OBJECTIVES: This study aimed to develop and validate a simple questionnaire for chronic neuropathic pain that can be administered as a screening tool by general practitioners and internists in order to help them identify patients with probable neuropathic pain.
METHODS: Following a development phase and a pilot study, the revised version of the screening tool which included eleven descriptors associated with neuropathic pain both in English and Filipino languages was validated on 120 consecutive patients with any type of pain except psychogenic pain, recruited in the out-patient clinics of six hospitals. The questionnaire was validated by assessing the sensitivity, specificity, positive and negative predictive value of each item and the overall questionnaire. The internal consistency of the questionnaire items was assessed using the Kuder-Richardson formula 20.
RESULTS: Overall, the internal consistency of the SigN-PQ using the Kuder-Richardson formula 20 was 0.7837; the sensitivity was 91.89% with specificity of 80.22%, PV (+) was 65.38% and PV(-) was 96.0%. For the English version, the descriptors with the highest scores were burning (Sensitivity: 100%, Specificity: 93%) and electricity-like (Sensitivity: 100%, Specificity: 93%). For the Filipino version, mainit (burning) has the highest sensitivity of 88% with specificity of 82.6%, followed by gumagapang (tingling) with sensitivity of 86.96% and specificity of 85.42%. The sensation of saksak (stabbing) and hiwa (lancinating) have the lowest sensitivity, 60% and 54% respectively, although their specificity scores are high. Since this study is a validation of a screening tool for neuropathic pain, the investigators decided to choose descriptors with higher sensitivity. Thus, in the final version of the SignN-PQ, the descriptors saksak and hiwa were removed.
CONCLUSION: The SigN-PQ Neuropathic Pain Questionnaire has a high overall sensitivity of 91.89% and specificity of 80.22%. The pain descriptors in the questionnaire are consistent with the descriptors cited in the literature. It is a valid screening instrument for neuropathic pain that can be easily incorporated in the daily practice of general practitioners and internists.