Localization in Clinical Neurology by Paul W. Brazis MD Joseph C. Masdeu MD PhD & José Biller MD FACP FAAN FAHA

Author:Paul W. Brazis, MD, Joseph C. Masdeu, MD, PhD & José Biller, MD, FACP, FAAN, FAHA [Brazis, Paul W., MD; Masdeu, Joseph C., MD, PhD; Biller, José, MD, FACP, FAAN, FAHA]
Language: eng
Format: epub
ISBN: 978-1-4511-5358-3
Publisher: Wolters Kluwer
Published: 2011-09-24T16:00:00+00:00

Postparalytic Spasm and Synkinetic Movements

After recovery from peripheral facial nerve paralysis (e.g., Bell’s palsy), various phenomena may occur. These include postparalytic hemifacial spasm, the “crocodile tears” phenomenon (eating provokes lacrimation), facial contractures, and various synkinesias (abnormal synchronization of the movement of different muscles that normally do not contract together), such as contraction around the mouth with eye blinking and eyelid closure on full opening of the mouth or movement of the jaw laterally (Marin-Amat syndrome or “inverse Marcus Gunn phenomenon”) [157]. Synkinesis most often occurs as a result of aberrant regeneration of the facial nerve after injury, but it also rarely occurs in muscles innervated by two different cranial nerves, including a rare facial–trigeminal synkinesis [173]. With postparalytic muscle contracture, the more relaxed, normal contralateral side may appear weak on casual inspection. However, when facial movements are performed, the actual state and side of the pathology are revealed. These various abnormalities are probably secondary to faulty fiber regeneration after peripheral facial lesions or abnormal activity of residual motor units.