Videolaryngoscopy will be performed as part of standard clinical care. Vocal fold image and cough airflow will be recorded simultaneously during voluntary cough production with the flexible endoscope in nasopharynx. A second part of the study will include spirometry and expiratory muscle strength assessments. Video images of the vocal fold movement during vowel phonation and cough production will be recorded and stored on a CD for later analysis. The cough airflow recordings will be displayed, stored, and analyzed using LabChart software for Windows.