[Correlation between sensory action potentials and vibratory perception in uremic polyneuropathy (author's transl)]

Detection of uremic neuropathy by reflex response latency

Dialysis time necessary for treatment of terminal renal failure is very different in different patients. Adequacy of therapy cannot be controlled by laboratory measures but only clinical means. Uremic peripheral neuropathy is regarded as the most reliable indicator of insufficient dialysis treatment. Serial measurements of peripheral nerve function therefore make individual adjustment of dialysis schedule possible. In some cases motor nerve conduction velocity is not sensitive enough for this purpose, as conduction velocity in afferent nerve fibers is disturbed at an earlier stage of uremic intoxication. Measurement of sensory nerve conduction velocity is time consuming and afferent fibers can also be examined in proprioceptive reflexes. Ths suitability of H-reflex response latency (RRL) for detection of slight uremic neuropathy was analysed. The wide range of RRL in healthy subjects can be explained by the different length of neural pathway in different subjects. A strong correlation between RRL and body height was found in healthy subjects. Relating RRL to the body height gives a highly sensitive measure of peripheral nerve function. Asymptomatic uremic neuropathy was detected very much earlier by RRL than by motor nerve conduction velocity. The method proved to be well suited for routine monitoring of uremic neuropathy in patients on dialysis.

Normal sensory conduction in the saphenous nerve in man

Measurements of the sensory conduction velocity and the parameters of nerve action potentials in the saphenous nerve offer many advantages, compared with measurements in other nerves of the leg, regarding accuracy and the time required to complete the investigations. Therefore, the electroneurographical examination of the saphenous nerve is recommended in the early diagnosis of polyneuropathies and is indispensable in the exact diagnosis of proximal neuropathies and lesions of the femoral nerve. In the present study we indicate the proximal and distal segments of the saphenous nerve and illustrate the nerve action potentials from 70 normal subjects.

Changes in peripheral nerve function with long-term hemofiltration treatment

The changes in the peripheral nerve function of three patients with chronic renal failure who were treated over a period of 1-1/2 to 2 years by hemofiltration have been analyzed in the form of a longitudinal study by quantitative measurements of vibratory perception threshold and nerve conduction velocity. Changes in vibratory perception threshold were measured in six patients both before and after treatment. Despite increased values of creatinine and BUN, an improvement in the peripheral nerve function of all patients undergoing hemofiltration could be observed, although vibratory perception and nerve conduction velocity did not return to normal. All of the vibratory perception threshold measurements made directly after hemofiltration showed an improved vibratory perception in comparison to the original values. A comparison of the measurement methods showed a good correlation and clearly indicated the advantage of vibratory perception threshold measurements as a means for the routine diagnosis of nephrogenic polyneuropathy.