Peripheral facial palsy and dysfunction of the oropharynx

The facial nerve contributes to the oropharyngeal phase of deglutition via the buccinator, perioral, digastricus posterior, and stylohyoid muscles. The gustatory and salivatory functions of the facial nerve are also known to contribute to swallowing. The relation between peripheral facial nerve palsy (PFP) and swallowing dysfunction has never been studied systematically. Forty four patients with unilateral Bell's palsy (acute or chronic stages) and 20 normal control subjects were investigated. In 66% of patients with PFP, oropharyngeal swallowing was disturbed as demonstrated electrophysiologically by the patients' dysphagia limit at or below 20 ml of water. In patients with PFP investigated within the first 2 weeks of the palsy, the dysphagia limit normalised during the period of recovery. Normalisation of the dysphagia limit is highly correlated with the recovery of PFP. Thus, subclinical deglutition is very frequent in patients with PFP. The severity of abnormal deglutition increased with the severity of the PFP, especially with the involvement of the perioral and buccinator muscles.