Speech-language-hearing instruments to assess peripheral facial palsy: an integrative literature review

Purpose: to describe and analyze the clinical instruments that assess peripheral facial palsy through an integrative literature review. Methods: the precepts for this type of review were followed: research question, iden -tification, selection of studies, and critical analysis. The Virtual Health Library (VHL), Scientific Electronic Library Online (SciELO), Google Scholar, and PubMed databases were accessed to search for fully available articles published in national journals between January 2008 and July 2018. The terms used in the search were “Speech, Language and Hearing Sciences”, “Evaluation”, and “Facial Paralysis”, in both English and Portuguese. The data obtained were organized per author, title, objective, instru ments used, description of the instruments, and application procedures used in the articles. Results: out of the total 992 articles found, only 18 met the inclusion criteria of the research. In most of them, there was only the citation of the assessment instruments or considerations about them, without fully describing the application procedures. Conclusion: the study identified publications that indicate the use of clinical and speech-language-hearing assessment instruments. However, further detailing is nec essary regarding the assessment procedures to help develop and refine the speech-language-hearing methodologies and techniques.


INTRODUCTION
The VII cranial nerve, named the facial nerve, has peculiarities that distinguish it from other cranial nerves. One of its unique characteristics is that this nerve runs through a long path inside the bone, which helps understand the neural lesion, degeneration, and regeneration process. Thus, the facial nerve is subject to inflammatory processes caused by traumas, viral or bacterial infections, and so forth 1 .
The said lesion may lead to peripheral facial palsy (PFP), caused by reduced or interrupted axonal transport, which in turn paralyzes either totally or partially the mimic and expression of the affected hemiface. Also, changes may occur in taste, salivation, lacrimation, hyperacusis, and external auditory canal hypesthesia² -⁴.
The peripheral facial palsy prognosis is usually satisfactory, as 80 to 90% of the patients soon recover. As for the others, if they do not have satisfactory results within 6 months, they may have moderate to severe sequelae. When PFP has an unsatisfactory prognosis, risk factors are considered: having severe facial palsy, being older than 60 years, having Ramsay Hunt syndrome, and secondary PFP⁵.
The adequate PFP treatment requires a precise and in-depth clinical evaluation to investigate the impairment of the facial nerve, the etiology, degree of severity, detailed diagnosis, and clinical prognosis⁵. The examinations needed for the clinical investigation of the condition encompass blood tests, audiometric tests, imaging tests (such as computed tomography scan and/or magnetic resonance imaging), electrophysiological tests (such as electroneuromyography), and so on⁶.
The House-Brackmann scale (HB)⁷, described in 1985, is widely used to identify the degree of impairment and clinical evolution of PFP in patients. It is divided into six degrees, namely: normal (I), slight dysfunction (II), moderate dysfunction (III), moderately severe dysfunction (IV), severe dysfunction (V), and total paralysis (VI). This is evaluated by the physician, though other health professionals, including the speech-language-hearing (SLH) therapist, may also use the scale.
The initial aspects to be considered in SLH evaluation are the previous complaint history, time of PFP onset, gradual or sudden loss of the face movements face, spontaneous improvement, and treatment history 1,5,6 .
The SLH clinical evaluation is essential to diagnose orofacial myofunctional aspects, helping define the changes that take place in PFP, such as mobility, muscle tone, proprioception, subtle speech, chewing, and swallowing changes, and possible sequelae of PFP 1 .
There are various evaluation approaches, and the instruments chosen to be used in the SLH clinic determine the success of the therapy. A detailed SLH evaluation considering the function of each facial mimic musculature provides a more detailed view that enables the severity of the changes to be established and compared with the evolution throughout the treatment 1 .
Knowing the assessment instruments available to the SLH therapist and using them properly can help define the planning and the clinical prognosis of PFP. For an in-depth evaluation, the instruments must be standardized, precise, and effective in their approach and extensive detailing, contributing to the therapeutic rationale.
Achieving satisfactory and effective results in PFP treatment means the person's recovering their facial expression and mimic functions. Moreover, it makes the person recover their identity with facial expressions, a fundamental element in human communication [8][9][10][11] .
Thus, this research aimed to describe and analyze the clinical assessment instruments of PFP through an integrative literature review.

