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

Facial palsy day 3

When individuals experience incomplete recovery after a facial disorder, such as facial palsy, they may experience various sequelae that interfere with their facial function. Common sequelae are:

• Asymmetry
• Muscle contracture
• Facial muscle weakness
• Synkinesis

These sequelae can have an impact on a patient's psychosocial well-being and quality of life. It is important, therefore, to implement an effective treatment to reduce the impact of ongoing dysfunction. Neuromuscular facial re-education (NMR) is one treatment that has been shown to be effective in encouraging the recovery of symmetrical movement in the face and eliminating or reducing functional deficits.

Basic Concepts

Facial movements, expressions, and functions are the result of a combination of different muscle contractions. Unlike skeletal muscles in the rest of the body, facial muscles 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 the internal sensory receptors that usually provide intrinsic proprioceptive feedback.

Facial expressions result from either:

• Brain activity involving the motor cortex (i.e. cortical behaviour)
  • These expressions are usually voluntary
• The activity of a network of subcortical nuclei and parts of the brainstem (i.e. subcortical behaviour)
  • These expressions are usually reactionary - i.e. in response to something that happens (e.g. shock, laughter, sneezing)

Useful Points for the Rehabilitation of Facial Palsy

Because the facial muscles provide little intrinsic information about posture and movement, it is difficult for patients to perform voluntary facial movements 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.

Activation of the facial muscles alone is not, however, sufficient to recover facial expressions. It has been proposed that because emotions generate specific facial muscle contractions to achieve reactionary expressions (e.g. a smile via subcortical activity), 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, it may be beneficial to retrain the muscles that are responsible for certain expressions, rather than focusing on the restoration of facial movement. From a practical perspective, it is useful to consider incorporating facial exercises that focus on emotions and expressions into a rehabilitation programme. For example, ask the patient to remember a time when she / he was very happy when practising a smile in order to activate the positive effect marker associated 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 and those they wish to avoid. 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

Van Swearingen 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 to marked asymmetry at rest (e.g. drooped face)
• Marked asymmetry with voluntary movement or other spontaneous expressions and functions
• No synkinesis
• Difficulty with facial functions, such as eye closure / blinking, eating, drinking and talking
• Very little or absent contraction of the affected side

Treatment

• Active-assisted exercises
  • Patients are instructed to start the movement with the help of their hand and to perform small range movements to prevent the unaffected side from contracting
• Massage and stretch for the affected side to improve blood flow in the soft tissue
• Education
  • The therapist should explain the usual process of recovery and educate patients about signs that indicate recovery

Facilitation (≥ Six Months of Impairment)

Characteristics

• Medium to moderate asymmetry at rest
• The patient can start a movement, but asymmetry will be noticeable if the movement continues
• Little or no synkinesis
• Primary movement problems are:
  • Insufficient eye protection due to difficulty closing / maintaining eye closure
  • Some issues (typically minor) with eating, drinking, and rinsing the mouth
• There are usually fewer psychosocial issues in this phase than the initiation phase as symptoms are less severe

Treatment

• Active and resisted exercises to increase facial movement
  • Start with active assisted exercises, to ensure that the unaffected side does not contract
  • Once this action has improved, the patient can start resisted movements
• Education
  • Patients must understand the importance of performing the exercises accurately rather than focusing on the number of exercises performed
  • They must also 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 than 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

• 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

• 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 re-learn 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 patients often restrict movement to protect against spasm
• Muscle weakness is not usually a significant issue
• The unaffected side produces 50 percent of voluntary movement and this generates contracture or tension of the soft tissue on the affected side
• Psychosocial problems are common as patients often worry about controlling facial spasms

Treatment

1. Relaxation exercises, such as Jacobson's relaxation technique 
2. Alternating rhythmic movements
3. Muscle inhibition techniques, including sustained stretching or Deep Friction Massage

Examples of Specific Exercises

Face Centering Exercises

To activate the upper portion of the levator muscle of the lips, orbicularis oris (i.e. the zygomatic muscle group) and the medial portion of the orbicular oculi, the patient is instructed to:

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

Because these muscles accompany facial functions, such as smiling and speech sounds, as well as expressions like disgust or perplexity, the following exercises can be helpful.

• Blowing while bringing eyebrows together as if thinking
• Blowing and then transitioning to a "fffff '' sound
  • Continue to alternate these actions while keeping air moving through the lips
• Make a sound "fffff '' sound and then add a smile
• Blow and then add a smile

As discussed above, when encouraging patients to smile for an exercise, they should also be reminded to think of a happy memory to activate the positive effect 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 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. This has an impact on the ability of the upper eyelid to descend. 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:

• Look down and close eyes - continue to look down
• 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 to reinforce facial movement patterns to achieve motor learning. These exercises should only be practised at home 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
• Be practised 2 times per day