 Patients with cervical and thoracic spinal cord injuries often have paralysis of a major portion of their expiratory muscles the muscles responsible for coughing and therefore, lack a normal cough mechanism. Consequently, most of these patients suffer from a markedly reduced ability to clear airway secretions, a factor which contributes to the development of recurrent respiratory tract infections such as pneumonia and bronchitis. Expiratory muscles can be activated by electrical stimulation of the spinal roots to produce a functionally effective cough. 