Portal de Periódicos da CAPES

On the origin of Neurostatus

2015; Elsevier BV; Volume: 4; Issue: 3 Linguagem: Inglês

10.1016/j.msard.2015.04.001

2211-0356

Ludwig Kappos, Marcus D’Souza, Jeannette Lechner‐Scott, Carmen Lienert,

Peripheral Neuropathies and Disorders

In his commentary ( Kurtzke, 2015 Kurtzke JF. On the origin of EDSS. Mult Scler Relat Disord. 2015; 4: 95-103 Abstract Full Text Full Text PDF PubMed Scopus (61) Google Scholar ) Dr. Kurztke recapitulates the rationale and the underlying evidence for the development of the Functional Systems (FS), the Disability Status Scale (DSS) and the Expanded Disability Status Scale (EDSS). This commentary and several of the author׳s previous publications on this topic ( Kurtzke, 1955 Kurtzke JF A new scale for evaluating disability in multiple sclerosis. Neurology. 1955; 5: 580-583 Crossref PubMed Google Scholar , Kurtzke, 1965 Kurtzke JF Further notes on disability evaluation in multiple sclerosis, with scale modifications. Neurology. 1965; 15: 654-661 Crossref PubMed Google Scholar , Kurtzke, 1970 Kurtzke JF. Clinical manifestations of multiple sclerosis. Multiple sclerosis and other demyelinating diseases. in: Handbook of clinical neurology. vol. 9. North-Holland, Amsterdam1970: 161-216 Google Scholar , Kurtzke, 1983 Kurtzke JF Rating neurologic impairment in multiple sclerosis. An expanded disability status scale (EDSS). Neurology. 1983; 33: 1444-1452 Crossref PubMed Google Scholar , Kurtzke, 1989 Kurtzke JF The disability status scale for multiple sclerosis: apologia pro DSS sua. Neurology. 1989; 39: 291-302 Crossref PubMed Google Scholar , Kurtzke, 2007 Kurtzke JF Origin of DSS: to present the plan. Mult Scler. 2007; 13: 120-123 Crossref PubMed Scopus (8) Google Scholar , Kurtzke, 2008 Kurtzke JF Historical and clinical perspectives of the expanded disability status scale. Neuroepidemiology. 2008; 31: 1-9 Crossref PubMed Scopus (69) Google Scholar ) underline his unique and widely appreciated contribution: Dr. Kurtzke created a scale that was a major step in comprehensively assessing neurologic impairment and disability in people with MS in the course of their disease. Although frequently criticized and challenged by other scales, the (E)DSS and its FS have persisted and hold a central role as an assessment tool in MS observational and therapeutic studies and have also – with some caveats – entered daily practice for the description and communication about the status of individual patients. Reemphasizing a statement from a previous review ( Kurtzke, 2008 Kurtzke JF Historical and clinical perspectives of the expanded disability status scale. Neuroepidemiology. 2008; 31: 1-9 Crossref PubMed Scopus (69) Google Scholar ), Dr. Kurtzke acknowledges that following his publications, the (E)DSS and FS entered the public domain and started being used in variable contexts all over the world. With increasing experience it was inevitable that investigators would also realize the scale׳s limitations. Many peer reviewed original publications, reviews and consensus statements ( Willoughby and Paty, 1988 Willoughby EW Paty DW Scales for rating impairment in multiple sclerosis: a critique. Neurology. 1988; 38: 1793-1798 Crossref PubMed Google Scholar , Noseworthy et al., 1989 Noseworthy JH Vandervoort MK Hopkins M Ebers GC A referendum on clinical trial research in multiple sclerosis: the opinion of the participants at the Jekyll island workshop. Neurology. 1989; 39: 977-981 Crossref PubMed Google Scholar , Francis et al., 1991 Francis DA Bain P Swan AV Hughes RA. An assessment of disability rating scales used in multiple sclerosis. Arch Neurol. 1991; 48: 299-301 Crossref PubMed Scopus (90) Google Scholar , Noseworthy, 1994 Noseworthy JH Clinical scoring methods for multiple sclerosis. Ann Neurol. 1994; 36: S80-S85 Crossref PubMed Scopus (81) Google Scholar , Whitaker et al., 1995 Whitaker JN McFarland HF Rudge P Reingold SC. 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BMC Neurol. 