Inclusion Criteria1. older than 18 years of age,
2. first episode of stroke within three months,
3. moderate to severe stroke impairment, defined as a NIHSS score from 5-36, and
4. the ability to follow instructions and engage in the study program.
Exclusion Criteria1. a medical history of persistent cardiopulmonary disease,
2. other coexisting brain disorders, such as brain tumor,
3. poorly controlled hypertension, which was defined as a blood pressure higher than 180/100 mmHg during the preceding 24 hours,
4. severe facial palsy or other oropharyngeal structural abnormality,
5. severe oral apraxia, and (6) having a tracheostomy.