Validation of self-reported neurological disability in multiple sclerosis.

In all 129 unselected patients with multiple sclerosis (MS) completed a 25 item auto-questionnaire for assessment of disability. Each patient was examined on the same day by a neurologist who was blind to patients' answers and gave Expanded Disability Status Scale (EDSS) scores. From the auto-questionnaire, eight scores were obtained, one for each of the seven functional systems rated by the EDSS and the eighth relating to walking difficulties. Analysis showed that correlation between patients' self assessments and the neurologist's ratings was high (r > 0.50) for five out of the eight scores and low for three, especially for brainstem and mental functions which were excluded from subsequent analysis. Using a linear regression model, it was possible to predict the EDSS scores given by the neurologist (+/- 1 point) from patients' answers in 73% of the cases. The performance of the model was robust and was not influenced by patients' characteristics (sex, age, disease course). This study shows that most aspects of MS disability can be self-assessed by patients, and suggest a useful approach when it is not feasible to examine each MS patient as in large community-based studies. Collaborative studies for defining and validating auto-questionnaires on disability should be encouraged.