Selecting a Test for Leprous Neuropathy Screening

Worldwide, leprosy represents a significant cause of disability due to progressive neurological impairment. Screening for leprous neuropathy is performed with Semmes-Weinstein monofilament (SWM) or ballpoint pen testing (BPT), which results in underreporting of its prevalence. The Pressure-specified sensory device (PSSD; Sensory Management Services, LLC, Baltimore, MD) is a sensitive, noninvasive, portable, neurosensory instrument, which has not been field-tested for leprosy screening. Early identification of leprous neuropathy would permit early antibiotic treatment to prevent contagion and early microsurgical neurolysis.

A prospective, clinical diagnostic, cross-sectional study screened a consecutive sample of patients for leprous neuropathy in the leprosy-endemic province of Los Ríos, Ecuador. Patients meeting the World Health Organization criteria for leprosy and complaining of neuropathy symptoms were classified as leprous neuropathy patients. Patients without any signs of leprosy were used as normal controls. Bilateral ulnar nerve screening with the PSSD, SWM (0.07, 0.4, 2, 4, 10, and 300 g), and BPT was performed in all patients. Sensitivity and specificity were calculated and compared across tests. A total of 71 patients (142 nerves) were evaluated.

Compared with the 10 g SWM and the BPT, the PSSD was found to have significantly higher sensitivity (78.3 vs. 0% with p < 0.001, for both) with comparable specificity (97.8 vs. 100% with p > 0.999, for both). Compared with the 0.07 g SWM (lightest filament in our series), the PSSD showed better sensitivity (78.3 vs. 65.2%, p = 0.514) and significantly higher specificity (97.8 vs. 51.1%, p < 0.001).

The PSSD provides superior diagnostic accuracy for detecting leprous neuropathy as compared with SWM and BPT.