Background

For decades, physical, occupational, and speech therapists have treated facial paralysis using gross facial exercises and electrical stimulation. Although outdated (and ineffective), these techniques have become “standard” and continue to be the norm for those therapists who rarely treat patients with facial paralysis and have not received current training. Each patient has a unique functional profile and psychosocial response to the condition, both of which require personal, individualized attention. A comprehensive “handout sheet of exercises” approach will never be possible. One reason facial NMR is not more common is simply the complexity of the problem. Many therapists are unaware the specialty exists because facial palsy is so unusual compared with other needs for therapy. Yet specific NMR for facial palsy began to appear in the literature more than 30 years ago.1–3 Using surface electromyography (sEMG) biofeedback, patients improved their function by modifying the manner in which they contracted their facial muscles.

Current programs are based largely on the works of Balliet et al,4 Diels,5 Beurskens,6 Ross et al,7 and Coulson and Croxson,8 the most important characteristics of treatment being detailed patient education, individualized program development and training, and active patient participation. Specific retraining procedures can include sEMG biofeedback; mirror, sensory, and proprioceptive feedback; and a wide variety of motor learning techniques. Upon reviewing the literature, Beurskens found little homogeneity with respect to patient population, intervention, and treatment plan.9 However, the studies of Ross et al,7 Segal et al,10 and Beurskens and Heymans11 showed significant positive outcomes of NMR on facial symmetry; functional abilities of eating, drinking, and speaking; and quality of life.

Acute versus Postacute Rehabilitation: Spontaneous Recovery versus New Learning

Although some patients may be evaluated acutely (while flaccid), the majority of specific NMR is started during and after reinnervation. If NMR is initiated acutely, it is impossible to differentiate spontaneous recovery from new motor learning. The recovery seen in postacute patients (having paresis or synkinesis) can clearly be attributed to the acquisition of new motor patterns through the retraining process and can occur even decades later.12

Educational Program Model: Training versus Therapy

Prior to injury, facial movement is mainly unconscious. In the first stage of motor learning, the patient must bring this otherwise spontaneous function under voluntary control. Facial NMR is not a therapy administered passively to the patient. This active process requires a skilled therapist who thoroughly understands and can teach facial anatomy, actions, and treatment techniques. The resulting model is a cost-effective program that reduces billed clinic hours while increasing overall treatment hours via home practice.

Patients may travel a great distance for training with a facial NMR specialist, with months between visits; therefore, comprehension is essential to ensure accurate follow-through and practice at home. As each program is so uniquely individualized, patients take detailed notes with their specific instructions in their own words. NMR is comparable in many ways to any training program (e.g., sports, music, etc.) in which the individual must be highly motivated and committed to daily practice of specific tasks designed to improve their skills. New motor patterns are learned through consistent practice and become more automatic over time.4 Patients return to the clinic periodically to refine movements, document progress, and establish new treatment goals.

Facial Muscles Differ from Skeletal Muscles

Facial muscles differ from skeletal muscles in several important ways. For treatment to be effective, techniques must incorporate the following unique characteristics into their design:

1. 
   

   Facial muscles lack muscle spindles.13 The spindle produces a muscle contraction in response to therapeutic facilitory techniques such as quick stretch, vibration, and tapping, commonly used for treating other disabilities. Because facial muscles have no spindles, these methods are useless for the treatment of facial paralysis.

   
   
2. 
   

   Facial muscles have small motor units14 enabling great refinement, complexity, and subtlety of movement. Practicing gross facial movements confounds this normal precision by producing unnaturally large motions that cause overflow from neighboring muscles.

   
   
3. 
   

   Facial muscles degenerate slowly15 and may remain viable for 3 or more years, so procedures used to maintain muscle viability (e.g., electrical stimulation) are unnecessary.

   
   
4. 
   

   Facial muscles receive emotional as well as volitional neural inputs.16 Emotional cueing during facial NMR is often helpful to reestablish more natural patterns after paralysis.

