Health

What is an actigraphy and what is it done for?

Actigraphy is a test performed with a device similar to a bracelet to assess what a person’s sleep is like. We explain what it consists of.

What is an actigraphy and what is it done for?

Actigraphy is a test used to assess what a person’s dream is like. That is, it helps to estimate how long the rest lasts and what the rest patterns are like. It is a useful test in adults, simple to perform and increasingly available to the general population.

Sleep is a fundamental aspect of life. It allows to restore the physical and psychological functions essential to maintain adequate performance. However, it is affected by numerous factors.

There are many tools to be able to study sleep and diagnose conditions that negatively influence it. In this article we explain what actigraphy consists of, when it is indicated and what is its usefulness.

What is actigraphy?

Actigraphy is a test used in sleep study units. It allows estimating the usual duration of rest.

Therefore, it can be used to understand what sleep patterns are like in a person. To do this, a device called an actigraph is used. It is a small device, similar to a wristwatch, that is worn on the wrist or ankle. In fact, in some cases it can be incorporated into a watch.

The actigraph is very easy to carry; It almost looks like an accessory. Currently there are some types that can be integrated into clothing or the bed itself.

Actigraphy allows the physician to obtain more information about the patient’s rest. Especially since the sleep record is something complex to perform and people do not know how to give true and reliable information about how they actually sleep.

What is an actigraphy done for?

Actigraphy began to be used in the 1950s. At that time it was used to evaluate psychological disorders in children, with mechanical sensors. Today its main indication is to study sleep in adults.

First of all, actigraphy may be recommended in people who have insomnia. It is also used to study patients with circadian rhythm disorders or restless legs syndrome. In fact, it can be used to evaluate the response to their treatment.

According to a publication of the Spanish Sleep Society, actigraphy helps to examine patients with hypersomnia. Hypersomnia is a disorder that involves sleeping for many hours during the day and still having a constant feeling of tiredness.

This test is sometimes prescribed as a diagnostic adjunct to patients with apnea-hypopnea syndrome. The actigraph is combined with respiratory polygraphy to view total sleep time.

However, actigraphy has limited efficacy in the elderly and children. However, in older people it can serve to prevent them from going to a sleep unit.

What is an actigraphy and what is it done for?

Insomnia is one of the main indications for actigraphy, although it should be in adults and not in children for the best results.

How does an actigraph work?

The actigraph is a small device that is attached to a limb. This device records the movements of the wrist or ankle. For this it uses a sensitive accelerometer. Through a computerized algorithm, the parameters can be estimated based on how the limb has moved.

As explained from the Somno Clinic, some actigraphs have light sensors. Thanks to them, it is also possible to quantify how the exposure to light has been at night. This is very important for those with circadian disorders. The reason is that these disorders are highly influenced by exposure to light.

Actigraphs are kept for weeks or months. This is how sleep data is recorded 24 hours a day, over a long period of time.

Most actigraphs do not allow us to detect what the stages of sleep are like as such. However, they are useful to check for interruptions, the number of awakenings and the total hours of rest.

Still, sleep and rest go beyond a person being still. That is, someone can be without moving and the actigraph interpret that she is asleep, when it is not reality.

However, the devices used incorporate new parameters every time to increase the reliability of the test. In addition, actigraphy can be combined with other tests, such as polysomnography.

Conditions that can be identified with actigraphy

Actigraphy can be used to identify many sleep problems. First, it allows progress in the diagnosis of circadian rhythm disorders and insomnia.

One of the utilities is regarding the delay of the sleep phase. It consists in that the person has difficulty falling asleep at an early hour and usually goes to bed in the early morning.

It is also useful for advanced stage sleep syndrome. The opposite is true of the above. Actigraphy can detect disorders such as jet lag or shift work disorder.

Lastly, actigraphy may be helpful in sleepwalking and restless leg syndrome. The latter is a pathology that consists of an urgent need to move the legs because a constant discomfort is felt in them.

What is an actigraphy and what is it done for?

In restless legs syndrome, patients mobilize their lower limbs during the night constantly, altering their rest.

Limitations and error factors

Actigraphy has a number of important limitations. As we have pointed out, its mechanism is based on registering the movement of the limb on which the device is placed. Depending on whether there is a lot of movement or not, the device assumes that you are sleeping or awake.

Therefore, if a person takes off the actigraph or remains very still, they can simulate their rest. In addition, as a study published in the journal Chest points out, devices tend to have limited memory. Hence, it is necessary to download the information periodically.

To avoid misinterpretation, it is recommended to keep a sleep diary. However, it is true that actigraph technology advances fast. That is why they are increasingly useful as a diagnostic method.

Actigraphy is useful in combination with other methods

Actigraphy is used to estimate the duration of sleep. It is a simple, innocuous and little bothersome test for the patient. However, it cannot calculate latency or daytime sleep. It is indicated in circadian rhythm disorders and as a complement to sleep-disordered breathing.

In addition, it also works in the context of depression and dementia. However, doctors recommend always using it in combination with other techniques. For example, polysomnography, sleep diaries and the medical history itself.