Non-invasive assessment of vibration perception and protective sensation in people with diabetes mellitus: inter- and intra-rater reliability

Abstract Background Testing of protective sensation and vibration perception are two of the most commonly used non-invasive methods of screening for diabetes-related peripheral neuropathy (DPN). However, there is limited research investigating the reliability of these tests in people with diabetes. The aim of this study was to determine the inter- and intra-rater reliability of methods used to test vibration perception and protective sensation in a community-based population of adults with type 2 diabetes. Methods Three podiatrists with varying clinical experience tested four- and 10-site, 10 g monofilament and vibration perception threshold (VPT). In a separate cohort, the reliability of a graduated tuning fork as well as two methods of conventional tuning fork (on/off method and dampening method) was undertaken by a new graduate podiatrist and podiatrist with one-year’s clinical experience. The intra- (Cohen’s К) and inter-rater (Cohen’s or Fleiss’ К) reliability of each test was determined. Results Fifty participants (66% male, 100% type 2, 32% with DPN) underwent monofilament and neurothesiometer testing with 44 returning for the retest. Twenty-four participants (63% male, 100% type 2, 4% with DPN) underwent tuning fork testing and returned for retest. All tests demonstrated acceptable inter-rater reliability ranging from moderate (10-site monofilament, К: 0.54, CI: 0.38–0.70, p = 0.02) to substantial (graduated tuning fork, К: 0.68, CI: 0.41–0.95, p