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Waddell's signs are a group of physical signs, first described in a 1980 article in Spine, and named for the article's principal author, Gordon Waddell. Waddell's signs may indicate non-organic or psychological component to chronic low back pain. Historically they have also been used to detect malingering in patients with back pain. While testing takes less than one minute, it has been described as time-consuming and alternatives have been proposed.
Use of Waddell's signs 
Waddell, et al. (1980) described five categories of signs:
- Tenderness tests: superficial and diffuse tenderness and/or nonanatomic tenderness
- Simulation tests: these are based on movements which produce pain, without actually causing that movement, such as axial loading and pain on simulated rotation
- Distraction tests: positive tests are rechecked when the patient's attention is distracted, such as a straight leg raise test
- Regional disturbances: regional weakness or sensory changes which deviate from accepted neuroanatomy
- Overreaction: subjective signs regarding the patient's demeanor and reaction to testing
Any individual sign marks its category as positive. When three or more categories were positive, the finding was considered clinically significant. However, assessing the patient on the basis of overreaction has raised concerns regarding observer bias and idiosyncrasies related to the patient's culture. Consequently, a practitioner may assess the patient on the remaining four categories, with two or more positive categories being considered clinically significant.
One or two Waddell's signs can often be found even when there is not a strong non-organic component to pain. Three or more are positively correlated with high scores for depression, hysteria and hypochondriasis on the Minnesota Multiphasic Personality Inventory.
Although Waddell's signs can detect a non-organic component to pain, they do not exclude an organic cause. Clinically significant Waddell scores are considered indicative only of symptom magnification or pain behavior, and have been misused in medical and medico-legal contexts. Waddell's signs are not considered a de facto indicator of deception for the purpose of financial gain.
In a 2003 review, Fishbain, et al. stated that Waddell's signs do not reliably distinguish organic from psychological pain but instead tend to underestimate the amount of pain that is actually experienced. In a 2004 review, Fishbain, et al. concluded, "there was little evidence for the claims of an association between Waddell signs and secondary gain and malingering. The preponderance of the evidence points to the opposite: no association".
In 2010, a neuroanatomical basis of Wadell's signs has been proposed which argues that since the brain is organic, and even society is composed of a group of organic beings, the term "nonorganic" should be replaced by a term put forward by Chris Spanswick in 1997, "behavioral responses to physical examination." With the possible exception of cogwheel rigidity, these are best understood as neuroanatomical maladaptations to long-continued pain and, as Waddell and colleagues have stressed, do not indicate faking or malingering but rather that there are psychosocial issues that mitigate against successfully treating low back pain by lumbar discectomy, and which in themselves require other treatment.
- Waddell, Gordon; John McCulloch, Ed Kummel, Robert Venner (March/April 1980). "Nonorganic Physical Signs in Low-Back Pain". Spine 5 (2): 117–125. doi:10.1097/00007632-198003000-00005. ISSN 0362-2436. OCLC 2589719. PMID 6446157.
- Blom, Ashley; Adrian Taylor, Sarah Whitehouse, Bill Orr, Evert Smith (September 2002). "A new sign of inappropriate lower back pain" (pdf). Annals of the Royal College of Surgeons of England (Royal College of Surgeons of England) 84 (5): 342–343. doi:10.1308/003588402760452682. ISSN 0035-8843. OCLC 2832178. PMC 2504150. PMID 12398129.
- Kurt Hegmann, ed. (2007). "Low Back Disorders (revised)". Occupational Medicine Practice Guidelines (2 ed.). American College of Occupational and Environmental Medicine. pp. 43–44.
- Main, Chris; Gordon Waddell (November 1998). "Behavioral Responses to Examination: A Reappraisal of the Interpretation of 'Nonorganic Signs'". Spine 23 (21): 2367–2371. doi:10.1097/00007632-199811010-00025. ISSN 0362-2436. OCLC 2589719. PMID 9820920.
- Fishbain, David; Brandly Cole, R. B. Cutler, John Lewis, H. L. Rosomoff, R. Steele Rosomoff (5 June 2003). "A Structured Evidence-Based Review on the Meaning of Nonorganic Physical Signs: Waddell Signs". Pain Medicine (American Academy of Pain Medicine) 4 (2): 141–181. doi:10.1046/j.1526-4637.2003.03015.x. ISSN 1526-2375. OCLC 42267277. PMID 12911018.
- Fishbain, David; R. B. Cutler, H. L. Rosomoff, R. Steele Rosomoff (November/December 2004). "Is There a Relationship Between Nonorganic Physical Findings (Waddell Signs) and Secondary Gain/Malingering?". Clinical Journal of Pain (American Academy of Pain Medicine) 20 (6): 399–408. doi:10.1097/00002508-200411000-00004. ISSN 0749-8047. OCLC 11198567. PMID 15502683.
- Ranney, DA. A Proposed Neuroanatomical Basis of Waddell's Nonorganic Signs, Am J Phys Med Rehabil 2010;89: 1036-1042.