What physical exam techniques are useful to detect malingering?
The Abductor sign, based on a similar theory that thigh abductors work in concert, was developed and studied by one individual.7 In this diagnostic case-control study, the single author tested 33 patients from his practice, 17 with organic paresis, and 16 with nonorganic paresis. The author differentiated organic from nonorganic paresis by history, physical exam, and various imaging studies with no independent assessment. He reported his test as 100% accurate. We did not find any published studies of the Arm Drop test, where feigned paralysis of an upper extremity is tested by holding the arm over the face of the supine patient and letting go.
The Midline Split test attempts to detect nonorganic causes of sensory loss. The fact that cutaneous nerves cross the midline is the basis for the idea that a sharp midline split denotes nonorganic sensory loss. In 1 diagnostic cohort study of 100 people presenting to a neurology department with complaints of decreased sensation on one side of the face, 80 patients were determined to have organic deficits such as multiple sclerosis or stroke. The author did not describe how these diseases were diagnosed. Of those with organic deficits, 7.5% showed midline splitting of sensory loss, falsely suggesting a nonorganic process. Only 20% of the patients with nonorganic sensory loss showed the expected midline split.8 The author apparently performed the sensory exam without blinding or independent confirmation.
TABLE 1
Summary of tests for the detection of malingering
| TEST | SYMPTOMS | DESCRIPTION | EVIDENCE/OUTCOMES | SOR |
|---|---|---|---|---|
| McBride’s | Back pain with radicular symptoms | Stand on one leg. Flex symptomatic leg and raise to chest. Refusal or pain = nonorganic | No published studies | C (expert opinion) |
| Mankopf’s | Back pain | 1700 g pressure applied to the middle phalanx of the second finger of the nondominant hand. True pain should increase heart rate. | Did not correlate with organic pain | C (small inconclusive diagnostic case-control study) |
| Waddell’s | Back pain | Positive signs from 3 or more categories (TABLE 2) | Cannot discriminate organic from nonorganic | C (from SR) |
| Associated with poorer treatment outcomes | C (from SR) | |||
| Not associated with secondary gain | B (from SR) | |||
| Hoover’s | Leg paresis | Cup heels and have patient press down with paretic limb. Then have patient raise opposite limb. True paresis if no difference in downward pressure at heels | Indicates nonorganic paresis | C (extrapolated from small diagnostic case-control study using strain gauge) |
| Abductor | Leg paresis | Ask patient to abduct paretic leg to resistance. In true paresis, opposite leg should abduct. | Indicates nonorganic causes | C (small, lower-quality case-control study) |
| Arm Drop | Arm paresis | Hold paretic hand above face and drop it. If hand misses face, paresis is nonorganic | No published studies | C (expert opinion) |
| Midline Split | Sensory loss | Test facial sensation to pinprick. Nonorganic loss of sensation is delineated by the midline. | Very weakly indicates nonorganic cause | C (small diagnostic case-control study) |
| SOR, strength of recommendation (see page 722); SR, systematic review. | ||||
TABLE 2
Waddell’s signs
| CATEGORY | SIGNS |
|---|---|
| Tenderness | Superficial: light pinching causing pain = positive Nonanatomic: deep tenderness over a wide area = positive |
| Simulation | Axial loading: downward pressure on the head causing low back pain = positive Rotation: Examiner holds shoulders and hips in same plane and rotates patient. Pain = positive |
| Distraction | Straight leg raise causes pain when formally tested, but straightening the leg with hip flexed ninety degrees to check Babinski does not |
| Regional | Weakness: multiple muscles not enervated by the same root Sensation: glove and stocking loss of sensation. |
| Overreaction | Excessive show of emotion |
Recommendations from others
The DSM-IV recommends suspicion of malingering for patients who present with 2 or more of the following: medicolegal issues, disagreement between objective and subjective stress or disability, noncompliance with evaluation or treatment, or antisocial personality disorder.1
The American Medical Association published the Guides to the Evaluation of Permanent Impairment, which states, “Confirmation of malingering is extremely difficult and generally depends on intentional or inadvertent surveillance.”9
