Warm immersion recovery test in assessment of diabetic neuropathy - A proof of concept study

The aim of this article was to present results of warm immersion recovery test in the diabetic foot with neuropathy using a liquid crystal-based contact thermography system. It is intended to provide a 'proof of concept' for promoting the role of supplementary thermal assessment techniques and evidence-based diagnosis of diabetic neuropathy. A total of 81 subjects from the outpatient department of MV Hospital for Diabetes, India, were assessed using a liquid crystal thermography system. Each subject was assigned to one of three study groups, that is diabetic neuropathy, diabetic non neuropathy and non diabetic healthy. The room temperature and humidity were consistently maintained at 24°C and less than 50%, respectively, with air conditioning. The right foot for each subject was located on the measurement platform after warm immersion in water at 37°C. Whole-field thermal images of the plantar foot were recorded for 10 minutes. Local measurements at the most prevalent sites of ulceration, that is metatarsal heads, great toe and heel, show highest temperature deficit after recovery for diabetic neuropathy group. The findings of the current study support the ones of a previous study by the authors, which used cold immersion recovery test for the neuropathic assessment of the diabetic foot. A temperature deficit between the recovery and the baseline temperature for the neuropathic group suggests degeneration of thermoreceptors. Thermal stimulus tests can be useful to validate the nutritional deficits' (during plantar loading and thermal stimulus) contribution in foot ulceration.