Diagnostic utility of Freyss motor examination, House-Brackmann grading, topognostic tests, and electrophysiological assessments for unilateral peripheral facial nerve disorder

Unilateral peripheral facial nerve disorder is most often idiopathic, and the determination of the cause may be necessary to guide appropriate treatment. There is no standard diagnostic test for determining the cause or location of the lesion; therefore, clinicians may rely on a variety of diagnostic methods such as the Freyss system of motor examination, House-Brackmann grading, topognostic tests (Schirmer, stapedius reflex, gustatometry), and electrophysiological investigations (nerve conductivity, blink reflex, needle EMG). However, few studies have directly compared the suitability of these different diagnostic methods according to disease characteristics (severity, onset, etc.). This descriptive cross-sectional study compared results using these diagnostic modalities among 44 consecutive patients. There was a significant concordance (Kappa R = 0.5, p < 0.05) between the Freyss motor system examination results and House-Brackmann scoring for 32 patients with chronic onset and moderate-to-severe damage. Alternatively, there was poor agreement (Kappa R = 0.011, p = 0.935) between topognostic and electrophysiological investigation for determining lesion location. In 13 patients with chronic onset and moderate-to-severe damage, lesion location could not be determined based on electrophysiology, while topognostic examination was able to determine the location for both acute- and chronic onset cases. For lesions that cannot be assessed by electrophysiology, Freyss and House-Brackmann motor tests can be used for diagnoses and prognosis.