Facial Paralysis: Recognizing the Symptoms and Understanding the Differences Between Peripheral and Central Types

Facial paralysis is a condition that occurs when the facial nerve becomes damaged, leading to impaired muscle movement on one side of the face. This neurological disorder can develop suddenly and significantly affect daily functions such as speaking, eating, and expressing emotions. The symptoms vary depending on the type and severity of nerve involvement, with peripheral facial palsy typically presenting more pronounced signs than central forms.

Common Physical Signs of Peripheral Facial Paralysis

Loss of Forehead Wrinkles

One of the most noticeable early symptoms is the disappearance of forehead wrinkles on the affected side. Patients may find it difficult or impossible to raise their eyebrows or frown normally. When attempting these movements, only the healthy side of the forehead responds, resulting in an asymmetrical appearance. This hallmark sign helps differentiate peripheral from central facial paralysis.

Eye-Related Changes: Wide Eye Opening and Incomplete Closure

Another prominent symptom is an abnormally wide eye opening (increased palpebral fissure) due to weakened orbicularis oculi muscles. This leads to incomplete eyelid closure, especially when blinking or sleeping. A visible white crescent (sclera) often appears beneath the iris during attempted eye closure—a phenomenon known as the "lagophthalmos sign." This can cause dryness, irritation, and increased risk of corneal damage if not properly managed.

Altered Facial Contours Around the Mouth

The nasolabial fold—the natural crease running from the nose to the corner of the mouth—becomes noticeably shallower or flattened on the paralyzed side. Individuals may also experience difficulty puffing out their cheeks, which results in air leakage from the affected corner of the mouth. This weakness compromises oral control and can lead to drooling or difficulty with certain speech sounds.

Mouth Asymmetry and Drooping

At rest, the corner of the mouth on the affected side tends to droop downward. When smiling or showing teeth, the asymmetry becomes even more apparent, with the mouth pulling toward the unaffected (healthy) side. This uneven expression can be distressing for patients and may impact social interactions and self-confidence.

Additional Sensory and Functional Impairments

Beyond motor deficits, peripheral facial paralysis can also affect sensory functions. A significant number of patients report partial or complete loss of taste over the anterior two-thirds of the tongue on the affected side. This occurs because the chorda tympani branch of the facial nerve, responsible for taste transmission, is often involved in the nerve damage.

Due to reduced muscle tone and poor cheek mobility, food particles frequently become trapped between the gums and cheeks on the paralyzed side. This not only causes discomfort but also increases the risk of dental decay and gum inflammation if oral hygiene is neglected.

Distinguishing Peripheral vs. Central Facial Paralysis

It's crucial to understand that not all facial paralysis is the same. While peripheral facial palsy (such as Bell's palsy) affects the entire facial nerve pathway and presents with full facial weakness including forehead involvement, central facial paralysis—often caused by stroke or other brain lesions—spares the upper face.

In central cases, patients usually retain the ability to wrinkle their forehead and close their eyes tightly because the upper facial muscles receive bilateral brain input. Additionally, taste disturbances and ear-related symptoms are generally absent in central types. Recognizing this distinction is vital for accurate diagnosis and appropriate treatment planning.

Early recognition of these symptoms enables timely medical intervention, which can improve recovery outcomes. If you or someone you know experiences sudden facial weakness, seeking immediate evaluation from a healthcare provider is strongly recommended to determine the underlying cause and initiate proper management.