Towards an embedded symptom validity indicator for the rivermead postconcussion symptom questionnaire.

This simulation study aimed to develop and test an embedded symptom validity indicator for use with the Rivermead Post Concussion Symptoms Questionnaire (RPQ). Seven mild traumatic brain injury (mTBI) experts assisted in generating a shortlist of 15 atypical postconcussion symptoms. A modified RPQ (mRPQ) was constructed by embedding these items with the 16 standard RPQ items. Eighty-four mTBI simulators completed the mRPQ after random allocation to a symptom-exaggeration condition (ES group; n = 46) or simulation-only condition (S group; n = 38). They also completed the Test of Memory Malingering (TOMM) and the Recognition Memory Test (RMT), and the groups were re-formed and compared using modified criteria for Malingered Neurocognitive Dysfunction (mMND). There was no significant group by item-type interaction for either grouping methods (i.e. as allocated or as reclassified). Exploratory analyses of the main effects showed that ES group had higher mRPQ scores than the S group, and standard symptoms were endorsed more than atypical symptoms. If further developed, the mRPQ could eventually aid the screening of PCS over-reporting.