Muscles of Facial Expression

It is not within the scope of this chapter to detail the muscles of facial expression (see Fig. 1.7 in Chapter 1); however, it is imperative that the therapist and patient be thoroughly educated and familiar with facial muscle structure and function. Knowledge of the anatomic origins and insertions of the muscles to bone or tissue is fundamental to understanding facial kinematics. Even the actions of facial nerve innervated muscles not frequently used in expression (e.g., platysma and buccinator) are important as they often participate in abnormal synkinetic patterns.

The considerable individual variation in facial muscle function, expression, and symmetry can be even more pronounced after facial nerve injury. Patients receive a detailed diagram illustrating the major facial muscle groups, nerve branches, and angles of muscular pull, which is referred to extensively during the education and training process ( Fig. 25.1 ). The most effective way to learn facial muscle actions is to create the movement by (a) mimicking the therapist, (b) producing it on the unaffected side, and (c) using mirror feedback. Teaching is time-consuming but essential for laying the foundation for NMR. Instructing the patient in even very simple muscle actions can radically change how that patient perceives and executes a movement. Learning, for example, that the smile is created by flexing the cheek (zygomatic) rather than mouth (orbicularis oris or buccinator) will immediately change the manner in which the movement is attempted.

Etiologies Treated

The etiology of facial nerve palsies varies extensively. The most common etiologies seen for facial NMR are viral infection (Bell palsy, herpes zoster oticus), postsurgical (acoustic neuroma, etc.), traumatic injury, Lyme disease, congenital, and others (e.g., otitis media, parotid gland carcinoma, Guillain-Barré syndrome, polyneuritis, etc.). Timing for NMR referral depends more on degree of nerve injury and recovery than etiology.

Patient Selection

The following criteria are considered when determining which patients are good candidates for facial NMR:

1. 
   

   Neural supply: The facial nerve must be intact or surgically repaired to establish a neural supply to the facial muscles. If there is no innervation, NMR is not indicated.

   
   
2. 
   

   Motivation: Facial NMR is hard work, requiring commitment to training. Home practice sessions require focused concentration for 30 to 60 minutes per day. The patient must be compliant, disciplined, and persistent to achieve optimal benefit.

   
   
3. 
   

   Cognition: Adequate cognitive function is necessary for both the educational process and accurate home program practice. Cognitive or attention deficits may limit successful participation in NMR.

Patient Intake and Evaluation

A thorough history and facial evaluation are completed during the initial consultation. Demographic and medical information including diagnosis, previous therapies, affected side, and occurrence of first visible movement is recorded. Sequelae of facial paralysis are documented according to the International Classification of Functioning, Disability, and Health:

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  Impairments: Asymmetry at rest, asymmetry during voluntary facial movements, synkineses, stiffness, pain, tear secretion, nasal obstruction, sensory changes

  
  
• 
  

  Disabilities in eating, drinking, rinsing, speaking, nonverbal communication, and eye-tearing

  
  
• 
  

  Psychosocial health problems such as isolation, decreased quality of life, sense of shame, or “loss of face”

Reliable and valid measurement instruments are used, where available, for objective assessment to establish baseline function and to evaluate outcomes following treatment. The data can also be used for research purposes. The House-Brackmann Facial Grading System has been used extensively as an overall measure of facial impairment.17 However, for the purposes of facial NMR, a more sensitive grading scale was developed by Ross et al.18 The Sunnybrook Facial Grading System is simple, quick to administer, and sensitive enough to quantify small functional changes that occur during the course of treatment, especially in the scoring of synkinesis. The Sunnybrook Facial Grading System measures the face at rest and during five facial movements, and scores associated synkinesis during those five movements. Pain is assessed using the Visual Analogue Scale, and tearing, nasal obstruction, and sensation are assessed by subjective report.

Physical and social well-being are measured with The Facial Disability lndex.19 Video and photo evaluations are essential in the initial evaluation.5 Recordings should be standardized, controlling variables such as distance to the camera, light, and posture of the patient. Evaluation results are discussed with the patient, including prognosis and course of treatment. The treatment plan is then developed.