Effectiveness of Semmes–Weinstein monofilament examination for diabetic peripheral neuropathy screening

Abstract

Objective To evaluate the effectiveness of the Semmes–Weinstein monofilament examination (SWME) for diabetic peripheral neuropathy (DPN) screening at an outpatient clinic. Methods Eighty-two type 2 diabetic outpatients were questioned about 13 subjective symptoms and tested for deep reflexes. They were examined using two types of quantitative sensory testing: SWME (using 4.31/2 g and 5.07/10 g monofilaments) and vibration testing (using the C-64 quantitative tuning fork). The patients were diagnosed with DPN when two of the following three criteria from both legs were met: (1) the presence of either pain, numbness, or paraesthesia; (2) a diminished or absent ankle reflex; or (3) a scale below 4 for their vibration perception thresholds (VPT). Results The most common subjective symptoms were muscle cramps and numbness in the extremities. SWME 4.31/2 g at the great toe or the plantar aspect of the fifth metatarsal was the most useful diagnostic test for DPN, providing 60.0% sensitivity and 73.8% specificity. SWME 4.31/2 g was correlated with lower limb VPT ( P=.029) and three subjective symptoms including fainting. SWME 5.07/10 g was correlated with lower limb VPT ( P=.011), the ankle reflex ( P=.013), the knee reflex ( P=.031), and two subjective symptoms. However, the sensitivity to diagnose DPN was low (30.0%). Conclusions The abnormalities indicated by SWME correlated well with those identified by lower limb VPT. Moreover, SWME 4.31/2 g correlated with fainting, suggesting that it could detect abnormalities in the small fibers. Considering the minimal time for this examination, SWME 4.31/2 g is a useful examination in an outpatient setting along with lower limb VPT and ankle reflex testing.