A wearable thorax percussion device for dislodging mucous buildup in the airways of a human patient, the device comprising a garment fitting over the thorax, a rigid element attached to the external surface of the garment, an electromechanical actuator retained by the rigid element to intermittently percuss the thorax, and an electronic controller for generating and modulating an electrical signal to energize the actuator. The rigid element may be adjustably positioned on the garment to accommodate thoraxes of different dimensions. The actuator may be compressible between the rigid element and the thorax to better maintain contact with the thorax.