Comparison between impairment and disability scales in immune-mediated polyneuropathies

• Published in: Muscle & nerve Vol. 28; no. 1; pp. 93 - 100
• Main Authors: Merkies, Ingemar S.J., Schmitz, Paul I.M., van der Meché, Frans G.A., van Doorn, Pieter A.
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc., A Wiley Company 01.07.2003; Wiley
• Subjects: Adolescent; Adult; Aged; Biological and medical sciences; Demyelinating Autoimmune Diseases, CNS - diagnosis; Demyelinating Autoimmune Diseases, CNS - physiopathology; Disability Evaluation; disability scales; Female; Follow-Up Studies; Guillain-Barre Syndrome - diagnosis; Guillain-Barre Syndrome - physiopathology; Guillain-Barré syndrome; Hand Strength - physiology; Humans; Immune System Diseases - complications; Immune System Diseases - diagnosis; Immune System Diseases - physiopathology; immune-mediated polyneuropathies; impairment measures; Male; Medical sciences; Middle Aged; Multiple sclerosis and variants. Guillain barré syndrome and other inflammatory polyneuropathies. Leukoencephalitis; Neurology; outcome measures; Polyneuropathies - diagnosis; Polyneuropathies - etiology; Polyneuropathies - physiopathology; responsiveness; Treatment Outcome; Walking; Human; impairment measures; Nervous system diseases; Evaluation scale; outcome measures; Chronic inflammatory demyelinating neuropathy; Polyneuropathy; Guillain-Barré syndrome; Inflammatory disease; responsiveness; Disability; disability scales; Peripheral nerve disease; Measurement method; Guillain Barré syndrome; Immune system; immune-mediated polyneuropathies
• ISSN: 0148-639X; 1097-4598
• DOI: 10.1002/mus.10410

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–Barré 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. Muscle Nerve 28: 93–100, 2003