Fig. 1

Measurement setup. a Postural interventions were provided using an automated bed, which can elevate the trunk of the sleeping user. A custom-made built-in microphone was used to trigger trunk elevation. In addition, a reference microphone and a IR-camera were used to monitor the user. b The inclination angles provided by the bed were 10 ^∘ (P10), 15 ^∘ (P15), and 20 ^∘ (P20) provided at the location where the users hip joint is to be expected. At the beginning of the night on during episodes of silence the bed was set to neutral postion (P0)