Assessment method influences the severity and type of symptoms reported after self-reported mild traumatic brain injury

Objective: To investigate the influence of assessment method (spontaneous report versus checklist) on the report of postconcussive syndrome (PCS) symptoms after mild traumatic brain injury (mTBI). Setting: Community. Participants: Thirty-six participants (58% female) with postacute self-reported mTBI (i.e., sustained 1-6 months prior to participation) and 36 age-, gender-, and ethnicity-matched controls with no history of mTBI. Design: Cross-sectional. Main measures: Spontaneous symptom report from open-ended questions and checklist endorsed symptoms from the Neurobehavioral Symptom Inventory (both measures administered online). Results: Assessment method significantly affected individual symptom item frequencies (small to large effects), the number of symptoms reported, the total severity score, domain severity scores (i.e., somatic/sensory, cognitive, and affective symptom domains), and the number of participants who met a PCS caseness criterion (large effects; checklist > spontaneous report). The types of symptoms that were different between the groups differed for the assessment methods: Compared to controls, the nonclinical mTBI group spontaneously reported significantly greater somatic/sensory and cognitive domain severity scores, whilst no domain severity scores differed between groups when endorsed on a checklist. Conclusions: Assessment method can alter the number, severity, and types of symptoms reported by individuals who have sustained an mTBI and could potentially influence clinical decisions.