METHODS
This study was designed as an integrative literature review because it summarizes the state of the knowledge of a given topic, besides revealing gaps in it that need to be filled with new studies¹².
This study was methodologically designed based on the research question: "What assessment instruments can be used by SLH therapists when attending people presented with PFP?".
The articles were surveyed in national -Virtual Health Library (VHL), Google Scholar, and Scientific Electronic Library Online (SciELO) -and international databases -PubMed. These were chosen for being the most researched databases, containing the main scientific health science journals, and being open access to the public or via universities in Brazil.
The terms used to search the publications in these databases were the following: "facial paralysis" combined with "evaluation" and "Speech, Language and Hearing Sciences", in both English and Portuguese. The search keys used were: "facial paralysis" AND "evaluation", "facial paralysis" AND "Speech, Language and Hearing Sciences", "facial paralysis" AND "evaluation" AND "Speech, Language and Hearing Sciences".
The following inclusion criteria were established to select the studies for this review: Fully available scientific articles approaching SLH evaluation of people with PFP, published between January 2008 and July 2018. The exclusion criteria encompassed repeated publications and studies that did not describe the PFP assessment instruments.
The studies were selected through stages, namely: 1) Researching the publications in each predefined database; 2) Systematizing all the studies identified in Microsoft Office Excel 2016 for the researchers' control; 3) Preselecting the studies according to the preestablished inclusion criteria, excluding the repeated articles; 4) Selecting the articles that answered the research question (i.e., that approached the SLH assessment instruments for PFP) by reading their title and abstract, when available; 5) Checking, by a second assessor, the sample of publications selected in each database; 6) Fully reading the selected studies and extracting their data (authors, title, objectives, and PFP assessment instruments); 7) Defining the articles to be included in the review based on the description of the assessment instruments used.
After the survey, the results were summarized into two tables with the authors, title, objective, and instrument used for PFP assessment. The description was subdivided into SLH assessment instruments and self-reported and quality-of-life assessment instruments. Then, the instruments found were described.
The selected articles were analyzed based on the data of the abovementioned summary. The analysis made it possible to know the evaluation procedures and the selection of assessment instruments, systematizing them to better understand the scientific productions on the investigated topic.

LITERATURE REVIEW
A total of 992 publications were identified in the database search, of which 18 articles were included in the review. The organizational chart with the detailed study identification, selection, and inclusion process is shown in Figure 1. The findings were organized as charts in the chronological order of publication in the journals and subdivided into SLH assessment instruments (Chart 1) and Chart 1. Result of the literature review on speech-language-hearing assessment instruments

Authors
Title Objective Assessment instruments

FREITAS et al. (2008) 13
Degree of perception and discomfort regarding the facial condition in subjects with peripheral facial paralysis in sequelae stage To correlate the patient's selfassessment of the facial condition, its degree of discomfort regarding the sequelae, and the impairment in daily attitudes, with data found in the speech-language-hearing assessment. Möbius Sequence: anamnesis and evaluation protocol: a case report To disseminate the protocol used at the institution where the research was conducted with patients with Möbius syndrome, and report a case attended at the service for the sake of exemplification. Surface electromyography in peripheral facial paralysis patients To study the electromyographic activity of the frontalis, orbicularis oculi, zygomaticus major, and orbicularis oris muscles in normal people and patients with facial palsy, as well as the symmetry rate between the two sides of the face. Angular measurement for determining muscle tonus in facial paralysis To propose the lip commissure angle and assess its reliability as an objective resource to assess facial muscle tone changes in the evolution of facial palsy. Interdisciplinary approach for comminuted condyle fracture of by firearms -myofunctional focus To present the procedures and results obtained in the nonsurgical treatment associated with orofacial myofunctional therapy, in a clinical case of comminuted condyle fracture causing traumatic facial palsy due to firearm projectile.
-Assessment protocol 20 -Photographic documentation Comparison between myofunctional therapy and myofunctional therapy associated with acupuncture on treatment for peripheral facial paralysis To compare the effectiveness of speech therapy and acupuncture associated with speech therapy in patients with PFP.
-Digital caliper -Assessment protocol¹ SASSI et al. To correlate electromyographical data of the muscles that lift the angle of the mouth with the facial inability rate in patients with long-lasting facial palsy.

