Satyendra Nath Chakrabartty*

Indian Ports Association, India

*Corresponding Author: Satyendra Nath Chakrabartty, Indian Ports Association, India.

Received: May 05, 2023; Published: June 03, 2023

Abstract

Background: Existing tests to assess disabilities due to functional deficits in Multiple sclerosis (MS) differ in number of items, number of response-categories, domains covered, scoring systems, etc. and are not comparable.

Objective: The paper proposes two methods to convert discrete raw scores of items/domains of MS tests to continuous scores following normal distribution satisfying desired properties and facilitating meaningful comparisons, assessment of progress/deterioration, parametric statistical analysis and symmetric equivalent-scores for better comparisons and integration of MS tests.

Methods: Ordinal raw scores are converted to equidistant scores by weighted sum followed by linear transformations (Method 1) and alternate method of scoring health-state-profiles in 5-Domain 5-Level set up (Method 2). Proposed equivalent-scores having equal areas under normal curve help to derive meaningful cut-off scores, equivalent boundary points of the classes and integration of MS tests

Results: Proposed scores under each method help in computation of total score reflecting total disorder by overall index of disability in MS, with the same score range of items satisfy desired properties of measurement including meaningful arithmetic aggregations, minimization of tied scores. Domain scores and test scores follow normal and facilitate better ranking, comparisons, quantify changes from longitudinal data, and parametric statistical analysis, computation of reliability, validity, etc. Symmetric equivalent scores avoid conversion tables generated from the Crosswalk Studies which may vary by several points and may not provide inverse function for each score. The Method 2 indicates domain-wise status of a patient and helps practitioners to decide priorities and course of action accordingly. However, Method 2 requires significant modifications of existing tests to fit 5D-5L set up.

Conclusions: Considering theoretical advantages including meaningfulness of operations, easy comprehension, better comparisons, Method 1 is recommended with the suggestion to report test score and also domain scores.

Keywords: Multiple Sclerosis, Cognitive Tests; Normal Distribution; Equivalent Scores; Reliability; Responsiveness

