Central facial nerve palsy
- Remain mobile forehead muscles (frowning is possible) and eyelid closure.
- Intact forehead function and involvement of the middle as well as lower parts of the face → central (supranuclear) lesion.
- Paralysis of the muscles of the mouth and cheeks.
Important notice.
- The motor facial nuclei originate not only from the precentral region (frontal lobe), but also from the diencephalon (diencephalon). They are mainly co-innervated during emotional stirring. This leads to the fact that a separation between voluntary motor activity and emotional motor activity can exist. Thus, neurologically there may be a focal motor deficit with restriction of the mouth branch (= central facial paresis), which, however, “disappears” for the observer during spontaneous laughter.
Peripheral facial nerve palsy
If the facial nerve is peripherally paralyzed, all mimic musculature fails ipsilaterally (on the affected side) and typical symptoms occur (depending on the location of the nerve damage):
- Frowning not possible; the forehead appears smooth and wrinkle-free or wrinkle-poor.
- Asymmetry of the forehead furrows
- Active mouth movements not possible: corners of the mouth droop, the oral fissure can be closed only weakly and not completely.
- Fluid leakage when drinking can be the first symptom!
- Articulation disorders – deviations in the pronunciation of sounds or sound compounds due to speech motor problems.
- Inability to laugh or smile (the face becomes distorted).
- Lagophthalmos – incomplete closure of the eyelids (Bell phenomenon).
- Decreased tear and salivary secretion – damage to petrosal nerve and chorda tympani (petrosal nerve major).
- Hyperacusis (increased hearing in the sense of pathological fine hearing) – due to failure of the stapedius nerve (innervation of the stapedius muscle).
- Taste disorders in the anterior two-thirds of the tongue (due to damage to the chorda tympani).
- Retroauricular (located behind the ear) pain.
- Abnormal sensations of the equilateral cheek
The paralysis occurs within hours and is usually unilateral (monoplegia facialis). A bilateral form is also possible (diplegia facialis).
