I would like to know what you think of using a tuning fork to detect neuropathy in the feet. In June 2005, I went to an endocrinologist who used a microfilament only and told me I had no signs and symptoms of neuropathy. This confused me because I was told by another endocrinologist previously, in April 2005 that I did have neuropathy.

Recently, I was assessed by a new endocrinologist who noted signs of neuropathy. He explained why and showed me what was going on with the tuning fork. I feel like it had stopped vibrating on my feet but when it was touched to my hand it was clearly still vibrating. Another thing I noticed on the first assessment, when they said I did have neuropathy, was that the doctor put a cold metal instrument to the lower part of my leg and it felt comfortable, and then higher on the leg it was actually uncomfortably cold. I have only had diabetes for five years, so this is concerning for me.

Also, can you tell me what you think of dosing Regular insulin prandially at lunch if you are on NPH? This is part of the reason I think the physician who claimed I did not have signs or symptoms of neuropathy might be confused. He had switched me from Lantus and Humalog to NPH and Regular against my wishes and also had me dosing the NPH prandially at lunch. He did not indicate a reason for doing this, such as high-post prandials after the noon meal.

You have seen physicians who have used different tools to assess nerve function. Whether you have neuropathy is a clinical decision. There are different types of nerve fibers that lead from sensors in the extremities. We test feet because the nerves to the feet are statistically most likely to be involved because they are the longest. Small, unmyelinated fibers perceive pain and temperature, while myelinated nerve fibers are best at detecting vibratory sensation. Like most things, if you are careful and deliberate, you will get more information than if you are in a hurry and not careful. The cold test tests temperature sensation. The tuning fork tests vibratory sensation. The ability to sense the monofilament fiber has been associated with protection from developing foot ulcers. This is not sensitive enough to say no neuropathy. Therefore, it is possible to sense the monofilament fiber, but you can still have some evidence of sensory loss with other tests. The most important thing is that you work on improved blood sugar control. Keep your physicians working for you by taking off your shoes and socks at your next clinic visit so they will be sure and test your sensation in your feet. The monofilament test is the easiest to use. If used serially, it has been objectively shown to be able to identify those who are at risk for developing foot ulcers and skin breakdown. Just because you feel the filament does not mean you don’t have neuropathy.

When you take NPH twice a day, the weakness in your regimen is what happens after lunch. If sugars go up enough, you may need to use some form of rapid-acting insulin to bring down high post-lunch sugars. This is an alternative to increasing morning NPH and is probably better than increasing NPH in the morning. Some have also used NPH at lunch to help with stability of blood sugars after supper.

JTL