Janssen developed a scale for evaluating facial paralysis following surgery based on the relative importance of different facial regions for individual expressive functions. This can be used to monitor the patient during recovery. The study was reported in a thesis from the University of Amsterdam.


Method: The observer compares the affected and unaffected sides of the face and estimates the percent of normal function in the affected regions.


Regions of observation:

(1) face at rest

(2) forehead

(3) eye

(4) mouth


percent total function =

= (0.30 * (percent of normal function for face at rest)) + (0.10 * (percent of normal function for forehead)) + (0.30 * (percent of normal function for eye)) + (0.30 * (percent of normal function for mouth))



• minimum value: 0% (total paralysis)

• maximum value: 100%

• The higher the percent, the more normal the function observed.


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