Actigraphy, Wearable EEG Band and Smartphone for Sleep Staging

This study aims to evaluate the viability of the combined use of wearable and portable technologies for sleep staging. The results will be compared with polysomnography, in order to achieve clinical and diagnostic validation. Three domains of devices will be used:

• Movement sensors: Devices equipped with movement sensors (such as an accelerometer) able to monitor movement over the using period, converting this information in data related to the sleep-wakefulness cycle. In this category, the reference devices are the actimeters/actigraphs (ACT). Its use is recommended by the American Academy of Sleep Medicine to the diagnosis of insomnia and circadian sleep disorders, and should be used for 3 to 14 consecutive days. Other wearable devices, such as smartwatches, are also used with the same purpose, although not validated for clinical use. In this study two wearable devices with movement sensors will be used, with the following minimal specifications: accelerometer in three axes, minimal sampling rate of 25Hz, maximum weight of 100g, battery lasting at least a week and support for Bluetooth connection. The desirable criteria are: light, body temperature and hearth rhythm sensors.
• Wearable EEG band: EEG is a mandatory feature for type-1 polysomnography and a requirement for regular sleep staging. In this project, the EEG will be used in combination with actigraphy to allow a better estimation of sleep stages. In this study two wearable EEG bands will be tested, with the following minimal specifications: dry EEG electrode (no need of paste, gel or other conductor), presented as a head band or stripe, minimal sampling rate of 500Hz, noise, high and low filters, battery lasting at least 8h, maximum weight of 200g (including the whole device) and support for Bluetooth connection.
• Smartphones: Additionally to the movement sensors and the EEG bands, the evaluation of sleep pattern will be based on smartphone-based accelerometers. This is the most common approach among the currently available sleep tracking applications, although is the least accurate. In this project the smartphones will be equipped with SleepUp's app and its sleep tracking functionality.

The project will be composed of three stages:

In the first stage, the use of the combination of actigraphy and EEG will be used for sleep staging in a sample of 12 healthy volunteers from 20 to 80 years old, both genders and with no sleep disorders for each combination of ACT+EEG. Considering there will two of each (thus four combinations), the final sample will be composed of 48 individuals. Once recruited, evaluated according to the inclusion and exclusion criteria and consented with the terms of this study, the participants will be referred to the sleep lab, in which they will undergo a full night type-1 in lab polysomnography, following the setup recommended by the American Academy of Sleep Medicine. Concomitantly with the polysomnography, the participants will also use the combination of ACT+EEG.

In the second stage, the most successful combination tested in the first stage will be tested in a clinical sample, composed by 60 participants from both genders, from 20 to 80 years old and with at least one sleep disorder or complaint. Among these, at least 30% of the sample should have moderate to severe insomnia (as measured by the insomnia severity index), 30% should have high risk to sleep apnea (as measured by the STOP-BANG questionnaire) and 70% should have excessive sleepiness scale (as measured by the Epworth sleepiness scale). All the procedures, including the polysomnography will be performed identically to the first step.