The semi-quantitative measurement of vibration sensitivity can be performed with the aid of the Rydel-Seiffer Graduated Tuning Fork. It has triangles marked on the damping weights and, due to the creation of an optical illusion when vibrating, these triangles appear in the center of the weights and the apex of each triangle appears to point at the parallel numerical scales which have 8 divisions (Octals). To use the Rydel Seiffer Graduated Tuning Fork, squeeze the two weighted heads together and release them rapidly to induce vibration. Apply the base of the tuning fork squarely over the bony prominence to be tested and initially, symply ensure that the patient can detect the vibration or "buzzing" sensation. Then reapply, asking the patient to advise you immediately when he/she is no longer able to feel the sensation. At this time, read off the scale shown on the weighted head to determine the "Vibratory Perception Threshold". Essentially, a threshold of 4 Octals or less is considered to be clinically signifcant, indicating the individual tested as being at greater risk of ulceration. This test should ALWAYS be conducted in conjunction with other tests including knee/ankle jerks, light touch, blunt/sharp discrimination, and cutaneous pressure perception.

WARNING: NEVER strike a tuning fork against a hard object (such as the corner of a bench) to induce vibration. This can damage the tuning fork. The Rydel Seiffer Graduated Tuning fork is fitted with pre-set weights which MUST NOT be removed or repositioned.

This tuning fork should NOT be Autoclave Sterilised.