stillness suggests sleep while movement indicates wakefulness, though quiet wakefulness can look like sleep and restless sleep can look like wake. It doesn’t measure brain activity, heart rate, or blood oxygen—those require other methods like polysomnography, heart-rate monitoring, or oximetry.

Actigraphy uses a wrist-worn accelerometer to monitor movement and infer sleep or wakefulness over time. By analyzing activity levels, it estimates sleep-wake patterns in each time interval, allowing calculation of total sleep time, sleep efficiency, sleep onset latency, and awakenings. The underlying idea is that stillness suggests sleep while movement indicates wakefulness, though quiet wakefulness can look like sleep and restless sleep can look like wake. It doesn’t measure brain activity, heart rate, or blood oxygen—those require other methods like polysomnography, heart-rate monitoring, or oximetry.