A new approach to improve pulmonary function in quadriplegic people using dual synchronized functional electrical stimulation

The main cause of death in individuals with high thoracic paraplegia and quadriplegia is the complication of the respiratory system. Transcutaneous functional electrical stimulation (TFES) synchronized with spontaneous breathing is a possible technique for respiratory rehabilitation. In this paper, we introduce a new approach to synchronized TFES and the two main muscles of ventilation: diaphragmatic and abdominal. The system under development can automatically perform a double synchronization with TFES and ventilatory muscles. It uses strain gage sensors-based load cell coupled to an elastic belt that is positioned on the thoraco-abdominal region so as to acquire the respiratory signal, and a detection algorithm of inspiratory and expiratory events for synchronization of TFES. After testing in four healthy persons, it was concluded that the proposed sensing system can be employed in the acquisition of respiratory signals. The described algorithm can provide TFES synchronization with the patient in quasi-static situation.