Post-Paretic Facial Synkinesis
Post-paretic facial synkinesis primarily arises after a facial nerve injury. The damage causes a miscommunication within the nerve pathways leading to the facial muscles. Instead of isolated, controlled movements, the brain may mistakenly trigger muscle groups that shouldn’t operate together.
Causes and Mechanisms of Post-Paretic Facial Synkinesis
Facial nerve injury is key
Facial nerve injury, the root cause, disrupts its complex control of facial muscles, rendering it vulnerable to diverse forms of damage.
Nerve Mis-Regeneration
Facial synkinesis develops due to misdirected nerve regrowth following damage to the facial nerve, leading to unintended muscle co-contractions
Misdirected Axonal Sprouting
Instead of re-establishing connections with their original muscle targets, regenerating axons may form inappropriate connections.
Resultant Aberrant Reinnervation
The miswiring leads to aberrant reinnervation, where muscles receive signals from the wrong nerve fibers.
Neurological Miscommunication
The brain's signals for specific facial movements are misinterpreted by the damaged and regenerating nerve pathways.
Common Preceding Conditions
Several conditions can precipitate facial nerve injury and subsequent synkinesis: Bell's palsy - Trauma - Surgical interventions - Infections - Tumors