Interrater and intrarater reliability of the semmes-weinstein monofilament 4-2-1 stepping algorithm

Introduction: Semmes-Weinstein Monofilaments (SWM) are used to examine light touch sensation of the skin. Reliability of the 4-2-1 stepping algorithm approach for determining light touch detection thresholds has not been examined. The purpose of this study was to determine the interrater and intrarater reliability of the SWM 4-2-1 stepping algorithm on the plantar surface of the foot. Methods: Four raters with varying levels of SWM assessment experience tested light touch sensation over the plantar aspect of the first metatarsal head in 14 healthy adults. During the initial session, all raters performed the 4-2-1 stepping algorithm technique on each subject to determine interrater reliability. One week later, subjects were reassessed by 2 raters to determine intrarater reliability. Results: Interrater reliability ranged from moderate-to-good (ICC_2,1=0.62-0.92). Intrarater reliability also ranged from moderate-to-good (ICC_2,1=0.61-0.85). Conclusions: The 4-2-1 stepping algorithm demonstrated acceptable interrater and intrarater reliability when measured in healthy adults.