 Preliminary studies in our laboratory in animal experiments and those of others in humans have suggested that the abdominal muscles can be stimulated directly by surface electrodes. The purpose of the present study, therefore, is to assess the utility of abdominal muscle stimulation in quadriplegics and paraplegics to simulate cough. A range of stimulus parameters and electrode locations will be assessed to determine optimal stimulus paradigms. Airway pressure and expiratory airflow will be used as indices of cough effectiveness. If successful, abdominal muscle stimulation may be a useful tool to restore cough and hopefully reduce the incidence of respiratory complications such as atelectasis and infection in spinal cord injured patients. 