Comparison between monofilament, tuning fork and vibration perception tests for screening patients at risk of foot complication.

OBJECTIVE: To compare normal and pathologic values of three different tests for screening patients at risk of foot complications: mono-filament, tuning fork and vibration threshold perception (VTP).
METHODS: Two hundred and fifty consecutive patients followed-up in a diabetic clinic were screened for sensitive polyneuropathy by three different tests in three different examinations in a blind design. The 10 g mono-filament, tuning fork and Horwell neuro-esthesiometer were applied to different sites on the patients' legs and feet.
RESULTS: Thirty eight patients were identified having abnormal tests and being at risk of foot complications using the mono-filament test; 33 of them and 9 more (42 patients (33 + 9)) were identified using the tuning fork applied to the malleolus and eight more (50 patients (33 + 9 + 8)) when the tuning fork was applied to the big toe; twenty more patients (70 (33 + 9 + 8 + 20)) were identified as being at risk using the VTP at a cut-off of 25 V.
CONCLUSION: The mono-filament test identified patient with the highest risk of foot complications, but 37 more patients were identified to be at risk from a VTP > 25 V. These patients were not detected using the mono-filament test. The VTP test provides numerical values that can help to follow the course of the risk for foot insensitivity by allowing the care team to grade the education and follow-up of the at-risk group.