Disclosed are a composite bio-parameter sensor assembly and a wearable device including same, for detecting vital signs of a subject person. The sensor assembly includes one or more sensors, mounted on an outer contact surface of the assembly, having a sensing surface to optically detect one or more parameters of a pulse of the subject. The sensor assembly further includes an additional sensor, facing an inner cavity of the assembly, for optically detecting displacement of the one or more outer sensors. The one or more sensors and the additional sensor are positioned on the opposite sides of a printed circuit board (PCB).
