What is Residual Effects (Synkinesis)?

People recover at different rates, but generally the regeneration of nerves will be complete in the three months after onset. If recovery is delayed you may begin to notice movements in areas of the face that you are not even trying to move, this is referred to as Residual Effects. Residual effects can be present in cases where recovery from Bell’s palsy is delayed beyond the 3 months point. Generally, the longer the recovery takes beyond the initial three months, the more severe the residual effects. For example, when you smile the eye may close or twitch or when you close you eye the corner of your mouth may pull up or out to the side. This condition is known as synkinesis. It is characterized by uncoordinated or unsynchronized facial movements that occur along with normal movements. Synkinesis varies in severity from mild to severe. In its worst form it can result in uncontrollable movement of the facial muscles on the affected side during any attempted expression. The affected side of the face may feel tight as the result of the uncontrolled muscle contractions (spasms).

Synkinesis is theorized to be the effect of abnormal nerve regeneration. Some of the healing facial nerve fibers can actually implant themselves into the wrong muscles. The facial nerve is like the telephone cable. Within that strand are between 6000-7000 different nerve fibers that conduct the electrical signal from the brain to the facial muscles causing them to contract. They are very delicate. Inflammation from the Bell’s palsy can harm, or “break” some of these very frail fibers. In time the damaged fibers heal. They regenerate at the rate of about 1-2mm per day. But there’s no mechanism that directs these fibers back into their original muscles. The brain sends the signal for the muscle to contract thinking the nerve fiber is still connected to the original muscle, but instead, the nerve may be lodged in an entirely different muscle.

Treatment for residual synkinesis can be effective at any time after it is noticed. The focus of the treatment is on re-coordinating the various muscles rather than stimulating them. We know that when synkinesis is present the facial muscles are viable, or “alive”. Even an abnormal movement is still a movement. It is possible to restore more normal movement patterns and expression with specific, appropriate training.