No examination technique objectively proves malingering (strength of recommendation [SOR]: C, expert opinion). Waddell’s signs are associated with poor treatment outcomes but cannot discriminate organic from nonorganic causes (SOR: B, systematic review of low-quality studies). Hoover’s and the Abductor sign indicate nonorganic paralysis (SOR: C, small, lower-quality case-control studies) (TABLE 1).
Meticulous examination and documentation will save time and trouble down the road
Tim Huber, MD
US Navy, Camp Pendleton, Calif
Warning flags for malingering include persistent noncompliance during prescribed evaluation or treatment, striking inconsistency between physical findings and stated symptoms, and an attorney or insurance company referring the patient to you. If monetary compensation is involved, malingering can potentially be prosecuted as fraud.
Meticulous examination and documentation will save you time and trouble down the road. If you find evidence of malingering, confronting the patient directly will likely result in animosity towards you from the patient and may result in litigation. The confrontation may escalate into violent behavior. Further complicating matters, specialist referral often reinforces the malingering behavior. A common option at approaching the potentially malingering patient is to allow him or her the opportunity to save face: “Well, Mr. Q, I am not finding the usual signs that go along with the complaints you are having….”
If you are in doubt of a diagnosis of malingering, it is generally safest to assume a person is not malingering until you specifically witness a contradictory event.
The 4th edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) defines malingering as “the intentional production of false or grossly exaggerated physical or psychological symptoms motivated by external incentives such as avoiding military duty, avoiding work, obtaining financial compensation, evading criminal prosecution, or obtaining drugs.”1 Malingering is not considered a mental disorder because symptoms are intentionally produced for external incentives.
No physical exam maneuver can determine a patient's external incentives. Traditionally, a physician uses certain exam techniques to determine if symptoms are of functional, or nonorganic, origin. Both terms denote the absence of a structural or physiological source for the phenomena, and include malingering and mental disorders such as factitious disorder, conversion disorder, and somatoform disorders. Our literature search only found studies concerning the detection of nonorganic causes of back pain, paralysis, and sensory loss.
Several exam tests are commonly thought to detect nonorganic causes of low back pain. Gordon Waddell described 8 signs in 5 categories (TABLE 2) used to “identify [back pain] patients who require more detailed psychological assessment.”2 A systematic review critiqued 60 studies of Waddell’s signs published between 1980 and 2000.3 The authors performed a thorough database search, including hand searches of key pain journals, meeting abstracts, and textbooks. The majority of the reviewed studies were small and of lower quality. The review found little evidence on test-retest or interrater reliability. There was consistent evidence that Waddell’s signs are associated with poorer treatment outcomes and generally consistent evidence that they are not associated with secondary gain and cannot discriminate organic from nonorganic problems.
A small, diagnostic case-control study of Mankopf’s test, which is based on the theory that pain increases heart rate, investigated 20 chronic low back pain patients considered nonorganic vs 20 pain-free controls using mechanical pain stimulus applied to subjects’ fingers.4 There was no significant difference in heart rate response between groups, and no significant effect of pain on heart rate in either group. The authors did not define their criteria for determining patients’ back pain as non-organic, nor did they include patients with low back pain caused by an identifiable pathology. There was no mention of blinding. This literature search found no published studies of McBride’s test, where the patient’s refusal to stand on the unaffected leg and flex the affected leg to the chest determines a feigned radiculopathy.
A few tests attempt to detect nonorganic causes of paralysis. In Hoover’s test, a patient is asked to alternately press down with the paralyzed leg and raise the unaffected leg to resistance, while the hand of the examiner cups the heel of the affected leg.5 A small, diagnostic case-control study using a computer-assisted strain gauge to measure movement effort during Hoover’s test involved 7 women with true paresis, 9 with nonorganic paresis, and 10 controls.6 The investigators diagnosed nonorganic paresis by history, neurological exam, and lack of positive neuroradiologic findings. The authors calculated a maximal involuntary to voluntary ratio for each patient’s extremities. The calculation discriminated between all 9 nonorganic patients and both the normal controls and patients with true paresis. The authors did not mention blinding in the study. No attempt was made to compare the strain gauge measurements with a clinician-performed Hoover’s test.