Acute intermittent hypoxia (AIH) involves 1-2min of breathing low oxygen air to stimulate neuroplasticity. Animal and human studies show that AIH improves motor function after neural injury, particularly when paired with task-specific training. Using a double blind cross-over study we will test whether AIH and task-specific airway protection training improves airway protection more than training alone in individuals with chronic mild-moderate traumatic brain injury (TBI).

Recent studies have found that acute intermittent hypoxia (AIH)-or repetitive exposure to brief episodes of low inspired oxygen--is a promising new strategy that can help restore motor function by promoting neuroplasticity throughout the central nervous system (CNS). Both rodent and human studies show that motor function is further enhanced when AIH is paired with task-specific training/rehabilitation (TST). Therefore, this study will investigate the therapeutic potential of combining AIH with a task-specific airway protection training. We propose that the combined use of AIH + TST will enhance the magnitude and duration of TST training alone in individuals with chronic traumatic brain injury.

Inclusion Criteria:

• Adults aged 21-80 years
• A mild to moderate traumatic brain injury (TBI) confirmed by medical records
• A Glasgow Coma Scale score between 9-15
• Able to consent independently
• Women of child-bearing age must be comfortable confirming a negative pregnancy prior to participating in the study

Exclusion Criteria:

• Other neurological diagnoses or a diagnosis of a severe psychiatric disorder
• Severe aphasia preventing a participant from understanding the protocol and consent form
• Pre-existing hypoxic pulmonary disease
• History of obstructive lung diseases such as chronic obstructive pulmonary disease (COPD) or significant asthma)
• Severe hypertension (>160/100)
• History of head and neck cancer
• Allergy to barium sulfate
• Ischemic cardiac disease

Participants and assessors will be blinded to group allocation.