[Diabetic neuropathy. Difficulties of diagnosis and choice of tests]

None of the classifications of diabetic neuropathy already published is perfect. "Experts" now recommend an operational classification based on the quantification of signs and neurological deficits, on an electrophysiological investigation and on an easy exploration of autonomic neuropathy. Quantitative evaluation of symptoms can be performed with questionnaires or scales. Quantitative evaluation of deficits can be performed with devices which quantify vibratory and thermic sensations; reproducibility of the results is not yet perfect, but it represents a clear progress over clinical examination. Investigation of the autonomic control of cardiovascular system with standardized tests is the simplest way of exploring the vegetative nervous system; these tests have a fair sensitivity and an excellent reproducibility. Therapeutic trials, particularly with aldose reductase inhibitors or gangliosides, require this wide panel of neurological investigations.