After a cerebrovascular accident, which facial movement is generally lost?

In the context of a cerebrovascular accident (CVA), or stroke, facial movements can be affected, particularly those that are innervated by the facial nerve (cranial nerve VII). After a stroke, if it affects the areas of the brain responsible for motor control of the facial muscles, patients may experience weakness or paralysis in certain facial movements.

Raising both sides of the mouth involves the muscles of facial expression that are primarily controlled by the facial nerve. In cases of a stroke that impacts the region of the brain controlling the facial nerve, this symmetrical movement may be lost, leading to facial drooping on one side. Evidence shows that after a stroke, patients often struggle with movements that require bilateral control or involve muscles that are innervated by one side of the facial nerve due to unilateral brain damage.

Other movements, such as raising the eyebrows and wrinkling the forehead, can sometimes still occur even if one side of the face is affected. This is because these actions can be performed with some degree of compensation from the unaffected side of the brain, particularly if the stroke is in the part of the motor cortex that affects lower facial muscles more than upper facial muscles. Closing both eyes may also still be possible to some extent, as it involves