Measurement properties of the Inflammatory Rasch-built Overall Disability Scale (I-RODS) in patients with Guillain–Barré syndrome

Farah Pelouto; Nowshin Papri; Juanita A. Haagsma; David R. Cornblath; Eduardo Nobile-Orazio; Eveline J. A. Wiegers; Thomas Harbo; Yusuf A. Rajabally; Pieter A. van Doorn; Kenneth C. Gorson; Caroline B. Terwee; Bart C. Jacobs; Mike C. Horton; The IGOS Consortium

doi:10.1007/s00415-026-13684-6

Measurement properties of the Inflammatory Rasch-built Overall Disability Scale (I-RODS) in patients with Guillain–Barré syndrome

Farah Pelouto
, Nowshin Papri
, Juanita A. Haagsma
, David R. Cornblath
, Eduardo Nobile-Orazio
, Eveline J. A. Wiegers
, Thomas Harbo
, Yusuf A. Rajabally
, Pieter A. van Doorn
, Kenneth C. Gorson
, Caroline B. Terwee
, Bart C. Jacobs^*
, Mike C. Horton
, The IGOS Consortium

^*Corresponding author for this work

College of Health and Life Sciences

Research output: Contribution to journal › Article › peer-review

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Abstract

Guillain–Barré syndrome (GBS) is an acute immune-mediated polyneuropathy with a high disease impact, even after good clinical recovery. The Inflammatory Rasch-built Overall Disability Scale (I-RODS) is a Patient-Reported Outcome Measure (PROM) developed for patients with immune-mediated neuropathies that measures limitations in daily activities and social participation. It consists of 24 items, scored from 0–48. The present study aimed to validate the measurement properties of the I-RODS in patients with GBS included in the prospective International GBS Outcome Study (IGOS). The current study focussed on structural validity, cross-cultural validity, internal consistency, and construct validity of I-RODS using Rasch-based methods. The study was conducted in 1226 patients diagnosed with GBS with a median I-RODS score of 28 (IQR 10–41) 4 weeks after inclusion into IGOS. Rasch analyses revealed adequate internal consistency (PSI = 0.95; α = 0.98) and sufficient construct validity, indicated by strong correlations (R = − 0.91 to − 0.77). Targeting was acceptable, although there was a skew towards the floor (10.1%) and ceiling (9.4%). However, the I-RODS showed poor unidimensionality (12.1% CI 10.7–13.5%) and poor overall fit to the Rasch model. Category thresholds were correctly ordered. Misfit was found in two items. Additionally, 15 of 276 item pairs showed local dependency. While no differential item functioning (DIF) was evident for age or sex, significant DIF by geographic region was observed, with the strongest DIF in one item. These results suggest that the current version of I-RODS could be improved or alternative PROMs for patients with GBS could be developed.

Original language	English
Article number	164
Number of pages	14
Journal	Journal of neurology
Volume	273
Early online date	25 Feb 2026
DOIs	https://doi.org/10.1007/s00415-026-13684-6
Publication status	Published - 25 Feb 2026

Bibliographical note

Copyright © The Author(s) 2026. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit https://creativecommons.org/licenses/by/4.0/.

Funding

The IGOS study is financially supported by the GBS-CIDP Foundation International, GAIN, Erasmus MC University Medical Center Rotterdam, the University of Glasgow, CSL Behring, Grifols, Annexon, and Hansa Biopharma. The study sponsors had no role in the collection, analysis, or interpretation of data, nor in the writing of the manuscript. Additional support for this study was provided through a research grant from the Prinses Beatrix Spierfonds (grant number W. OR20-04).