(2011b) 24
Correlation between electromyographic data and facial disability index in patients with long-term facial paralysis: implications for treatment outcomes To correlate electromyographical data of the muscles that lift the angle of the mouth with the facial inability rate in patients with long-lasting facial palsy.
-Assessment protocol 23 -Surface electromyography Effectiveness of speech therapy in patients with facial paralysis after parotidectomy To verify the effectiveness of speech therapy in patients with facial palsy due to manipulation of the VII cranial nerve during surgery to treat parotid gland neoplasm, as well as identify and promote speech-language-hearing interventions of sucking, chewing, and swallowing changes. Early speech therapy intervention in a patient with facial paralysis after otomastoiditis To rehabilitate a patient presented with facial palsy after otomastoiditis with early speech-language-hearing intervention, and describe the application of a differentiated therapy intervention approach. Psychological contents and social effects associated to peripheral facial paralysis: a speech-language approach To investigate the psychological contents and the effects associated with PFP in adult subjects, with comparative analysis in three groups of people with PFP: in the flaccid, recovery, and sequela phases.

SANTOS & GUEDES (2011) 35
Study on the quality of life in subjects with acquired chronic peripheral facial palsy To analyze the quality of life in people with acquired chronic PFP.
-House-Brackmann Scale⁷ -degree of perceived discomfort due to the facial condition in people with peripheral facial palsy in the phase of sequelae 36

Description of the Instruments Found in the Research
Facial Grading System 14 : The Facial Grading System aims to evaluate the face at rest and making mimic movements: raising the forehead, smiling, pouting, lifting the nose, and closing the eyes. It also quantifies the contractures and synkinesis in cases of sequelae. An overall assessment grade is obtained, which corresponds to the movement grade minus the at-rest and synkinesis grade. This instrument was used in other studies as well 10,13 .
House-Brackmann Scale 7 : The HB scale evaluates the face at rest and in movement, such as raising the eyebrows, closing the eyes, smiling, and pouting. The classification comprises six degrees, namely: I -Normal; II -Slight dysfunction; III -Moderate dysfunction; IV -Moderately severe dysfunction; V -Severe dysfunction; VI -Total paralysis.
In one of the studies 16 , the HB scale was used to measure the degree of PFP in video recordings, whereas the other article did not give details about this measure.
Another study suggested using the anthropometric measurement of the face to assess and compare PFP. The instrument was meant to assess the face at restsymmetry and tone -and in movement -forehead, eyes, and mouth 35 .
A third study 29 commented that in this scale the assessment is conducted separately, considering the three different sections: forehead, eyes, and mouth. Also, the HB scale allows the assessor to analyze the face both at rest and in movement.
Other articles were found 10,18,19,22,26,34 in which the HB scale was used by a neurologist or SLH therapist.
Chevalier Scale 27 : The Chevalier Scale was used by assessors who asked the patient to respond to verbal and visual commands for movement assessment, considering each facial mimic muscle individually and classifying them as normal, partially changed, or totally changed 26 .
This process took place in other studies 29,34 with the same scale. However, in the assessment of facial musculature mobility, the patients were asked to make each movement five times to establish more precisely one of the five degrees (0 -not visible contraction either with the naked eye or overhead light, to 4 -the movement is broad, synchronous, and symmetrical with the healthy side).
Photographic Documentation: Used to assess facial tone at absolute rest to record the lip commissure angle assessment (LCA) 16 .
In another study 34 , the functional condition assessment was photographed to record and confirm it. This resource can be used to assess the face at rest 26 .
The photographic documentation can be used to record the face of the patient while making expressions such as rest, faint smile, open smile, eyes closed, raised forehead, pout, scared face, and ugly-smell face, to identify changes in facial mobility in upper, lower, or midface 24,32 .
Video Documentation: Two articles used this instrument, though neither of them had bibliographical references of the procedure. The video documentation was used to assess facial movements and grade the PFP on the HB scale 16 .
To this end, the patients were asked to do the following tasks twice: say their full name and count from 1 to 10, raise their eyebrows and relax (look surprised), narrow the eyebrows (look angry), blink gently, close the eyelids gently (zoom in), close the eyelids tightly, contract the nose musculature (ugly-smell face), pout and relax, blow the cheeks, smile with the mouth closed and relax, lower the corners of the mouth and relax, and lastly smile with mouth open and relax 15 .
Surface Electromyography (EMG): The EMG was used to pick up the muscle activity with surface electrodes attached to the face 18 . This article 18 did not furnish any bibliographical references of the procedure. The electrodes were placed on both sides of the face, on the frontalis, orbicularis oculi, and orbicularis oris muscles (simultaneously), and the zygomaticus major and orbicularis oculi muscles (simultaneously), whereas the ground electrode was placed under the sternocleidomastoid muscle.
The patients performed the following seven tasks with maximum effort for 8 seconds: raising the forehead, closing the eyes tightly, the activity of the lips while closing the eyes tightly, protruding the lips, the activity of the eyes while protruding the lips, retracting the lips, and activity of the eyes while retracting the lips.
Likewise, another article 33 did not have any bibliographical reference of the use of EMG. The authors did not explain the positioning of the electrodes, although they pointed out that each participant was instructed to remain as still and relaxed as possible for 1 minute. Three independent collections were made at rest, each one lasting 30 seconds. After the rest, each participant was asked to smile voluntarily for 5 seconds and then keep the musculature relaxed for another 5 seconds; this procedure was repeated three times.
One study 25 performed surface EMG assessment based on the methodology of a previous study 30 , assessing the muscle groups involved in smiling (risorius and zygomaticus). The electrical activity of the risorius and zygomaticus muscles was assessed in both hemifaces. Each muscle region was assessed separately while at rest and smiling voluntarily as open as possible.

