The language of low back pain: factor structure of the McGill pain questionnaire.

Low back pain patients' responses to the McGill Pain Questionnaire were factor analyzed using a method of factor extraction which, relative to the procedures employed in previous investigations, minimized distortion of the factor solution. Four factors were found which accounted for 51% of the total variance. Three of the factors were composed solely of sensory, affective and evaluative descriptor subclasses, respectively. The fourth was defined by both sensory and affective subclasses. The results provided strong support for the continued use of the sensory, affective and evaluative pain rating indices. Suggestions regarding replication of the present study and use of pain language factor scales for predictive purposes were discussed.