Highlights
- •A measure combining the Irritability/Lability and Agitation/Aggression subscales of the Neuropsychiatric Inventory (NPI) has been developed for use with individuals with traumatic brain injury (TBI).
- •The new measure (the Rasch NPI Irritability and Aggression Scale for TBI [NPI-TBI-IA]) was developed with Rasch analysis and includes responses to all specific items on these subscales.
- •The minimal clinically important difference (MCID) is the smallest change on a clinical measure that is associated with a meaningful perceived difference in an individual's condition, function, or quality of life.
- •We determined the MCID for this measure using distribution-based statistical methods and by anchoring the measure to Global Impression of Change Scales completed by individuals with TBI, their observers, and their physicians.
- •Our analysis suggests that the MCID for the NPI-TBI-IA is 0.5 SD and that a 1 SD change indicates a robust clinically important difference for both observer ratings and participant self-ratings.
Abstract
Objective
To determine the minimal clinically important difference (MCID) for a Rasch measure
derived from the Irritability/Lability and Agitation/Aggression subscales of the Neuropsychiatric
Inventory (NPI)—the Rasch NPI Irritability and Aggression Scale for Traumatic Brain
Injury (NPI-TBI-IA).
Design
Distribution-based statistical methods were applied to retrospective data to determine
candidates for the MCID. These candidates were evaluated by anchoring the NPI-TBI-IA
to Global Impression of Change (GIC) ratings by participants, significant others,
and a supervising physician.
Setting
Postacute rehabilitation outpatient clinic.
Participants
274 cases with observer ratings; 232 cases with self-ratings by participants with
moderate-severe TBI at least 6 months postinjury.
Interventions
Not applicable.
Main Outcome Measure
NPI-TBI-IA.
Results
For observer ratings on the NPI-TBI-IA, anchored comparisons found an improvement
of 0.5 SD was associated with at least minimal general improvement on GIC by a significant
majority (69%–80%); 0.5 SD improvement on participant NPI-TBI-IA self-ratings was
also associated with at least minimal improvement on the GIC by a substantial majority
(77%–83%). The percentage indicating significant global improvement did not increase
markedly on most ratings at higher levels of improvement on the NPI-TBI-IA.
Conclusions
A 0.5 SD improvement on the NPI-TBI-IA indicates the MCID for both observer and participant
ratings on this measure.
Keywords
List of abbreviations:
AIMS (Amantadine Irritability Multisite Study), GIC (Global Impression of Change), MCID (minimal clinically important difference), NPI (Neuropsychiatric Inventory), NPI-TBI-IA (Rasch Neuropsychiatric Inventory Irritability and Aggression Scale for Traumatic Brain Injury), RCI (reliable change index), RCID (robust clinically important difference), TBI (traumatic brain injury)To read this article in full you will need to make a payment
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Article info
Publication history
Published online: September 13, 2017
Footnotes
The contents of this article were developed under grants from the National Institute on Disability, Independent Living, and Rehabilitation Research (NIDILRR grant nos. H133A20016, H133A080035, 90DP0001-01-01). NIDILRR is a Center within the Administration for Community Living (ACL), Department of Health and Human Services (HHS). The contents of this article do not necessarily represent the policy of NIDILRR, ACL, HHS, and you should not assume endorsement by the Federal Government.
Disclosures: F.M.H. has a financial relationship with Avanir Steering Committee outside the submitted work. The other authors have nothing to disclose.
Identification
Copyright
© 2017 by the American Congress of Rehabilitation Medicine
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- Rasch Analysis, Dimensionality, and Scoring of the Neuropsychiatric Inventory Irritability and Aggression Subscales in Individuals With Traumatic Brain InjuryArchives of Physical Medicine and RehabilitationVol. 99Issue 2
- PreviewTo develop, for versions completed by individuals with traumatic brain injury (TBI) and an observer, a more precise metric for the Neuropsychiatric Inventory (NPI) Irritability and Aggression subscales using all behavioral item ratings for use with individuals with TBI and to address the dimensionality of the represented behavioral domains.
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