Digital Caliper:
The research that used this instrument did not present any bibliographical reference they followed. Hence, the description made here is of measuring made in the research.
The measurements were made in facial mimic movement, always going from a fixed point to a movable point: the caliper was first placed at the tragus (fixed point) opening to the lip commissure. Then, the fixed point was the outer corner of the eye, opening to the lip commissure. Lastly, it was placed on the inner corner of the eye opening to the ala nasi.
Another study 32 , on the other hand, presented a reference 17 also measuring from the lip commissure to the tragus at rest, in a faint smile and open smile. 20 : Intended for anamnesis followed by the assessment of the child's stomatognathic system.

Structural and functional SLH evaluation of phono-articulatory organs in children with congenital facial palsy
The investigation encompassed mobility, motor functions, tone, and posture of the phono-articulatory organs (lip, tongue, cheeks, palate, mandible, maxilla, teeth), as well as the activities of the neurovegetative functions (sucking, swallowing, chewing, and breathing). Also, the muscles responsible for facial expression were assessed individually to obtain data on those patients' actual manifestations.

Lip Commissure Angle Assessment (LCA):
In the studies found 16,19 the LCA was measured with a caliper, according to the bibliography 21 . According to the articles, the LCA is determined following the line that connects anthropometric points: from the glabella (the most prominent part between the eyebrows or between the epicanthal folds) to the gnathion (the junction of the two hemimandibles, forming a shallow fossa).
Crosswise to this line, another one was traced passing from the right cheilion to the left cheilion (the junction that forms the lip commissure). The glabella and gnathion are fixed points, while the cheilion on the paralyzed side is a movable point.
The crossing of these lines forms the LCA, which is measured with a protractor.

Assessment procedures for psychological contents and social effects associated with PFP 34 :
The principles of the assessment instrument used in the research aimed to investigate the psychological contents and the social effects associated with PFP in adult subjects to achieve greater effectiveness in the SLH clinical method. The face was assessed to compare the degree of severity, stage of the PFP, and psychological and social contents based on the Chevalier Scale 27 .
Questionnaire on the person's opinion about their face regarding the muscles at rest and in movement 13 : In one of the studies 35 , this closedended questionnaire was administered to the subjects concerning the presence of complaint, and degree of discomfort due to synkinesis and contractures, as well as loss in social and professional activities. The questions were asked during the assessment and were divided into the following four items for the patient's self-assessment:

1.
Assessment of the face at rest (scoring from 0horrible, to 4 -great); 2. Assessment of the face when moving the forehead, eyes, nose, and lips (scoring from 0 -horrible, to 4 -great); 3. Presence of complaint and degree of discomfort due to synkinesis and contractures (0 -none, to 4 -much); 4. Loss in social and professional activities and its degree (0 -none, to 4 -much).
The questions were analyzed and compared with the degree of facial palsy, according to the HB scale.

