The Bio-Thesiometer is an instrument designed to measure simply and accurately the threshold of appreciation of vibration in human subjects, used in many neurological diseases. It is essentially an "electrical tuning fork" whose amplitude may be set to any predetermined level or whose amplitude may be gradually increased until the threshold of vibratory sensation is reached. Conversely, the amplitude may be lowered until the vibration is no longer discernible. In all cases the amplitude may be determined at any given level with a high degree of accuracy. The Bio-Thesiometer is not only far superior to a tuning fork in accuracy, but will detect neurological changes that are not disclosed with a tuning fork.
In a sense every person with diabetes has increased risk of developing foot ulceration and needs to take precautions to prevent it from occurring. However, some people have very low risk and some people have very high risk. Grading the risk helps the individuals and the health professionals to take appropriate measures without being too relaxed or too strict. Patients at low risk only need general advice. Patients at high risk need detailed, specific and practical footcare instruction. The overall risk of an individual developing a diabetic foot ulcer is determined by a combination of factors. In general, the risk is higher if neuropathy is more severe (because more sensation is lost)
There are many different methods of diagnosing and grading diabetic neuropathy.
The most important aspect of grading diabetic neuropathy from foot ulceration point of view is to assess the degree of loss of sensation in the feet. Doctors usually do this by testing if the patient can feel the pain of a pin prick or the touch of a cotton wool or the vibration of a tuning fork.
These are perfectly useful and time honoured techniques. However, the problems with testing sensation with a pin prick, cotton wool or tuning fork is that every doctor does it in a slightly different way. It is very difficult to standardize the procedures and the results. To overcome these problems, two other methods are often used :
1. Testing vibration sensation with a biothesiometer.
2. Testing touch pressure sensation with a monofilament.
The presence or absence of pain is not a major factor in determining the risk of neuropathic ulceration.