A questionnaire to assess neurological impairment in multiple sclerosis

Abstract

This study assessed the feasibility of using a self-report questionnaire to measure neurological impairment in multiple sclerosis (MS). Thirty patients aged 21-67 years participated. Each patient was examined and scored on three commonly used impairment scales; the extended disability status scale (EDSS), the neurologic rating scale (NRS) and the ambulation index (A1). Two other scales were also determined; the sum of the EDSS functional scores (SFS), and a five point scale rating functional status (FS). The physician also filled out a copy of the questionnaire based on interview and examination of the patient. All of these scores were determined and the physical questionnaire filled out blind to the patient's answers on their self-report questionnaire. The first 15 consecutive patients served as the pilot group to develop a computer program to convert answers on the questionnaire into predicted scores on each of the five scales. The second 15 patients served as the independent test group to assess the validity of the computer program. Using this program, both patient and physician questionnaires accurately predicted (r > 0.87) the scores on each of the five scales measured manually. In addition, the scores on all five scales were highly cross-correlated (r > 0.85) suggesting that, in fact, each measured a similar attribute of MS (i.e., impairment). Therefore, the five scales were combined into a single measure, the mean disability score (MDS), which showed the highest correlations (r > 0.95) of any scale between the predicted scores and the actual scores determined by examination. The results of this study indicate that the self-report questionnaire is a valid measure of neurological impairment in MS and, thus, that it can be used to survey this health outcome in an MS population. Moreover, this questionnaire can be filled out by a physician (based directly on the neurological examination) and, together with the computer program for scoring each patient, can be used to provide consistent scoring in clinical trials.