CHICAGO—Clinicians often assume that a head injury patient either has true cognitive deficits or is malingering—but not both. In reality, however, the two designations frequently overlap, because a head injury patient with legitimate impairment may exaggerate existing deficits or feign additional ones. This raises an intriguing question: Does experiencing a head injury improve a patient’s ability to malinger?

Surprisingly, the answer seems to be no, David T. R. Berry, PhD, and colleagues reported at the annual meeting of the International Neuropsychological Society. “Intuitively, you would think that having been through a significant head injury, patients would be better able to recognize a realistic or credible pattern of deficits,” said Dr. Berry, who is Professor of Psychology at the University of Kentucky in Lexington. “But they’re not able to do it.”

The researchers asked 42 adults with a history of moderate to severe head injury and 36 community controls to complete an extensive battery of neuropsychologic tests, including the Controlled Oral Word Association Test, the Digit Span and Digit Symbol subtests of the Wechsler Adult Intelligence Scale–Third Edition, the Stroop Color-Word Test, and several others. Participants also completed four tests designed to identify malingerers: the Digit Memory Test, the Letter Memory Test, the Test of Memory Malingering, and the 27-item short form of the Portland Digit Recognition Test. (The use of multiple malingering measures not only improves detection but can serve as an antidote for the real-world concern that some patients may receive outside “coaching” on how to appear impaired when taking cognitive tests.)

Half of the participants in each group were instructed to complete each test to the best of their ability, while the remainder were asked to “feign or exaggerate cognitive symptoms in a believable manner” and told that avoiding detection would earn them $20. To qualify as a successful malingerer, participants had to perform below the fifth percentile on at least one of the 10 neuropsychologic tests but not fall below the appropriate cutoff on any of the malingering measures.

Given the severity of their injuries—their mean Glasgow Coma Scale score at hospital admission had been 8.4—it is not surprising that the head injury group performed notably worse than controls on the neuropsychologic tests, despite the fact that an average of five years had passed since their injuries. Moreover, as expected, the researchers found that participants asked to malinger performed worse than those asked to do their best.

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However, having experienced a head injury did not prove to be an asset in helping would-be malingerers to escape detection. Despite their uniformly low scores on all 10 neuropsychologic tests, the head-injured subjects who were asked to feign cognitive symptoms were no better at malingering than their uninjured counterparts. In fact, while four of 18 controls (22%) were able to malinger successfully, not one of 21 head-injured individuals managed to do so (P < .05). “The community malingerers seemed to be the only group able to avoid being picked up on at least one malingering test,” Dr. Berry said.

Might the subjects’ cognitive deficits have interfered with their ability to malinger? Probably not, said Dr. Berry, noting that in an earlier study he found that college students with a history of mild head injury were similarly unable to escape detection when asked to malinger, despite having little or no residual impairment. Moreover, the fact that head-injured persons were unable to translate their experiences into successful malingering is consistent with an Australian study in which registered nurses who regularly worked with neurologic patients showed no special aptitude for feigning cognitive deficits.

Dr. Berry cautioned that the study, which was the basis for coauthor Chad Vickery’s doctoral thesis, used “analog” rather than true malingerers, so its relevance to real-world malingering must remain presumptive. But the fact that head-injured patients were unable to avoid detection when asked to malinger is nonetheless enlightening, he said, and points to the value of using malingering tests even when patients appear to have legitimate problems. “It’s pretty clear that we have to give these measures in a forensic evaluation,” he stated. “We should give at least one well-validated motivational test, and perhaps it would be wise to use more than one given the concern about these tests being circulated or disseminated.”

—Peter Doskoch

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