Psychometric evaluation of a new handicap scale in immune-mediated polyneuropathies

Abstract

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--Barré 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 <.0001). Also, good reliability (r =.89--.98; P <.0001) and high responsiveness values (standardized response mean values >.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.