Differential item functioning of the functional independence measure in higher performing neurological patients

Annet J. Dallmeijer, Joost Dekker, Leo D. Roorda, Dirk L. Knol, Bianca van Baalen, Vincent de Groot, Vera P.M. Schepers, Gustaaf J. Lankhorst

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Abstract

Objective: When comparing outcomes of the Functional Independence Measure (FIM™) between patient groups, item characteristics of the FIM™ should be consistent across groups. The purpose of this study was to compare item difficulty of the FIM™ in 3 patient groups with neurological disorders. Subjects: Patients with stroke (n = 295), multiple sclerosis (n = 150), and traumatic brain injury (n = 88). Methods: FIM™ scores were administered in each group. The FIM™ consists of a motor domain (13 items) and a cognitive domain (5 items). Rasch rating scale analysis was performed to investigate differences in item difficulty (differential item functioning) between groups. Results: Answering categories of the FIM™ items were reduced to 3 (from the original 7) because of disordered thresholds and low answering frequencies. Two items of the motor domain ("bladder" and "bowel") did not fit the Rasch model. For 7 out of the 11 fitting motor items, item difficulties were different between groups (i.e. showed differential item functioning). All cognitive items fitted the Rasch model, and 4 out of 5 cognitive items showed differential item functioning. Conclusion: Differential item functioning is present in several items of both the motor and cognitive domain of the FIM™. Adjustments for differential item functioning may be required when FIM™ data will be compared between groups or will be used in a pooled data analysis.

Original languageEnglish
Pages (from-to)346-352
Number of pages7
JournalJournal of rehabilitation medicine
Volume37
Issue number6
DOIs
Publication statusPublished - 1 Nov 2005
Externally publishedYes

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Nervous System Diseases
Multiple Sclerosis
Urinary Bladder
Stroke
Traumatic Brain Injury

Keywords

  • Disability evaluation
  • Neurological disorders
  • Rasch analysis
  • Rehabilitation

Cite this

Dallmeijer, A. J., Dekker, J., Roorda, L. D., Knol, D. L., van Baalen, B., de Groot, V., ... Lankhorst, G. J. (2005). Differential item functioning of the functional independence measure in higher performing neurological patients. Journal of rehabilitation medicine, 37(6), 346-352. https://doi.org/10.1080/16501970510038284
Dallmeijer, Annet J. ; Dekker, Joost ; Roorda, Leo D. ; Knol, Dirk L. ; van Baalen, Bianca ; de Groot, Vincent ; Schepers, Vera P.M. ; Lankhorst, Gustaaf J. / Differential item functioning of the functional independence measure in higher performing neurological patients. In: Journal of rehabilitation medicine. 2005 ; Vol. 37, No. 6. pp. 346-352.
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Dallmeijer, AJ, Dekker, J, Roorda, LD, Knol, DL, van Baalen, B, de Groot, V, Schepers, VPM & Lankhorst, GJ 2005, 'Differential item functioning of the functional independence measure in higher performing neurological patients' Journal of rehabilitation medicine, vol. 37, no. 6, pp. 346-352. https://doi.org/10.1080/16501970510038284

Differential item functioning of the functional independence measure in higher performing neurological patients. / Dallmeijer, Annet J.; Dekker, Joost; Roorda, Leo D.; Knol, Dirk L.; van Baalen, Bianca; de Groot, Vincent; Schepers, Vera P.M.; Lankhorst, Gustaaf J.

In: Journal of rehabilitation medicine, Vol. 37, No. 6, 01.11.2005, p. 346-352.

Research output: Contribution to journalArticleAcademicpeer-review

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T1 - Differential item functioning of the functional independence measure in higher performing neurological patients

AU - Dallmeijer, Annet J.

AU - Dekker, Joost

AU - Roorda, Leo D.

AU - Knol, Dirk L.

AU - van Baalen, Bianca

AU - de Groot, Vincent

AU - Schepers, Vera P.M.

AU - Lankhorst, Gustaaf J.

PY - 2005/11/1

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N2 - Objective: When comparing outcomes of the Functional Independence Measure (FIM™) between patient groups, item characteristics of the FIM™ should be consistent across groups. The purpose of this study was to compare item difficulty of the FIM™ in 3 patient groups with neurological disorders. Subjects: Patients with stroke (n = 295), multiple sclerosis (n = 150), and traumatic brain injury (n = 88). Methods: FIM™ scores were administered in each group. The FIM™ consists of a motor domain (13 items) and a cognitive domain (5 items). Rasch rating scale analysis was performed to investigate differences in item difficulty (differential item functioning) between groups. Results: Answering categories of the FIM™ items were reduced to 3 (from the original 7) because of disordered thresholds and low answering frequencies. Two items of the motor domain ("bladder" and "bowel") did not fit the Rasch model. For 7 out of the 11 fitting motor items, item difficulties were different between groups (i.e. showed differential item functioning). All cognitive items fitted the Rasch model, and 4 out of 5 cognitive items showed differential item functioning. Conclusion: Differential item functioning is present in several items of both the motor and cognitive domain of the FIM™. Adjustments for differential item functioning may be required when FIM™ data will be compared between groups or will be used in a pooled data analysis.

AB - Objective: When comparing outcomes of the Functional Independence Measure (FIM™) between patient groups, item characteristics of the FIM™ should be consistent across groups. The purpose of this study was to compare item difficulty of the FIM™ in 3 patient groups with neurological disorders. Subjects: Patients with stroke (n = 295), multiple sclerosis (n = 150), and traumatic brain injury (n = 88). Methods: FIM™ scores were administered in each group. The FIM™ consists of a motor domain (13 items) and a cognitive domain (5 items). Rasch rating scale analysis was performed to investigate differences in item difficulty (differential item functioning) between groups. Results: Answering categories of the FIM™ items were reduced to 3 (from the original 7) because of disordered thresholds and low answering frequencies. Two items of the motor domain ("bladder" and "bowel") did not fit the Rasch model. For 7 out of the 11 fitting motor items, item difficulties were different between groups (i.e. showed differential item functioning). All cognitive items fitted the Rasch model, and 4 out of 5 cognitive items showed differential item functioning. Conclusion: Differential item functioning is present in several items of both the motor and cognitive domain of the FIM™. Adjustments for differential item functioning may be required when FIM™ data will be compared between groups or will be used in a pooled data analysis.

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KW - Rasch analysis

KW - Rehabilitation

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DO - 10.1080/16501970510038284

M3 - Article

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SP - 346

EP - 352

JO - Journal of rehabilitation medicine

JF - Journal of rehabilitation medicine

SN - 1650-1977

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ER -