Testing Information

There are two tests for determining nerve damage, the Tactile Vibrometer and Thermal Aesthesiometer. Impaired blood supply to the fingers is measured with the Finger Rewarming Test. The complete set of tests will take around 2 hours to perform.

Holding the mouse pointer over various parts of the images below will indicate the key components of each test.

Tactile Vibrometer

The Tactile Vibrometer test investigates the subject’s sensitivity to vibration, by holding their finger on a vibrating pad. The test is conducted as follows:

1. The finger is placed on the vibrating pad, and held there as the vibrations gradually increase.
2. When the vibrations are felt in the finger, the responsive button is held down, causing the force of vibrations to decrease.
3. When the vibrations can no longer be felt, the responsive button is released, at which point the vibrations will increase again.
4. This procedure is repeated over a number of cycles.

These tests are performed at two different frequencies, the first being 31.5 Hz and the second at 125 Hz. The index and little fingers of both hands are tested.

Thermal Aesthesiometer

The Thermal Aesthesiometer test is similar to the vibrometer test, except that it tests the subject's sensitivity to hot and cold:

1. The finger is held on the metal plate, which gradually heats up.
2. When the heat is felt the responsive button is pressed once, causing it to cool down and then reheat.
3. This process is repeated over several cycles.

A second test determines sensitivity to cold:

1. The finger is held on the metal plate, which gradually cools down.
2. When it is felt to be cold, the responsive button is pressed, causing the plate to reheat and then cool down again.
3. This process is repeated over a number of cycles.

These two tests are performed on the index and little fingers of both hands.

Finger Rewarming Test

Impaired blood flow is measured with the Finger Rewarming Test, and measures how quickly the fingers rewarm after being placed in cool water. The temperature of the water is maintained at 15°C, and the hands are held in the bath for 5 minutes. Sensors monitor the temperature of each finger, and, once removed from the bath, the software measures how quickly the fingers warm by 4°C over an 11 minute period.

Demonstration Videos

Demonstration videos of the tests being used can be seen here.