When the lesion to the Vagus is above the pharyngeal branch, the soft palate and larynx will demonstrate deficits on the same side and the resulting speech will be hypernasal and breathy. A brainstem stroke or tumor may affect more than one cranial nerve. Flaccidity and atrophy are the major characteristics. May be congenital as in Moebius Syndrome. May be adventitious as in surgical or accidental trauma to peripheral nervous system.
Deficits are usually unilateral.
Both the larynx and velum should be checked if one is paralyzed. The nasal air escape is caused by forcing the breath stream through a constriction of the velum against the posterior pharyngeal wall while the tongue stops oral air flow. Since velopharyngeal function is normal, the stop-plosives do not have nasal air escape and resonance is normal. The velum is neurologically and anatomically capable of closure at the time of evaluation. May represent a history of transient VPI, now resolved.