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The ability of a scale to detect clinical relevant changes over time, i.e., its "responsiveness," may help clinicians to choose among valid and reliable measures. Therefore, we investigated the responsiveness' rank ordering (best to worse) of six selected valid and reliable scales, namely the Medical Research Council (MRC)-sumscore, sensory-sumscore, grip-strength (Vigorimeter), nine-hole peg, ten-meters walking, and a disability-sumscore, in immune-mediated polyneuropathies. Patients with newly diagnosed Guillain-Barre syndrome (n = 7) or chronic inflammatory demyelinating polyneuropathy (n = 13) were examined over 52 weeks. Responsiveness of each scale was measured using different methods (effect-size, standardized response mean score, Wilcoxon matched-pairs signed-rank, and a newly devised Schmitz's distribution-free responsiveness score), and the obtained scores in each method were plotted against the follow-up period, thus allowing area-under-the-curve calculations (higher area-under-the-curve indicating better responsiveness). Also, longitudinal correlations were performed between the scales' values and patients' own clinical judgments (deteriorated, unchanged, improved) (higher correlation = better responsiveness). A consistent rank ordering was observed in each technique with the disability-sumscore, MRC-sumscore, and Vigorimeter being among the best responsive scales. Hence, the primary use of these measures is suggested in studies of immune-mediated polyneuropathies.

A new handicap measure, the Rotterdam nine-item handicap scale, was developed and its validity, reliability, and responsiveness evaluated in patients with immune-mediated polyneuropathies. We evaluated 113 stable patients, of whom 83 had Guillain--Barre syndrome (GBS), 22 had chronic inflammatory demyelinating polyneuropathy (CIDP), and 8 had a gammopathy-related polyneuropathy. We also studied 20 patients with recently diagnosed GBS (n = 7) or CIDP (n = 13) and changing clinical conditions (longitudinal group). Significant discriminatory validity and correlation with the Rankin scale were demonstrated for the Rotterdam nine-item handicap scale (stable group: Spearman's test, r = minus sign.76 to minus sign.78; longitudinal group: intraclass correlation coefficient, r =.83; P .8) were obtained for the Rotterdam nine-item handicap scale. In contrast to the Rankin scale, the Rotterdam scale not only provided information regarding mobility but also highlighted physical independence, occupation, and social integration. These results illustrate the clinical usefulness of the Rotterdam nine-item handicap scale under these conditions.