Keywords

Guillain–Barré syndrome (GBS)
Inflammatory Rasch-built Overall Disability Scale (I-RODS)
Measurement properties
Patient-reported outcome measure (PROM)

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10.1007/s00415-026-13684-6Licence: CC BY 4.0

Measurement properties of the Inflammatory Rasch-built Overall Disability Scale (I-RODS) in patients with Guillain–Barré syndrome
Copyright © The Author(s) 2026. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit https://creativecommons.org/licenses/by/4.0/.
Final published version, 1.87 MBLicence: CC BY 4.0

Cite this

Pelouto, F., Papri, N., Haagsma, J. A., Cornblath, D. R., Nobile-Orazio, E., Wiegers, E. J. A., Harbo, T., Rajabally, Y. A., van Doorn, P. A., Gorson, K. C., Terwee, C. B., Jacobs, B. C., Horton, M. C., & Consortium, T. IGOS. (2026). Measurement properties of the Inflammatory Rasch-built Overall Disability Scale (I-RODS) in patients with Guillain–Barré syndrome. Journal of neurology, 273, Article 164. https://doi.org/10.1007/s00415-026-13684-6

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title = "Measurement properties of the Inflammatory Rasch-built Overall Disability Scale (I-RODS) in patients with Guillain–Barr{\'e} syndrome",

abstract = "Guillain–Barr{\'e} syndrome (GBS) is an acute immune-mediated polyneuropathy with a high disease impact, even after good clinical recovery. The Inflammatory Rasch-built Overall Disability Scale (I-RODS) is a Patient-Reported Outcome Measure (PROM) developed for patients with immune-mediated neuropathies that measures limitations in daily activities and social participation. It consists of 24 items, scored from 0–48. The present study aimed to validate the measurement properties of the I-RODS in patients with GBS included in the prospective International GBS Outcome Study (IGOS). The current study focussed on structural validity, cross-cultural validity, internal consistency, and construct validity of I-RODS using Rasch-based methods. The study was conducted in 1226 patients diagnosed with GBS with a median I-RODS score of 28 (IQR 10–41) 4 weeks after inclusion into IGOS. Rasch analyses revealed adequate internal consistency (PSI = 0.95; α = 0.98) and sufficient construct validity, indicated by strong correlations (R = − 0.91 to − 0.77). Targeting was acceptable, although there was a skew towards the floor (10.1\%) and ceiling (9.4\%). However, the I-RODS showed poor unidimensionality (12.1\% CI 10.7–13.5\%) and poor overall fit to the Rasch model. Category thresholds were correctly ordered. Misfit was found in two items. Additionally, 15 of 276 item pairs showed local dependency. While no differential item functioning (DIF) was evident for age or sex, significant DIF by geographic region was observed, with the strongest DIF in one item. These results suggest that the current version of I-RODS could be improved or alternative PROMs for patients with GBS could be developed.",

keywords = "Guillain–Barr{\'e} syndrome (GBS), Inflammatory Rasch-built Overall Disability Scale (I-RODS), Measurement properties, Patient-reported outcome measure (PROM)",

author = "Farah Pelouto and Nowshin Papri and Haagsma, \{Juanita A.\} and Cornblath, \{David R.\} and Eduardo Nobile-Orazio and Wiegers, \{Eveline J. A.\} and Thomas Harbo and Rajabally, \{Yusuf A.\} and \{van Doorn\}, \{Pieter A.\} and Gorson, \{Kenneth C.\} and Terwee, \{Caroline B.\} and Jacobs, \{Bart C.\} and Horton, \{Mike C.\} and Consortium, \{The IGOS\}",

note = "Copyright {\textcopyright} The Author(s) 2026. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit https://creativecommons.org/licenses/by/4.0/.",

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Pelouto, F, Papri, N, Haagsma, JA, Cornblath, DR, Nobile-Orazio, E, Wiegers, EJA, Harbo, T, Rajabally, YA, van Doorn, PA, Gorson, KC, Terwee, CB, Jacobs, BC, Horton, MC & Consortium, TIGOS 2026, 'Measurement properties of the Inflammatory Rasch-built Overall Disability Scale (I-RODS) in patients with Guillain–Barré syndrome', Journal of neurology, vol. 273, 164. https://doi.org/10.1007/s00415-026-13684-6

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AU - Cornblath, David R.

AU - Nobile-Orazio, Eduardo

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AU - Harbo, Thomas

AU - Rajabally, Yusuf A.

