What to Expect at a Foot Exam
|Neuropathy: Early Detection Offers Hope|
Experts recommend that people with diabetes have a thorough foot exam once a year to check for signs of neuropathy (and standard checks at every office visit). The American Diabetes Association recommends a monofilament test plus one additional sensation test—either pinprick, vibration, or ankle reflex—to screen for nerve damage. Once you've taken off your shoes and socks, here is what to expect.
Monofilament Test: The monofilament is essentially a short piece of nylon fishing line, says Lee Sanders, DPM, of the VA Medical Center in Lebanon, Pa. The doctor asks you to close your eyes and then presses the monofilament to the foot, often starting with the toe and then moving to other spots. "If you are unable to feel the application of the monofilament, you have some loss of sensory perception," says Sanders. "People may not feel it at the level of the toes, but they may feel it at the ball or the arch or the heel." Testing at multiple locations gives the doctor a sense of how far the condition has progressed.
Pinprick Test: The doctor uses a safety pin to touch the bottom of the foot. With eyes shut, you tell the doctor when you can feel the pinprick. Sanders says this test has fallen out of favor because the pin can break the skin, a risk for infection.
Vibration Tests: The tuning-fork test measures sensitivity to vibration. The doctor will take a 128-Hz tuning fork, ping it against his or her hand or some surface, then lightly press it against a few places on the foot and ask if you feel it. The doctor will hold it there so you can say when you no longer feel the vibration. If the doctor feels the vibration for much longer than the patient, this indicates nerve damage. Another check, the vibration perception threshold test, employs a device called a biothesiometer. It contains a vibrating knob a doctor can control at the touch of a button, varying the intensity of the vibration. "You turn it up to the point they can feel it," says Sanders, "then turn it down until they can't feel it." The test gives the doctor an idea of the severity of neuropathy.
Ankle Reflex Test: This is similar to the familiar test where a doctor hits just below a patient's knee with a small mallet, causing the patient to kick. In this version, a doctor taps on the Achilles tendon, which runs down the back of the ankle. If the nerves are in good condition, the foot will reflexively move down in a pointing motion. If the reflex is weak or nonexistent, "it tells you [the neuropathy] is a little more advanced," says Sanders.