Dutch researchers (B. Schmand et al. Journal of Neurology, Neurosurgery and Psychiatry (1998) 64:339-343) examined the problem of exaggeration following whiplash injury. These injuries are problematic because neurologists lack hard findings that could validate the injuries. As litigation is a frequent consequence of whiplash accidents, the patient's symptom picture may be further muddled by feigned or exaggerated symptoms. This study was designed to determine if a substantial proportion of whiplash victims deliberately performed poorly on neuropsychological tests as a means of validating a measure of malingering.
Researchers gathered a subject pool of 108 consecutive neurological outpatients with a late (averaging two to three years post-accident) whiplash syndrome. These were compared to 20 patients with closed head injuries and 46 controls. All patients in the study were administered a battery of neuropsychological tests, including measures of memory, sequencing, verbal learning, attention and concentration.
Included in the battery was a new measure of malingering, the Amsterdam Short Term Memory test for malingering (ASTM). This is a measure of under-performance which presents to the patient a series of five familiar words that all come from the same semantic category such as names of countries. The patient is asked to later recall these names. The beauty of this form of malingering assessment is that the task appears to be harder than it really is. Patients with severe brain injury commonly perform above 97 percent correct. Validation studies, using normal patients instructed to do poorly on the task produced scores of between 83 and 94 percent correct.
The instrument was effective in differentiating between those patients who ostensibly had a reason to malinger (those in litigation) from those who presumably did not. Litigants who were faking (true positives) 61%, honest non-litigants (true negatives) 71%, honest litigants (false negatives) 39%, and, non-litigants who were faking (false positives) 29%. The differences between the litigation and non-litigation groups were highly significant (p=O.OO3). The researchers concluded that a significant proportion of post-whiplash patients seemed to be performing below their actual capacities.
The promise of the ASTM for forensic clinicians is somewhat compromised because of the high false positive rate. In forensic settings, misclassing almost a third of honest responders as malingering could prove both unfair and indefensible. A similar problem plagues several malingering instruments validated in the U.S. These include the Test of Memory Malingering (TOMM), and the just-published Validity Indication Profile (VIP).
One concern about malingering research in real-world settings is the difficulty of accurately defining a malingering group. While anyone who has ever done an evaluation in a forensic setting has observed some degree of exaggeration of symptoms or under-performance on cognitive tasks, it is not fair to assume that all or even most litigants are faking. The irony of experimental assumptions about faking litigants is that the larger the proportion of litigants who do not fake, the more inaccurate the malingering measure appears.
