Trigeminal neuralgia and atypical facial pain: use of the McGill Pain Questionnaire for discrimination and diagnosis.

Although trigeminal neuralgia and atypical facial pain can usually be distinguished on the basis of several well-established criteria, differential diagnosis is difficult in a small number of patients. The purpose of this study was to determine whether the McGill Pain Questionnaire (MPQ) is capable of discriminating between the two syndromes and might therefore serve as a diagnostic aid. The MPQ was administered to 74 patients in Pittsburgh and the data were analyzed statistically in Montreal. In an analysis of the data of 53 patients, 91% of the patients were correctly classified on the basis of 7 descriptors. To determine whether the key descriptors were able to predict the diagnosis of a second group, the discriminant function derived from the first analysis was applied to a new group of 21 patients. A correct prediction was made for 90% of the patients. The results indicate that, in difficult cases, the MPQ may be a useful tool to aid in differential diagnosis.