Obstructive sleep apneas in relation to severity of cervical spinal cord injury

Thirty-three subjects (28 men, five women) with complete or incomplete cervical cord injury representing a wide range of neurological impairment were investigated with regard to the prevalence of Obstructive Sleep Apnea (OSA). The relation between OSA and neurological function, respiratory capacity, body mass index and symptoms associated with OSA were studied. Overnight sleep recordings employed combined oximetry and respiratory movement monitoring. Pulmonary function tests included static and dynamic spirometry, maximal static inspiratory and expiratory pressures at the mouth. The subjects answered a questionnaire concerning sleep quality and tiredness. The prevalence of OSA was 15% (5/33) in this nonobese cervical cord injury study population. Nine percent of the subjects (3/33) fulfilled the criteria for obstructive sleep apnea syndrome, but daytime sleepiness or fatigue were also common in subjects without OSA. There was an inverse correlation between oxygen desaturation index and American Spinal Injury Association (ASIA) motor score in the subjects with complete injury, while there was no such correlation in the whole study group. There were significant correlations between maximal inspiratory and expiratory pressures and vital capacity and between ASIA motor score and vital capacity.