Reliability and Responsiveness of an 18 Site, 10-g Monofilament Examination for Assessment of Protective Foot Sensation

PURPOSE: Older persons including those with diabetes are at increased risk for loss of protective sensation in the feet. The 5.07 (10-g) monofilament is recognized as a valid instrument to test for the presence or absence of protective sensation in the foot. Few studies report reliability and no studies report responsiveness for a multisite examination using the 10-g monofilament. The purpose of this study was to determine the responsiveness and reliability for the 10-g monofilament in evaluating protective sensation in the feet. MATERIALS/METHODS: A convenience sample of 28 (20 women and 8 men) participants between the ages 50 and 78 years were recruited for the study. Sensory testing was performed on 18 different sites (9 per foot) by 3 testers for each participant using the 10-g monofilament. Participants were tested on 2 occasions with approximately 1 week between tests. Participants' eyes were closed for the duration of the examination to blind them to the tester. Testers were blinded to each other and previous test results. RESULTS: Intratester and intertester reliability were calculated using intraclass correlation coefficients (ICC). Intratester ICC (3, 1) and minimal detectable change at the 95% confidence level (MDC(95)) were calculated for each tester and then averaged yielding the following: ICC = 0.76 (95% CI: 0.68-0.84), MDC(95) = 2.83. Intertester ICC (2, 1) was 0.78 (95% CI: 0.64-0.88). MDC(95) was 2.81. This gives an MDC(95) for this test of 3 sites. CONCLUSIONS: The results of this study support the use of the 10-g monofilament as a reliable clinical tool to assess changes in protective sensation of the feet for our participant pool. An 18-site sensory examination using the 10-g monofilament must result in sensory change at 3 or more sites to indicate actual change in protective sensation.