Actigraphy (Actigraph)

What is actigraphy?

Actigraphy is the measurement of your activity and rest.

A healthcare provider will measure actigraphy using an actigraph. An actigraph is a wearable device that detects movement. It’s the same size as a watch and you can wear it on your wrist or ankle. You may need to wear this device for a few days or up to two weeks as it collects data about your movements. A healthcare provider will review the data in addition to other tests to diagnose sleep disorders.

If you’re having trouble sleeping, a healthcare provider may recommend you create a sleep diary or sleep log to track when you go to bed and when you wake up. It can be difficult to remember to write down these times. An actigraph device makes keeping a sleep diary easy by recording this information for you. You may still need to keep a sleep diary in addition to wearing this device.

What does actigraphy measure?

Actigraphy measures your movement using an actigraph device. While you wear the device, it tracks how often you move both during the daytime and at night, including:

• When you fell asleep at night.
• If you wake up and fall back asleep in the middle of the night.
• When you wake up in the morning.
• How long you were sleeping.
• How long it takes for you to fall asleep.
• How much time you spend awake.

The device doesn’t directly measure sleep. It identifies the absence of movement as sleep. The patterns of movement and non-movement help your healthcare provider identify underlying conditions that could affect your sleep-wake cycle.

When a healthcare provider gives you instructions to wear this device, don’t take it off until your healthcare provider tells you to. When you take off the device, it assumes you’re sleeping since it isn’t recording any movement.

Some devices can measure light and body temperature in addition to movement. These components may interfere with your ability to sleep well, and they can give insights for your healthcare provider to make a diagnosis.

How does actigraphy work?

The components within the actigraph device record actigraphy movements (activity and rest) multiple times per second. The brain within an actigraph is the accelerometer. The accelerometer measures waves of movement like vibrations and how fast the movements are (speed).

This tool is also a component of many devices you use during the day, like your smartphone. For example, an accelerometer is the part of your smartphone that turns the image on your screen when you turn your phone sideways. It also tells your screen to turn on when you pick up your smartphone.

What do actigraphy results show?

After wearing an actigraph device, a healthcare provider will download the actigraphy information (data) based on what the accelerometer collected. It appears in a graph. The graph displays an analysis of your movement while you were wearing the device. The bars on the graph are high when you’re awake and moving around. The highest points of the graph show activities like running or exercising. The bars on the graph won’t show up (flat) when you’re sleeping (not moving).

A healthcare provider will review the actigraphy data to interpret your sleep-wake cycle. For example, if you don’t have a lot of flat areas on your graph during the night, it’s a sign that you’re not getting enough sleep and it could be a sleep disorder like insomnia.

What is a normal actigraphy result?

A healthcare provider reviews your movement data in a chart to see how many times you woke up in the middle of the night or when and how long you’re able to sleep. Results vary based on what your healthcare provider is looking for. Having fewer wakeups during the night, and falling and staying asleep then waking up at the desired time, are considered a “normal” actigraphy result, but normal can vary from person to person.

What sleep disorders can actigraphy detect?

Actigraphy identifies patterns or cycles of activity and non-activity to determine your sleeping patterns. Wearing an actigraph can help your healthcare provider diagnose an underlying sleep disorder, like:

• Insomnia and conditions that affect your ability to fall asleep and stay asleep.
• Central disorders of hypersomnolence (excessive sleepiness) or conditions that prevent you from staying awake like narcolepsy.
• Circadian rhythm sleep disorders that affect your internal clock like delayed sleep phase syndrome.

An actigraph isn’t an accurate tool to diagnose periodic limb movement disorder or restless legs syndrome (RLS).

How do I use an actigraph?

Using an actigraph device is easy. All you need to do is secure the actigraph to your nondominant wrist (nearest the hand you don’t write with regularly) or ankle. Make sure the device fits comfortably on your wrist (or ankle) and isn’t too tight or too loose. You can adjust the strap around the device to fit it against your skin. It shouldn’t move up and down your arm while you’re wearing it (that means it’s too loose).

A healthcare provider will let you know how long you need to wear the device to collect actigraphy data. You should wear it continuously throughout the day and night. Ask your healthcare provider if the device they provide is waterproof. If it is, you don’t need to remove it to take a bath or shower. Keep track of the dates and times when you remove the device if you need to remove it.

Your healthcare provider will download the data onto a computer when you finish using it. Then, they’ll go over the actigraphy results with you.

Is an actigraph the same as a smartwatch?

No, an actigraph isn’t the same as a smartwatch, like an Apple Watch for example. An actigraph only detects your movements. It’s similar to an activity tracker like a Fitbit. A smartwatch, fitness tracker and an actigraph all contain a component called an accelerometer that collects actigraphy data on your movements. Smartwatches and fitness trackers have more technology within the devices so you can do more with those, like get text message notifications or change the song you’re listening to. An actigraph likely won’t have any features for you to interact with (the time is usually not even displayed). All you do is wear it. You’ll likely not need to charge it during the time you’re wearing it.

A note from Cleveland Clinic

Actigraphy is a way to measure your activity and movements. A healthcare provider will use an actigraph device to measure this data to detect sleep disorders. It tells you when and for how long you slept to give your healthcare provider more information to make an accurate diagnosis. The device looks similar to a wristwatch, so it won’t clash with your outfit. Your provider will let you know how long you need to wear the device before returning it to them so they can evaluate the actigraphy data.