Low scores on BDAE Complex Ideational Material are associated with invalid performance in adults without aphasia

Complex Ideational Material (CIM) is a sentence comprehension task designed to detect pathognomonic errors in receptive language. Nevertheless, patients with apparently intact language functioning occasionally score in the impaired range. If these instances reflect poor test taking effort, CIM has potential as a performance validity test (PVT). Indeed, in 68 adults medically referred for neuropsychological assessment, CIM was a reliable marker of psychometrically defined invalid responding. A raw score ≤9 or T-score ≤29 achieved acceptable combinations of sensitivity (.34-.40) and specificity (.82-.90) against two reference PVTs, and produced a zero overall false positive rate when scores on all available PVTs were considered. More conservative cutoffs (≤8/ ≤ 23) with higher specificity (.95-1.00) but lower sensitivity (.14-.17) may be warranted in patients with longstanding, documented neurological deficits. Overall, results indicate that in the absence of overt aphasia, poor performance on CIM is more likely to reflect invalid responding than true language impairment. The implications of the clinical interpretation of CIM are discussed.