Severity and specificity of neglect-like symptoms in patients with complex regional pain syndrome (CRPS) compared to chronic limb pain of other origins

In the literature, the neglect-like syndrome is described as an additional phenomenon of CRPS. The perception of the affected limb as strange, disordered and not belonging to the body is typical of and characterises this syndrome. Since this phenomenon has never been studied in other pain conditions, we assessed occurrence and extent of neglect-like symptoms in patients with CRPS of the upper and lower limb (n = 123) and in a control group with chronic limb pain of other origins (n = 117). Our questionnaire for describing the neglect-like syndrome encompassed five items following Galer and Jensen [Galer BS, Jensen M. Neglect-like symptoms in complex regional pain syndrome: results of a self-administered survey. Journal of Pain and Symptom Management 1999;18:213-6], with a six-point response scale inquiring the extent of respective symptoms. Results show that CRPS-patients as well as patients with non-CRPS limb pain exhibit the so-called neglect-like syndrome. However, the number of patients confirming such symptoms was significantly higher (OR = 2.87) in the CRPS group, moreover, these patients reported more severe symptoms (F = 17.74; p = 0.001). If the neglect-like total score is ≥5, the diagnostic sensitivity is low (21.1%), but the specificity for the diagnosis of CRPS reaches 90.6%. In this study, patients with CRPS of the upper and lower limb were included. The only difference between these two localisations concerning the neglect-like syndrome was the symptom of 'involuntary movements', which occurs significantly more often in affected legs. In conclusion, we recommend to evaluate neglect-like symptoms and to use them as an additional criterion in the diagnosis of CRPS. High scores of ≥5 confirm the diagnosis of CRPS, whereas lower scores must not be used for disease classification.