It is the unwanted contractions of the muscles of the face during attempted movement.
It occurs after injury to facial nerve.
Cause of injury may be –
. Bell’s palsy
. Ramsay Hunt Syndrome
. after any skull surgery
. skull fracture.
The type of synkinesis is commonly described by combining the names of the two involved muscle groups, with the first part referring to the voluntary motor group and the second part referring to the involuntary muscle group. For ex.-
• Ocular-oral synkinesis is when voluntary eye contraction such as blinking or brow lifting elicits an involuntary mouth movement
• Oral-ocular synkinesis is when an involuntary eye contraction accompanies a volitional mouth movement such as smiling and lip puckering.
Causes for synkinesis-
1. Aberrant regeneration "miss-wiring"
It occurs when axons regrow from the facial nucleus to incorrect peripheral muscle groups.
2. Ephaptic transmission - electrical cross-talk between nerve branches. It happens when nerves are poorly insulated.
3. Nuclear hyperexcitability
• Nucleus creates additional neurotransmitter receptors and, thus, becomes hypersensitive
• Because of this hypersensitivity, it responds to neurotransmitters provided by another nerve nearby.
4. Maladaptive cortical plasticity
• In this there is cortical
reorganization.
Symptoms of synkinesis-
When recovery and re-innervation of the affected side of the face after flaccid facial palsy, you may experience the involuntary linking of movements with voluntary movements.
For ex. - When raising the eyebrows or closing the eyes, the corner of the mouth on the affected side of the face raises.
How to see synkinesis at rest –
When you are not moving your face synkinesis may still be visible.
• Affected eye smaller in size than the other eye.
• Affected nasolabial fold deeper than the contralateral side, and often it sits in a raised position.
• The corner of the mouth may sit higher than the unaffected side.
How to see synkinesis when face is moving -
It is frequently more apparent on facial movements, and large ranges of movement cause greater asymmetry.
Physiotherapy in synkinesis –
Along with facial exercises we need to take care of synkinesis for that we can use 1. neuromuscular retraining – it is the process of relearning facial movements with the help of feedback with the help of feedback patients learn to increase muscle activation which must move and decrease muscle activation which should not move.
