Early detection of neuropathy in leprosy: a comparison of five tests for field settings

Abstract

BackgroundEarly detection and treatment of neuropathy in leprosy is important to prevent disabilities. A recent study showed that the Nerve Conduction Studies (NCS) and Warm Detection Thresholds (WDT) tests can detect leprosy neuropathy the earliest. These two tests are not practical under field conditions, however, because they require climate-controlled rooms and highly trained staff and are expensive. We assessed the usefulness of alternative test methods and their sensitivity and specificity to detect neuropathy at an early stage.MethodsThrough a literature search we identified five alternative devices that appeared user-friendly, more affordable, portable and/or battery-operated: the Neuropad®, Vibratip™, NC-Stat®DPNCheck™, NeuroQuick and the Thermal Sensibility Tester (TST), assessing respectively sweat function, vibration sensation, nerve conduction, cold sensation and warm sensation. In leprosy patients in Bangladesh, the posterior tibial and sural nerves that tested normal for the monofilament test and voluntary muscle test were assessed with the NCS and WDT as reference standard tests. The alternative devices were then tested on 94 nerves with abnormal WDT and/or NCS results and on 94 unaffected nerves. Sensitivity and specificity were the main outcomes.ResultsThe NeuroQuick and the TST showed very good sensitivity and specificity. On the sural nerve, the NeuroQuick had both a sensitivity and a specificity of 86%. The TST had a sensitivity of 83% and a specificity of 82%. Both the NC-Stat®DPNCheck™ and Vibratip™ had a high specificity (88% and 100%), but a low sensitivity (16% and 0%). On the posterior tibial nerve, the NeuroQuick and the TST also showed good sensitivity, but the sensitivity was lower than for the sural nerve. The Neuropad® had a sensitivity of 56% and a specificity of 61%.ConclusionsThe NeuroQuick and TST are good candidates for further field-testing for reliability and reproducibility. The feasibility of production on a larger scale should be examined.Electronic supplementary materialThe online version of this article (doi:10.1186/s40249-017-0330-2) contains supplementary material, which is available to authorized users.

Transmissão da hanseníase na Bahia, 2001-2015: modelagem a partir de regressão por pontos de inflexão e estatística de varredura espacial*

“…These forms of infection are important in the transmission chain and substantially increase the risk of physical disabilities. 3,24 Whereas at the beginning of the time series (2001), 48.82% of new cases were multibacillary, at the end of the series they accounted for two thirds (66.54%). Proportional increase in multibacillary cases has also been found in other Brazilian states, such as Mato Grosso, 20 Pará 25 and Tocantins, 12 as well as in municipalities such as Ribeirão Preto, in the state of São Paulo, 3 and Fortaleza.…”

Instruments of Choice for Assessment and Monitoring Diabetic Foot: A Systematic Review

“…The tuning fork was more specific (90%) than the 10 g monofilament (83%), but the 10 g monofilament was more sensitive (84%) than the tuning fork (69%). In the leprosy population (which implies a distal neuropathy similar to diabetics), the 10 g monofilament had lower sensitivity (38%) and greater specificity (91%) compared to those values in diabetes mellitus [48].…”

“…Similar to diabetes, Sudoscan shows 67.44% sensitivity and 83.33% specificity for the diagnosis of autonomic neuropathy in Parkinson's disease, therefore it could be useful in both conditions [54]. Neuropad is valid for assessment of the autonomic neuropathy component in leprosy, although it has lower psychometric properties for this disease (56% sensitivity and 61% specificity) [48].…”

“…Neuropad and Sudoscan were presented as good options for the diagnosis of diabetic autonomic neuropathy based on their psychometric properties. In addition, they are also valid for other pathologies involving autonomic neuropathy [48,53,54]. Neuropad is valid for type 1 and 2 diabetes, but Sudoscan has only been studied in type 2 diabetes.…”

Neurological Complications of Leprosy

“…A recent study of five tests meant for "field testing" validated Thermal Sensitivity Tester (detects warm sensation) and NeuroQuick (detects cold sensation) as the two that may have the earliest sensitivity for neuropathy. 66 NCS may identify neuropathies with clinical correlation in addition to subclinical new lesions indicative of a leprosy reaction. 53 In a study of NCS of ulnar nerves, axonal and demyelinating changes were seen in both T1R and T2R, with temporal dispersion predominantly seen in the former and conduction block in the latter.…”