The usefulness of clinical findings in localising lesions in Bell's palsy: comparison with MRI.

BACKGROUND: Although electrophysiological tests and brain MRI provide information about the site of the lesion in Bell's palsy, clinicians usually depend on clinical data. However, the accuracy of clinical findings in identifying lesions has never been evaluated.

METHOD: A total of 57 patients with idiopathic peripheral facial palsy were included in this study. We determined the sites of the lesions based on associated symptoms and by brain MRI. We then compared the two to assess the value of clinical findings in determining lesion sites.

RESULTS: Of the 57 patients, 27 were men. The mean age of all patients was 50.6+/-16.7 years. The lesion sites determined from clinical findings were as follows: the infrageniculate-suprastapedial segment, 13 (23%); the infrastapedial-suprachordal segment, 9 (16%); and the mastoid segment, 35 (61%). No sites were classified as involving the suprageniculate segment. On brain MRI, 51 (89%) of the 57 patients showed abnormal enhancement of the facial nerve, with the most common area being the suprageniculate segment, including the distal intrameatal, labyrinthine and geniculate ganglion.

CONCLUSIONS: We demonstrate that clinical history is not helpful in determining the site of a lesion in Bell's palsy. The segment most frequently involved in Bell's palsy is the suprageniculate segment.