Description of the Protocols Used in Research
Orofacial Myofunctional Assessment Protocol 23 : Used to observe aspects of oral-motor functions, such as response to pain, limited head movement, motor and sensitivity deficit, bite, maximum mouth amplitude, mandible lateralization, along with other functional aspects. In the article found 33 , this protocol was used for assessment before and after SLH myofunctional therapy.

PFP Anamnesis and Assessment Protocol 1 :
The research that included this protocol 36 counts on the instrument 17 to measure facial palsy with a digital caliper. The rest of the study was developed following the said protocol with some adaptations conducted by the author.

Facial Palsy Clinical Assessment Protocol 37 :
In these studies 22,25,33 the instrument 37 verified the aesthetic/functional symmetry of the face. The muscle groups in each hemiface were assessed in different voluntary facial expressions, scoring zero (0) if there was no movement; one (1) if there was a partial or moderate movement; and two (2) if there was a complete or sharp movement.
The frontal region was assessed raising the eyebrows, moving the eyelids to close the eyes, lifting the upper lip while wrinkling the nose, slanting the upper lip to smile, moving the upper lip sideways in a cynical smile, closing the lips in protrusion, and contracting the lower lip to show the lower teeth. 24 : This is a set of instruments 1,17,27 developed to measure the facial movement with a caliper. Also, the stomatognathic functions were assessed, namely: sucking, chewing, and swallowing, with the following consistencies: liquid (water), creamy (yogurt), and solid (sandwich cookie). The patients were not given any instructions for the functional observation, except being asked to consume the food in their usual manner.

Facial palsy assessment and measuring protocol with a digital caliper and evaluation of the stomatognathic functions
Oral-motor function assessment protocol 32 : This protocol is an adaptation of previous studies 37, 38 to enable more detailed observations of the phono-articulatory organs and the functions of the stomatognathic system 32 .
Most of the articles approached here do not allow the assessment instruments to be visualized; many of them only cite the instrument and do not describe how it was used. Among the ones that do, the most present instrument is the photographic documentation, used in five articles, and the HB Scale 7 , described in four articles. In other ones, the assessment instruments were only cited as inclusion criteria of the research according to the degree of paralysis.
Despite being the oldest assessment instrument cited, the HB Scale is still the most renowned and used to assess the absence or presence of facial movements and asymmetry and to verify eye gap at rest.
However, in SLH therapy it is also necessary to assess the detailed facial mimic movements, as well as their functions. The survey found few instruments for such assessment, including the Facial Grading System 14 , Chevalier Scale 27 , and the structural and functional SLH evaluation of phono-articulatory organs in children with congenital facial palsy 20 .
The instruments found were mostly mentioned and described, although they were not fully presented -i.e., they are used at the institutions where the studies were carried out. Of the abovementioned ones, the validation of the Facial Grading System 14 , Chevalier Scale 27 , and HB Scale was cited 7 .
Some of the studies analyzed used assessment instruments to obtain numerical and comparative data. That was the case of the caliper 17,32 , EMG 18,25,30,33 , photographic record, and video record 16,34 , whose importance is pointed out both to assess and follow up the evolution of the case.
As years go by, the instruments become even more specific, which means they assess precise aspects of PFP. The literature review showed an increased number of studies in 2011, although it decreased in the following years.
Another problem found in the research was the difference between instrument and protocol. The instrument is characterized as a tool or material the professional uses to plan the protocol -hence, the protocols are a set of instruments 38 . The protocols found in the researched articles were the Myofunctional Assessment Protocol 23 , PFP Anamnesis and Assessment Protocol 1 , and Facial Palsy Clinical Assessment Protocol 37 . Each of these was cited in only one article.
Only two articles were found on the quality of life, referring to the subject's self-assessment of their problem -Assessment procedures for psychological contents and social effects associated to PFP 34 and Questionnaire on the person's opinion about their face regarding the muscles at rest and in movement 13 . Both conclude that regardless of the degree of PFP, the social consequences have an impact on the subject's life and can interfere with clinical recovery.
The importance of instruments that show the patient's view of their problem must be highlighted, as they point out their anguish, anxiety, and frustration regarding the possible changes taking place in their life, due to PFP 10,11 .