Facial nerve function index: A clinical measurement of facial nerve activity in patients with facial nerve palsies Martyn J. Fields, MB ChB, FDS RCS, and Ninian S. Peckitt, FRCS Ed, FFD RCS, FDS RCS, Chepstow, Wales ST. LAWRENCE An objective index (FNFI). nerve palsies. (ORAL

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HOSPITAI clinical assessment of facial nerve This index is useful in monitoring

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function is described the return of facial

in terms of a facial nerve function nerve function in patients with facial

1990;69:681-2)

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acial nerve weakness in patients is often difficult to assess objectively, and a simple, reproducible clinical measurement of facial nerve function would be useful. This would allow assessment of the degree of weakness and monitoring of any recovery or deterioration of nerve function. At present, electromyographic assessment’ of facial nerve function is time consuming and requires expensive equipment and skilled operators. These facilities are not always available. The method has been developed to record the progress of patients affected by facial nerve palsies, including those resulting from trauma and surgery.

at

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Fig.

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METHOD

With the teeth or dentures in centric occlusion, and the lips at rest, the distance from the outer canthus of the eye to the ipsilateral commissure of the lips is recorded for each side of the face (Fig. 1). D1 is the measurement denoted for the unaffected side of the face, and dl is the measurement denoted for the affected side. In the normai situation D1 = dl. The patient is then asked to smile as broadly as possible and the measurements are repeated: D2 is the functional measurement for the unaffected side, and dZ is the functional measurement for the affected side. These measurements are then used to calculate the

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facial nerve function index (FNFI), which expressed as a percentage of normal function. FNFI

is

dl _-6 D2x 100 = D,

DISCUSSION

FNFI measurements can be repeated at follow-up clinics to monitor recovery of facial nerve function being expressed as a percentage of the function of the normal side. It is a quick and simple method of objective clinical assessment, easily reproducible by different clinicians, allowing monitoring of therapy. The currently accepted criteria for grading facial nerve recovery were proposed by House*; these have been adapted by the Facial Nerve Disorder Committee of 681

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the American Academy of Otolaryngology-Head and Neck Surgery. We believe that the FNFI may be a useful augmentation of assessment of facial nerve function in the clinical situation. REFERENCES I. Brundy J, Hammerschlag PE, Cohen NL, Ransohoff J. Electromyographic rehabilitation of facial function and introduction of a facial paralysis grading scale for hypoglossalfacial nerve anastomosis. Laryngoscope 1988;98:40510.

2. House JW. Facial 1983;93:1056-69.

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Reprint requests lo. Dr. Martyn J. Fields Department of Oral & Maxillofacial St. Lawrence Hospital Chepstow Gwent NP6 5YX Wales

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Laryngoscope