Facial Grading System

Original Editor - Wendy Walker

Lead Editors - Wendy Walker, Jess Bell, Vidya Acharya, Kim Jackson, Rishika Babburu and Alexandra Stead

Introduction

The Facial Grading System [FGS] is also known as the Sunnybrook Facial Grading System as it was devised and established at the Sunnybrook Health Sciences Centre in Toronto. The clinicians who developed the FGS intended to create a measure that provided a quantitative score for reporting purposes, which would be sensitive enough to detect clinically important change over time or with treatment.

Objective

The FGS is a tool used in the clinical evaluation of facial nerve function. It scores range of movement of the facial muscles as a percentage - full range movement is scored as 100 percent. It is easy for the clinician to compare range of movement on the affected side of the face to the unaffected side. No specialist training is required for acceptable reliability.

Intended Population

The FGS is intended for use on people with facial palsy irrespective of the cause of the facial palsy or weakness.

Method of Use

The FGS comprises three areas of evaluation:

1. Evaluation of resting symmetry
2. Degree of voluntary excursion of facial muscles
3. Degree of synkinesis associated with specific voluntary movement

The regions of the face are evaluated separately, with the use of five standard expressions:

• Eyebrow raise
• Eye closure
• Open mouth smile
• Lip pucker
• Snarl / show teeth

All the above items are evaluated on point scales and a cumulative composite score is calculated.

Reliability

Studies have found the FGS to have good intra- and inter-rater reliability.

One study concluded: "The intrarater reliability coefficients for the raters ranged from .838 to .929 ... The FGS is as reliable when applied by novice users as by expert users."

Comparison to Other Facial Nerve Grading Instruments

A comprehensive 2015 systematic review examined a large number of grading instruments of facial nerve function, scoring each system against the following criteria:

• Convenience of clinical use
• Regional scoring
• Static and dynamic measures
• Features secondary to facial palsy (e.g. synkinesis)
• Reproducibility with low inter-observer and intra-observer variability
• Sensitivity to changes over time and / or following intervention

The authors concluded that they "recommend widespread adoption of the Sunnybrook Facial Grading Scale as the current standard in reporting outcomes of facial nerve disorders."

A 2021 prospective reliability study examined the inter-rater and intra-rater reproducibility of the FGS across 31 raters from multiple disciplines: ENT specialists, physiotherapists and speech and language therapists, with varying experience levels. The study demonstrated good-to-excellent inter-rater reliability (ICC 0.847) and excellent intra-rater reliability (ICC 0.915) for the composite (ie. Total) score, confirming the FGS as "a reliable tool for both novice and expert users".

A prospective follow-up study comparing patient-reported facial and psychosocial function (FaCE scale and Facial Disability Index outcome measures) with physician-graded facial function (Sunnybrook and House-Brackmann grading) in the early and follow-up stages in Bell’s palsy patients showed low to fair correlation between FaCE/FDI and Sunnybrook score in early stages. This suggests that quality of life (QOL) designs are less suited for the acute stage. Higher correlations at follow-ups suggest that it is more beneficial to use questionnaires for QOL evaluation in later phases.

Usefulness in Physiotherapy for Facial Palsy

The FGS is extremely useful for measuring improvements made in physiotherapy / facial rehabilitation. Its sensitivity means that even small changes in range of movement will be recognised. Moreover, the synkinesis section enables an increased score even when there is no increase in range of movement, provided that synkinesis is reduced.

These factors mean that the FGS can be used on a regular basis to quantify progress made in therapy, providing useful feedback to the patient of the gains made, and helping with motivation.

It is for these reasons that many physiotherapists working with facial palsy use the FGS in preference to the House-Brackmann Scale.

Clinicians should remember that the goal of achieving 100% on the FGS is not only unrealistic in people with facial palsy, but that in fact many people who have never had facial palsy or damage to the facial nerve do not have completely symmetrical faces. One 2024 study looked at this issue, using the FGS to evaluate the facial symmetry and found that in the non-palsy population normal FGS scores typically range from 91-100% (IQR), with individual variation extending as low as 65%.