Sleep-Disordered Breathing in Chronic SCI

Investigators will examine the effect of PAP therapy and sleep apnea on thinking (especially memory, learning and concentration), sleep quality, and risks for future heart (cardiovascular) problems in persons with chronic spinal cord injury (SCI).

SDB is a condition where there are pauses in breathing or shallow breathing during sleep due to airway narrowing. This leads to low oxygen levels during sleep and sleep disruption. The usual treatment for sleep apnea is PAP (Positive Airway Pressure) worn while sleeping. This involves the use of usually a mask connected to a machine that supplies enough pressure to keep the airway open during sleep.

SDB will be diagnosed in SCI participants using unattended portable level II polysomnography (PSG) (a portable at home sleep study for one night).

Sleep quality (SQ), SDB risk, insomnia severity, daytime sleepiness,and mood will be measured using questionnaires.

Cognitive evaluations will be completed prior to randomization on all participants who also complete a portable PSG to evaluate general and pre-morbid function, immediate verbal memory, simple and sustained attention, processing speed, and executive function.

Blood and urine samples will be taken for participants with SDB diagnosis after randomization.

All randomized subjects will be fitted with a nasal or full-face mask and head gear. PAP will be delivered by an auto-titrating device. These devices automatically set the level of delivered pressure to ensure upper airway patency, to treat detected apneas, and hypopneas. All subjects will be instructed to use the device nightly during sleep, for the ensuing four months. All outcome measurements will be reassessed after four months of PAP.

Inclusion criteria

• Chronic tetraplegia or paraplegia (C4-L1)
• American Spinal Injury Association (ASIA) Impairment Scale A, B, C or D
• 18 years and older
• At least one year post injury
• Hearing and vision suitable for comprehension of instructions, and perception of cognitive test stimuli
• No color blindness as measured by a brief screen with color perception Ishihara cards
• Stable medical condition for 2 weeks prior to enrollment. Patients admitted to hospital will be eligible for enrolment if the acute illness precipitating admission is in recovery phase for 2 weeks or longer

Exclusion criteria

• Diagnosis of SDB and successful positive airway pressure (PAP) therapy prior to injury. Those with a diagnosis of SDB post injury who are not receiving therapy for SDB (PAP, surgical, and/or oral appliance) are eligible for study enrollment
• Patients who are intubated, have a tracheostomy, and/or are using long term invasive/non-invasive positive pressure ventilation
• Participants with predominant central sleep apnea on PSG requiring bi-level PAP therapy
• Severe traumatic brain injury (GCS < 8 at first assessment)
• Unable to understand or read English at a grade 5 level
• Inability to provide informed consent
• Evidence of advanced neurological or systemic disease that may affect cognitive functioning (e.g., Alzheimer's disease, Dementia, Parkinson's disease)
• Significant aphasia or language impairments
• Positive airway pressure therapy may be contraindicated in some patients with the following preexisting conditions:
• severe bullous lung disease
• pneumothorax
• pathologically low blood pressure
• dehydration
• cerebrospinal fluid leak, recent cranial surgery, or trauma.