The effects of random vibrations on the vibratory perception threshold of the foot and standing balance in people with diabetic neuropathy

People with diabetes mellitus often suffer from polyneuropathy. Reduced
somatosensation of the feet due to polyneuropathy is one of the major risk
factors for ulceration at the plantar side of the feet and may often cause
problems in balance. It has been shown that the application of a mechanical
noise signal to the feet (a vibration with a random frequency) can reduce the
sensation threshold and improve standing balance. However, techniques used in
research so far have several problems that limit applicability in daily
practice. New vibrating insoles have been developed that overcome these
problems, but it is unknown if these insoles have the same effects.

To investigate the effects of vibrating insoles on vibration perception
threshold (VPT) and balance of people with diabetic neuropathy.

A double-blind cross-over design in a controlled laboratory setting where
participants will serve as their own controls.

The intervention will be the use of vibrating insoles. These are insoles that
are developed to be put on the market. As an immediate effect of the insoles is
expected, measurements will be performed during the intervention lasting less
than 1 minute per intervention/measurement. The control intervention is the use
of the same insoles, but with the vibration turned off.

To enable the measurement of VPT the insoles are adapted. Holes are made in the
insole to allow for access to the plantar skin of the foot with the probe of
the biothesiometer.
Standard insoles and standard shoes are used for the balance related outcomes.

Participants have to visit Ziekenhuisgroep Twente once for testing. Preparation
and measurements will take up to one hour. There are no known risks for the
participants.