Inclusion Criteria: transient ischemic attack - Exclusion Criteria:age <45 years; respiratory distress or known sleep-disordered breathing; chronic obstructive pulmonary disease (COPD) requiring oxygen; pregnancy; time from symptom onset to beginning of study intervention 72 hours; life expectancy <6 months; cognitive impairment (Mini-Mental Status Exam<20); inability to provide informed consent; inability to communicate in English; residence outside the greater New Haven area; or any condition where the monitoring required by the study would constitute a risk to the patient or impair his or her care.