SYMPATHETIC SKIN-RESPONSES AND HEART-RATE -VARIABILITY IN DIABETIC-PATIENTS WITH DIFFERENT GRADES OF POLYNEUROPATHY

The sympathetic skirt responses (SSR) and the variations of the R-R in terval of rite electrocardiogram (the difference between rite maximum and minimum heart rates at rest, the ratio between rite maximum and mi nimum heart rates during the Valsalva manoeuvre or Valsalva ratio, and during an active orthostatic test or orthostatic ratio) have been mea sured in 32 control subjects and 53 diabetic patients. These latter on es were classified according to the existence and the increasing sever ity of a polyneuropathy (PNP) into 4 grades (0 to III) based on Dyck's classification modified depending oil. the presence ol the absence of cutaneous impairments tts in grade II. There was ail important inter- individual variability for SSR as well as for R-R interval results, ii the control group. In the absence of PNP, the vegetative tests showed normal values. These tests were severely degraded in the diabetic pat ients with a PNP grade III, ov even could not be performed The SSR amp litude was decreased irt all diabetic patients. In the presence of cli nical signs of dysautonomia, the SSR amplitude, the heart rate variabi lity at rest and the orthostatic ratio were significantly different fr om those of the control subjects. The presence of trophic disorders ap pearing at PNP grade II, did not significantly modify the results of t he tests. Although they did riot allow arty differenciation of the PNP intermediary grades, SSR and R-R intervals are of interest irt apprec iating the infra clinical existence and the importance of the neuroveg etative disorders occuring during diabetic polyneuropathies.