Influence of sympathetic activity, temperature, ischemia and diazepam on thermal and vibration thresholds.

In healthy volunteers thermal specific, thermal pain and vibration thresholds were assessed and correlated to each other and to sympathetic nervous system parameters. Additionally, different factors such as temperature, diazepam and ischemia affecting perception thresholds were evaluated. The thresholds assessed did not correlate significantly to each other and to sympathetic skin response latency or amplitude. Diazepam influenced the thermal specific, thermal pain and vibration thresholds assessed. The preingestion and postingestion (after 30, 60 and 90 minutes) thresholds did not differ significantly, meanwhile the scatter of thermal and vibration thresholds increased obviously. The skin temperature within the range of naturally occurring values of control subjects in a state of "thermal comfort" affected neither the warm-cold difference limen nor the heat and cold pain thresholds. Considerable temperature changes (the warming for 5 degrees C and cooling for 10 degrees C) influenced the vibration thresholds measured. Warming increased and cooling decreased the values recorded. Tourniquet-induced ischemia influenced only the vibration disappearance thresholds. Vibration perception and vibration thresholds varied but differences were not significant.