Objectives: To analyze the validity and reliability of assigning House-Brackmann facial nerve grade based on a patient-administered questionnaire. Specifically, the use of a questionnaire was studied for evaluation of the long-term facial function after microsurgical resection of vestibular schwannoma (VS).
Study design: Three neurotologists with more than 25 years of experience and 3 neurotology clinical fellows rated facial nerve grade in a blinded fashion based on the questionnaire. The standard to which the questionnaires were compared was the facial nerve grade assigned to the patient during an office visit near the same time as the completed patient questionnaire.
Methods: Thirty-four patients had an office evaluation of facial function at least 1 year after microsurgical resection of a VS. Thirty patients had a sporadic VS, whereas 4 patients had neurofibromatosis 2. The average tumor size was 2.2 cm. A postoperative questionnaire regarding facial function was completed within 2 months of the office evaluation. Statistical analyses were performed to compare the office evaluation rating with the questionnaire rating (validity) and to analyze interobserver reliability.
Results: The association between the facial nerve grade assigned by the office evaluation and the questionnaire was highly significant (p<0.01), with a mean correlation (Spearman [rho]) equal to 0.94. The interobserver reliability was high, with coefficients ranging from 0.93 to 0.99 (p<0.01; mean=0.97). Because a large proportion of patients had normal (House-Brackmann Grade I) facial function, an additional analysis was performed with these patients excluded. The high levels of interobserver reliability persisted (average=0.96).
Conclusion: When compared with office evaluation, a patient-administered questionnaire provides a valid and reliable measure of long-term facial function after VS surgery.