A modified score to identify and discriminate neuropathic pain: a study on the German version of the neuropathic pain symptom inventory (NPSI)

Claudia Sommer,Christoph Maier,Helmut Richter,Jule Frettlöh,Margitta Lungenhausen,Jan P Rogausch

doi:10.1186/1471-2377-11-104

Abstract

BackgroundNeuropathic pain must be correctly diagnosed for optimal treatment. The questionnaire named Neuropathic Pain Symptom Inventory (NPSI) was developed in its original French version to evaluate the different symptoms of neuropathic pain. We hypothesized that the NPSI might also be used to differentiate neuropathic from non-neuropathic pain.MethodsWe translated the NPSI into German using a standard forward-backward translation and administered it in a case-control design to patients with neuropathic (n = 68) and non-neuropathic pain (headache and osteoarthritis, n = 169) to validate it and to analyze its discriminant properties, its sensitivity to change, and to detect neuropathic pain subgroups with distinct profiles.ResultsUsing a sum score (the NPSI-G score), we found sensitivity to change (r between 0.37 and 0.5 for pain items of the graded chronic pain scale) and could distinguish between neuropathic and other pain on a group basis, but not for individual patients. Post hoc development of a discriminant score with optimized diagnostic properties to distinguish neuropathic pain from non-neuropathic pain resulted in an instrument with high sensitivity (91%) and acceptable specificity (70%). We detected six different pain profiles in the patient group with neuropathic pain; three profiles were found to be distinct.ConclusionsThe NPSI-G potentially combines the properties of a diagnostic tool and an instrument to identify subtypes of neuropathic pain.

Highlights

Neuropathic pain must be correctly diagnosed for optimal treatment
We examined the diagnostic power of the Neuropathic Pain Symptom Inventory (NPSI)-G score using a receiver operating characteristic (ROC) diagram [16]
Since our patient population was biased toward neuropathic pain of peripheral origin, the NPSI-G will have to be validated in a separate sample including patients with other neuropathic pain syndromes, e.g. with central pain

Summary

Introduction

Neuropathic pain must be correctly diagnosed for optimal treatment. The questionnaire named Neuropathic Pain Symptom Inventory (NPSI) was developed in its original French version to evaluate the different symptoms of neuropathic pain. We hypothesized that the NPSI might be used to differentiate neuropathic from non-neuropathic pain. Several screening tools have been developed to differentiate neuropathic from non-neuropathic pain [1]. These include the Leeds Assessment of Neuropathic Symptoms and Signs (LANSS [2]), the Neuropathic Pain Questionnaire [3], the DN4 [4], the painDETECT questionnaire [5], and the ID pain [6]. Another goal of pain questionnaires is the use of effective pain descriptors to identify subgroups of patients identify distinct subgroups among patients with neuropathic pain. We hypothesized that the NPSI might be used to differentiate neuropathic from non-neuropathic pain, a distinction which was not tested in the original study. To enhance the separation qualities of the NPSI-G for neuropathic and non-neuropathic pain, we used discriminant analysis to construct a weighted sum score of the variables

Methods

Results

Discussion

Conclusion