2014; 14: 58 Crossref PubMed Scopus (333) Google Scholar ) raised concerns about several aspects of the scale, including its bimodal distribution (both cross-sectional and longitudinal), its low sensitivity to change, the ordinal character of the FS and EDSS gradings and the underrepresentation of important manifestations of MS, such as mental impairment, upper extremity function and fatigue. One important concern related to the low intrarater and even lower interrater reliability of assigned FS and (E)DSS scores ( Amato et al., 1988 Amato MP Fratiglioni L Groppi C Siracusa G Amaducci L. Interrater reliability in assessing functional systems and disability on the Kurtzke scale in multiple sclerosis. Arch Neurol. 1988; 45: 746-748 Crossref PubMed Scopus (128) Google Scholar , Noseworthy et al., 1990 Noseworthy JH Vandervoort MK Wong CJ Ebers GC Interrater variability with the expanded disability status scale (EDSS) and functional systems (FS) in a multiple sclerosis clinical trial. The Canadian cooperation MS study group. Neurology. 1990; 40: 971-975 Crossref PubMed Google Scholar , Francis et al., 1991 Francis DA Bain P Swan AV Hughes RA. An assessment of disability rating scales used in multiple sclerosis. Arch Neurol. 1991; 48: 299-301 Crossref PubMed Scopus (90) Google Scholar , Verdier-Taillefer et al., 1991 Verdier-Taillefer MH Zuber M Lyon-Caen O Clanet M Gout O Louis C et al. Observer disagreement in rating neurologic impairment in multiple sclerosis: facts and consequences. Eur Neurol. 1991; 31: 117-119 Crossref PubMed Scopus (28) Google Scholar , Goodkin et al., 1992 Goodkin DE Cookfair D Wende K Bourdette D Pullicino P Scherokman B et al. Inter- and intrarater scoring agreement using grades 1.0 to 3.5 of the Kurtzke expanded disability status scale (EDSS). Multiple sclerosis collaborative research group. Neurology. 1992; 42: 859-863 Crossref PubMed Google Scholar , Sharrack et al., 1999 Sharrack B Hughes RA Soudain S Dunn G The psychometric properties of clinical rating scales used in multiple sclerosis. Brain. 1999; 122: 141-159 Crossref PubMed Scopus (214) Google Scholar ). In his "apologia pro DSS sua" ( Kurtzke, 1989 Kurtzke JF The disability status scale for multiple sclerosis: apologia pro DSS sua. Neurology. 1989; 39: 291-302 Crossref PubMed Google Scholar ) Dr. Kurtzke tried to alleviate this concern by referring to a publication from 1969 he had co-authored and which describes a study with 5 examiners examining 10 patients with 3 measures (standard neurological examination, the FS and DSS and a 7-day symptom score) that reported very high levels of agreement between these investigators for all 3 measures ( Kuzma et al., 1969 Kuzma JW Namerow NS Tourtellotte WW Sibley WA Kurtzke JF Rose AS et al. An assessment of the reliability of three methods used in evaluating the status of multiple sclerosis patients. J Chronic Dis. 1969; 21: 803-814 Abstract Full Text PDF PubMed Scopus (17) Google Scholar ). In the same "apologia" Dr. Kurtzke stated that the low reliability described by Amato et al., 1988 Amato MP Fratiglioni L Groppi C Siracusa G Amaducci L. Interrater reliability in assessing functional systems and disability on the Kurtzke scale in multiple sclerosis. Arch Neurol. 1988; 45: 746-748 Crossref PubMed Scopus (128) Google Scholar might have been due to "the neurologic examination per se" as performed by the Italian neurologists. Even if we accept this explanation of the low reliability of the EDSS and the FS that has been consistently reported in the pertinent literature it is clear that a standardized, comprehensive neurologic assessment must be performed as the basis for the determination of the FS and the EDSS. In our own experience and in the continuous interactions with neurologists all over the world it has also become clear that the definitions provided to guide the determination of the FS and EDSS grades were not always unambiguous or even consistent. Based on the same findings different examiners would in good faith come to assignments of different grades.