Neuromuscular Reeducation in Facial Palsy

Original Editor - Claudia Karina

Top Contributors - Claudia Karina, Jess Bell, Wendy Walker, Kim Jackson, Tarina van der Stockt, Claire Knott and Lucinda hampton  

Introduction

The loss or decrease in facial movements, expressions, and functions such as eating, drinking or talking have a negative impact on the psychosocial well-being of people with neuromotor facial disorders, thus affecting all aspects of an individual's quality of life.

The incomplete recovery of a facial disorder, specifically facial palsy, produces sequelae that interfere with facial expressions and, therefore, affect self-esteem and social interaction. The most common are:

• Asymmetry
• Muscle contracture
• Muscular facial weakness
• Synkinesis

It is very important to implement an efficient treatment that reduces the presence of sequelae. Neuromuscular facial re-education (NMR) has been shown to be the most effective treatment because it enables recovery of symmetrical movement in the face and eliminates or reduces problems in the patient's facial functions.

Basic Concepts

Facial Movement System

Facial movements, expressions, and functions are the result of a combination of different muscle contractions.

The facial muscles are small and, unlike skeletal muscles in the rest of the body, have no fascial encasement or tendons binding them directly to the bones. Thus, their origin and insertion are able to move freely. They also lack internal sensory receptors that provide them with intrinsic proprioceptive feedback.

Influence of Emotions on the Rehabilitation Process

Facial expressions result from either:

• Brain activity involving the motor cortex (i.e. cortical behaviour)
  • Usually voluntary
• The activity of a network of subcortical nuclei and parts of the brain-stem (i.e. subcortical behaviour)
  • Usually a reaction to something (e.g. shock, laughter, sneezing)

It has been proposed that because emotions can generate specific facial muscle contractions to achieve an expression (e.g. a smile), it is possible that facial muscle activities may actually create or enhance emotions. It is known that psychological distress affects the relationship between impairment and disability in patients with facial palsy. Thus, the "presence of a marker of positive affect predicts greater response to therapy to increase lip corner movement with smiling in individuals with a facial neuromotor disorder." Thus, it may be beneficial to retrain the muscles that are responsible for certain expressions, rather than focusing on the restoration of facial movement (i.e. an impairment level).

Useful Tools for the Rehabilitation Process

Because there is little intrinsic information about facial muscle posture and movement, it is difficult to achieve a specific voluntarily movements of the facial muscles without some feedback, such as using a mirror or surface EMG biofeedback. This feedback enables the patient to modify muscle activity by increasing or decreasing muscle contraction.

The activation of the facial muscles alone is not, however, sufficient to recover facial expressions. Thus, it is important to incorporate facial exercises that focus on emotions and expressions into a rehabilitation programme - i.e. ask the patient to remember a time when she / he was very happy when practising a smile, in order to activate the "positive affect marker, the orbicularis oculi contraction in association with smiling".

Neuromuscular Facial Re-Education

Neuromuscular facial re-education is the: "process of relearning facial movement using specific and accurate feedback to (1) facilitate facial muscle activity in functional patterns of facial movement and expression and (2) suppress abnormal muscle activity interfering with facial function." It is based on patient education and the use of extrinsic feedback to achieve re-education or physical learning.

As mentioned above, facial muscles lack intrinsic feedback information (i.e. they do not have internal sensory receptors) and a variety of muscle synergies can be created by small contractions of a single muscle. Thus, exercise rehabilitation should be done "delicately through neuroplasticity" in order to reduce the risk of creating abnormal patterns of movement (i.e. synkinesis).

The physiotherapist must educate patients to ensure that they are aware of their motor dysfunction and can recognise the patterns they want to achieve (i.e. the correct pattern of muscle activation) and those they wish to avoid (i.e. abnormal pattern of muscle activation). This may reduce the patient's risk of facial palsy sequelae, particularly when combined with extrinsic biofeedback, which allows patients to modify muscular activity by:

• Increasing muscle activation in muscles that must move, but do not move
• Decreasing muscle activation in muscles that do not have to move, but do move

Evaluation of Treatment Approaches

Evidence supports the use of assessment tools that can guide the physiotherapist in the process of determining the specific goals of treatment for each patient based on the signs and symptoms or sequelae. The most commonly used assessment tools are:

• Facial grading system (FGS)
• Facial disability index (FDI)
• House–Brackmann Scale
• Photoshop method

Treatment Categorisation

VanSwearingen has classified patients with facial neuromotor disorders into four treatment-based categories:

1. Initiation
2. Facilitation
3. Movement control
4. Relaxation

Initiation (i.e. Acute Phase)

Characteristics

• Moderate-marked asymmetry at rest (e.g. drooped face)
• Marked asymmetry with voluntary movement or other spontaneous expressions and functions
• They do not have abnormal movement (i.e. synkinesis)
• Facial functions, such as eye closure / blinking, eating, drinking, talking, are difficult for this group
• Contraction of the affected side very little or absent