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AU - Terwee, Caroline B.

AU - Jacobs, Bart C.

AU - Horton, Mike C.

AU - Consortium, The IGOS

N1 - Copyright © The Author(s) 2026. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit https://creativecommons.org/licenses/by/4.0/.

PY - 2026/2/25

Y1 - 2026/2/25

N2 - Guillain–Barré syndrome (GBS) is an acute immune-mediated polyneuropathy with a high disease impact, even after good clinical recovery. The Inflammatory Rasch-built Overall Disability Scale (I-RODS) is a Patient-Reported Outcome Measure (PROM) developed for patients with immune-mediated neuropathies that measures limitations in daily activities and social participation. It consists of 24 items, scored from 0–48. The present study aimed to validate the measurement properties of the I-RODS in patients with GBS included in the prospective International GBS Outcome Study (IGOS). The current study focussed on structural validity, cross-cultural validity, internal consistency, and construct validity of I-RODS using Rasch-based methods. The study was conducted in 1226 patients diagnosed with GBS with a median I-RODS score of 28 (IQR 10–41) 4 weeks after inclusion into IGOS. Rasch analyses revealed adequate internal consistency (PSI = 0.95; α = 0.98) and sufficient construct validity, indicated by strong correlations (R = − 0.91 to − 0.77). Targeting was acceptable, although there was a skew towards the floor (10.1%) and ceiling (9.4%). However, the I-RODS showed poor unidimensionality (12.1% CI 10.7–13.5%) and poor overall fit to the Rasch model. Category thresholds were correctly ordered. Misfit was found in two items. Additionally, 15 of 276 item pairs showed local dependency. While no differential item functioning (DIF) was evident for age or sex, significant DIF by geographic region was observed, with the strongest DIF in one item. These results suggest that the current version of I-RODS could be improved or alternative PROMs for patients with GBS could be developed.

AB - Guillain–Barré syndrome (GBS) is an acute immune-mediated polyneuropathy with a high disease impact, even after good clinical recovery. The Inflammatory Rasch-built Overall Disability Scale (I-RODS) is a Patient-Reported Outcome Measure (PROM) developed for patients with immune-mediated neuropathies that measures limitations in daily activities and social participation. It consists of 24 items, scored from 0–48. The present study aimed to validate the measurement properties of the I-RODS in patients with GBS included in the prospective International GBS Outcome Study (IGOS). The current study focussed on structural validity, cross-cultural validity, internal consistency, and construct validity of I-RODS using Rasch-based methods. The study was conducted in 1226 patients diagnosed with GBS with a median I-RODS score of 28 (IQR 10–41) 4 weeks after inclusion into IGOS. Rasch analyses revealed adequate internal consistency (PSI = 0.95; α = 0.98) and sufficient construct validity, indicated by strong correlations (R = − 0.91 to − 0.77). Targeting was acceptable, although there was a skew towards the floor (10.1%) and ceiling (9.4%). However, the I-RODS showed poor unidimensionality (12.1% CI 10.7–13.5%) and poor overall fit to the Rasch model. Category thresholds were correctly ordered. Misfit was found in two items. Additionally, 15 of 276 item pairs showed local dependency. While no differential item functioning (DIF) was evident for age or sex, significant DIF by geographic region was observed, with the strongest DIF in one item. These results suggest that the current version of I-RODS could be improved or alternative PROMs for patients with GBS could be developed.

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KW - Inflammatory Rasch-built Overall Disability Scale (I-RODS)

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KW - Patient-reported outcome measure (PROM)

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U2 - 10.1007/s00415-026-13684-6

DO - 10.1007/s00415-026-13684-6

M3 - Article

SN - 0340-5354

VL - 273

JO - Journal of neurology

JF - Journal of neurology

M1 - 164

ER -

Measurement properties of the Inflammatory Rasch-built Overall Disability Scale (I-RODS) in patients with Guillain–Barré syndrome

Abstract

Bibliographical note

Funding

Keywords

Access to Document

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