References

1. Sharrack B and Hughes RA. “The Guy's Neurological Disability Scale (GNDS): a new disability measure for multiple sclerosis”. Multiple Sclerosis Journal4 (1999): 223-233.
2. Twork S., et al. “Disability status and quality of life in multiple sclerosis: non-linearity of the Expanded Disability Status Scale (EDSS)”. Health and Quality of Life Outcomes8 (2010): 55.
3. Benedict RH., et al. “Brief International Cognitive Assessment for MS (BICAMS): international standards for validation”. BMC Neurology 12 (2012): 55.
4. Saccà F., et al. “The EDSS integration with the Brief International Cognitive Assessment for Multiple Sclerosis and orientation tests”. Multiple Sclerosis Journal 23 (2017): 1289-1296.
5. Alonso RN., et al. “Brain Function Assessment of Patients with Multiple Sclerosis in the Expanded Disability Status Scale: A Proposal for Modification”. International Journal of MS Care1 (2020): 31–35.
6. Kurtzke JF. “On the evaluation of disability in multiple sclerosis”. Neurology 11 (1961):686-694.
7. Kurtzke JF. “Rating neurologic impairment in multiple sclerosis: an expanded disability status scale (EDSS)”. Neurology 33 (1983): 1444-1452.
8. Kappos L., et al. “On the origin of Neu­rostatus”. Multiple Sclerosis and Related Disorders 4 (2015): 182-185.
9. Goldman Myla., et al. “Possible clinical outcome measures for clinical trials in patients with multiple sclerosis”. Therapeutic Advances in Neurological Disorders 3 (2010): 229-239.
10. Rudick R., et al. “Recommendations from the National Multiple Sclerosis Society Clinical Outcomes Assessment Task Force”. Annals of Neurology 42 (1997): 379-382.
11. Hobart J., et al. “The multiple sclerosis impact scale (MSIS-29): a new patient-based outcome measure”. Brain 124 (2001): 962-973.
12. Ware JE., et al. “SF-36 Health Survey: manual and interpretation guide”.The Health Institute, New England Medical Center: Boston, MA (1993).
13. Krupp L., et al. “The fatigue severity scale. Application to patients with multiple sclerosis and systemic lupus erythematosus”. Archives of Neurology 46 (1989): 1121-1123.
14. Ritvo PG., et al. “Multiple Sclerosis Quality of Life Inventory: A User’s Manual”. National Multiple Sclerosis Society: New York (1997).
15. Cella DF., et al. “Validation of the functional assessment of multiple sclerosis quality of life instruments”. Neurology 47 (1996): 129-139.
16. Tremlett H., et al. “Impact of multiple sclerosis relapses on progression diminishes with time”. Neurology 73 (2009): 1616-1623.
17. Bejaoui K and Rolak L. “What is the risk of permanent disability from a multiple sclerosis relapse?” Neurology 74 (2010): 900-902.
18. Confavreux C., et al. “Relapses and progression of disability in multiple sclerosis”. The New England Journal of Medicine 343 (2000): 1430-1438.
19. Goodkin DE., et al. “Inter- and intrarater scoring agreement using grades 1.0 to 3.5 of the Kurtzke Expanded Disability Status Scale (EDSS)”. Neurology 42 (1992): 859-863.
20. Willoughby EW and Paty DW. “Scales for rating impairment in multiple sclerosis: a critique”. Neurology 38 (1988): 1793-1798.
21. Van Winsen L., et al. “Outcome measurement in multiple sclerosis: detection of clinically relevant improvement”. Multiple Sclerosis Journal 5 (2010): 604-610.
22. Rudick R., et al. “Gray matter atrophy correlates with MS disability progression measured with MSFC but not EDSS”. Journal of the Neurological Sciences 282 (2009): 106-111.
23. Zurawski J., et al. “Time between expanded disability status scale (EDSS) scores, Multiple Sclerosis and Related Disorders 30 (2019): 98-103.
24. Lewin RJP., et al. “Validation of the Cardiovascular Limitations and Symptoms Profile (CLASP) in chronic stable angina”. Journal of Cardiopulmonary Rehabilitation and Prevention 22 (2002): 184-191.
25. Munshi Jamal. “A Method for Constructing Likert Scales”. SSRN Electronic Journal (2014).
26. Šimkovic M and Träuble B. “Robustness of statistical methods when measure is affected by ceiling and/or floor effect”. PloS one8 (2019): e0220889.
27. Norman GR and Streiner DL. “Principal components and factor analysis. In: Norman GR, Streiner OL (ed.) Mosby: St. Louis, Missouri (1993): 129-142
28. Livingston SA. “Equating test scores (without IRT)”. Princeton, NJ: ETS (2004).
29. Chakrabartty Satyendra Nath. “Alternate measure of disability intensity: Modified Rankin Scale, Journal of Stroke Medicine (2019): 1-8.
30. Chakrabartty Satyendra Nath. “Alternate method of scoring Euroqol Five- Dimensional Scales”. Health Science Journal6 (2021): 847.
31. Chakrabartty Satyendra Nath. “Reliability of Test Battery”. Methodological Innovation2 (2020): 1-8.
32. Parkerson HA., et al. “Factorial Validity of the English Language Version of the Pain Catastrophizing Scale Child Version”. The Journal of Pain 11 (2013): 1383-1389.
33. Chakrabartty and Satyendra Nath. “Integration of various scales for Measurement of Insomnia”. Research Methods in Medicine and Health Sciences3 (2013): 102-111.
34. Goswami S and Chakrabarti. “A Quartile clustering: a quartile based technique for generating meaningful clusters”. Journal of Computing 4 (2012): 48-55.

Citation

Citation: Satyendra Nath Chakrabartty. “Index of Overall Disability due to Multiple Sclerosis". Acta Scientific Neurology 6.7 (2023): 02-09.

Copyright

Copyright: © 2023 Satyendra Nath Chakrabartty. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.