Table 1.
Summary of recently developed wearable systems for sleep monitoring applications
| Parameters | Data | Sensors | Sensor locations | References |
|---|---|---|---|---|
| Brain waves | EEG | Wet/dry electrode | Scalp | (Arnal et al., 2019) |
| Forehead | (Arnal et al., 2019), (Levendowski et al., 2017), (Lin et al., 2017), (Shustak et al., 2019) | |||
| Ear | (Alqurashi et al., 2018), (Sterr et al., 2018), (Mikkelsen et al., 2019) | |||
| Heart activity | ECG | Wet/dry electrode | Chest | (Klum et al., 2020), (Ilen et al., 2019), (Di Rienzo et al., 2018), (Yoon et al., 2018) |
| ICG | Wet electrode | Chest | (Klum et al., 2020) | |
| PCG | Stethoscope | Chest | (Klum et al., 2020) | |
| SCG | Accelerometer | Chest | (Di Rienzo et al., 2018) | |
| Pulse wave | PPG | LED & photodiode | Finger | (Liao et al., 2020), (Kinnunen et al., 2020) |
| Nose | (Manoni et al., 2020) | |||
| Forehead | (Arnal et al., 2019), (Levendowski et al., 2017) | |||
| SpO2 | LED & photodiode | Wrist | (Braun et al., 2020) | |
| Forehead | (Beppler et al., 2018) | |||
| Ear | (Davies et al., 2020) | |||
| IPG | Dry electrode | Wrist | (Schneider et al., 2018) | |
| Pulse pressure | Pressure sensor | Wrist | (Meng et al., 2020) | |
| Respiration | Body movement | Strain gauge, accelerometer, magnetometer | Chest | (Klum et al., 2020), (Ding et al., 2018), (Ramírez et al., 2019), (Di Rienzo et al., 2018), (Milici et al., 2018) |
| Head | (Arnal et al., 2019) | |||
| Air flow | Humidity sensor | Nose | (Jin et al., 2017) | |
| Lung sound | Stethoscope | Chest | (Klum et al., 2020) | |
| Movement | EMG | Dry electrode | Leg | (Jortberg et al., 2018) |
| Actigraphy | Accelerometer, gyroscope, magnetometer | Wrist | (Liao et al., 2020), (Kwasnicki et al., 2018) | |
| Leg | (Bobovych et al., 2020) | |||
| Chest | (Ilen et al., 2019), (Kwasnicki et al., 2018) | |||
| Body position | Accelerometer, gyroscope, magnetometer | Wrist | (Kwasnicki et al., 2018) | |
| Chest | (Yun et al., 2020), (Kwasnicki et al., 2018) | |||
| Nose | (Manoni et al., 2020) | |||
| Others | EDA | Dry electrode | Wrist | (Romine et al., 2019), (Kim et al., 2021) |
| Finger | (Lam and Szypula, 2018) | |||
| Tongue deformation | Ultrasonic transducer | Chin | (Weng et al., 2017) | |
| Body temperature | Thermometer | Chest, wrist | (Di Rienzo et al., 2018), (Liao et al., 2020) | |
| Snoring sound | Microphone | Forehead | (Levendowski et al., 2017) |