Neurologic aspects of sleep apnea: is obstructive sleep apnea a neurologic disorder?

The upper airway caliber is determined by afferent sensory input to the brainstem respiratory centers and efferent motor neural output to the upper airway structures. Upper airway caliber is altered in obstructive sleep apnea. The mechanosensory receptors of the upper airway are capable of responding to changes in airway pressure, airflow, temperature, and to the upper airway muscle tone itself. Application of topical anesthesia change chronic snorers in apneic patients during sleep and prolong sleep apnea in obstructive sleep apnea (OSA) patients. Respiratory-related evoked potential are significantly reduced in OSA patients during non-rapid eye movement sleep indicating a sleep-related blunted cortical response to inspiratory occlusion. Histologic investigations of palatopharyngeal muscles from OSA patients show evidence of motor neuron lesions and actual damage to the muscles. Currently demonstrated local neurologic impairment and lesions can explain the development of sleep apneas and hypopneas.