Treatment

• Active-assisted exercises
  • The patient starts the movement with the help of his hand and performs small range movements to prevent the unaffected side from acting (i.e. avoid contraction of the unaffected side, so the unaffected side does not over-power the affected side)
• Massage and stretch for affected side
  • Improves blood flow in soft tissue
• Education
  • Explain the usual process of recovery and educate about the signs that indicate recovery

Facilitation (≥ Six Months of Impairment)

Characteristics

• Medium-moderate asymmetry at rest
• The patient can start a movement, but the asymmetry is noticeable if movement continues
• Little or no synkinesis
• Primary movement problems are:
  • Insufficient eye protection to due difficulty closing / maintaining closure
  • Some problems with eating, drinking, and rinsing the mouth - typically mild
• There is usually less psychosocial distress than is apparent during the initiation phase as symptoms are less severe

Treatment

• Active and resisted exercises to increase facial movement
  • Start with active assisted exercises so that unaffected side does not activate
  • Once this action has improved, the patient can start resisted movements
• Education
  • Patients must understand the importance of performing the exercises accurately (over quantity) and must be able to identify abnormal movement patterns that may develop

Movement Control

Characteristics

• Asymmetry - more obvious on movement than at rest
  • Generated by contraction or retraction of soft tissues rather that by weakness
• Synkinesis
  • Noticeable involuntary movement of a facial region when performing any movement or facial expression
• Abnormal movement patterns during facial functions such as difficulty keeping the eye open while talking, yawning or eating, or biting the inside of the cheek

Treatment

• Thermotherapy
• Massage and stretching for facial retraction
• In the short-term, create movements and facial expressions without synkinesis
  • This can be achieved by making small movements or accepting very few synkinetic movements until correct

• In the long-term, guide the patient to re-learn to isolate muscle contractions and thus decrease the activation of abnormal patterns of movement
  • While patients relearn the appropriate patterns of activation, they will be reclassified in the facilitation group for their rehabilitation process

Relaxation

Characteristics

• Marked asymmetry of facial posture at rest, combined with spontaneous twitching and spasms of the facial muscles
  • These spasms are more frequent and larger during movements, so movement is often restricted by the patient to protect against spasm
• Muscle weakness is not usually a significant issue
• The unaffected side produces 50 percent of voluntary movements, which generates contracture or tension of the soft tissue of the affected side
• Psychosocial problems are common as patients often worry about controlling facial spasms

Treatment

1. Thermotherapy
2. Relaxation exercises, such as Jacobson's relaxation technique 
3. Alternating rhythmic movements
4. Muscle inhibition techniques: sustained stretching or cross friction massage

Examples of Specific Exercises

To activate the upper portion of the levator muscle of the lips and orbicular of the lips (zygomatic muscle group) and the medial portion of the orbicular muscle of the eyes, the patient is instructed to:

• Suck the cheeks between the teeth
• Wrap your lips
• Make a sustained‘‘f’’ sound
• Blow through a straw

Because these muscles accompany other facial expressions and functions, such as smiling, speech sounds and facial expressions such as disgust of being perplexed, following exercises can also be helpful.

1. Blowing while bringing eyebrows together as if thinking
2. Blowing and then transitioning to a '' fffff '' sound - continue to alternate these actions while keeping air moving through the lips
3. Make a sound '' fffff '' sound and then add a smile
4. Blow and then add a smile

As discussed above, when encouraging patients to smile for an exercise, they should also be reminded to remember a happy memory to activate the positive affect marker.

Exercises for Recovering Eye Closure

It is important to ensure that the combined motion of downward movement of the eyeball and closure of the upper eyelid is recovered. When the eye closes, the eyeball will usually come down to rest in a downward position. This occurs as follows:

• The elevator muscle allows the upper eyelid to descend (i.e close)
• The superior rectus muscle contracts immediately after the upper lid relaxes, which moves the eyeball up
• A brief contraction of orbicularis oculi inhibits the superior rectus muscle, to prevent this upward movement
• The eyeball instead comes to rest in a downward position while the eyes are closed

When there is weakness of the orbicularis oculi, there is upward movement of the eyeball, which affects the upper eyelid from descending - this phenomenon is known as Bell's phenomenon and can persist post-reinnervation / recovery of facial movements.

To help address this issue, the patient can be instructed to:

1. Look down and close your eyes - continue to look down
2. Squint eyes - look down and close eyes

Home Exercise Programme

As well as one on one therapy sessions, it can be useful to include a home exercise programme to help the patient reinforce facial movement patterns to achieve motor learning. These exercises should only be included once the patient is able to perform them all accurately (and recognise any inaccuracies). A typical programme would include:

• 3 to 5 exercises
• 5 to 10 repetitions
• 2 times per day