What device is used to perform the vibration perception test in a diabetic foot exam?

• A. 128 Hz tuning fork
• B. 256 Hz tuning fork
• C. Monofilament nylon tip
• D. Semmes-Weinstein esthesiometer

Answer: (A)

The vibration perception test checks the function of large nerve fibers in the foot. A tuning fork provides a simple, consistent vibratory stimulus, and the 128 Hz frequency is the standard choice because it gives reliable, easily detectable vibrations at distal sites (like the great toe or ankle). The 256 Hz fork isn’t the conventional option for this test, and using it isn’t as widely validated in routine exams. The other devices—monofilament nylon tip and the Semmes-Weinstein esthesiometer—measure different senses (protective touch/pressure), not vibration. To perform, strike the tuning fork and place it on a bony area, asking the patient to report when the vibration starts and ends, then compare sides.