Montreal Cognitive Assessment as a screening tool: Influence of performance and symptom validity.

Background: We evaluated Montreal Cognitive Assessment (MoCA) performance in a veteran traumatic brain injury (TBI) population, considering performance validity test (PVT) and symptom validity test (SVT) data, and explored associations of MoCA performance with neuropsychological test performance and self-reported distress.

Methods: Of 198 consecutively referred veterans to a Veterans Administration TBI/Polytrauma Clinic, 117 were included in the final sample. The MoCA was administered as part of the evaluation. Commonly used measures of neuropsychological functioning and performance and symptom validity were also administered to aid in diagnosis.

Results: Successively worse MoCA performances were associated with a greater number of PVT failures (s < 0.05). Failure of both the SVT and at least 1 PVT yielded the lowest MoCA scores. Self-reported distress (both posttraumatic stress disorder symptoms and neurobehavioral cognitive symptoms) was also related to MoCA performance.

Conclusions: Performance on the MoCA is influenced by task engagement and symptom validity. Causal inferences about neurologic and neurocognitive impairment, particularly in the context of mild TBI, wherein the natural course of recovery is well known, should therefore be made cautiously when such inferences are based heavily on MoCA scores. Neuropsychologists are well versed in the assessment of performance and symptom validity and thus may be well suited to explore the influences of abnormal performances on cognitive screening.