Neurobehavioral Symptom Inventory Item-Level Change Complements the Reliable Change Method.

Abstract

To determine correspondence between the statistically derived 8-point reliable change index for the Neurobehavioral Symptom Inventory (NSI) against clinically significant item-level change in symptom severity from intake to discharge for mild traumatic brain injury (mTBI). Brain Injury Rehabilitation Service at Brooke Army Medical Center, Fort Sam Houston, San Antonio, Texas. In total, 655 active-duty service members with a diagnosis of mTBI who received treatment and completed self-report measures between 2007 and 2020. Observational retrospective analysis of outpatient clinical outcomes data. NSI total score change was used to divide patients into responder and nonresponders based on whether they met an 8-point decrease between intake and discharge. In addition, patients who had at least one NSI item that changed from a rating of 3 (severe) or 4 (very severe) at intake to a rating of 0 (none) or 1 (mild) at discharge were coded as an individual with significant item-level change. Forty-five percent of the sample had significant item-level change and were classified as responders according to the reliable change method. Eight percent of the sample had significant item-level change but did not meet the 8-point reliable change threshold. Fifteen percent of the sample did not experience significant item-level change but were classified as responders according to reliable change. Thirty-one percent did not meet either method's criterion for change. Classification agreement between the reliable change and item-level change methods was 76%, which was statistically significant ( = 181.32, P < .001). There is good correspondence between reliable change and item-level change on the NSI in this population. Reliable change is easily calculated and thus much more accessible than the item-level change method. There may be some situations where calculating item-level change may be helpful.