Respiratory dysfunction in stroke.

Respiratory function depends on numerous neurologic structures, the organization of which extends from the cerebral cortex to the medulla. The study of patients who have had strokes has allowed deductions about this organization, and various neurologic pathways have been increasingly recognized. The voluntary pathway travels with the corticospinal motor tract. It is typically damaged in the "locked-in" syndrome and leads to normal automatic breathing that cannot be voluntarily altered. The automatic pathway takes its origin in the lower brainstem and is damaged mainly in lateral medullary strokes. Even a unilateral lesion here may lead to complete failure of respiration and result in death during sleep (Ondine's curse). The preservation of the limbically induced fluctuations of respiration in automatic breathing suggests a third pathway that may share its distal extent with the automatic pathway. Respiratory dysfunctions may also provide useful information regarding the cause and prognosis of stroke.